Biology - Topic 3 - Genetics L3

Question 1

What is DNA made of?

Answer 1

DNA is a polymer made of two strands coiled into a double helix.

Question 2

What holds the strands of DNA together?

Answer 2

Complementary base pairs (A-T and C-G) joined by weak hydrogen bonds.

Question 3

What are the components of a nucleotide?

Answer 3

A sugar, a phosphate group, and a base (A, T, C, or G).

Question 4

Which bases pair together in DNA?

Answer 4

A pairs with T, C pairs with G.

Question 5

Where are chromosomes found?

Answer 5

In the nucleus of cells.

Question 6

What are chromosomes made of?

Answer 6

Chromosomes are made of DNA.

Question 7

What is the purpose of meiosis?

Answer 7

To produce gametes (sex cells).

Question 8

What are gametes?

Answer 8

Sex cells: sperm and egg in animals, pollen and egg in plants.

Question 9

How many daughter cells are produced in meiosis?

Answer 9

4 haploid daughter cells.

Question 10

How does meiosis differ from mitosis?

Answer 10

Meiosis results in 4 non-identical haploid cells, mitosis makes 2 identical diploid cells.

Question 11

What happens to the number of chromosomes during meiosis?

Answer 11

The number is halved.

Question 12

Why are gametes genetically different?

Answer 12

Each receives a random set of chromosomes, introducing variation.

Question 13

What is fertilisation?

Answer 13

The fusion of two gametes (egg and sperm).

Question 14

What is formed after fertilisation?

Answer 14

A zygote.

Question 15

How many chromosomes are in human gametes?

Answer 15

23 chromosomes.

Question 16

How many chromosomes does a human zygote have?

Answer 16

46 chromosomes (23 from each parent).

Question 17

Why is fertilisation important for variation?

Answer 17

It mixes genetic material from two parents.

Question 18

What is asexual reproduction?

Answer 18

Reproduction involving one parent with no gametes joining; produces clones.

Question 19

What process is used in asexual reproduction?

Answer 19

Mitosis.

Question 20

What is an example of a plant that reproduces asexually?

Answer 20

The spider plant.

Question 21

What is sexual reproduction?

Answer 21

Reproduction involving the fusion of male and female gametes.

Question 22

What are advantages of asexual reproduction?

Answer 22

No need to find a mate, fast reproduction, energy efficient.

Question 23

What are disadvantages of asexual reproduction?

Answer 23

No variation, population vulnerable to environmental changes.

Question 24

What are advantages of sexual reproduction?

Answer 24

Variation, selective breeding, adaptability.

Question 25

What are disadvantages of sexual reproduction?

Answer 25

Slower, requires more energy, must find a mate.

Question 26

How many chromosomes does a normal body cell have?

Answer 26

46 chromosomes (23 pairs).

Question 27

How many chromosomes does a gamete have?

Answer 27

23 chromosomes.

Question 28

What are diploid cells?

Answer 28

Cells with two sets of chromosomes (46 total).

Question 29

What are haploid cells?

Answer 29

Cells with one set of chromosomes (23 total).

Question 30

What are the gametes in animals?

Answer 30

Sperm (male) and egg (female) cells.

Question 31

What is the genome?

Answer 31

The entire DNA of an organism.

Question 32

What is a gene?

Answer 32

A section of DNA that codes for a specific protein.

Question 33

What was the Human Genome Project?

Answer 33

A project to sequence all the genes in the human genome.

Question 34

What does a gene code for?

Answer 34

A sequence of amino acids (which forms a protein).

Question 35

How do genes influence the body?

Answer 35

They control our characteristics through proteins.

Question 36

How does the Human Genome Project help in medicine?

Answer 36

Helps identify useful genes, understand diseases, and develop treatments.

Question 37

How does genome sequencing help evolution research?

Answer 37

Helps track how species are related and evolved.

Question 38

How does genome research help agriculture?

Answer 38

Allows selective breeding of organisms with desirable traits.

Question 39

What is the first step to extract DNA from fruit?

Answer 39

Crush fruit in a buffer solution.

Question 40

What does detergent do in DNA extraction?

Answer 40

Dissolves the cell membrane.

Question 41

What does protease enzyme do in DNA extraction?

Answer 41

Breaks down proteins in the membrane, releasing DNA.

Question 42

Why is the mixture heated during DNA extraction?

Answer 42

To break down cell structures and help release DNA.

Question 43

Why is ethanol added during DNA extraction?

Answer 43

Because DNA is insoluble in ethanol and forms white strands.

Question 44

What are the two stages of protein synthesis?

Answer 44

Transcription and translation.

Question 45

Where does transcription take place?

Answer 45

In the nucleus.

Question 46

What happens during transcription?

Answer 46

mRNA is made from the DNA code.

Question 47

What base replaces thymine in RNA?

Answer 47

Uracil (U).

Question 48

Where does translation take place?

Answer 48

In the cytoplasm.

Question 49

What happens during translation?

Answer 49

mRNA is read by the ribosome, and amino acids are assembled into a protein.

Question 50

What is a codon?

Answer 50

A triplet of bases on mRNA that codes for one amino acid.

Question 51

What joins amino acids together?

Answer 51

A peptide bond.

Question 52

What happens after a polypeptide chain is made?

Answer 52

It folds into a specific 3D shape to form a protein.

Question 53

How is the order of amino acids determined?

Answer 53

By the sequence of DNA bases.

Question 54

How many bases code for one amino acid?

Answer 54

Three bases (a codon).

Question 55

Why is the protein's shape important?

Answer 55

It determines the protein's function.

Question 56

What is a polypeptide?

Answer 56

A chain of amino acids linked by peptide bonds.