AQA A-LEVEL BIOLOGY PAPER 1 QUESTIONS WITH THE LATEST & UPDATED SCORE

AQA A-LEVEL BIOLOGY PAPER 1 QUESTIONS WITH THE
LATEST & UPDATED SCORE.


1) Describe the role of a ribosome in the production of a polypeptide. /3 -- Answer
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✔✔ 1. mRNA binds to ribosome;
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2. Idea of TWO codons/binding sites;
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3. tRNA with ANTICODONS binds;
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4. (Catalyzes) formation of PEPTIDE bond between AMINO ACIDS (held by tRNA
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molecules);
5. Moves along (mRNA to the next codon);
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2) Describe the structure of glycogen. /2 -- Answer ✔✔ 1. Polysaccharide of α-
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glucose;
OR
polymer of α-glucose; t t




2. (Joined by) glycosidic bonds
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OR
Branched structure; t




3) NHE3 actively transports one sodium ion into the cell in exchange for one proton
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(hydrogen ion) out of the cell. t t t t t




Use your knowledge of transport across cell membranes to suggest how NHE3
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does this. /3 -- Answer ✔✔ 1. Co-transport;
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2. Uses (hydrolysis of) ATP;
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3. Sodium ion and proton bind to the protein;
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4. Protein changes shape (to move sodium ion
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and/or proton across the membrane);
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4) Explain the curves for max protease activity over time at 50C and 60C. /4 --
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Answer ✔✔ 1. Both denatured (by high temperature);
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2. Denaturation faster at 60 °C due to more (kinetic) energy;
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, 3. Breaks hydrogen/ionic bonds (between amino acids/R groups);
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4. Change in shape of the active site/active site no longer complementary so fewer
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enzyme-substrate complexes formed; t t




5) Describe the action of these membrane-bound dipeptidases and explain their
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importance. /2 -- Answer ✔✔ 1. Hydrolyse (peptide bonds) to release amino acids;
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2. Amino acids can cross (cell) membrane;
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OR
Dipeptides cannot cross (cell) membrane; t t t t




OR
Maintain concentration gradient of amino acids for absorption;
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6) Explain why the scientists suggested that patients should be treated with both the
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current antibiotic and the new one.
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Use information from Figure 2 (old antibiotic decreases number of bacteria, new
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one decreases it more) and your knowledge of evolution of antibiotic resistance in
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bacteria in your answer. /3 -- Answer ✔✔ 1. (From Fig 2) New/old antibiotic does
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not kill all bacteria;
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OR
(From Fig 2) Some bacteria are resistant to the new/old antibiotic;
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2. Resistant bacteria will reproduce to produce (more) resistant bacteria;
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3. (Use of both) one antibiotic will kill bacteria resistant to the other antibiotic;
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OR
Unlikely that bacteria are resistant to both the new and the old antibiotic;
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OR
Use of both antibiotics (likely to) kill all/most bacteria;
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7) When measuring the leakiness of herbicide-treated cell membranes to ions, why
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did the scientists gently shake the flasks containing the leaf discs? /1 -- Answer ✔✔
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(Shaking) So all surfaces of the leaf discs are exposed (to water)/so all submerged;
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OR
To maintain diffusion/concentration gradient (for ions out of leaf discs);
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8) Scientists have found a virus that produces a protein very similar to human collagen.
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Suggest how the immune response to this viral protein can result in the
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