mod 5

Question 1

Outline the differences between asexual and sexual reproduction

Answer 1

Asexual reproduction involves one parent and produces genetically identical offspring, whereas sexual reproduction requires two parents and produces genetically varied offspring.

Question 2

Explain how internal and external fertilisation strategies affect reproductive success

Answer 2

Internal fertilisation protects gametes and zygotes, increasing success in terrestrial environments. External fertilisation enables large offspring numbers but with higher risk of predation and lower survival rates.

Question 3

Discuss how reproduction in fungi demonstrates both sexual and asexual strategies

Answer 3

Fungi can reproduce asexually through budding or spore formation for rapid colonisation, and sexually to increase genetic variation when environmental conditions are challenging.

Question 4

Explain the advantages of vegetative propagation in agriculture

Answer 4

It ensures offspring are genetically identical to parents, preserving desirable traits, and enables faster, more reliable crop production.

Question 5

Outline the key phases of the cell cycle and their purpose

Answer 5

G1 (growth), S (DNA replication), G2 (error check), M (mitosis). Together they ensure accurate cell division and genetic continuity.

Question 6

Explain how meiosis contributes to genetic diversity

Answer 6

Meiosis introduces variation via crossing over and independent assortment, producing genetically unique gametes.

Question 7

Discuss the role of DNA replication in maintaining hereditary information

Answer 7

Accurate DNA replication ensures that identical genetic information is passed from cell to cell or generation to generation.

Question 8

Explain how polypeptides are synthesised from DNA templates

Answer 8

Through transcription, DNA is copied into mRNA, which is translated by ribosomes into amino acid chains (polypeptides) using tRNA.

Question 9

Outline the significance of protein folding in determining protein function

Answer 9

The 3D shape of a protein, determined by the folding of its polypeptides, dictates how it interacts with other molecules and performs cellular roles.

Question 10

Discuss how environmental factors can influence gene expression

Answer 10

Factors like temperature and chemical exposure can alter epigenetic markers, turning genes on or off without changing the DNA sequence.

Question 11

Explain the process of transcription in protein synthesis

Answer 11

DNA is transcribed into mRNA in the nucleus, where RNA polymerase builds a complementary RNA strand from the DNA template.

Question 12

Explain the role of mRNA in translation

Answer 12

mRNA carries the genetic code from DNA to the ribosome, where codons are read to assemble a polypeptide chain.

Question 13

Describe the structure and function of tRNA

Answer 13

tRNA has an anticodon that matches mRNA codons and carries the appropriate amino acid to the ribosome for protein synthesis.

Question 14

Outline how mutations in DNA can affect protein function

Answer 14

Mutations can change amino acid sequences in proteins, potentially altering their shape and function or rendering them non-functional.

Question 15

Explain the consequences of point mutations using sickle cell anaemia as an example

Answer 15

A single base substitution changes one amino acid in haemoglobin, causing red blood cells to sickle, reducing oxygen transport efficiency.

Question 16

Discuss the differences between mitosis and meiosis

Answer 16

Mitosis produces two identical diploid cells for growth/repair; meiosis produces four non-identical haploid gametes for sexual reproduction.

Question 17

Explain how codominance and incomplete dominance influence phenotypes

Answer 17

Codominance expresses both alleles (e.g. AB blood type), while incomplete dominance blends traits (e.g. red and white = pink flower).

Question 18

Describe the use of pedigrees in tracking inherited traits

Answer 18

Pedigrees help identify inheritance patterns (dominant, recessive, sex-linked) and predict the likelihood of traits in offspring.

Question 19

Explain how sex-linked inheritance affects the transmission of genetic disorders

Answer 19

X-linked traits appear more in males due to having only one X chromosome; females can be carriers.

Question 20

Discuss the importance of accurate DNA sequencing in biotechnology

Answer 20

Precise sequencing allows gene identification, mutation detection, and personalised medical treatments.

Question 21

Outline how PCR is used in molecular biology

Answer 21

PCR amplifies small DNA samples, enabling analysis in forensics, medical diagnostics, and genetic research.

Question 22

Explain the role of electrophoresis in DNA analysis

Answer 22

It separates DNA fragments by size, creating unique banding patterns used in profiling or genetic testing.

Question 23

Discuss the societal impacts of DNA profiling

Answer 23

It improves criminal justice and paternity cases but raises ethical concerns around privacy and consent.

Question 24

Explain how natural selection influences allele frequencies in populations

Answer 24

Advantageous traits become more common over generations, altering the gene pool and driving evolution.

Question 25

Outline the role of genetic drift in small populations

Answer 25

Random changes in allele frequency can lead to loss of genetic variation, especially in isolated groups.

Question 26

Discuss how the founder effect and bottleneck effect alter genetic diversity

Answer 26

Both reduce genetic diversity — founder effect from new populations started by few individuals, bottleneck from population reduction.

Question 27

Explain how gene flow affects population genetics

Answer 27

Migration introduces new alleles into a population, increasing variation and potentially altering allele frequencies.

Question 28

Describe the significance of mtDNA in tracing maternal ancestry

Answer 28

mtDNA is inherited from the mother and mutates slowly, making it useful for tracing lineage and evolutionary studies.

Question 29

Discuss the ethical considerations in using biotechnology for genetic modification

Answer 29

Concerns include consent, accessibility, environmental impact, and potential misuse for eugenics or bioweapons.

Question 30

Explain how artificial insemination and pollination are used in agriculture

Answer 30

They introduce desirable genes quickly across populations, improving traits like yield or disease resistance.

Question 31

Describe the purpose of artificial cloning in genetic research

Answer 31

Cloning allows for the replication of organisms with desirable traits and study of gene expression in identical conditions.

Question 32

Discuss how CRISPR technology is revolutionising genetic engineering

Answer 32

CRISPR allows precise DNA edits, enabling gene therapy, disease resistance, and trait enhancement, but poses ethical risks.

Question 33

Explain the potential consequences of reduced genetic diversity in crops

Answer 33

It increases vulnerability to pests, disease, and environmental changes, risking food security.

Question 34

Outline the process of creating a DNA profile from a biological sample

Answer 34

DNA is extracted, amplified with PCR, cut with restriction enzymes, and separated by electrophoresis to produce a banding pattern.

Question 35

Discuss how SNPs are used in genetic research and forensics

Answer 35

SNPs are common variations in DNA used to identify individuals, predict disease risk, and trace ancestry.

Question 36

Explain the concept of genotype vs phenotype

Answer 36

Genotype is the genetic makeup; phenotype is the observable trait influenced by genotype and environment.

Question 37

Describe how conjugation, transduction and transformation introduce variation in bacteria

Answer 37

They allow bacteria to share or acquire genetic material, increasing adaptability and resistance.

Question 38

Outline the steps of fertilisation in humans

Answer 38

Sperm meets egg, their nuclei fuse to form a zygote, which implants in the uterus and begins development.

Question 39

Explain how hormones regulate the menstrual cycle

Answer 39

FSH and LH control follicle development and ovulation; oestrogen and progesterone prepare the uterus and inhibit other hormones.

Question 40

Discuss the role of feedback mechanisms in hormonal regulation

Answer 40

Negative feedback ensures hormone levels are balanced — e.g., high oestrogen suppresses FSH to prevent multiple ovulations.

Question 41

Explain the role of protein structure in enzyme function

Answer 41

The shape of an enzyme's active site must match the substrate; changes in structure due to mutations can disable function.

Question 42

Outline the relationship between DNA, genes, and chromosomes

Answer 42

DNA is organised into genes, which code for proteins, and packed into chromosomes in the nucleus.

Question 43

Discuss the process and significance of gene expression in development

Answer 43

Gene expression determines cell function and development; misexpression can lead to disease or malfunction.

Question 44

Explain how biotechnology can be used to conserve endangered species

Answer 44

Techniques like cloning, gene banks, and assisted reproduction preserve genetic diversity and support population recovery.

Question 45

Describe the purpose and application of gene therapy

Answer 45

It aims to replace or repair faulty genes to treat or prevent genetic diseases, especially in single-gene disorders.