Biology 9700 · AS & A Level
Proteins
100 practice questions on Proteins, with worked solutions and instant marking.
When proteins are combined with certain organic solvents, hydrophobic interactions and hydrogen bonding change within the protein molecules. Which levels of protein structure would be affected?
Feb/March 2016
A gene contains the instructions for making what kind of molecule?
Feb/March 2016
The table outlines the mode of action of two antibacterial drugs that can affect protein synthesis. If bacteria are treated with both drugs, what immediate effects will occur?
Feb/March 2016
The diagram illustrates how three different carbon dioxide concentrations affect the oxygen dissociation curve for human haemoglobin. $X$ = partial pressure of carbon dioxide: $3.0\,\text{kPa}$ $Y$ = partial pressure of carbon dioxide: $5.0\,\text{kPa}$ $Z$ = partial pressure of carbon dioxide: $7.0\,\text{kPa}$ What effect does a rise in carbon dioxide concentration have on haemoglobin?
Feb/March 2016
An enzyme hydrolyses the two heavy polypeptide chains in an antibody molecule. This hydrolysis takes place at the hinge region and splits the antibody into three fragments. How many of these fragments can bind to antigens?
Feb/March 2016
The molecules present in animal tissues can be arranged into three groups. 1 glucose, cholesterol, triglycerides, water 2 glycogen, antibodies, adenine, phospholipids 3 haemoglobin, carbon dioxide, mRNA, monosaccharides Which of these groups contain one or more molecules that always have nitrogen atoms?
Feb/March 2017
Haemoglobin is made up of two $\alpha$ chains and two $\beta$ chains. About $5\%$ of all humans have a change in one amino acid in the $\beta$ chain, which alters the structure and stability of haemoglobin. Which levels of protein structure could be affected in the haemoglobin of these humans?
Feb/March 2017
Which row shows the correct description of both a collagen molecule and a collagen fibre?
Feb/March 2017
The structures of two amino acids are shown in the diagrams; each one contains two amine ($-\text{NH}_2$) groups. A peptide bond is made between these two amino acids. Which groups could make the peptide bond?
Feb/March 2017
Rifampicin is an antibiotic used for treating tuberculosis. Its action is to block RNA polymerase in bacteria. Which of the following processes would be directly blocked by this antibiotic?
Feb/March 2017
The diagram illustrates the stages involved in producing part of a polypeptide. DNA nucleotide sequence (template strand): $\text{TACGACAATCGC}$. mRNA sequence: $\text{AUGCUGUUAGCG}$. Amino acid sequence: met leu leu ala. Which feature of the triplet code is shown by the information provided?
Feb/March 2017
The graph displays the oxygen dissociation curves of haemoglobin taken from two mammal species, S and T. Which statements might account for the difference between the oxygen dissociation curves of species S and species T?
Feb/March 2017
Which of the following statements could describe the effect of carbon monoxide in cigarette smoke?
Feb/March 2017
People G and H each received an injection intended to protect them from a specific pathogen. One of them was given antibodies by injection. The other was given a vaccine by injection. The graph shows how the concentration of the antibody against this pathogen in the blood of G and H changes during the 20 days after the injection. Which row gives the correct description of the type of immunity shown by G and H?
Feb/March 2017
Which of these molecules are globular proteins?
Feb/March 2018
After hydrolysis, which molecules yield products that contain a carboxyl group?
Feb/March 2018
The table lists three anticodons for different amino acids. Which DNA triplet on the DNA template strand specifies the amino acid serine?
Feb/March 2018
Which of the following statements about the formation of haemoglobonic acid are correct? 1 It is dependent on the formation of carbaminohaemoglobin. 2 It removes surplus hydrogen ions, stopping the blood from becoming too acidic. 3 It is associated with the action of carbonic anhydrase.
Feb/March 2018
Which substance is able to bind to the haem group in a haemoglobin molecule?
Feb/March 2018
The hybridoma method is used to produce monoclonal antibodies. Which two cell types are involved in this method?
Feb/March 2018
A vaccine is given to produce artificial active immunity. Once a person has received a vaccine, there is a time interval before long-term immunity to the disease develops. Which statement about this time interval accounts for this delay?
Feb/March 2018
Which diagram correctly illustrates the formation of a peptide bond between two amino acids?
Feb/March 2018
A DNA fragment was analysed and sequenced. $24\%$ of its nitrogenous bases were adenine. What percentage of the bases is cytosine?
Feb/March 2019
Which statements about how haemoglobinic acid is formed are correct?
Feb/March 2019
The graph illustrates the oxygen dissociation curves of haemoglobin in eight species of mammal. Which conclusion agrees with the data in the graph?
Feb/March 2019
In what location are antibodies present during an immune response?
Feb/March 2019
The graph illustrates how the concentration of antibodies in a baby's blood changes before birth and throughout the first few months after birth. Which statement correctly describes the changes in immunity during the first few months after birth?
Feb/March 2019
Which statement concerning collagen is correct?
Feb/March 2021
A double-stranded DNA fragment with $12 \times 10^3$ nucleotides is transcribed and then translated to form one polypeptide. What is the greatest possible number of amino acids in this polypeptide?
Feb/March 2021
The table presents the data used to construct an oxygen dissociation curve for adult haemoglobin. What is the percentage increase in the volume of oxygen per gram of haemoglobin when the partial pressure of oxygen rises from $3\,\text{kPa}$ to $5\,\text{kPa}$?
Feb/March 2021
The graph presents the oxygen dissociation curves for adult haemoglobin at two carbon dioxide concentrations. Which letters indicate measurements taken in the capillaries of the lungs and in the capillaries of active muscle?
Feb/March 2021
Which substances are able to combine with adult haemoglobin and lower the blood’s oxygen-carrying capacity?
Feb/March 2021
People who have the autoimmune disease myasthenia gravis can receive treatment to reduce the symptoms. In this treatment, one component of their blood is taken out. Which blood component is taken out?
Feb/March 2021
The diagrams illustrate three examples of various bonds. Which bonds are able to keep the quaternary structure of proteins joined together?
Feb/March 2022
Which row gives the correct description of the primary structure, secondary structure, tertiary structure and quaternary structure of certain proteins?
Feb/March 2022
Within the hybridoma method, what is cultured by cell culture to make monoclonal antibodies?
Feb/March 2022
Which row correctly indicates the levels of protein structure that each type of interaction can hold together?
Feb/March 2023
A DNA molecule is formed from two polynucleotide strands. Which statement is correct?
Feb/March 2023
Evidence shows that the oxygen dissociation curves for haemoglobin in smaller mammals lie to the right of those for larger mammals. What does this imply about the haemoglobin of smaller mammals?
Feb/March 2023
What do all viruses contain?
Feb/March 2023
Which molecule is produced under the direct control of DNA?
Feb/March 2024
Oxyhaemoglobin, carbaminohaemoglobin, haemoglobinic acid and carbonic anhydrase are present inside red blood cells. How many of these substances will have an overall fall in concentration as a red blood cell moves through capillaries in the lungs?
Feb/March 2024
Monoclonal antibodies are now used in the treatment of certain human diseases. What explains why monoclonal antibodies are suitable for this use?
Feb/March 2024
Hydroxyproline is formed when an -OH group is added onto the R-group of the amino acid proline. Hydroxyproline is a major component of collagen and helps to improve the stability of its structure. Which statement explains why adding an -OH group to proline could make collagen more stable?
Feb/March 2025
Which levels of protein structure are always involved in the formation of an enzyme’s active site?
Feb/March 2025
The diagram shows the transcription of a gene within the nucleus of an animal cell. Which row correctly identifies P, Q and R?
Feb/March 2025
The graph displays the dissociation curves for haemoglobin at two different partial pressures of carbon dioxide. Which labelled point on the oxygen dissociation curves would produce the greatest concentration of haemoglobinic acid?
Feb/March 2025
The diagrams illustrate three different bonds. Which of these bonds are present in an antibody molecule?
Feb/March 2025
Some monoclonal antibodies can be used to treat certain cancers. Trastuzumab is one example, and it can be used for treating cancer-related tumours. Which statements might help to explain why monoclonal antibodies such as trastuzumab are suitable for this purpose?
Feb/March 2025
What characteristic of haemoglobin makes it a globular protein?
May/June 2010
How many base substitutions, at minimum, are needed to convert the nucleotide sequence of the HbA (normal) allele into the HbS (sickle cell) allele?
May/June 2010
In a DNA molecule, the base sequence AGT specifies the amino acid serine. Which base sequence is found in the anti-codon on the tRNA that serine attaches to?
May/June 2010
In a study of the immune response, a volunteer was given two different antigens, X and Y. The level of antibody in the blood was recorded at regular intervals over 60 days. The graph indicates the time at which the volunteer was exposed to each antigen and shows antibody concentration against time for antigens X and Y. What is the explanation for the results shown on the graph?
May/June 2010
Which characteristic of haemoglobin means that it is a globular protein?
May/June 2010
What is the smallest number of base substitutions needed to alter the nucleotide sequence of the HbA (normal) allele into the HbS (sickle cell) allele?
May/June 2010
Within a DNA molecule, the base sequence AGT specifies the amino acid serine. What base sequence is found in the anti-codon on the tRNA that serine attaches to?
May/June 2010
Which protein-structure levels can determine an enzyme’s specificity?
May/June 2011
The events below happen during transcription. Before the mRNA leaves the nucleus, which events will have taken place twice?
May/June 2011
Which group of statements accurately describes haemoglobin?
May/June 2011
The diagram illustrates the structure of the amino acid cysteine. When two of these amino acids combine, what bond(s) are formed?
May/June 2011
The table gives the tRNA anticodons for four amino acids. A cell produces a polypeptide with this amino acid sequence: glutamic acid - asparagine - threonine - proline What sequence of bases was present in the DNA that produced this?
May/June 2011
At which levels of protein structure are ionic bonds present?
May/June 2011
Myoglobin is a protein that carries out a role similar to haemoglobin. Yet myoglobin has no quaternary structure. Why is there no quaternary structure in myoglobin?
May/June 2011
These events take place during transcription. By the time the mRNA leaves the nucleus, which of these events will have happened twice?
May/June 2011
Which rows indicate the chemical groups found in the biological molecules listed?
May/June 2011
Which group of statements gives the correct description of haemoglobin?
May/June 2011
Which level of protein structure preserves the globular forms of enzymes?
May/June 2012
Which substances are composed of carbon, hydrogen, oxygen and nitrogen?
May/June 2012
Which statement explains a process that happens during protein synthesis?
May/June 2012
A double-stranded DNA segment contains 120 nucleotides and codes for polypeptide X. What is the greatest possible length of polypeptide X?
May/June 2012
A rise in carbon dioxide concentration within human blood causes the oxyhaemoglobin dissociation curve to move to the right. Why does this happen?
May/June 2012
Which statement is correct regarding the affinity of haemoglobin for the gases carbon dioxide, carbon monoxide and oxygen?
May/June 2012
Antibodies can protect the body from pathogenic bacteria in several different ways. Which event would not take place after antigen-antibody binding?
May/June 2012
What does the process of transcription need?
May/June 2012
A peptide is made up of ten amino acids belonging to four distinct types. What is the theoretical minimum number of different tRNA molecules needed to translate the mRNA for this peptide?
May/June 2012
Which of the following statements about tRNA structure are correct?
May/June 2012
The diagram illustrates the Bohr effect. What brings about the change from X to Y?
May/June 2012
The graph indicates the amount of antibody produced in response to an antigen. Based on the graph, which statement is correct?
May/June 2012
Which substances are made up of carbon, hydrogen, oxygen and nitrogen?
May/June 2012
Which level of protein structure is responsible for preserving the globular shapes of enzymes?
May/June 2012
A double-stranded DNA molecule contains $120$ nucleotides and encodes polypeptide X. What is the maximum possible length of polypeptide X?
May/June 2012
Which statement refers to a process that takes place during protein synthesis?
May/June 2012
Antibodies can protect the body against pathogenic bacteria in several different ways. Which event would not happen after antigen-antibody binding?
May/June 2012
Which statement is correct about haemoglobin’s affinity for the gases carbon dioxide, carbon monoxide and oxygen?
May/June 2012
An increase in carbon dioxide in human blood causes the oxyhaemoglobin dissociation curve to move to the right. What explains this effect?
May/June 2012
The characteristics of four proteins, W, X, Y and Z, are given below. W is made up of two polypeptides joined by disulfide bonds. X is made up of three polypeptides wound tightly around each other. Y is made up of four polypeptides, and each one has a prosthetic group. Z is made up of four polypeptides joined together by disulfide bonds. Which row correctly matches the named proteins?
May/June 2013
The table shows the tRNA anticodons for four amino acids. A cell produces a polypeptide with the following amino acid sequence: glutamic acid - asparagine - threonine - proline What is the sequence of bases in the DNA strand that was complementary to the mRNA used to form this polypeptide?
May/June 2013
Haemoglobin is able to bind with carbon dioxide, carbon monoxide and oxygen. Which statement about the binding sites of haemoglobin is correct?
May/June 2013
Which substances cause oxygen to be displaced from oxyhaemoglobin?
May/June 2013
Which of these molecules contains a carboxyl group?
May/June 2013
The table lists the diameters of some atoms when they make bonds. Using the values in the table, the approximate length of the amino acid shown below was estimated as $0.7\,\text{nm}$. What is the approximate length of a dipeptide made from this amino acid?
May/June 2013
What kind of molecule is produced at the end of translation?
May/June 2013
A polypeptide molecule has the amino acid order: glycine - leucine - lysine - valine. The table lists the DNA codes for these amino acids. glycine: CCC; leucine: GAA; lysine: TTT; valine: CAA. Which tRNA anticodons are required to make this polypeptide?
May/June 2013
Which statement accurately describes the Bohr effect?
May/June 2013
Amino acid R groups (side chains) may be hydrophobic, hydrophilic, acidic, or basic. The diagram presents four different amino acid R groups. Ala: $\text{CH}_3$ Asp: $\text{COOH}$ attached to $\text{CH}_2$ Lys: $\text{NH}_2$ attached to $(\text{CH}_2)_4$ Ser: $\text{OH}$ attached to $\text{CH}_2$ Which row is correct for these amino acid R groups?
May/June 2013
What happens to proteins during denaturation caused by extremes of pH?
May/June 2013
Which molecule is specified by the code in one gene?
May/June 2013
A polypeptide contains the amino acid sequence glycine - arginine - lysine - serine. The table shows the possible tRNA anticodons for each amino acid. Which sequence of bases on DNA would code for this polypeptide?
May/June 2013
What is the smallest number of hydrogen bonds in a length of DNA containing 700 nucleotides?
May/June 2013
Which row gives the changes in haemoglobin properties caused by the Bohr effect?
May/June 2013