A Level Paper 1 2017 - Exam Questions

Question 1

1.1) Give the 2 types of molecule from which a ribosome is made

Answer 1

Ribosomal RNA and amino acids

Question 2

1.2) Describe the role of a ribosome in the production of a polypeptide. Don’t include transcription

Answer 2

1. mRNA binds to ribosome
2. Idea of 2 codons/binding sites
3. (Allows) tRNA with anticodons to bind/associate
4. Catalyses formation of peptide bond between amino acids
5. Moves along to the next codon

Question 3

1.4) In a Eukaryotic cell, the base sequence of the mRNA might be different from the sequence of the pre-mRNA. Explain why

Answer 3

1. Introns
2. Removal sections of (pre-mRNA)/splicing

Question 4

Answer 4

1. Polysaccharide of a - glucose
2. Joined by glycosidic bonds

Question 5

Answer 5

1. Hydrolysed
2. Glucose used for respiration

Question 6

Answer 6

Question 7

Answer 7

3.28x10-5

Question 8

Answer 8

1. Co-transport
2. Uses (hydrolysis of) ATP
3. Sodium ion and proton bind to the protein
4. Protein changes shape (to move sodium ion and/ or proton across the membrane)

Question 9

Answer 9

Question 10

3.3) High absorption of salt from the diet can result in a higher than normal concentration of salt in the blood plasma entering the capillaries. This can lead to a build-up of tissue fluid. Explain how.

Answer 10

1. Higher salt results in lower water potential of tissue fluid.
2. So less water returns to capillary by osmosis

Question 11

4.1) Describe how bacteria divide

Answer 11

1. Binary Fission
2. Replication of DNA
3. Division of cytoplasm to produce 2 daughter cells
4. Each with single copy of (circular) DNA

Question 12

Answer 12

Question 13

4.3) Suggest 1 advantage to a bacterium of secreting an extracellular protease in its natural environment

Answer 13

1. To digest protein
2. So they can absorb amino acids for growth