Mitosis & Meiosis (Review)

Question 1

Define genes

Answer 1

Units of hereditary information in the form of a linear sequence of DNA nucleotides

Question 2

Define chromosomes

Answer 2

A structure that consists of one very long DNA molecule and associated proteins

Question 3

Define DNA

Answer 3

A nucleic acid molecule composed of hundreds to thousands of nucleotides in the form of a double-stranded helix

Question 4

What is the relationship between genes, chromosomes, and DNA?

Answer 4

A gene is a linear sequence of DNA nucleotides

DNA molecules are packaged into chromosomes

Question 5

T or F: eukaryotic chromosomes can contain 100s-1000s of genes?

Answer 5

True

Question 6

Describe prokaryotic chromosomes

Answer 6

Prokaryotes have a single, circular chromosome

Question 7

Define genome

Answer 7

one complete set of chromosomes

Question 8

How many chromosomes are in the human genome?

Answer 8

2 copies of 23 chromosomes

n=23

Question 9

How many chromosomes are in the fruit fly (Drosophila melanogaster) genome?

Answer 9

2 copies of 4 chromosomes

n=4

Question 10

T or F: typically DNA is condensed

Answer 10

False. Typically DNA is not condensed

DNA condenses before cell division

Question 11

When can DNA be seen in a microscope? When it is condensed or uncondensed?

Answer 11

Condensed

Question 12

Define diploid cells

Answer 12

2 copies of every chromosome

Question 13

Define haploid cells

Answer 13

1 copy of every chromosome

Question 14

Define homologous chromosomes/homologues

Answer 14

a pair of chromosomes that have the same length, centromere, and genes (though they might have different alleles for those genes)

Question 15

Where does each of the chromosome originate from in a homologous pair?

Answer 15

1 from mother

1 from father

Question 16

Define sister chromatids

Answer 16

identical copies of chromosomes

Question 17

Describe mitosis

Answer 17

Cell division that occurs in the body/somatic cells to create identical copies of the parent cell

Question 18

What are the 3 functions of mitosis?

Answer 18

asexual reproduction

growth in multicellular organisms

cell replacement in multicellular organisms

Question 19

Can mitosis occur in a) haploid cells, b) diploid cells, or c) both

Answer 19

Both

Question 20

Describe meiosis

Answer 20

Cell division that occurs in the sex cells (gametes) to produce genetically unique cells

Question 21

What are the functions of meiosis?

Answer 21

sexual reproduction

increase genetic diversity

reduce number of chromosomes by half

Question 22

What are the four phases of mitosis?

Answer 22

Prophase
Metaphase
Anaphase
Telophase & Cytokinesis

Question 23

What major events happen during prophase of mitosis?

Answer 23

chromosomes condense

duplicated chromosomes appear as sister chromatids joined at centromeres

spindle forms

centrosomes move apart

Question 24

What major events happen during metaphase of mitosis?

Answer 24

centrosomes at opposite spindle poles

sister chromatids line up along metaphase plate, each with an individual kinetochore microtubule that is attached to the spindle pole on its side

Question 25

What major events happen during anaphase of mitosis?

Answer 25

Sister chromatids are pulled to opposite poles by spindle fibres

Question 26

What major events happen during telophase & cytokinesis of mitosis?

Answer 26

cells cleave and 2 identical daughter cells are created

Question 27

What happens during the G1 phase of the cell cycle?

Answer 27

Gene expression and cell activity

preparation for DNA synthesis

Question 28

What happens during the S phase of the cell cycle?

Answer 28

DNA is replicated and chromosomes are duplicated

Question 29

What happens during the G2 phase of the cell cycle?

Answer 29

Prep for cell division

Question 30

What happens during the G0 phase of the cell cycle?

Answer 30

Cell differentiation is terminated and division stops

This could lead to either final specialization and no more division or cell death (apoptosis)

Question 31

What happens during the G0 phase of the cell cycle?

Answer 31

Cell differentiation is terminated and division stops

This could lead to either final specialization and no more division or cell death (apoptosis)

Question 32

What major events happen during prophase I of meiosis?

Answer 32

sister chromatid pairs form homologous pairs

centrosomes and spindles form

Question 33

What major events happen during metaphase I of meiosis?

Answer 33

Homologous pairs of sister chromatids align along metaphase plate with a homologous pair facing either pole and spindle fibres attach to each homologue

Question 34

What major events happen during anaphase I of meiosis?

Answer 34

Homologous pairs are pulled to opposite poles by spindle fibres

Question 35

What major events happen during telophase I and cytokinesis of meiosis?

Answer 35

cytoplasm is divided as the cell cleaves creating two genetically unique cells with sister chromatids

Question 36

What is the difference between meiosis I and meiosis II?

Answer 36

Meiosis II follows meiosis I and will divide the sister chromatids apart.

Difference is that meiosis I separates homologous pairs and meiosis II separates sister chromatids

Question 37

What are the major differences between mitosis and meiosis?

Answer 37

1. Meiosis only occurs in diploid germ-line cells (gametes), whereas mitosis occurs in diploid or haploid somatic cells
2. Meiosis includes 2 cell divisions, whereas mitosis only includes 1 cell division
3. Mitosis produces 2 genetically identical cells that are also genetically identical to the parent cell
4. Meiosis produces 4 genetically unique daughter cells that have half the number of chromosomes (haploid)
5. Mitosis is involved in asexual reproduction, cell replacement, and growth of multicellular organisms. Whereas meiosis functions in sexual reproduction to create genetic diversity by halving the number of chromosomes in each daughter cell.