Meiosis And Mutations

Question 1

What is meiosis?

Answer 1

Meiosis is a type of cell division that reduces the chromosome number by half, resulting in four haploid cells.

Question 2

Fill in the blank: Meiosis consists of two rounds of division called _____ and _____.

Answer 2

meiosis I and meiosis II

Question 3

What is the end product of meiosis?

Answer 3

Four genetically different haploid cells.

Question 4

Multiple Choice: During which phase does crossing over occur?

Answer 4

Prophase I

Question 5

What is the significance of crossing over in meiosis?

Answer 5

It increases genetic diversity among the offspring.

Question 6

What happens during anaphase I?

Answer 6

Homologous chromosomes are pulled apart to opposite poles of the cell.

Question 7

True or False: In meiosis II, sister chromatids are separated.

Answer 7

True

Question 8

What is the role of the spindle fibers during meiosis?

Answer 8

They help separate chromosomes during cell division by pulling them to the opposite ends of the cell by their centromere.

Question 9

Fill in the blank: The genetic variation in meiosis is primarily due to _____ and _____.

Answer 9

crossing over and independent segregation

Question 10

What is independent segregation? And how does it happen?

Answer 10

The random distribution of maternal and paternal chromosomes into gametes during meiosis.
It happens when the pairs are separated in meiosis I and it is completely random which chromosome from each pair ends up in which daughter cell.

Question 11

How many chromosomes does a human gamete contain?

Answer 11

23

Question 12

True or False: Meiosis occurs only in reproductive cells.

Answer 12

True

Question 13

Fill in the blank: The _____ phase of meiosis I is crucial for genetic diversity.

Answer 13

prophase I

Question 14

What is the term for the exchange of genetic material between homologous chromosomes?

Answer 14

Crossing over

Question 15

Which stage of meiosis involves the formation of gametes?

Answer 15

Meiosis II

Question 16

What are gametes?

Answer 16

Gametes are the reproductive cells (sperm and eggs) that are produced through meiosis.

Question 17

True or False: All organisms undergo meiosis.

Answer 17

False

Question 18

Fill in the blank: The final result of meiosis is _____ haploid cells from one diploid cell.

Answer 18

four

Question 19

What occurs during fertilisation?

Answer 19

A haploid sperm fuses with a haploid egg, forming a diploid cell.

Question 20

What is the chromosome composition of the cell formed after fertilisation?

Answer 20

Half the chromosomes are from the father and half are from the mother.

Question 21

Is fertilisation random or selective?

Answer 21

Fertilisation is random.

Question 22

What does random fertilisation produce?

Answer 22

Zygotes with different combinations of chromosomes from both parents.

Question 23

Fill in the blank: During fertilisation, a haploid sperm fuses with a haploid _______.

Answer 23

[egg]

Question 24

What happens before meiosis starts?

Answer 24

The DNA unravels and replicates so there are two copies of each chromosome called chromatids

Question 25

What is a mutagenic agent?

Answer 25

A factor that increases mutations e.g UV light, ionising radiation or toxins.

Question 26

What is a mutation?

Answer 26

A mutation is a change in the DNA sequence of an organism.

Question 27

True or False: All mutations are harmful.

Answer 27

False

Question 28

What is a point mutation?

Answer 28

A point mutation is a change in a single nucleotide in the DNA sequence.

Question 29

What is a frameshift mutation?

Answer 29

A frameshift mutation is caused by the insertion or deletion of nucleotides that shift the reading frame of the genetic code.

Question 30

What is a silent mutation?

Answer 30

A silent mutation is a change in the DNA sequence that does not affect the amino acid sequence of the protein.

Question 31

Multiple Choice: Which type of mutation results in a premature stop codon? A) Missense B) Nonsense C) Silent D) Inversion

Answer 31

B) Nonsense

Question 32

Fill in the blank: Mutations can lead to genetic _____, which is the variety of different genetic traits within a population.

Answer 32

diversity

Question 33

What is a missense mutation?

Answer 33

A mutation that results in a different amino acid.

Question 34

What is a gene mutation?

Answer 34

The change of one base in the DNA sequence that can lead to a change in the amino acid sequence of the polypeptide which can alter the function of a protein

Question 35

What is a chromosomal mutation?

Answer 35

A spontaneous change in the structure of number of whole chromosomes.

Question 36

How does a chromosomal mutation usually occur?

Answer 36

Due to a fault during meiosis when making gametes and chromosomes fail to properly separate. It can lead to polyploidy organisms.

Question 37

What is a polyploidy organism?

Answer 37

Changes in the number of whole sets of chromosomes in an organism.

Question 38

How are sister chromatids created?

Answer 38

From DNA replication

Question 39

What happens in the first division of meiosis?

Answer 39

Homologous pair of chromosomes separate with one in each daughter cell so there is a haploid number

Question 40

How is genetic variation produced in meiosis?

Answer 40

Crossing over and Independant segregation and mutations

Question 41

What is an event that occurs in division 2 but not division 1?

Answer 41

Sister chromatids separate by division of the centromere.

Question 42

Why would all cells of the body have a non disjunction mutation of chromosomes?

Answer 42

All cells are derived from a single cell by mitosis. Mitosis produces genetically identical cells.

Question 43

Explain how a gene mutation could result in a new protein

Answer 43

Change in the base sequence as a result of deletion/substitution/addition Results in a change in amino acid sequence so a change in tertiary structure of protein

Question 44

How is the chromosome number halved during meiosis?

Answer 44

In the first division of the cell, the homologous chromosomes split and one from each pair goes to each daughter cell

Question 45

Describe the process of crossing over and how it increases genetic diversity

Answer 45

The alleles in the Non-sister chromatids in homologous pairs are exchanged to produce a new combination of alleles. This happens when the chromatids twist and entangle.

Question 46

What is a haploid cell

Answer 46

Gametes have one copy of chromosomes (half normal number)

Question 47

What is a diploid cell

Answer 47

Normal body cell, contains 2 chromosomes one maternal one paternal. Full set of chromosomes