Practical 3 - Cell Divisoon

Question 1

What are sister chromatids?

Answer 1

Sister chromatids are two copies of DNA that exist after replication, joined at the centromere.

They are essential for proper chromosome segregation during cell division.

Question 2

What is the centromere?

Answer 2

The centromere is the point where sister chromatids are joined.

It plays a critical role in chromosome movement during cell division.

Question 3

What is the purpose of mitosis?

Answer 3

Mitosis is used by eukaryotes for growth, repair of tissues, and other purposes, resulting in genetically identical parent and daughter cells.

Mitosis ensures that genetic information is accurately copied and distributed.

Question 4

What occurs during prophase?

Answer 4

Chromosomes become visible due to condensation, and mitotic spindles form.

This is the first stage of mitosis.

Question 5

What happens during prometaphase?

Answer 5

The nuclear envelope disassembles, and spindle fiber microtubules attach to chromosomes at kinetochores.

Some textbooks refer to this stage as late prophase.

Question 6

What are the arms of a chromosome?

Answer 6

The regions extending past the centromere.

Chromosomes have a short arm and a long arm.

Question 7

What is the metaphase stage in cell division?

Answer 7

Chromosomes are rearranged to occupy a position in the middle of the cell along the metaphase plate

This arrangement is facilitated by spindle fiber microtubules.

Question 8

What occurs during anaphase?

Answer 8

Sister chromatids segregate towards opposite ends of the cell due to the release of adherent proteins and shortening of spindle fibers

This marks the separation of the chromatids.

Question 9

What happens in telophase?

Answer 9

New nuclear membranes form around each group of chromosomes

This stage is crucial for re-establishing the nuclei in daughter cells.

Question 10

Where does cell division actually complete?

Answer 10

Outside of mitosis during cytokinesis

Cytokinesis is the final step of cell division.

Question 11

What is cytokinesis?

Answer 11

The actual division of the cytoplasm occurs

It follows mitosis and leads to the formation of two daughter cells.

Question 12

How does cytokinesis differ in animal cells compared to plant cells?

Answer 12

Animal cells use a contractile ring; plant cells form a cell plate from vesicles

This difference is due to the presence of a cell wall in plant cells.

Question 13

What structure is used for cytokinesis in animal cells?

Answer 13

Contractile ring

This band of actin pinches the membrane to separate the daughter cells.

Question 14

What forms the cell plate during plant cytokinesis?

Answer 14

Vesicles containing cell wall materials and phospholipids

The cell plate eventually develops into a new cell wall between daughter cells.

Question 15

What is sexual reproduction in eukaryotes?

Answer 15

A way to generate genetic diversity through the combination of male and female gametes

This process involves fertilization, leading to the formation of a zygote.

Question 16

What specialized type of cell division produces gametes?

Answer 16

Meiosis

This process reduces the chromosome number by half for gamete formation.

Question 17

What are homologous chromosomes?

Answer 17

Chromosomes that have the same shape and contain the same genes

Homologous chromosomes come in pairs, one from each parent.

Question 18

What does ploidy refer to?

Answer 18

The number of complete copies of each chromosome molecule present in a cell

Ploidy does not account for absolute gene copy number.

Question 19

What is the notation for a diploid cell?

Answer 19

2n

n represents the number of separate homologous chromosome molecules.

Question 20

What is the notation for a haploid cell?

Answer 20

n

A haploid cell contains one of each unique homologous chromosome.

Question 21

If a cell is described as 2n = 6, what does this indicate?

Answer 21

There are two copies of each unique chromosome with a total of six chromosomes

The notation shows ploidy and chromosome number.

Question 22

Fill in the blank: If a cell has two copies of each unique homologous chromosome, it is termed _______.

Answer 22

diploid

Question 23

Fill in the blank: A cell with only one of each unique homologous chromosome is called _______.

Answer 23

haploid

Question 24

What is meiosis?

Answer 24

A type of cell division required for sexual reproduction that produces cells with the same ploidy as the parent cells

Meiosis allows for the combination of DNA from two different organisms.

Question 25

How many rounds of cell division occur in meiosis?

Answer 25

Two rounds called Meiosis I and Meiosis II ## Footnote This is in contrast to mitosis, which has only one round.

Question 26

How many daughter cells are produced by meiosis?

Answer 26

Four daughter cells ## Footnote Mitosis produces two daughter cells.

Question 27

What process occurs during meiosis I that contributes to genetic uniqueness?

Answer 27

Synapsis ## Footnote During synapsis, homologous chromosomes pair and can exchange genetic material.

Question 28

What is recombination in the context of meiosis?

Answer 28

The exchange of chromosome parts between homologous chromosomes ## Footnote This results in recombinant chromosomes that are a mix of parental genes.

Question 29

When do sister chromatids segregate in meiosis?

Answer 29

During Meiosis II Anaphase II ## Footnote In Meiosis I, homologous chromosomes segregate while sister chromatids remain attached.

Question 30

What is the primary function of meiosis?

Answer 30

To generate gametes for sexual reproduction ## Footnote Gametes are produced in the sex organs of eukaryotes.

Question 31

What is the ploidy of gametes produced by meiosis?

Answer 31

Half the ploidy of the parent cell ## Footnote For example, if the parent cell is 2n, the gametes will be n.

Question 32

In which types of tissues does mitosis mainly occur?

Answer 32

Somatic tissues of animals ## Footnote Examples include skin and bone tissues.

Question 33

What are the key differences between mitosis and meiosis?

Answer 33

Mitosis results in two identical daughter cells; meiosis results in four genetically unique daughter cells ## Footnote Mitosis is for growth and repair, while meiosis is for reproduction.

Question 34

Fill in the blank: During prophase I of Meiosis I, pieces of homologous chromosomes are _______.

Answer 34

traded ## Footnote This trading enhances genetic diversity in gametes.

Question 35

Chromosome

Question 36

During which phase is the cell not actively dividing?

Answer 36

Interphase ## Footnote Interphase includes the stages G1, S, and G2 where the cell prepares for division.

Question 37

What phases are included in interphase?

Answer 37

G1, S, G2 ## Footnote G1 is the first gap phase, S is the synthesis phase where DNA is replicated, and G2 is the second gap phase where the cell checks for DNA errors.

Question 38

What occurs during the S-phase?

Answer 38

DNA synthesis occurs ## Footnote The S-phase is crucial for the replication of the cell's DNA before it divides.

Question 39

What happens during the G2 phase?

Answer 39

Cell performs checks to ensure DNA has been completely replicated ## Footnote G2 phase is important for quality control of DNA before proceeding to mitosis.

Question 40

White fish cell divison

Question 41

Cell division onion root