Question 1
Which of the following options is not a source of stem cells?
Umbilical cord blood
Bone marrow
An embryo
Blood plasma
Which of the following options is not a source of stem cells?
Umbilical cord blood
Bone marrow
An embryo
Blood plasma
The electron micrograph below shows a plant cell.
The scale bar (measuring 45 mm in length) on this drawing represents a length of 10 μm.
Which of the following correctly represents the magnification of the electron micrograph?
x45000
x4.5
x4500
x450
Paramecium is a genus of unicellular eukaryotic organisms which carry out several functions in order to stay alive. The table below lists four of these functions and descriptions on how Paramecium carry them out.
Which of the following rows correctly describes the processes of the Paramecium?
Metabolism | Reproduction | Response | Nutrition | |
A. | Carry out photosynthesis in their chloroplasts | Commonly asexual | Beating cilia moves them through water in response to external stimuli | Get their nutrition from the products of photosynthesis |
B. | Reactions such as respiration take place in the cytoplasm | Commonly asexual | Beating cilia moves them through water in response to external stimuli | Take in nutrients via their oral groove which they digest using enzymes |
C. | Carry out photosynthesis in their chloroplasts | Mostly sexual | Beating 'tail' called a flagellum moves them through water in response to external stimuli | Get their nutrition from the products of photosynthesis |
D. | Reactions such as respiration take place in the cytoplasm | Mostly sexual | Beating 'tail' called a flagellum moves them through water in response to external stimuli | Take in nutrients via their oral groove which they digest using enzymes |
The cube below has sides that measure 2 cm in length.
Which of the following represents the correct surface area : volume ratio of this cube?
1:1
6:1
3:1
2:1
Which changes can occur when a cell differentiates from a stem cell into a specialised cell?
I. The shape of the cell can change
II. The number and type of proteins in the cell changes
III. Enzymes cut out the DNA that is no longer needed
I. and II.
II. and III.
I. and III.
All of the options