Genes and Health | Edexcel A-Level Biology A (Salters-Nuffield) (9BN0)

Genes and Health

259 questions
19 subtopics
Topics 1 to 4, examined on all three papers
Paper 1, Paper 2 and Paper 3

Covers gas exchange and how substances cross membranes, the structure of DNA and how it is read into protein, enzymes, replication and mutation, and the inheritance, effects and screening of cystic fibrosis..

It covers gas exchange surfaces and Fick's Law, the fluid mosaic model of the cell membrane, osmosis, diffusion and active transport, surface area and volume calculations, the structure of DNA and RNA, transcription, translation and the genetic code, amino acids and the levels of protein structure, globular and fibrous proteins: haemoglobin and collagen, alternative splicing and tissue-specific proteins, enzyme specificity, the active site and activation energy, rates of reaction, Vmax and Core Practical 4, semi-conservative replication and Meselson-Stahl, types of mutation and the CFTR gene, alleles, genotype and monohybrid inheritance, pedigree diagrams and the inheritance of cystic fibrosis, the effects of cystic fibrosis, and the chi-squared test, prenatal genetic testing: PGD, amniocentesis and CVS and the ethics of genetic screening.

Sample questions from Genes and Health

Answer each one closed book first, then open the answer.

Gas exchange surfaces and Fick's Law

State Fick's Law in words.

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The rate of diffusion is proportional to the surface area multiplied by the concentration difference, divided by the thickness of the exchange surface.
Osmosis, diffusion and active transport

What types of proteins are involved in facilitated diffusion?

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Carrier proteins and channel proteins.
The structure of DNA and RNA

Which pyrimidine base is found in both DNA and RNA?

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Cytosine.
Translation and the genetic code

Define a codon.

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A sequence of three bases on mRNA that codes for a specific amino acid or a stop signal.
Globular and fibrous proteins: haemoglobin and collagen

What are the two types of polypeptide chains in haemoglobin?

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Two alpha chains and two beta chains.
Enzyme specificity, the active site and activation energy

What happens to the shape of the active site when a substrate binds according to the induced fit model?

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The active site changes shape slightly, moulding around the substrate to form a more precise fit.
Semi-conservative replication and Meselson-Stahl

What is the function of DNA polymerase in DNA replication?

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DNA polymerase catalyses the formation of phosphodiester bonds between adjacent nucleotides, joining them to form the new strand.
Alleles, genotype and monohybrid inheritance

Under what condition is a recessive allele expressed in the phenotype?

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A recessive allele is only expressed in the phenotype when present in the homozygous state.

The 19 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Gas exchange surfaces and Fick's Law	Recall questions on what makes a good exchange surface, Fick's Law and its terms, and how the alveoli are adapted for gas exchange.	18
The fluid mosaic model of the cell membrane	Recall questions on the phospholipid bilayer, cholesterol, proteins, glycoproteins and glycolipids, and on how temperature and alcohol affect permeability.	18
Osmosis, diffusion and active transport	Recall questions on osmosis, diffusion, facilitated diffusion, active transport, endocytosis and exocytosis, and the proteins each uses.	16
Surface area and volume calculations	Recall questions on the formulae for the area and volume of common shapes, and on why the ratio between them matters biologically.	9
The structure of DNA and RNA	Recall questions on mononucleotides, purines and pyrimidines, base pairing and hydrogen bonding, and the double helix.	20
Transcription	Recall questions on RNA polymerase, the template strand, and how messenger RNA is built.	9
Translation and the genetic code	Recall questions on ribosomes, transfer RNA, codons and anticodons, start and stop codons, and why the code is described as triplet, non-overlapping and degenerate.	15
Amino acids and the levels of protein structure	Recall questions on the structure of an amino acid, the peptide bond, and the primary, secondary, tertiary and quaternary levels.	13
Globular and fibrous proteins: haemoglobin and collagen	Recall questions on what distinguishes globular from fibrous proteins, and on the structures of haemoglobin and collagen.	16
Alternative splicing and tissue-specific proteins	Recall questions on how one gene can produce several proteins, and on post-transcriptional modification.	12
Enzyme specificity, the active site and activation energy	Recall questions on the lock and key and induced fit models, activation energy, and intracellular against extracellular enzymes.	15
Rates of reaction, Vmax and Core Practical 4	Recall questions on measuring initial rate, the effect of enzyme and substrate concentration, Vmax, and the controls in Core Practical 4.	17
Semi-conservative replication and Meselson-Stahl	Recall questions on the role of DNA polymerase, and on how Meselson and Stahl showed replication to be semi-conservative.	12
Types of mutation and the CFTR gene	Recall questions on substitution, deletion, insertion and frameshift mutations, and on the mutation that causes cystic fibrosis.	9
Alleles, genotype and monohybrid inheritance	Recall questions on genes, alleles, genotype and phenotype, dominance, and the ratios expected from a monohybrid cross.	12
Pedigree diagrams and the inheritance of cystic fibrosis	Recall questions on reading a pedigree, identifying carriers, and the inheritance pattern of cystic fibrosis.	8
The effects of cystic fibrosis, and the chi-squared test	Recall questions on the CFTR protein and the effects on the lungs, digestion and fertility, and on using the chi-squared test.	15
Prenatal genetic testing: PGD, amniocentesis and CVS	Recall questions on what each test involves, when it can be carried out, and the risks attached.	12
The ethics of genetic screening	Recall questions on false positives and negatives, confidentiality, and the ethical arguments for and against screening.	13

Genes and Health is 259 of the 1,892 questions in the guide.Get the guide, £8

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.