Topic 2- Genes and health

Question 1

2.1. (i). Know the properties of gas exchange surfaces in living organisms (large surface area to volume ratio, thickness of surface, difference in concentration).

Question 2

2.1. (ii). Understand how the rate of diffusion is dependent on these properties and
can be calculated using Fick’s Law of Diffusion.

Question 3

2.1. (iii). Understand how the structure of the mammalian lung is adapted for rapid
gaseous exchange.

Question 4

2.2. (i). Know the structure and properties of cell membranes.

Question 5

2.2. (ii). Understand how models such as the fluid mosaic model of cell membranes
are interpretations of data used to develop scientific explanations of the
structure and properties of cell membranes.

Question 6

Discuss Core practical 3: Effect of alcohol concentration or temp on membrane permeability.

Question 7

2.3. What is meant by osmosis in terms of the movement of free water
molecules through a partially permeable membrane (consideration of water
potential is not required).

Question 8

2.4. (i). What is meant by passive transport (diffusion, facilitated
diffusion), active transport (including the role of ATP as an immediate source of
energy), endocytosis and exocytosis.

Question 9

2.4. (ii). Explain the involvement of carrier and channel proteins in membrane
transport.

Question 10

2.5. (i). Know the basic structure of mononucleotides (deoxyribose or ribose linked to a phosphate and a base, including thymine, uracil, cytosine, adenine or
guanine) and the structures of DNA and RNA (polynucleotides composed of
mononucleotides linked through condensation reactions).

Question 11

2.5. (ii). Know how complementary base pairing and the hydrogen bonding between
two complementary strands are involved in the formation of the DNA double
helix.

Question 12

2.6. (i). Understand the process of protein synthesis (transcription) including the role
of RNA polymerase, translation, messenger RNA, transfer RNA, ribosomes and
the role of start and stop codons.

Question 13

2.6. (ii). Understand the roles of the DNA template (antisense) strand in
transcription, codons on messenger RNA and anticodons on transfer RNA.

Question 14

2.7. Understand the nature of the genetic code (triplet code, non-overlapping and
degenerate).

Question 15

2.8. Know that a gene is a sequence of bases on a DNA molecule that codes for a
sequence of amino acids in a polypeptide chain.

Question 16

2.9. (i). Know the basic structure of an amino acid (structures of specific amino acids are not required)

Question 17

2.9. (ii). Understand the formation of polypeptides and proteins (amino acid
monomers linked by peptide bonds in condensation reactions).

Question 18

2.9. (iii). Understand the significance of a protein’s primary structure in determining
its three-dimensional structure and properties (globular and fibrous proteins
and the types of bonds involved in its three-dimensional structure).

Question 19

2.9. (iv). Know the molecular structure of a globular protein and a fibrous protein and
understand how their structures relate to their functions (including haemoglobin and collagen).

Question 20

2.10. (i). Understand the mechanism of action and the specificity of enzymes in terms of their three-dimensional structure.

Question 21

2.10. (ii). Understand that enzymes are biological catalysts that reduce activation
energy.

Question 22

2.10. (iii). Know that there are intracellular enzymes catalysing reactions inside cells
and extracellular enzymes produced by cells catalysing reactions outside of
cells.

Question 23

Discuss Core Practical 4: effects of enzyme and substrate concentration on initial rates of reaction.

Question 24

2.11. (i). Understand the process of DNA replication, including the role of DNA
polymerase.

Question 25

2.11. (ii). Understand how Meselson and Stahl’s classic experiment provided new data that supported the accepted theory of replication of DNA and refuted competing
theories.

Question 26

2.12. (i). Understand how errors in DNA replication can give rise to mutations.

Question 27

2.12. (ii). Understand how cystic fibrosis results from one of a number of possible gene mutations.

Question 28

2.13. (i). Know the meaning of the terms: gene, allele, genotype, phenotype,
recessive, dominant, incomplete dominance, homozygote and heterozygote.

Question 29

2.13. (ii). Understand patterns of inheritance, including the interpretation of genetic pedigree diagrams, in the context of monohybrid inheritance.

Question 30

2.14. Understand how the expression of a gene mutation in people with cystic fibrosis
impairs the functioning of the gaseous exchange, digestive and reproductive
systems.

Question 31

2.15. (i). Understand the uses of genetic screening, including the identification of
carriers, pre-implantation genetic diagnosis (PGD) and prenatal testing, including amniocentesis and chorionic villus sampling

Question 32

2.15. (ii). Understand the implications of prenatal genetic screening.

Question 33

2.16. Be able to identify and discuss the social and ethical issues related to genetic
screening from a range of ethical viewpoints.