Mutations & Meiosis

Question 1

Mutations

Answer 1

Changes in DNA sequence

Question 2

Additon mutations

Answer 2

Where one or more bases are added to the DNA sequence.

E.g. ATCGTT → ATCCGTT

Question 3

Deletion mutations

Answer 3

Where one or more bases are removed from the DNA sequence.

E.g. ATCGTT → ATCTT

Question 4

Substitution mutations

Answer 4

Where one or more bases are changed in the DNA sequence.

Question 5

Mutation agents

Answer 5

ncrease the rate at which mutations occur.

Question 6

Mutagenic agents include:

Answer 6

Chemicals (e.g. bromine and benzene).

Exposure to ionising radiation and ultraviolet radiation.

Question 7

Non-Disjunction Mutations

Answer 7

mutations in the number of chromosomes in the cells.

Question 8

Meiosis

Answer 8

A type of cell division that produces four genetically different daughter cells (gametes) with a haploid number of chromosomes. It involves two divisions.

Question 9

Haploid

Answer 9

Have half the number of chromosomes as diploid cells).

Question 10

Diploid

Answer 10

An organism with two copies of every chromosome

Question 11

What is the term to describe an organism that has two copies of every chromosome?

Answer 11

A diploid organism

Question 12

Steps of meisosis include:

Answer 12

1. Chromosomes replicate to produce sister chromatids
2. Chromosomes condense to form a double-armed chromosome
3. Chromosomes are arranged in the center of the cell
4. Chromosomes in a homologous pair are separated
5. The cell divides and one chromosome from each pair is in each daughter cell
6. The sister chromatids are separated

Question 13

Homologous pairs

Answer 13

chromosomes with identical genes but different alleles

Question 14

What does meisosis II produce?

Answer 14

Four genetically different haploid cells

Question 15

What is the process of separating chromosomes into random combinations?

Answer 15

Independent segregation

Question 16

Explain how the orientation of homologous chromosomes during metaphase I of meiosis contributes to greater variation in gametes.

Answer 16

The random alignment of homologous chromosomes at the metaphase plate ensures the random destination of the chromosomes in the daughter cells

Question 17

Which three processes lead to variation among offspring that have the same two parents?

Answer 17

Fertilization, crossing over, random chromosome assortment

Question 18

Reproductive cells in most species are different from the cells that make up the rest of the organism.

What are the “body” cells called and how are they different from the reproductive cells?

Answer 18

Somatic cells and have double the number of chromosomes found in reproductive cells

Question 19

In prophase I, the homologous chromosomes are paired up and linked together. What binds the chromosomes together and maintains their alignment?

Answer 19

Tertrads

Question 20

What causes mutations?

Answer 20

Additon of bases
Deletion of bases
Subsitiution of bases

Question 21

What type of substances can increase the rate at which mutations occur?

Answer 21

Mutagenic agents

Question 22

How many chromosomes are found in cells produced during human meiosis?

Answer 22

23

Question 23

What is the percentage difference in the amino acid sequence between mammals and insects?

Answer 23

33%

Question 24

What statistical measures should be used to ensure accurate results when investigating variation?

Answer 24

Standard devation
Calculating the mean
Random sampling

Question 25

What statistical measure shows how far away the measured values are from the mean average?

Answer 25

The standard devation

Question 26

When does crossing over occur?

Answer 26

Prophase I