9700_w23_qp_12
A paper of Biology, 9700
Questions:
40
Year:
2023
Paper:
1
Variant:
2
Login to start this paper & get access to powerful tools
8
A student carried out the Benedict’s test on four different concentrations of glucose solution and then recorded the time taken for the first appearance of a colour change (the end-point). The student found it difficult to identify the first appearance of a colour change and consistently timed each solution for two seconds after the colour change first appeared. This introduced a source of error into the experiment. Which statements about this error are correct?
2. Biological molecules  →  2.1. Testing for biological molecules
Open
13
The graph shows the results of two experiments on the effect of increasing substrate concentration on the rate of an enzyme-catalysed reaction. One experiment was at a high concentration of enzyme and the second was at a low concentration of enzyme. All other variables were standardised. initial rate of reaction substrate concentration high enzyme concentration low enzyme concentration X What would limit the initial rate of reaction at point X?
3. Enzymes  →  3.2. Factors that affect enzyme action
13. Photosynthesis  →  13.2. Investigation of limiting factors
Open
23
The RNA codon wheel is a tool used to find which amino acid would be translated from an mRNA sequence. Stop G A U C G G G G A A A A C C C C U U U U CU CU AG AG AG AG AG UC CUAG CUAG CUAG CUAG UC UC UC UC AG A G UCAG UCAG G ACU UCAG UCAG Cys Stop Tyr Ser Leu Phe Gly Glu Asp Ala Val Arg Ser Lys Asn Thr Met Ile Arg Gln His Pro Leu Trp Codon position 1 is in the centre of the wheel, codon position 2 is in the middle of the wheel and codon position 3 is near the edge of the wheel. The three letters on the outside edge of the wheel identify the amino acid. The diagram shows a section of DNA coding for one amino acid. The template strand is outlined in a box and the DNA base sequence is read in the 5′ to 3′ direction. template strand Which amino acid is coded for by this section of DNA?
6. Nucleic acids and protein synthesis  →  6.2. Protein synthesis
Open
37
Organism X produces molecule Y, which blocks the activity of 70S ribosomes. An experiment was carried out to investigate the effect of Y on bacterial cells. An agar plate with bacteria growing all over its surface had four wells cut into the agar. Different substances were added to each well and the agar plate with bacteria was incubated for a week. The diagram shows the results after a week. intact cells of organism X sterile distilled water only concentrated solution made from the cytoplasm of lots of organism X cells commonly used antibiotic no bacterial growth bacterial growth Which conclusions can be made from these results?
10. Infectious diseases  →  10.2. Antibiotics
19. Genetic technology  →  19.1. Principles of genetic technology
Open
39
A patient with kidney failure can be given a kidney transplant. In a kidney transplant, a healthy kidney is taken from another person and put into the patient’s body. Sometimes the donated kidney cells are killed by the patient’s body. In this primary immune response, T-lymphocytes bind to antigens on the donated kidney cells and are activated. The statements describe the next stages of the primary immune response. Activated T-lymphocyte secretes cytokines. B-lymphocytes differentiate into plasma cells and make antibodies. T-killer cells bind to antigens on donor kidney cells. T-killer cells release toxins that destroy the donor kidney cells. T-lymphocytes multiply by mitosis and differentiate into T-killer cells. Which order correctly explains how donor kidney cells are killed?
11. Immunity  →  11.1. The immune system
11. Immunity  →  11.2. Antibodies and vaccination
Open