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Topic 1: Cell biology

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Core » Topic 1: Cell biology

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Overview of the essential ideas for this topic.

1.1: The evolution of multicellular organisms allowed cell specialization and cell replacement.

1.2: Eukaryotes have a much more complex cell structure than prokaryotes.

1.3: The structure of biological membranes makes them fluid and dynamic.

1.4: Membranes control the composition of cells by active and passive transport.

1.5: There is an unbroken chain of life from the first cells on Earth to all cells in organisms alive today.

1.6: Cell division is essential but must be controlled.

Directly related questions

17M.2.HL.TZ2.3d: State what change there has been in the cell surface area to volume ratio in red blood cell 1.
17N.1.SL.TZ0.01: Which function is accomplished by structures X and Y in the Paramecium?
22M.2.HL.TZ2.2a.i:
Identify, with a reason, the stage shown at X.
22M.1.HL.TZ1.7: What is a universal characteristic of the genetic code? A. There are more than 64 different...
22M.1.HL.TZ2.3: Which plasma membrane is the least fluid at high temperatures?
22M.2.SL.TZ2.2d: Discuss how the use of stem cells to treat hereditary diseases could affect the person who...
17M.1.SL.TZ2.2: The image shows an electron micrograph of mesophyll cells. What is the name of the structure...
17M.2.HL.TZ2.3b: Define osmolarity.
18M.2.HL.TZ1.5a.i: Identify the structure labelled X.
18N.1.SL.TZ0.6: How does mitosis produce two genetically identical nuclei? A. By separation of homologous...
18N.1.HL.TZ0.22: How are villi, alveoli and nephrons similar? A. They are internal organs. B. They provide...
21M.1.SL.TZ2.2:
What function is performed by the part of the cell shown in the electron micrograph?

[Source: George E. Palade Electron Microscopy Slide Collection Harvey Cushing/John Hay Whitney Medical Library Yale University Library.]

A. Locomotion

B. Synthesis of proteins

C. Movement of chromosomes

D. Breakdown of cellular organelles
17M.2.SL.TZ2.2b.ii: Using the table, identify the organelles labelled I and II on the electron micrograph with their...
21N.1.SL.TZ0.2: Which features of phospholipids give them their amphipathic properties? A. Basic phosphate...
21N.2.HL.TZ0.3b: Stem cells can be used to treat Stargardt’s disease. State one other condition treated using stem...
19M.1.SL.TZ2.2:
The magnification of the micrograph is 2000×.

[Source: https://upload.wikimedia.org/wikipedia/commons/6/6c/HeLa_cells_stained_with_Hoechst_33258.jpg
by TenOfAllTrades.]

What is the maximum diameter of the nucleus in the cell labelled X?

A. 10 μm

B. 10 nm

C. 20 μm

D. 20 nm
19N.1.HL.TZ0.1: Stargardt’s disease, a genetic disorder that causes vision loss, is being treated using retinal...
21M.1.SL.TZ2.4: Which graph best represents the relationship between the concentration of chloride ions in the...
17N.1.SL.TZ0.02: What evidence from the image of Paramecium indicates whether the organism is a prokaryote or a...
17N.1.SL.TZ0.13: What occurs during meiosis but not mitosis? A. Spindles are formed from microtubules. B....
17N.2.SL.TZ0.02a: State a reason for using an electron microscope to view this virus rather than a light microscope.
17N.1.SL.TZ0.24: Dialysis membrane was set up to model digestion and absorption in the small intestine. What is...
17M.2.HL.TZ2.8a: Cells go through a repeating cycle of events in growth regions such as plant root tips and animal...
18M.2.SL.TZ2.3a.ii:
Outline the function of the structure labelled III.
18M.3.SL.TZ1.3c: Identify the structure labelled A.
16N.3.HL.TZ0.3b: Suggest reasons for different amounts of sucrose in the leaf phloem sap of the potato plants.
17M.1.HL.TZ2.3: The image shows an electron micrograph of pancreatic exocrine cells. What is the role of the...
16N.1.SL.TZ0.3: The cell membrane model proposed by Davson–Danielli was a phospholipid bilayer sandwiched between...
22M.1.SL.TZ2.4: Pasteur used swan-necked flasks and a nutrient broth to demonstrate that spontaneous generation...
18M.1.SL.TZ1.29: Neural pathways in living brains can now be mapped by tracking the movement of water molecules...
18M.1.SL.TZ2.1: When compared to other body cells, which characteristic of stem cells is the most important for...
18M.1.SL.TZ2.3: Which molecule regulates the fluidity of cell membranes? A. Phospholipid B. Cholesterol C....
18M.3.SL.TZ1.3b:
Deduce the magnification of the image.
22M.2.SL.TZ2.2a: State the main characteristic of stem cells.
18M.1.SL.TZ2.4: Pasteur carried out a series of experiments that provided strong evidence against a widely...
18M.1.SL.TZ1.4: Which organelle provides evidence that eukaryotic cells originated when large prokaryotes...
22M.1.SL.TZ1.2: More than 90 % of cellular cholesterol is located in the cell’s plasma membrane. What is the main...
22M.2.HL.TZ2.2a.ii:
Calculate the length of the entire cell labelled Y, showing your working.
18N.1.SL.TZ0.1: If cells of a multicellular organism have the same genes, how can there be many different cell...
18N.2.SL.TZ0.2a.i:
Label the area where cellulose is found in the micrograph of a plant cell.

[Source: BIOPHOTO ASSOCIATES/Getty Images]
18N.1.HL.TZ0.1: The image shows an electron micrograph of a fungus, Candida albicans. Which terms identify the...
18N.2.SL.TZ0.5c: Discuss the cell theory and its limitations.
18N.3.SL.TZ0.3a: Deduce, with a reason, which stage of mitosis is shown.
18M.2.SL.TZ2.3a.i: State the name of the structures labelled I and II.
19N.2.HL.TZ0.5b: Discuss whether the tissue shown in the micrograph consists of cells or not.
19M.3.SL.TZ2.1b.ii:
Label the model B diagram to show a phospholipid.
17M.2.SL.TZ1.2b.i: State the function of life in Paramecium that is carried out by: cilia.
22M.1.SL.TZ2.2:
The images of the radiolarian, a single-celled marine organism, were produced using a light microscope (left) and a scanning electron microscope (right).

[Source: Munir,S.;Sun,J.;Morton, S.L. The First Record and Classification of Planktonic Radiolarian
(Phylum Retaria) and Phaeodarian (Phylum Cercozoa) in the Eastern Indian Ocean. Biology 2021, 10, 202.
https://doi.org/10.3390/biology10030202 Copyright: © 2021 by the authors. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).]

What is a reason for the difference in quality of these images?

A. Light cannot pass through the specimen.

B. Higher magnification can be achieved with the electron microscope.

C. The resolution of the electron microscope is higher.

D. Samples are stained with methylene blue when viewed with the light microscope.
22M.1.SL.TZ2.7:
Which feature(s) allow(s) transport of glucose in blood plasma?

I. It is hydrophobic.

II. It is polar.

III. Its solubility is low at 37 °C.

A. I only

B. II only

C. I and II only

D. II and III only
22M.1.HL.TZ1.1: Two cells have the following characteristics. Which deduction is supported by this...
22M.1.HL.TZ2.2:
Red blood cells from a small mammal were immersed in NaCl (sodium chloride) solutions of different concentrations for 2 hours. The graph shows the percentage of hemolysed (ruptured) red blood cells at each concentration.

[Source: Zaidan, T. , de Matos, W. , Machado, É. , Junqueira, T. , Vicentini, S. , Presta, G. and Santos-Filho, S. (2010)
Cellular effects of an aqueous solution of Losartan^® on the survival of Escherichia coli AB1157 in the presence
and absence of SnCl2, and on the physiological property (osmotic fragility) of the erytrocyte. Advances
in Bioscience and Biotechnology, 1, 300–304. doi: 10.4236/abb.2010.14039. Available at https://www.scirp.org/pdf/ABB20100400005_18844979.pdf Licensed under a Creative
Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).]

What can be deduced from the graph?

A. At Y, the net movement of Na ions between red blood cells and the NaCl solutions is zero.

B. At X, Na and Cl ions disrupt the structure of cell membranes.

C. At Y, the hypertonic NaCl solutions diffuse into the red blood cells.

D. At X, water has moved by osmosis into the red blood cells.
22M.1.HL.TZ2.5:
Which feature(s) allow(s) transport of glucose in blood plasma?

I. It is hydrophobic.

II. It is polar.

III. Its solubility is low at 37 °C.

A. I only

B. II only

C. I and II only

D. II and III only
19N.1.SL.TZ0.1:
The electron micrograph shows a thin section through a plant mesophyll cell.

[Source: https://commons.wikimedia.org/wiki/File:Euglena_sp.jpg, by Deuterostome
https://creativecommons.org/licenses/by-sa/3.0/legalcode]

What is the magnification of the image?

A. × 75

B. × 300

C. × 3000

D. × 7500
21M.1.SL.TZ1.1: In mammals, mature red blood cells are specialized in that they lack nuclei, mitochondria or...
17N.3.SL.TZ0.03a: Identify the vein by labelling it with the letter V.
21N.1.SL.TZ0.1:
The image shows part of a mammalian cell.

[Source: Louisa Howard, Katherine Connollly - Dartmouth Electron Microscope Facility. Available at:
https://en.wikipedia.org/wiki/File:Microvilli.jpg.]

What is the specialized function of this mammalian cell?

A. Locomotion

B. Absorption

C. Reception of stimuli

D. Gas exchange
19N.2.SL.TZ0.5a: Draw a section of the Singer-Nicolson model of an animal cell membrane.
19N.1.SL.TZ0.5: Students examined micrographs and counted cells in the different stages of mitosis as well as...
17M.1.HL.TZ1.4: The diagram shows the concentration of four cyclins during the cell cycle. Which curve represents...
21M.2.HL.TZ2.5c: Testis cells are eukaryotic cells. Identify the structures seen under the electron microscope in...
18M.1.SL.TZ1.3: How does potassium move across the membrane of a neuron during repolarization? A. Simple...
21N.2.SL.TZ0.6a:
Describe the endosymbiotic theory.
19N.3.SL.TZ0.1c: From the evidence provided by the graph, evaluate the reliability of these data.
20N.1.SL.TZ0.2: Which feature of the cell in the micrograph is consistent with the endosymbiotic theory? A. X...
18N.1.HL.TZ0.5: In a copy of Louis Pasteur’s famous experiment, broth was put into flasks as shown in the...
18N.1.SL.TZ0.4: What part of the plasma membrane is fluid, allowing the movement of proteins in accordance with...
21N.1.SL.TZ0.5:
The graph shows the mitotic index in the roots of lentil plants at different distances from the end of the root.

[Source: Physiologia Plantarum, Volume 105, Issue 1, January 1999, Pages 171–178, Effect of microgravity on the cell cycle
in the lentil root F. Yu, D. Driss-Ecole, J. Rembur, V. Legué, G. Perbal Wiley Online Library: https://onlinelibrary.wiley.
com/doi/abs/10.1034/j.1399-3054.1999.105125.x]

What can be deduced from the graph?

A. As the distance from the end of the root increases, more cells are undergoing mitosis.

B. At 0.5 mm from the end of the root, most of the cells are in prophase.

C. There were fewer cells observed at 1.5 mm than at 0.5 mm.

D. As the distance from the end of the root increases, the percentage of cells in interphase increases.
19M.3.SL.TZ2.1d: State one technological improvement, other than enzymatic digestion, that led to the...
19M.2.HL.TZ2.2a.ii: Outline what is indicated by the mitotic index of tissue taken from a tumour.
18N.3.HL.TZ0.2a: Label tissues X and Y.
19M.1.SL.TZ1.4:
Which process(es) occur(s) by osmosis?

I. Uptake of water by cells in the wall of the intestine

II. Loss of water from a plant cell in a hypertonic environment

III. Evaporation of water from sweat on the skin surface

A. I only

B. I and II only

C. II and III only

D. I, II and III
19M.1.SL.TZ2.5:
The table shows concentrations of potassium ions and sodium ions inside and outside human cells.

[Source: © International Baccalaureate Organization 2019]

What explains these concentrations?

A. Potassium ions diffuse in and sodium ions diffuse out.

B. Sodium ions diffuse in and potassium ions diffuse out.

C. Active transport pumps sodium ions in and potassium ions out.

D. Active transport pumps sodium ions out and potassium ions in.
19M.2.SL.TZ2.6a: Describe briefly the endosymbiotic theory.
19M.1.SL.TZ2.4: Which processes are involved in the development of cancer? I. Mutations occur in oncogenes. II....
21N.1.SL.TZ0.4: How do both mitochondria and chloroplasts provide evidence for the endosymbiotic theory? A. They...
17M.1.SL.TZ1.4: Which organelle is involved in generating vesicles destined for the cell membrane? A. Golgi...
17M.1.SL.TZ1.1: Which structure found in eukaryotes has a single membrane? A. Nucleus B. Lysosome C....
17M.1.SL.TZ2.3: What is a role of cholesterol in animal cells? A. It increases body fat. B. It controls...
22M.2.SL.TZ2.2b:
Calculate the maximum diameter of the stem cell cluster on the micrograph, showing your working and giving the units.

..........
18M.2.SL.TZ2.3a.iii: The plant from which this cell was taken is in the group angiospermophyta. State one...
17N.3.HL.TZ0.02b.ii: Identify the type of cell labelled Z.
17M.1.SL.TZ1.5: When during the cell cycle does DNA replication take place?
17M.1.HL.TZ1.2: Which evidence falsifies the Davson–Danielli model? I. The presence of globular proteins within...
16N.2.SL.TZ0.2a: The image is an electron micrograph. Determine, with a reason, whether the image is of a...
17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system....
17M.1.SL.TZ2.1: The giant alga Acetabularia has a feature that suggests it is an exception to the cell theory....
16N.1.SL.TZ0.1: Which feature of striated muscle cells allows them to be considered as a possible exception to...
17N.1.SL.TZ0.05: In the diagram, which part of the membrane structure does the molecule below form?
17M.1.SL.TZ2.5: The graph shows the survival probabilities for current smokers and for those who never smoked...
16N.3.SL.TZ0.3b: Identify the layer of tissue found at X.
17N.1.HL.TZ0.01: Which function is accomplished by structures X and Y in the Paramecium?
18M.1.HL.TZ2.4: Which type of transportation happens in the sodium–potassium pump? A. Facilitated diffusion B....
21M.1.HL.TZ2.2:
Three cell types are shown in the micrographs.

[Source: left: UCSF School of Medicine, Courtesy of Prof. D Schmucker. middle: Professor Roger Meicenheimer, Miami University, Department of Botany. right: Courtesy of visualhistology.com.]

What feature distinguishes striated muscle fibres from the three cell types shown in the images?

A. Mitochondria

B. Nucleoid regions

C. Multinucleate structure

D. Membrane-bound organelles
16N.1.HL.TZ0.4: The giant marine alga Halicystis ovalis is able to move sodium ions from vacuoles to the...
19M.2.SL.TZ1.2a: Identify which electron micrograph shows a mitochondrion, providing one observation to support...
18M.1.SL.TZ1.5:
The concentrations of cyclins rise and fall in cells at certain times.

[Source: https://en.wikipedia.org/wiki/Cyclin#/media/File:Cyclin_Expression.svg]

What times are these?

A. Day and night

B. Seasons of the year

C. Stages of mitosis and interphase

D. Developmental stages in the life cycle
18M.1.SL.TZ2.2:
The image shows an electron micrograph of a cell.

[Source: Junqueira’s Basic Histology, 15th edition, by Anthony L. Mescher, McGraw-Hill publisher.]

Which organelles correspond to the labels in the electron micrograph of this cell?
17M.2.SL.TZ1.2b.ii: State the function of life in Paramecium that is carried out by: the contractile vacuole.
17M.2.SL.TZ1.2c: Discuss the advantages and disadvantages of the use of adult stem cells.
19N.1.SL.TZ0.4:
In the micrograph, which letter points to a cell in anaphase?

[Source: Berkshire Community College Bioscience Image Library,
https://commons.wikimedia.org/wiki/File:Mitotic_Stages_in_Apical_Meristem_of_Allium_Root_Tip_(36762516673).jpg,
licensed under Creative Commons CC0 1.0 Universal Public Domain Dedication]
18M.1.SL.TZ2.5:
The image shows cells in the different stages of mitosis. Which cell is in telophase?

[Source: © The Trustees of Indiana University]
20N.1.SL.TZ0.4:
The diagram shows a section through a membrane. What are the modes of transport in the diagram?

[Source: © International Baccalaureate Organization 2020.]
19N.1.SL.TZ0.2: By which process do potassium ions move through potassium channels in axons? A. Active...
19N.3.SL.TZ0.1d: Explain one reason for calculating the percentage change in mass.
19N.2.SL.TZ0.3a: Outline the cell theory.
19N.2.HL.TZ0.4a.i: State the property of amphipathic phospholipids that enables them to form a bilayer.
16N.1.SL.TZ0.4:
What provides evidence for the endosymbiotic theory?

A. Mitochondrial DNA in eukaryotic cells
B. 70S ribosomes in prokaryotic cells
C. Gene transfer from prokaryotic cells to eukaryotic cells using plasmids
D. Prokaryotic cells (Escherichia coli) in the large intestine digest proteins
17M.1.HL.TZ2.4: What is evidence for the endosymbiotic theory? A. RNA can catalyse metabolic reactions. B....
19N.2.SL.TZ0.3b: State two functions of life.
19N.3.HL.TZ0.3b: If a zucchini is allowed to dry in the open air, predict how the osmolarity of the zucchini cells...
18N.1.SL.TZ0.2: The electron micrograph shows part of a cell. Which organelle is the site of aerobic respiration?
18N.1.SL.TZ0.5: Apparatus was set up as shown to collect data. The graph shows the results after 47 minutes of...
18N.3.SL.TZ0.3b: The cells visible in the onion root tip were classified and counted. Calculate the mitotic index.
16N.3.HL.TZ0.2d: One of the functions of this organ is absorption. On the micrograph, draw an arrow showing the...
22M.1.SL.TZ1.4: Which cell component arose first during the formation of the earliest cells? A. Chloroplast B....
22M.1.SL.TZ2.3:
In an experiment on osmosis, red blood cells were immersed in a salt solution for two hours. The micrographs show the appearance of these cells before and after immersion in the salt solution.

[Source: Ed Uthman, Acanthocytes, from peripheral blood [image online] Available at:
https://en.wikipedia.org/wiki/Acanthocyte#/media/File:Acanthocytes,_Peripheral_Blood_(3884092551).jpg
This file is licensed under the Creative Commons Attribution 2.0 Generic (CC BY 2.0) https://creativecommons.org/licenses/by/2.0/ Source adapted.]

What explains the observed changes?

A. The salt solution was hypertonic and entered the red blood cells.

B. The salt solution was hypotonic and disrupted the membranes of the red blood cells.

C. The salt solution was hypertonic and water moved into it from the red blood cells.

D. The salt solution was hypotonic and mineral salts were lost from the red blood cells.
22M.1.SL.TZ2.5: Cisplatin is an anti-cancer drug that prevents tumour cells from dividing by mitosis as it...
21M.1.SL.TZ1.2: What do chloroplasts and mitochondria have in common? A. Both are found in the cells of...
21M.1.SL.TZ1.4: A human organ is being prepared for transplant. In what type of solution must it be bathed? A. A...
17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
21M.1.HL.TZ2.1:
The image shows an electron micrograph of virus particles known to infect the bacterium Vibrio parahaemolyticus, which is associated with gastroenteritis, wound infections and septicemia in humans and animals.

[Source: Lin, Y. and Lin, C., 2012. Transmission electron micrograph of phage ϕpp2 particles with several structural proteins. [micrograph] (BMC Genomics, 13:224).]

What does a virus have in common with a living cell?

A. 70S ribosomes

B. Genetic material

C. Reproduction by binary fission

D. Anaerobic respiration
21M.1.SL.TZ2.5: Which statement is evidence for the endosymbiotic theory? A. Chloroplasts contain 70S...
21M.1.SL.TZ2.3: What special property of phospholipid molecules explains their ability to spontaneously assemble...
21M.1.HL.TZ2.4: When does DNA replication occur? A. S phase of interphase B. Early prophase C. G phase of...
21M.1.SL.TZ1.5: Which living structure is an exception to the cell theory? A. Striated muscle fibres B. A...
22M.2.HL.TZ2.2a.iii:
State the role of cyclins in the cell cycle.
22M.2.SL.TZ2.2c: State one therapeutic role of stem cells.
21M.1.HL.TZ1.3: Which solution has the highest salt concentration? A. The original solution B. Solution 1 C....
21M.1.HL.TZ1.2: Which process explains the observations shown in the images? A. Active transport B....
22M.1.SL.TZ1.5:
In the chimpanzee (Pan troglodytes), the haploid number of chromosomes is 24. How many sister chromatids are present in the G2 phase of a somatic cell, such as a cell in the bone marrow of the chimpanzee?

A. 12

B. 24

C. 48

D. 96
20N.2.HL.TZ0.3a:
Outline how the structures labelled X and Y are adapted to carry out the function of the mitochondrion.

X:

Y:
17N.1.SL.TZ0.14:
Which diagram(s) represent(s) processes used in asexual reproduction?

A. I only

B. I and II only

C. II only

D. I, II and III
22M.2.HL.TZ1.7a:
Outline reasons for the therapeutic use of stem cells.
22M.1.SL.TZ2.6:
The micrograph of a section through a plant stem shows at least ten different types of cells.

[Source: Joan Carles Juarez / Shutterstock.com.]

What explains the differences between these cells?

A. Only one gene is expressed in each cell type.

B. Different genes are expressed in each cell type.

C. Only useful genes remain in the DNA of each cell type.

D. Changes in the DNA sequence take place when these cells develop.
22M.2.HL.TZ2.2b.i:
Distinguish between the structure of chromosomes in prokaryotes and eukaryotes.
22M.2.SL.TZ1.6a:
Outline reasons for the therapeutic use of stem cells.
22M.2.SL.TZ2.4b:
The Davson-Danielli model of membrane structure was proposed in the 1930s. When electron micrographs of membranes were first produced, they were used as evidence for this model. The micrograph shows two adjacent membranes (indicated with arrows).

[Source: DENNIS KUNKEL MICROSCOPY/SCIENCE PHOTO LIBRARY.]

Explain how the appearance of membranes in electron micrographs was used as evidence to support the Davson-Danielli model.
22M.2.HL.TZ2.8a:
Outline four different processes, with examples, that allow substances to pass through the plasma membrane.
17N.3.HL.TZ0.02b.i: Calculate the actual size of the seminiferous tubule in the area indicated by the line across it,...
18N.1.SL.TZ0.3: The images are microscopic views of two similar cells. What is a reason for the differences...
20N.1.SL.TZ0.3: Which sequence has the cells arranged according to their ability to differentiate, starting from...
20N.1.SL.TZ0.1: What is the name of the cell component labelled Y? A. Golgi apparatus B. Nucleus C....
20N.2.HL.TZ0.2a.ii: State the role of cholesterol in animal cell membranes.
20N.3.HL.TZ0.1a:
Calculate the magnification of the image, showing your working.

. . . . . . . . . . . . . . . . . . . . x
18M.3.HL.TZ1.1a:
Data was collected on rabbit red blood cells that were exposed to sodium chloride (NaCl) and scorpion venom. Under some osmotic conditions red blood cells swell and burst, releasing hemoglobin (hemolysis). The graph shows the response of red blood cells to different concentrations of sodium chloride, with and without scorpion venom.

[Source: Adapted from Mirakabadi A Z, et al., (2006), J. Venom. Anim. Toxins incl. Trop. Dis., 12 (1), pages 67–77 (London: BioMed Central)]

Outline the effect of the venom on the hemolysis of red blood cells.
17M.2.SL.TZ2.2b.i: State the principal product of this cell.
18M.2.HL.TZ1.5a.ii: State the stage of mitosis of this cell.
17M.2.HL.TZ2.3c: Deduce, with a reason, which red blood cell has been placed in a hypertonic solution.
19M.1.SL.TZ1.5: The table shows the number of cells in various stages of the cell cycle in four samples of...
22M.1.SL.TZ1.1: A cell contains chloroplasts, plasma membrane and 80S ribosomes. What type of cell could it...
22M.1.SL.TZ1.3: What is/are required for facilitated diffusion? I. A concentration gradient II. ATP III. A...
19M.1.HL.TZ1.2:
The image shows a phagocytic white blood cell as seen with a transmission electron microscope.

[Source: http://www.wikidoc.org/index.php/File:Monocyte_TEM_0002.jpg, by Cafer Zorkun is licensed
under the Creative Commons Attribution/Share-Alike License]

Which features can be found both within this cell and in a photosynthetic bacterium?

A. Chloroplasts

B. Multiple nuclei

C. 70S ribosomes

D. Lysosomes
16N.3.SL.TZ0.3a: State from which organ the section was taken.
16N.1.SL.TZ0.5:
Which mitotic phase is labelled X in the micrograph of an onion (Allium cepa) root tip?

A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
16N.1.SL.TZ0.2: Which characteristic of stem cells makes them useful for treating Stargardt’s disease? A. They...
17M.2.SL.TZ2.3a:
Outline the use of human embryonic stem cells (hESC) to treat Stargardt’s disease.
18M.1.SL.TZ1.1: What feature of both striated muscle and aseptate fungal hyphae is different from typical cell...
19N.3.HL.TZ0.3a: Estimate the solute concentration of the zucchini cells.
19N.3.HL.TZ0.3d: Predict what would happen to a red blood cell placed in distilled water.
20N.2.SL.TZ0.2d: Apart from the ribosomes, explain the evidence for the endosymbiotic theory of the origin of...
16N.2.HL.TZ0.2b:
Explain how the cell cycle is controlled.
19M.3.SL.TZ1.1b: Explain how electron micrographs such as this helped to falsify the Davson–Danielli model of...
21M.2.HL.TZ1.1f:
Some anticancer drugs inhibit mitosis by blocking the formation of the spindle. Suggest one other way in which vinblastine could block mitosis.
21M.1.SL.TZ1.6: Which statement applies to cholesterol? A. It is hydrophobic and found on the outside of the...
20N.2.HL.TZ0.2a.i:
Outline how the amphipathic properties of phospholipids play a role in membrane structure.
17N.2.HL.TZ0.06a:
Cell biologists play an important role in research into disease, fertility, evolution and many other areas of science.

Describe the origin of eukaryotic cells according to the endosymbiotic theory.
18N.3.HL.TZ0.2b:
Calculate the actual width along line A-B of the parenchyma cell shown.
21M.2.SL.TZ2.2d:
The mitotic index is an important prognostic tool for predicting the response of cancer cells to chemotherapy. Outline how the mitotic index is calculated.
17N.1.SL.TZ0.04: In the diagram, which structure is an intrinsic or integral protein?
17N.1.SL.TZ0.03: The salt concentration inside an animal cell is 1.8 %. The salt concentration in the surrounding...
19M.3.SL.TZ1.1a:
Using the scale bar, calculate the magnification of the image.
17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
17M.2.HL.TZ1.5b: Outline four different functions of membrane proteins.
21M.2.HL.TZ1.1e:
By referring to both graphs, evaluate the hypothesis that vinblastine targets cells in mitosis and prevents them from completing the process.
21M.2.SL.TZ2.2b.ii:
Using the letter M, label the stage on the diagram where sister chromatids migrate to opposite poles.
21N.2.SL.TZ0.5b:
Describe transport across cell membranes by osmosis.
21M.2.HL.TZ1.2a:
State two structural similarities between mitochondria and chloroplasts.

1.

2.
18N.2.SL.TZ0.5a:
The structure of prokaryotic cells has been investigated using electron microscopy. Draw a labelled diagram to show prokaryotic cell structure.
18M.2.SL.TZ1.5b:
Unicellular and multicellular organisms share the same functions of life. Outline four functions of life.
19N.3.SL.TZ0.1a:
Using the graph, estimate isotonic sucrose solutions for potato tissue and carrot tissue.

Potato:

Carrot:
20N.1.SL.TZ0.5: How many chromosomes are there in a cell during anaphase of mitosis, if the diploid number of the...
20N.2.HL.TZ0.2b:
Describe what happens to the membranes of an animal cell during mitosis.
18M.2.HL.TZ1.6a:
Draw a labelled diagram to show the fluid mosaic model of the plasma membrane.
21M.2.HL.TZ1.1g:
Discuss one advantage and one disadvantage of using plant tissue to investigate drugs intended to treat cancer in humans.

Advantage:

Disadvantage:
20N.1.HL.TZ0.9: The first iron ore deposits in rocks appeared about 1.8 billion years ago. What took place to...
20N.2.SL.TZ0.3a:
Outline how the amphipathic properties of phospholipids play a role in membrane structure.
18M.3.SL.TZ1.3a:
Using the scale bar, determine the diameter of the nucleus of the cell on the left, giving the units.
21M.2.SL.TZ2.2c:
Distinguish between the outcomes of a cell dividing either by mitosis or meiosis.
21M.2.SL.TZ2.6a:
Outline the structures in M. tuberculosis that are not present in a human cell.
17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
17N.1.HL.TZ0.02: The salt concentration inside the Paramecium is 1.8 %. The salt concentration in the surrounding...
16N.2.SL.TZ0.2b:
(i) State the process that divides one nucleus into two genetically identical nuclei.

(ii) Explain how the cell cycle is controlled.
18M.3.HL.TZ1.1b :
Describe how the variables would be controlled in an experiment to estimate the osmolarity of plant tissue.
18M.2.HL.TZ2.5a: Discuss alternative models of membrane structure including evidence for or against each model.
18N.2.HL.TZ0.6a: Calcium is absorbed from food in the human gut by both active and passive processes. Outline...
18N.1.HL.TZ0.2: Which method provides biochemical evidence that cells have begun to differentiate? A. ...
22M.1.HL.TZ1.4:
In which stage of the cell cycle are chromosomes duplicated?

[Source: M1llx, 2019. Cell cycle simple pl. [online] Available at: https://commons.wikimedia.org/wiki/File:Cell_cycle_simple_pl.png This file is licensed
under the Creative Commons Attribution-Share Alike 4.0 International license.
https://creativecommons.org/licenses/by-sa/4.0/deed.en [Accessed 1 August 2019].]

A. G1 phase

B. G2 phase

C. S phase

D. Mitosis
18N.1.SL.TZ0.13: The diagram represents the nucleus of a cell 2 n = 8 in late prophase of mitosis. Which...
19M.3.SL.TZ2.1a: State the scientists who proposed model A.
17M.2.SL.TZ1.2a:
Pictured below are Louis Pasteur’s original drawings of swan-necked flasks.

Describe how Pasteur’s experiments provided convincing evidence to falsify the concept of spontaneous generation.
19M.1.SL.TZ2.1: Which structures are found only in prokaryotic cells? A. Ribosomes B. Pili C. Cell walls D....
19M.1.SL.TZ2.3:
The image shows a micrograph of a cell.

[Source: © 2014, https://commons.wikimedia.org/wiki/File:Mitosis_(261_13)_Pressed;_root_meristem_of_onion_(cells_
in_prophase,_metaphase,_anaphase,_telophase).jpg by Doc. RNDr. Josef Reischig, CSc.]

What explains the appearance of the cell in the micrograph?

A. The cell is dying.

B. The DNA is replicating.

C. The cell is in metaphase.

D. The cell is in telophase.
19M.1.HL.TZ2.17:
The diagram shows a stage in cell division.

[Source: © International Baccalaureate Organization 2019]

What is the stage shown?

A. Anaphase I of mitosis

B. Anaphase II of mitosis

C. Anaphase I of meiosis

D. Anaphase II of meiosis
19M.3.SL.TZ1.1c: Explain how the amphipathic nature of phospholipids allows them to form bilayers.
17N.2.HL.TZ0.01d.ii:
Muscle fibres are stimulated to contract by the binding of acetylcholine to receptors in their membranes and the subsequent depolarization.

Suggest a reason for increasing the concentration of sodium–potassium pumps in the membranes of diaphragm muscle fibres.
19M.2.HL.TZ1.5a: Outline the functions of rough endoplasmic reticulum and Golgi apparatus.
19M.1.HL.TZ1.3: Which is an essential feature of the Davson–Danielli model of membrane structure? A. A...
19M.2.HL.TZ1.3a: Compare and contrast the structure of a typical prokaryotic cell with that of a mitochondrion.
19M.2.SL.TZ1.7b: Describe the functions of proteins in cell membranes.
19M.2.HL.TZ1.3b: Explain how mitochondria could have been formed from free living prokaryotes.
19M.2.HL.TZ1.6c: Explain how blood solute concentrations are kept within narrow limits in the human body.
19M.2.SL.TZ1.2b: Discuss the evidence for the theory that mitochondria may have evolved from free-living...
19M.2.HL.TZ1.5c: Explain how hydrophobic and hydrophilic properties contribute to the arrangement of molecules in...
19M.3.SL.TZ2.1c.i: Deduce one conclusion about the structure of the plasma membrane reached by the scientists from...
19M.3.SL.TZ2.1c.ii: Suggest one reason for maintaining a pH of 7.5 throughout the experiment.
19M.2.SL.TZ2.2a:
Identify the stage of mitosis labelled X in the image, giving a reason.

[Source: Copyright 2002, The Trustees of Indiana University]
19M.2.SL.TZ2.5a: Outline four types of membrane transport, including their use of energy.
19M.2.HL.TZ2.6a: Outline four types of membrane transport, including their use of energy.
17M.1.SL.TZ2.4: What is evidence for the endosymbiotic theory? A. RNA can catalyse metabolic reactions. B....
21N.1.SL.TZ0.3: How is facilitated diffusion in axons similar to active transport? A. They both require the...
19M.2.HL.TZ2.2a.i:
Identify the stage of mitosis labelled X in the image, giving a reason.

[Source: Copyright 2002, The Trustees of Indiana University]
19M.1.SL.TZ1.3:
The images show a sequence of changes in an organism.

[Source: Copyright (2007) National Academy of Sciences, U.S.A. 'A comparative analysis of frog early development'.
Eugenia M. del Pino, Michael Venegas-Ferrín, Andrés Romero-Carvajal, Paola Montenegro-Larrea, Natalia
Sáenz-Ponce, Iván M. Moya, Ingrid Alarcón, Norihiro Sudou, Shinji Yamamoto, and Masanori Taira,
PNAS July 17, 2007 104 (29) 11882–11888; https://doi.org/10.1073/pnas.0705092104]

What is the change and which process is necessary for it to occur?
21N.2.HL.TZ0.3a:
The image shows human red blood cells.

[Source: someoneice/123rf.com.]

Outline what will happen to human red blood cells if transferred to distilled water.
19M.1.SL.TZ1.1:
Which graph represents the change in cell surface area to volume ratio with increasing cell diameter?

[Source: © International Baccalaureate Organization 2019]
19N.3.SL.TZ0.1b: Suggest a reason for the difference in the isotonic points for the potato and the carrot tissues.
19N.3.HL.TZ0.3c: Explain one reason for calculating the percentage changes in mass.
19M.1.SL.TZ1.2:
The image shows an electron micrograph of part of a cell.

[Source: Dr. Eldon Newcomb – Emeritis Professor at The University of Wisconsin – Madison.]

Which features do the two structures labelled X and Y have in common?

A. They are surrounded by a double membrane.

B. They contain 70S ribosomes.

C. They contain naked DNA.

D. They are only found in leaf cells.
17N.2.HL.TZ0.01d.i:
Analyse the graph to obtain two conclusions about the concentration of sodium–potassium pumps.
18N.2.SL.TZ0.5b:
Outline the reasons for differences between the proteomes of cells within a multicellular organism.
18M.2.SL.TZ1.5a:
Draw a labelled diagram to show the fluid mosaic model of the plasma membrane.
18M.2.SL.TZ2.5a:
Draw an annotated diagram of the fluid mosaic model of membrane structure.
19N.1.SL.TZ0.3: Which statement provides evidence for endosymbiosis? A. Early prokaryotes contributed to a large...
17N.2.SL.TZ0.06a:
Describe the origin of eukaryotic cells according to the endosymbiotic theory.
21M.1.SL.TZ1.3:
The Davson–Danielli model of membrane structure proposed that membranes were composed of a phospholipid bilayer that lies between two layers of globular proteins, as shown in this diagram.

[Source: Cornell, B. 2016. https://ib.bioninja.com.au/standard-level/topic-1-cell-biology/13-membrane-structure/membrane-models.html]

What evidence supported this model?

A. An electron micrograph that showed two dark lines with a lighter band in between

B. Freeze-fracture electron microscopy

C. Evidence that all membranes are identical

D. The hydrophobic regions of protein would be in contact with water
21M.1.SL.TZ2.1:
The diagrams represent cells with the same concentration of dissolved substances in their cytoplasm. If all the cells were placed in the same hypertonic sucrose solution, which cell would show the greatest rate of change in the concentration of its cytoplasm?
21M.2.SL.TZ1.1e: Deduce the change in mitotic index after 72 hours compared to the control.
20N.2.SL.TZ0.6a:
Draw the ultrastructure of a prokaryotic cell based on electron micrographs.
20N.1.HL.TZ0.4: What would show that a person has developed metastatic cancer? A. Alveolus cells forming a...
20N.1.HL.TZ0.1: Chlorella and Paramecium are both unicellular eukaryotic organisms living in freshwater....
21M.2.SL.TZ2.2a:
State processes occurring during interphase.
21M.2.SL.TZ2.2b.i:
Using the letter C, label the stage on the diagram where chromosome supercoiling occurs.
18M.1.SL.TZ1.13: Where could genes be located in a prokaryotic cell?
17M.1.SL.TZ1.2: The following electron micrograph shows part of a palisade mesophyll cell. Which of the labelled...
17M.1.SL.TZ1.3: Which organism has DNA located in three organelles? A. A sponge B. A fern C. A flatworm D. A...
19M.3.SL.TZ2.1b.i:
Label the model A diagram to show a region of protein.
21M.1.SL.TZ1.7: A tissue sample was examined under the microscope in order to determine a mitotic index. The...

Sub sections and their related questions

1.1 Introduction to cells

16N.1.SL.TZ0.1: Which feature of striated muscle cells allows them to be considered as a possible exception to...
16N.1.SL.TZ0.2: Which characteristic of stem cells makes them useful for treating Stargardt’s disease? A. They...
16N.1.SL.TZ0.4:
What provides evidence for the endosymbiotic theory?

A. Mitochondrial DNA in eukaryotic cells
B. 70S ribosomes in prokaryotic cells
C. Gene transfer from prokaryotic cells to eukaryotic cells using plasmids
D. Prokaryotic cells (Escherichia coli) in the large intestine digest proteins
17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
17M.2.SL.TZ1.2b.i: State the function of life in Paramecium that is carried out by: cilia.
17M.2.SL.TZ1.2b.ii: State the function of life in Paramecium that is carried out by: the contractile vacuole.
17M.2.SL.TZ1.2c: Discuss the advantages and disadvantages of the use of adult stem cells.
17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
17M.1.SL.TZ2.1: The giant alga Acetabularia has a feature that suggests it is an exception to the cell theory....
17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system....
17M.2.SL.TZ2.3a:
Outline the use of human embryonic stem cells (hESC) to treat Stargardt’s disease.
17M.2.HL.TZ2.3d: State what change there has been in the cell surface area to volume ratio in red blood cell 1.
17N.3.HL.TZ0.02b.i: Calculate the actual size of the seminiferous tubule in the area indicated by the line across it,...
17N.3.HL.TZ0.02b.ii: Identify the type of cell labelled Z.
18M.1.SL.TZ1.1: What feature of both striated muscle and aseptate fungal hyphae is different from typical cell...
18M.1.SL.TZ1.4: Which organelle provides evidence that eukaryotic cells originated when large prokaryotes...
18M.1.SL.TZ2.1: When compared to other body cells, which characteristic of stem cells is the most important for...
18M.2.SL.TZ1.5b:
Unicellular and multicellular organisms share the same functions of life. Outline four functions of life.
18M.3.SL.TZ1.3a:
Using the scale bar, determine the diameter of the nucleus of the cell on the left, giving the units.
18M.3.SL.TZ1.3b:
Deduce the magnification of the image.
18M.3.SL.TZ1.3c: Identify the structure labelled A.
18N.1.SL.TZ0.1: If cells of a multicellular organism have the same genes, how can there be many different cell...
18N.1.SL.TZ0.3: The images are microscopic views of two similar cells. What is a reason for the differences...
18N.1.HL.TZ0.2: Which method provides biochemical evidence that cells have begun to differentiate? A. ...
18N.1.HL.TZ0.22: How are villi, alveoli and nephrons similar? A. They are internal organs. B. They provide...
18N.2.SL.TZ0.2a.i:
Label the area where cellulose is found in the micrograph of a plant cell.

[Source: BIOPHOTO ASSOCIATES/Getty Images]
18N.2.SL.TZ0.5b:
Outline the reasons for differences between the proteomes of cells within a multicellular organism.
18N.2.SL.TZ0.5c: Discuss the cell theory and its limitations.
19M.1.SL.TZ1.1:
Which graph represents the change in cell surface area to volume ratio with increasing cell diameter?

[Source: © International Baccalaureate Organization 2019]
19M.1.SL.TZ1.3:
The images show a sequence of changes in an organism.

[Source: Copyright (2007) National Academy of Sciences, U.S.A. 'A comparative analysis of frog early development'.
Eugenia M. del Pino, Michael Venegas-Ferrín, Andrés Romero-Carvajal, Paola Montenegro-Larrea, Natalia
Sáenz-Ponce, Iván M. Moya, Ingrid Alarcón, Norihiro Sudou, Shinji Yamamoto, and Masanori Taira,
PNAS July 17, 2007 104 (29) 11882–11888; https://doi.org/10.1073/pnas.0705092104]

What is the change and which process is necessary for it to occur?
19N.2.SL.TZ0.3a: Outline the cell theory.
19N.2.SL.TZ0.3b: State two functions of life.
19N.1.SL.TZ0.1:
The electron micrograph shows a thin section through a plant mesophyll cell.

[Source: https://commons.wikimedia.org/wiki/File:Euglena_sp.jpg, by Deuterostome
https://creativecommons.org/licenses/by-sa/3.0/legalcode]

What is the magnification of the image?

A. × 75

B. × 300

C. × 3000

D. × 7500
19N.2.HL.TZ0.5b: Discuss whether the tissue shown in the micrograph consists of cells or not.
19N.1.HL.TZ0.1: Stargardt’s disease, a genetic disorder that causes vision loss, is being treated using retinal...
20N.3.HL.TZ0.1a:
Calculate the magnification of the image, showing your working.

. . . . . . . . . . . . . . . . . . . . x
20N.1.SL.TZ0.3: Which sequence has the cells arranged according to their ability to differentiate, starting from...
21M.1.SL.TZ1.5: Which living structure is an exception to the cell theory? A. Striated muscle fibres B. A...
21M.1.SL.TZ2.2:
What function is performed by the part of the cell shown in the electron micrograph?

[Source: George E. Palade Electron Microscopy Slide Collection Harvey Cushing/John Hay Whitney Medical Library Yale University Library.]

A. Locomotion

B. Synthesis of proteins

C. Movement of chromosomes

D. Breakdown of cellular organelles
21M.1.HL.TZ2.2:
Three cell types are shown in the micrographs.

[Source: left: UCSF School of Medicine, Courtesy of Prof. D Schmucker. middle: Professor Roger Meicenheimer, Miami University, Department of Botany. right: Courtesy of visualhistology.com.]

What feature distinguishes striated muscle fibres from the three cell types shown in the images?

A. Mitochondria

B. Nucleoid regions

C. Multinucleate structure

D. Membrane-bound organelles
21N.2.HL.TZ0.3b: Stem cells can be used to treat Stargardt’s disease. State one other condition treated using stem...
22M.2.SL.TZ1.6a:
Outline reasons for the therapeutic use of stem cells.
22M.2.SL.TZ2.2a: State the main characteristic of stem cells.
22M.2.SL.TZ2.2b:
Calculate the maximum diameter of the stem cell cluster on the micrograph, showing your working and giving the units.

..........
22M.2.SL.TZ2.2c: State one therapeutic role of stem cells.
22M.2.SL.TZ2.2d: Discuss how the use of stem cells to treat hereditary diseases could affect the person who...
22M.2.HL.TZ1.7a:
Outline reasons for the therapeutic use of stem cells.

1.2 Ultrastructure of cells

16N.2.SL.TZ0.2a: The image is an electron micrograph. Determine, with a reason, whether the image is of a...
16N.3.SL.TZ0.3a: State from which organ the section was taken.
16N.3.SL.TZ0.3b: Identify the layer of tissue found at X.
16N.3.HL.TZ0.2d: One of the functions of this organ is absorption. On the micrograph, draw an arrow showing the...
17M.1.SL.TZ1.1: Which structure found in eukaryotes has a single membrane? A. Nucleus B. Lysosome C....
17M.1.SL.TZ1.2: The following electron micrograph shows part of a palisade mesophyll cell. Which of the labelled...
17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
17M.1.SL.TZ1.3: Which organism has DNA located in three organelles? A. A sponge B. A fern C. A flatworm D. A...
17M.1.SL.TZ1.4: Which organelle is involved in generating vesicles destined for the cell membrane? A. Golgi...
17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
17M.1.SL.TZ2.2: The image shows an electron micrograph of mesophyll cells. What is the name of the structure...
17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system....
17M.1.HL.TZ2.3: The image shows an electron micrograph of pancreatic exocrine cells. What is the role of the...
17M.2.SL.TZ2.2b.i: State the principal product of this cell.
17M.2.SL.TZ2.2b.ii: Using the table, identify the organelles labelled I and II on the electron micrograph with their...
17N.1.SL.TZ0.01: Which function is accomplished by structures X and Y in the Paramecium?
17N.1.SL.TZ0.02: What evidence from the image of Paramecium indicates whether the organism is a prokaryote or a...
17N.2.SL.TZ0.02a: State a reason for using an electron microscope to view this virus rather than a light microscope.
17N.3.SL.TZ0.03a: Identify the vein by labelling it with the letter V.
17N.1.HL.TZ0.01: Which function is accomplished by structures X and Y in the Paramecium?
18M.1.SL.TZ1.13: Where could genes be located in a prokaryotic cell?
18M.1.SL.TZ2.2:
The image shows an electron micrograph of a cell.

[Source: Junqueira’s Basic Histology, 15th edition, by Anthony L. Mescher, McGraw-Hill publisher.]

Which organelles correspond to the labels in the electron micrograph of this cell?
18M.2.SL.TZ2.3a.i: State the name of the structures labelled I and II.
18M.2.SL.TZ2.3a.ii:
Outline the function of the structure labelled III.
18M.2.SL.TZ2.3a.iii: The plant from which this cell was taken is in the group angiospermophyta. State one...
18N.1.SL.TZ0.2: The electron micrograph shows part of a cell. Which organelle is the site of aerobic respiration?
18N.1.SL.TZ0.3: The images are microscopic views of two similar cells. What is a reason for the differences...
18N.1.HL.TZ0.1: The image shows an electron micrograph of a fungus, Candida albicans. Which terms identify the...
18N.2.SL.TZ0.5a:
The structure of prokaryotic cells has been investigated using electron microscopy. Draw a labelled diagram to show prokaryotic cell structure.
18N.3.HL.TZ0.2a: Label tissues X and Y.
18N.3.HL.TZ0.2b:
Calculate the actual width along line A-B of the parenchyma cell shown.
19M.1.SL.TZ1.2:
The image shows an electron micrograph of part of a cell.

[Source: Dr. Eldon Newcomb – Emeritis Professor at The University of Wisconsin – Madison.]

Which features do the two structures labelled X and Y have in common?

A. They are surrounded by a double membrane.

B. They contain 70S ribosomes.

C. They contain naked DNA.

D. They are only found in leaf cells.
19M.1.HL.TZ1.2:
The image shows a phagocytic white blood cell as seen with a transmission electron microscope.

[Source: http://www.wikidoc.org/index.php/File:Monocyte_TEM_0002.jpg, by Cafer Zorkun is licensed
under the Creative Commons Attribution/Share-Alike License]

Which features can be found both within this cell and in a photosynthetic bacterium?

A. Chloroplasts

B. Multiple nuclei

C. 70S ribosomes

D. Lysosomes
19M.2.SL.TZ1.2a: Identify which electron micrograph shows a mitochondrion, providing one observation to support...
19M.1.SL.TZ2.1: Which structures are found only in prokaryotic cells? A. Ribosomes B. Pili C. Cell walls D....
19M.1.SL.TZ2.2:
The magnification of the micrograph is 2000×.

[Source: https://upload.wikimedia.org/wikipedia/commons/6/6c/HeLa_cells_stained_with_Hoechst_33258.jpg
by TenOfAllTrades.]

What is the maximum diameter of the nucleus in the cell labelled X?

A. 10 μm

B. 10 nm

C. 20 μm

D. 20 nm
19M.2.HL.TZ1.5a: Outline the functions of rough endoplasmic reticulum and Golgi apparatus.
19M.2.HL.TZ1.3a: Compare and contrast the structure of a typical prokaryotic cell with that of a mitochondrion.
20N.1.SL.TZ0.1: What is the name of the cell component labelled Y? A. Golgi apparatus B. Nucleus C....
20N.2.SL.TZ0.6a:
Draw the ultrastructure of a prokaryotic cell based on electron micrographs.
20N.2.HL.TZ0.3a:
Outline how the structures labelled X and Y are adapted to carry out the function of the mitochondrion.

X:

Y:
20N.1.HL.TZ0.1: Chlorella and Paramecium are both unicellular eukaryotic organisms living in freshwater....
21M.1.SL.TZ1.1: In mammals, mature red blood cells are specialized in that they lack nuclei, mitochondria or...
21M.1.SL.TZ1.2: What do chloroplasts and mitochondria have in common? A. Both are found in the cells of...
21M.2.HL.TZ1.2a:
State two structural similarities between mitochondria and chloroplasts.

1.

2.
21M.2.SL.TZ2.6a:
Outline the structures in M. tuberculosis that are not present in a human cell.
21M.2.HL.TZ2.5c: Testis cells are eukaryotic cells. Identify the structures seen under the electron microscope in...
21M.1.HL.TZ2.1:
The image shows an electron micrograph of virus particles known to infect the bacterium Vibrio parahaemolyticus, which is associated with gastroenteritis, wound infections and septicemia in humans and animals.

[Source: Lin, Y. and Lin, C., 2012. Transmission electron micrograph of phage ϕpp2 particles with several structural proteins. [micrograph] (BMC Genomics, 13:224).]

What does a virus have in common with a living cell?

A. 70S ribosomes

B. Genetic material

C. Reproduction by binary fission

D. Anaerobic respiration
22M.1.SL.TZ1.1: A cell contains chloroplasts, plasma membrane and 80S ribosomes. What type of cell could it...
22M.1.SL.TZ2.2:
The images of the radiolarian, a single-celled marine organism, were produced using a light microscope (left) and a scanning electron microscope (right).

[Source: Munir,S.;Sun,J.;Morton, S.L. The First Record and Classification of Planktonic Radiolarian
(Phylum Retaria) and Phaeodarian (Phylum Cercozoa) in the Eastern Indian Ocean. Biology 2021, 10, 202.
https://doi.org/10.3390/biology10030202 Copyright: © 2021 by the authors. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).]

What is a reason for the difference in quality of these images?

A. Light cannot pass through the specimen.

B. Higher magnification can be achieved with the electron microscope.

C. The resolution of the electron microscope is higher.

D. Samples are stained with methylene blue when viewed with the light microscope.
22M.1.SL.TZ2.6:
The micrograph of a section through a plant stem shows at least ten different types of cells.

[Source: Joan Carles Juarez / Shutterstock.com.]

What explains the differences between these cells?

A. Only one gene is expressed in each cell type.

B. Different genes are expressed in each cell type.

C. Only useful genes remain in the DNA of each cell type.

D. Changes in the DNA sequence take place when these cells develop.
22M.1.HL.TZ1.1: Two cells have the following characteristics. Which deduction is supported by this...
22M.2.HL.TZ2.2b.i:
Distinguish between the structure of chromosomes in prokaryotes and eukaryotes.

1.3 Membrane structure

1.4 Membrane transport

16N.1.HL.TZ0.4: The giant marine alga Halicystis ovalis is able to move sodium ions from vacuoles to the...
16N.3.HL.TZ0.3b: Suggest reasons for different amounts of sucrose in the leaf phloem sap of the potato plants.
17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system....
17M.2.HL.TZ2.3b: Define osmolarity.
17M.2.HL.TZ2.3c: Deduce, with a reason, which red blood cell has been placed in a hypertonic solution.
17N.1.SL.TZ0.03: The salt concentration inside an animal cell is 1.8 %. The salt concentration in the surrounding...
17N.1.SL.TZ0.24: Dialysis membrane was set up to model digestion and absorption in the small intestine. What is...
17N.2.HL.TZ0.01d.i:
Analyse the graph to obtain two conclusions about the concentration of sodium–potassium pumps.
17N.2.HL.TZ0.01d.ii:
Muscle fibres are stimulated to contract by the binding of acetylcholine to receptors in their membranes and the subsequent depolarization.

Suggest a reason for increasing the concentration of sodium–potassium pumps in the membranes of diaphragm muscle fibres.
17N.1.HL.TZ0.02: The salt concentration inside the Paramecium is 1.8 %. The salt concentration in the surrounding...
18M.1.SL.TZ1.3: How does potassium move across the membrane of a neuron during repolarization? A. Simple...
18M.1.SL.TZ1.29: Neural pathways in living brains can now be mapped by tracking the movement of water molecules...
18M.3.HL.TZ1.1a:
Data was collected on rabbit red blood cells that were exposed to sodium chloride (NaCl) and scorpion venom. Under some osmotic conditions red blood cells swell and burst, releasing hemoglobin (hemolysis). The graph shows the response of red blood cells to different concentrations of sodium chloride, with and without scorpion venom.

[Source: Adapted from Mirakabadi A Z, et al., (2006), J. Venom. Anim. Toxins incl. Trop. Dis., 12 (1), pages 67–77 (London: BioMed Central)]

Outline the effect of the venom on the hemolysis of red blood cells.
18M.3.HL.TZ1.1b :
Describe how the variables would be controlled in an experiment to estimate the osmolarity of plant tissue.
18M.1.HL.TZ2.4: Which type of transportation happens in the sodium–potassium pump? A. Facilitated diffusion B....
18N.2.HL.TZ0.6a: Calcium is absorbed from food in the human gut by both active and passive processes. Outline...
19M.1.SL.TZ1.4:
Which process(es) occur(s) by osmosis?

I. Uptake of water by cells in the wall of the intestine

II. Loss of water from a plant cell in a hypertonic environment

III. Evaporation of water from sweat on the skin surface

A. I only

B. I and II only

C. II and III only

D. I, II and III
19M.1.SL.TZ2.5:
The table shows concentrations of potassium ions and sodium ions inside and outside human cells.

[Source: © International Baccalaureate Organization 2019]

What explains these concentrations?

A. Potassium ions diffuse in and sodium ions diffuse out.

B. Sodium ions diffuse in and potassium ions diffuse out.

C. Active transport pumps sodium ions in and potassium ions out.

D. Active transport pumps sodium ions out and potassium ions in.
19M.2.SL.TZ2.5a: Outline four types of membrane transport, including their use of energy.
19M.2.HL.TZ1.6c: Explain how blood solute concentrations are kept within narrow limits in the human body.
19M.2.HL.TZ2.6a: Outline four types of membrane transport, including their use of energy.
19N.3.SL.TZ0.1a:
Using the graph, estimate isotonic sucrose solutions for potato tissue and carrot tissue.

Potato:

Carrot:
19N.3.SL.TZ0.1b: Suggest a reason for the difference in the isotonic points for the potato and the carrot tissues.
19N.3.SL.TZ0.1c: From the evidence provided by the graph, evaluate the reliability of these data.
19N.3.SL.TZ0.1d: Explain one reason for calculating the percentage change in mass.
19N.1.SL.TZ0.2: By which process do potassium ions move through potassium channels in axons? A. Active...
19N.3.HL.TZ0.3a: Estimate the solute concentration of the zucchini cells.
19N.3.HL.TZ0.3b: If a zucchini is allowed to dry in the open air, predict how the osmolarity of the zucchini cells...
19N.3.HL.TZ0.3c: Explain one reason for calculating the percentage changes in mass.
19N.3.HL.TZ0.3d: Predict what would happen to a red blood cell placed in distilled water.
20N.1.SL.TZ0.4:
The diagram shows a section through a membrane. What are the modes of transport in the diagram?

[Source: © International Baccalaureate Organization 2020.]
21M.1.SL.TZ1.4: A human organ is being prepared for transplant. In what type of solution must it be bathed? A. A...
21M.1.HL.TZ1.2: Which process explains the observations shown in the images? A. Active transport B....
21M.1.HL.TZ1.3: Which solution has the highest salt concentration? A. The original solution B. Solution 1 C....
21M.1.SL.TZ2.1:
The diagrams represent cells with the same concentration of dissolved substances in their cytoplasm. If all the cells were placed in the same hypertonic sucrose solution, which cell would show the greatest rate of change in the concentration of its cytoplasm?
21M.1.SL.TZ2.4: Which graph best represents the relationship between the concentration of chloride ions in the...
21N.1.SL.TZ0.3: How is facilitated diffusion in axons similar to active transport? A. They both require the...
21N.2.SL.TZ0.5b:
Describe transport across cell membranes by osmosis.
21N.2.HL.TZ0.3a:
The image shows human red blood cells.

[Source: someoneice/123rf.com.]

Outline what will happen to human red blood cells if transferred to distilled water.
22M.1.SL.TZ1.3: What is/are required for facilitated diffusion? I. A concentration gradient II. ATP III. A...
22M.1.SL.TZ2.3:
In an experiment on osmosis, red blood cells were immersed in a salt solution for two hours. The micrographs show the appearance of these cells before and after immersion in the salt solution.

[Source: Ed Uthman, Acanthocytes, from peripheral blood [image online] Available at:
https://en.wikipedia.org/wiki/Acanthocyte#/media/File:Acanthocytes,_Peripheral_Blood_(3884092551).jpg
This file is licensed under the Creative Commons Attribution 2.0 Generic (CC BY 2.0) https://creativecommons.org/licenses/by/2.0/ Source adapted.]

What explains the observed changes?

A. The salt solution was hypertonic and entered the red blood cells.

B. The salt solution was hypotonic and disrupted the membranes of the red blood cells.

C. The salt solution was hypertonic and water moved into it from the red blood cells.

D. The salt solution was hypotonic and mineral salts were lost from the red blood cells.
22M.1.SL.TZ2.7:
Which feature(s) allow(s) transport of glucose in blood plasma?

I. It is hydrophobic.

II. It is polar.

III. Its solubility is low at 37 °C.

A. I only

B. II only

C. I and II only

D. II and III only
22M.1.HL.TZ2.2:
Red blood cells from a small mammal were immersed in NaCl (sodium chloride) solutions of different concentrations for 2 hours. The graph shows the percentage of hemolysed (ruptured) red blood cells at each concentration.

[Source: Zaidan, T. , de Matos, W. , Machado, É. , Junqueira, T. , Vicentini, S. , Presta, G. and Santos-Filho, S. (2010)
Cellular effects of an aqueous solution of Losartan^® on the survival of Escherichia coli AB1157 in the presence
and absence of SnCl2, and on the physiological property (osmotic fragility) of the erytrocyte. Advances
in Bioscience and Biotechnology, 1, 300–304. doi: 10.4236/abb.2010.14039. Available at https://www.scirp.org/pdf/ABB20100400005_18844979.pdf Licensed under a Creative
Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).]

What can be deduced from the graph?

A. At Y, the net movement of Na ions between red blood cells and the NaCl solutions is zero.

B. At X, Na and Cl ions disrupt the structure of cell membranes.

C. At Y, the hypertonic NaCl solutions diffuse into the red blood cells.

D. At X, water has moved by osmosis into the red blood cells.

1.5 The origin of cells

17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
17M.2.SL.TZ1.2a:
Pictured below are Louis Pasteur’s original drawings of swan-necked flasks.

Describe how Pasteur’s experiments provided convincing evidence to falsify the concept of spontaneous generation.
17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
17M.1.SL.TZ2.4: What is evidence for the endosymbiotic theory? A. RNA can catalyse metabolic reactions. B....
17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system....
17M.1.HL.TZ2.4: What is evidence for the endosymbiotic theory? A. RNA can catalyse metabolic reactions. B....
17N.2.SL.TZ0.06a:
Describe the origin of eukaryotic cells according to the endosymbiotic theory.
17N.2.HL.TZ0.06a:
Cell biologists play an important role in research into disease, fertility, evolution and many other areas of science.

Describe the origin of eukaryotic cells according to the endosymbiotic theory.
18M.1.SL.TZ2.4: Pasteur carried out a series of experiments that provided strong evidence against a widely...
18N.1.SL.TZ0.5: Apparatus was set up as shown to collect data. The graph shows the results after 47 minutes of...
18N.1.HL.TZ0.5: In a copy of Louis Pasteur’s famous experiment, broth was put into flasks as shown in the...
19M.2.SL.TZ1.2b: Discuss the evidence for the theory that mitochondria may have evolved from free-living...
19M.2.SL.TZ2.6a: Describe briefly the endosymbiotic theory.
19M.2.HL.TZ1.3a: Compare and contrast the structure of a typical prokaryotic cell with that of a mitochondrion.
19M.2.HL.TZ1.3b: Explain how mitochondria could have been formed from free living prokaryotes.
19N.1.SL.TZ0.3: Which statement provides evidence for endosymbiosis? A. Early prokaryotes contributed to a large...
20N.1.SL.TZ0.2: Which feature of the cell in the micrograph is consistent with the endosymbiotic theory? A. X...
20N.2.SL.TZ0.2d: Apart from the ribosomes, explain the evidence for the endosymbiotic theory of the origin of...
20N.1.HL.TZ0.9: The first iron ore deposits in rocks appeared about 1.8 billion years ago. What took place to...
21M.1.SL.TZ2.5: Which statement is evidence for the endosymbiotic theory? A. Chloroplasts contain 70S...
21N.1.SL.TZ0.4: How do both mitochondria and chloroplasts provide evidence for the endosymbiotic theory? A. They...
21N.2.SL.TZ0.6a:
Describe the endosymbiotic theory.
22M.1.SL.TZ1.4: Which cell component arose first during the formation of the earliest cells? A. Chloroplast B....
22M.1.SL.TZ1.5:
In the chimpanzee (Pan troglodytes), the haploid number of chromosomes is 24. How many sister chromatids are present in the G2 phase of a somatic cell, such as a cell in the bone marrow of the chimpanzee?

A. 12

B. 24

C. 48

D. 96
22M.1.SL.TZ2.4: Pasteur used swan-necked flasks and a nutrient broth to demonstrate that spontaneous generation...
22M.1.HL.TZ1.7: What is a universal characteristic of the genetic code? A. There are more than 64 different...

1.6 Cell division