Inheritance, Variation and Evolution

Question 1

What is the difference between sexual and asexual reproduction?

Answer 1

Sexual reproduction involves the fusion of gametes, leading to genetic variation.
Asexual reproduction involves one parent, producing genetically identical offspring (clones).

Question 2

What type of cell division is involved in sexual reproduction?

Answer 2

Meiosis

Question 3

What type of cell division is involved in asexual reproduction?

Answer 3

Mitosis

Question 4

Give two examples of organisms that reproduce asexually.

Answer 4

Bacteria, strawberry plants

Question 5

Why is variation an advantage in sexual reproduction?

Answer 5

Increases the chance that some individuals will survive environmental changes.

Question 6

Why is asexual reproduction beneficial in stable conditions?

Answer 6

It allows rapid reproduction without needing a mate.

Question 7

What is meiosis?

Answer 7

A type of cell division that produces four non-identical gametes with half the chromosome number.

Question 8

How many chromosomes do human gametes have?

Answer 8

23 chromosomes

Question 9

How does meiosis create genetic variation?

Answer 9

Random shuffling of chromosomes during division.

Question 10

What is DNA?

Answer 10

A polymer made of two strands in a double helix that contains genetic instructions.

Question 11

What is a genome?

Answer 11

The entire set of genetic material in an organism.

Question 12

How has studying the human genome helped medicine?

Answer 12

Identifying disease-related genes, developing treatments, tracing human migration.

Question 13

What are the four bases in DNA?

Answer 13

A (adenine), T (thymine), C (cytosine), G (guanine)

Question 14

What is complementary base pairing?

Answer 14

A pairs with T, C pairs with G

Question 15

What is a gene?

Answer 15

A section of DNA that codes for a specific protein.

Question 16

How many amino acids are there?

Answer 16

20 different amino acids

Question 17

Where does protein synthesis occur?

Answer 17

In the ribosomes.

Question 18

What is the role of mRNA?

Answer 18

mRNA carries the genetic code from DNA in the nucleus to the ribosomes.

Question 19

What happens if there is a mutation in DNA?

Answer 19

It changes the protein, which may affect how it functions.

Question 20

What are alleles?

Answer 20

Different forms of the same gene.

Question 21

What is a dominant allele?

Answer 21

An allele that is always expressed, even if only one copy is present.

Question 22

What is a recessive allele?

Answer 22

An allele that is only expressed when two copies are present.

Question 23

What does homozygous mean?

Answer 23

Having two identical alleles for a gene (AA or aa).

Question 24

What does heterozygous mean?

Answer 24

Having two different alleles for a gene (Aa).

Question 25

What is the genotype?

Answer 25

The combination of alleles an individual has.

Question 26

What is the phenotype?

Answer 26

The physical characteristics expressed by the genotype.

Question 27

What is polydactyly?

Answer 27

A dominant disorder causing extra fingers or toes.

Question 28

What is cystic fibrosis?

Answer 28

A recessive disorder that affects cell membranes and causes thick mucus.

Question 29

How can genetic disorders be detected before birth?

Answer 29

Embryonic screening

Question 30

Why is embryonic screening controversial?

Answer 30

Ethical concerns about designer babies and selecting against certain traits.

Question 31

What are the sex chromosomes in males and females?

Answer 31

Females = XX, Males = XY

Question 32

What is the probability of having a male or female child?

Answer 32

50% chance of being male or female.

Question 33

What are the two causes of variation?

Answer 33

Genetics and environment

Question 34

Give an example of environmental variation.

Answer 34

A scar or plant growth affected by sunlight.

Question 35

What is a mutation?

Answer 35

A random change in DNA that may result in a new characteristic.

Question 36

What is evolution?

Answer 36

A gradual change in inherited traits over generations due to natural selection.

Question 37

Who proposed the theory of evolution by natural selection?

Answer 37

Charles Darwin

Question 38

What is natural selection?

Answer 38

Survival of the fittest – organisms with advantageous traits are more likely to survive and reproduce.

Question 39

What is speciation?

Answer 39

The formation of a new species when populations become so different they cannot interbreed.

Question 40

Who developed the idea of speciation?

Answer 40

Alfred Russel Wallace

Question 41

What is selective breeding?

Answer 41

Humans breeding organisms for desired characteristics.

Question 42

Give two examples of selective breeding.

Answer 42

Cows for more milk, plants for disease resistance.

Question 43

What is a risk of selective breeding?

Answer 43

Inbreeding, leading to a smaller gene pool and increased risk of genetic disorders.

Question 44

What is genetic engineering?

Answer 44

Modifying the genome by inserting genes from another organism.

Question 45

Give an example of a genetically engineered organism.

Answer 45

GM crops resistant to pests or bacteria producing insulin.

Question 46

Why is genetic engineering controversial?

Answer 46

Unknown long-term effects and ethical concerns about modifying life.

Question 47

Give two methods of cloning in plants.

Answer 47

Tissue culture, cuttings.

Question 48

Give two methods of cloning in animals.

Answer 48

Embryo transplants, adult cell cloning.

Question 49

What are risks of cloning?

Answer 49

Reduced genetic diversity, high failure rate, potential health problems.

Question 50

What are fossils?

Answer 50

The remains of ancient organisms preserved in rocks.

Question 51

Why do some organisms not leave fossils?

Answer 51

They were soft-bodied and decayed completely.

Question 52

Give two causes of extinction.

Answer 52

New predators, climate change, habitat destruction, competition.

Question 53

Why do bacteria evolve quickly?

Answer 53

Fast reproduction and high mutation rates.

Question 54

Give an example of antibiotic-resistant bacteria.

Answer 54

MRSA (superbug)

Question 55

How can we slow antibiotic resistance?

Answer 55

Complete antibiotic courses, reduce overuse, develop new drugs.