Which of the following enables tRNA activating enzymes to link an amino acid to a tRNA molecule?
The tertiary structure of the enzyme active site creates a complementary shape to both tRNA molecule and amino acid which allows them to bind together
The tertiary structure of the enzyme active site creates a shape that is similar to both tRNA molecule and amino acid to allow the them to bind together
The quaternary structure of the enzyme active site creates a shape that is complementary to the tRNA molecule in order for the amino acid to bind to the attachment site of tRNA
The tertiary structure of the specific tRNA molecule creates a shape that is complementary to the active site of the enzyme and also allows the amino acid to bind to its attachment site
Ustilago maydis is a fungal pathogen affecting maize. It secretes toxins, known as killer toxins, with the best-characterised one being the KP6 toxin. This particular toxin consists of two small polypeptides that are not linked by covalent bonds. The diagram below shows the ribbon structure of one of the polypeptides of the KP6 toxin.
Which of the following is the most accurate description of the structure of this polypeptide?
This polypeptide represents the tertiary structure of a protein due to the hydrogen bonds that form between the carboxyl group of one R-group and the amino group of another amino acid
This polypeptide represents the secondary structure of a protein due to the presence of hydrogen bonds that forms triple-helices and β-pleated sheets
This polypeptide represents the quaternary structure of a protein due to the existence of more than one chain that can fit together to form the toxin
This polypeptide represents the secondary structure of a protein due to the presence of hydrogen bonds that forms α-helices and β-pleated sheets
Leucine is an essential amino acid (EAA) that plays an important role in initiating the process of translation. Scientists investigated the effect of leucine on the process of protein synthesis and protein breakdown in muscles. Participants of the study were divided into three equal groups. Each group were given the same diet that was supplemented with different amounts of leucine (High, low and no added leucine) and the rate of protein synthesis and protein breakdown were monitored over time.
The diagram below shows the results of this study.
Which of the following provides the most plausible conclusion that can be drawn from the data?
Leucine led to a significant increase in protein synthesis while it also increased the rate of protein breakdown in the muscles
Low levels of leucine cause a significant increase in protein synthesis with no significant impact on the breakdown of protein in the muscles
Supplementing the diet with high levels of leucine will lead to protein being broken down at a higher rate than it is being synthesised in the muscles
A diet with no added leucine will have a negative impact on protein synthesis and may result in developing a protein deficiency
