3. Reproduction and Inheritance

Question 1

Difference between sexual and asexual reproduction?

Answer 1

Sexual involves two parents/gametes, genetic variation. Asexual is one parent, offspring identical.

Question 2

What is fertilisation?

Answer 2

Fusion of male and female gametes to form a zygote.

Question 3

Structure/adaptations of insect- and wind-pollinated flowers?

Answer 3

Insect: colorful petals, scent, nectar, sticky pollen; Wind: small/dull petals, exposed stamens/stigma, light pollen.

Question 4

How does fertilisation lead to seed/fruit formation?

Answer 4

Pollen tube grows to ovule, fertilisation occurs, ovule becomes seed, ovary becomes fruit.

Question 5

How do seeds germinate?

Answer 5

Use food reserves until seedling can photosynthesise.

Question 6

How can plants reproduce asexually?

Answer 6

Natural (runners), artificial (cuttings).

Question 7

Adaptations of human reproductive systems?

Answer 7

Male: sperm production and delivery; Female: egg production, receives sperm, supports embryo.

Question 8

Roles of oestrogen and progesterone?

Answer 8

Oestrogen: builds up uterus lining; Progesterone: maintains lining.

Question 9

Role of placenta?

Answer 9

Supplies nutrients and removes wastes for embryo.

Question 10

How is the embryo protected?

Answer 10

Amniotic fluid cushions it.

Question 11

Roles of oestrogen and testosterone in secondary sexual characteristics?

Answer 11

Oestrogen: breasts, hips, menstrual cycle; Testosterone: facial hair, muscle growth, voice.

Question 12

What is a genome?

Answer 12

The entire DNA of an organism.

Question 13

What is a gene?

Answer 13

A section of DNA that codes for a specific protein.

Question 14

Where are genes located?

Answer 14

On chromosomes in the cell nucleus.

Question 15

What are alleles?

Answer 15

Different versions of the same gene.

Question 16

Define dominant and recessive alleles.

Answer 16

Dominant: always expressed if present. Recessive: only expressed if two copies present.

Question 17

What do ‘homozygous’ and ‘heterozygous’ mean?

Answer 17

Homozygous: two same alleles. Heterozygous: two different alleles.

Question 18

Define phenotype and genotype.

Answer 18

Phenotype: physical appearance; Genotype: genetic makeup.

Question 19

What is polygenic inheritance?

Answer 19

Many genes control one trait.

Question 20

What is a monohybrid cross/genetic diagram?

Answer 20

Shows inheritance of a single gene.

Question 21

How to interpret a family pedigree?

Answer 21

Track inheritance of traits across generations.

Question 22

How is sex determined in humans?

Answer 22

XX = female, XY = male.

Question 23

How does mitosis work?

Answer 23

One cell divides to form two identical cells (growth, repair, cloning, asexual reproduction).

Question 24

How does meiosis work?

Answer 24

One cell divides to produce four genetically different gametes with half the chromosome number.

Question 25

What is genetic variation?

Answer 25

Differences in DNA among individuals, caused by mutation, meiosis, and random fertilisation.

Question 26

Human diploid and haploid chromosome numbers?

Answer 26

Diploid: 46 chromosomes; Haploid: 23 chromosomes.

Question 27

What is mutation?

Answer 27

Rare, random change in genetic material; can be inherited.

Question 28

What is Darwin’s theory of evolution by natural selection?

Answer 28

Organisms with advantageous traits survive and reproduce, passing on those traits.

Question 29

How does antibiotic resistance arise in bacteria?

Answer 29

Random mutations give resistance; resistant bacteria survive and multiply, especially with misuse of antibiotics.

Question 30

What are vectors in genetic engineering?

Answer 30

Plasmids/viruses that carry DNA into cells.