Lecture 2: Mitosis and Meiosis

Question 1

What is evolution

Answer 1

A change in genetic frequency in a population over time

Question 2

Prokaryotic cell characteristics

Answer 2

No nucleus
Unicellular
One circular DNA molecule (usually)
Small amount of DNA
No membrane bound organelles

Question 3

Eukaryotic cell characteristics

Answer 3

Nucleus present
Larger (Unicellular or multicellular)
Multiple linear DNA molecules w/histones
Large amount of DNA
Membrane bound organelles present

Question 4

Virus

Answer 4

Neither prokaryotic or eukaryotic

Outer protein coat surrounding nucleic acids

Question 5

Homologous chromosomes

Answer 5

Similar but not identical

Each homolog carries same genes, but the alleles for each trait may not be the same

Question 6

Diploid cells vs haploid cells

Answer 6

Two sets of genetic information vs one set

Diploids have two sets of chromosomes organized in homologous pairs

Question 7

Centromere

Answer 7

Attachment point on chromosome for spindle microtubules

Question 8

Submetacentric centromere

Answer 8

Centromere situated so that one set of arms is shorter than the other

Question 9

Metacentric centromere

Answer 9

Centromere in the middle

Question 10

Telocentric centromere

Answer 10

Centromere at the end with no short arm visible

Question 11

Acrocentric centromere

Answer 11

Centromere near the end producing a very short arm

Question 12

What happens in G1

Answer 12

Cell grows, proteins necessary for cell division produced

Question 13

What happens in G0

Answer 13

Non-dividing phase before G1/S checkpoint (cell may or may not have this)

Question 14

What happens after G1/S checkpoint

Answer 14

Cell is committed to dividing

Question 15

What happens in G2

Answer 15

Cell prepares for mitosis

Question 16

G2/M checkpoint and after?

Answer 16

Only passed if DNA is completely replicated and undamaged.

Cell can then divide

Question 17

Prophase

Answer 17

Chromosomes condense
Each chromosome has two sister chromatids
Mitotic spindle forms

Question 18

Prometaphase

Answer 18

Nuclear membrane disintegrates

Spindle microtubules attach to chromosomes

Question 19

Metaphase

Answer 19

Chromosomes line up on metaphase plate

Question 20

Anaphase

Answer 20

Sister chromatids separate and move toward opposite poles

Question 21

Telophase

Answer 21

Chromosomes arrive at spindle poles and nuclear membranes reform
Chromosomes decondense

Question 22

Meiosis is

Answer 22

The production of haploid gametes

Question 23

Fertilization

Answer 23

Fusion of haploid gametes

Question 24

A consequence of meiosis is

Answer 24

Genetic variation

Question 25

Tetrad

Answer 25

Closely associated four sister chromatids of two homologous chromosomes

Question 26

What is the first mechanism that produces genetic variation in newly formed gametes

Answer 26

Crossing over

Question 27

What is the second mechanism of generating genetic variation in newly formed gametes

Answer 27

Random distribution of chromosomes into newly divided cells during anaphase I

Question 28

Chiasmata is formed

Answer 28

During late prophase I, which means crossing over occurs during late prophase I

Question 29

Prophase II

Answer 29

Chromosomes recondense

Question 30

Metaphase II

Answer 30

Individual chromosomes line up on metaphase plate

Question 31

Anaphase II

Answer 31

Sister chromatids separate

Question 32

T or F: Prophase II occurs in all cells

Answer 32

False. It only occurs in cells in which the spindle has broken down, chromosomes relaxed and nuclear envelope reformed

Question 33

Negative result of crossing over

Answer 33

Unequal exchange of genetic material producing chromosomes with deleted or duplicated regions

Question 34

Positives of crossing over

Answer 34

Essential for normal segregation of chromosomes | Adds additional genetic variation

Question 35

Consequences of meiosis (cells produced, chromosome number, variance, epigenetics)

Answer 35

Four cells produced from each original cell Chromosome number in each new cell is half (haploid) Newly formed cells are genetically different from one another and from parent cell Epigenetic modifications are erased and parent specific modifications are added

Question 36

Sporophyte and gametophyte

Answer 36

Sporophyte is 2n, undergoes meiosis and becomes a 1n gametophyte (spore)