Topic 2 - Genes and Health

Question 1

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

Answer 1

2.1 (i)

Question 2

Understand how the rate of diffusion is dependent on these properties & can be calculated using Fick’s Law of diffusion.

Answer 2

2.1 (ii)

Question 3

Understand how the structure of the mammalian lung is adapted for rapid gaseous exchange.

Answer 3

2.1 (iii)

Question 4

Know the structure & properties of cell membranes.

Answer 4

2.2 (i)

Question 5

Understand how models such as the fluid mosaic model of cell membranes are interpretations of data used to develop scientific explanations of the structure & properties of cell membranes.

Answer 5

2.2 (ii)

Question 6

Investigate the membrane structure, including the effect of alcohol concentration or temperature or membrane permeability.

Answer 6

Core Practical 3

Question 7

Understand what is meant by osmosis in terms of the movement of free water molecules through a partially permeable membrane

Answer 7

2.3

Question 8

Understand what is meant by passive transport (diffusion, facilitated diffusion), active transport (including the role of ATP as an immediate source of energy), endocytosis & exocytosis.

Answer 8

2.4 (i)

Question 9

Understand the involvement of carrier & channel proteins in membrane transport.

Answer 9

2.4 (ii)

Question 10

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

Answer 10

2.5 (i)

Question 11

Know how complementary base pairing & the hydrogen bonding between 2 complementary strands are involved in the formation of the DNA double helix.

Answer 11

2.5 (ii)

Question 12

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

Answer 12

2.6 (i)

Question 13

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

Answer 13

2.6 (ii)

Question 14

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

Answer 14

2.7

Question 15

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.

Answer 15

2.8

Question 16

Know the basic structure of an amino acid

Answer 16

2.9 (i)

Question 17

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

Answer 17

2.9 (ii)

Question 18

Understand the significance of a protein’s primary structure in determining its 3 dimensional structure & properties (globular & fibrous proteins & 3 types of bonds involved in its 3 dimensional structure).

Answer 18

2.9 (iii)

Question 19

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

Answer 19

2.9 (iv)

Question 20

Understand the mechanism action & the specificity of enzymes in terms of their 3 dimensional structure.

Answer 20

2.10 (i)

Question 21

Understand that enzymes are biological catalysts that reduce activation energy.

Answer 21

2.10 (ii)

Question 22

Know that there are intracellular enzymes catalysing reactions inside cells & extracellular enzymes produced by cells catalysing reactions outside of cells.

Answer 22

2.10 (iii)

Question 23

Investigate the effect of enzyme & substrate concentrations on the initial rates of reactions.

Answer 23

Core Practical 4

Question 24

Investigate the effect of enzyme & substrate concentrations on the initial rates of reactions.

Answer 24

2.11 (i)

Question 25

Understand how Meselson & Stahl’s classic experiment provided new data that supported the accepted theory of DNA replication & refuted competing theories.

Answer 25

2.11 (ii)

Question 26

Understand how errors in DNA replication can give rise to mutations.

Answer 26

2.12 (i)

Question 27

Understand how cystic fibrosis results from 1 of a number of possible gene mutations.

Answer 27

2.12 (ii)

Question 28

Know the meaning of the terms: gene, allele, genotype, phenotype, recessive, dominant, incomplete dominance, homozygote & heterozygote.

Answer 28

2.13 (i)

Question 29

Understand patterns of inheritance, including the interpretation of genetic pedigree diagrams, in the context of monohybrid inheritance.

Answer 29

2.13 (ii)

Question 30

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

Answer 30

2.14

Question 31

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

Answer 31

2.15 (i)

Question 32

Understand the implications of prenatal genetic screening.

Answer 32

2.15 (ii)

Question 33

Be able to identify & discus the social & ethical issues related to genetic screening from a range of ethical viewpoints.

Answer 33

2.16