Q1.1) Name the type of bond between:
a) complementary base pairs
b) adjacent nucleotides in a DNA strand - Correct Answer 1. Hydrogen (bonds);
2. Phosphodiester (bonds);
Q1.3) Describe two differences between the structure of a tRNA molecule and the structure of an mRNA
molecule. (2) - Correct Answer 1. tRNA is 'clover leaf shape', mRNA is linear;
2. tRNA has hydrogen bonds, mRNA does not;
3. tRNA has an amino acid binding site, mRNA
does not;
4. tRNA has anticodon, mRNA has codon;
0 1 . 4 In a eukaryotic cell, the structure of the mRNA used in translation is different from the structure
of the pre-mRNA produced by transcription. Describe and explain a difference in the structure of these
mRNA molecules. - Correct Answer 1. mRNA fewer nucleotides
2. (Because of) splicing;
2 . 2 Describe how HIV is replicated. 4 marks - Correct Answer 1. Attachment proteins attach to
receptors on helper
T cell/lymphocyte;
2. Nucleic acid/RNA enters cell;
3. Reverse transcriptase converts RNA to DNA;
4. Viral protein/capsid/enzymes produced;
5. Virus (particles) assembled and released (from
cell);
3 . 1 Explain why it is not possible to determine the identity of the structures labelled X using an optical
microscope. - Correct Answer 1. Resolution (too) low;
, 2. Because wavelength of light is (too) long;
0 3 . 2 U. marinum cells ingest bacteria and digest them in the cytoplasm. Describe the role of one
named organelle in digesting these bacteria. - Correct Answer 1. Lysosomes;
2. Fuse with vesicle;
3. (Releases) hydrolytic enzymes;
0 3 . 4 In large cells of U. marinum, most mitochondria are found close to the cell-surface membrane. In
smaller cells, the mitochondria are distributed evenly throughout the cytoplasm. Mitochondria use
oxygen during aerobic respiration. Use this information and your knowledge of surface area to volume
ratios to suggest an explanation for the position of mitochondria in large U. marinum cells. - Correct
Answer 1. Large(r) cells have small(er) surface area to volume ratio;
2. (Takes) longer for oxygen to diffuse (to mitochondria)
4 . 1 Describe and explain the arrangement of the genetic material shown in Figure 4. - Correct Answer
1. Chromosomes (are) becoming visible/distinct;
2. Because (still) condensing
0 4 . 3 Name the fixed position occupied by a gene on a DNA molecule. - Correct Answer Locus/loci;
4 . 4 Describe how a gene is a code for the production of a polypeptide. Do not include information
about transcription or translation in your answer. - Correct Answer 1. (Because) base/nucleotide
sequence;
2. (In) triplet(s);
3. (Determines) order/sequence of amino acid sequence/primary structure (in polypeptide);
0 5 . 1 Describe how the structure of glycogen is related to its function (4) - Correct Answer 1.
Helix/coiled/branched so compact;
2. Polymer of glucose so easily hydrolysed;
3. Branched so more ends for faster hydrolysis;
4. Glucose (polymer) so provides respiratory substrate for energy (release);
5. Insoluble so not (easily) lost (from cell)
a) complementary base pairs
b) adjacent nucleotides in a DNA strand - Correct Answer 1. Hydrogen (bonds);
2. Phosphodiester (bonds);
Q1.3) Describe two differences between the structure of a tRNA molecule and the structure of an mRNA
molecule. (2) - Correct Answer 1. tRNA is 'clover leaf shape', mRNA is linear;
2. tRNA has hydrogen bonds, mRNA does not;
3. tRNA has an amino acid binding site, mRNA
does not;
4. tRNA has anticodon, mRNA has codon;
0 1 . 4 In a eukaryotic cell, the structure of the mRNA used in translation is different from the structure
of the pre-mRNA produced by transcription. Describe and explain a difference in the structure of these
mRNA molecules. - Correct Answer 1. mRNA fewer nucleotides
2. (Because of) splicing;
2 . 2 Describe how HIV is replicated. 4 marks - Correct Answer 1. Attachment proteins attach to
receptors on helper
T cell/lymphocyte;
2. Nucleic acid/RNA enters cell;
3. Reverse transcriptase converts RNA to DNA;
4. Viral protein/capsid/enzymes produced;
5. Virus (particles) assembled and released (from
cell);
3 . 1 Explain why it is not possible to determine the identity of the structures labelled X using an optical
microscope. - Correct Answer 1. Resolution (too) low;
, 2. Because wavelength of light is (too) long;
0 3 . 2 U. marinum cells ingest bacteria and digest them in the cytoplasm. Describe the role of one
named organelle in digesting these bacteria. - Correct Answer 1. Lysosomes;
2. Fuse with vesicle;
3. (Releases) hydrolytic enzymes;
0 3 . 4 In large cells of U. marinum, most mitochondria are found close to the cell-surface membrane. In
smaller cells, the mitochondria are distributed evenly throughout the cytoplasm. Mitochondria use
oxygen during aerobic respiration. Use this information and your knowledge of surface area to volume
ratios to suggest an explanation for the position of mitochondria in large U. marinum cells. - Correct
Answer 1. Large(r) cells have small(er) surface area to volume ratio;
2. (Takes) longer for oxygen to diffuse (to mitochondria)
4 . 1 Describe and explain the arrangement of the genetic material shown in Figure 4. - Correct Answer
1. Chromosomes (are) becoming visible/distinct;
2. Because (still) condensing
0 4 . 3 Name the fixed position occupied by a gene on a DNA molecule. - Correct Answer Locus/loci;
4 . 4 Describe how a gene is a code for the production of a polypeptide. Do not include information
about transcription or translation in your answer. - Correct Answer 1. (Because) base/nucleotide
sequence;
2. (In) triplet(s);
3. (Determines) order/sequence of amino acid sequence/primary structure (in polypeptide);
0 5 . 1 Describe how the structure of glycogen is related to its function (4) - Correct Answer 1.
Helix/coiled/branched so compact;
2. Polymer of glucose so easily hydrolysed;
3. Branched so more ends for faster hydrolysis;
4. Glucose (polymer) so provides respiratory substrate for energy (release);
5. Insoluble so not (easily) lost (from cell)
