Mitosis and Meiosis

Question 1

Fission

Answer 1

An animal produces a “copy” of
itself without embryonic development

Question 2

Parthenogenesis

Answer 2

An unfertilized egg develops into an embryo

Question 3

Sexual reproduction

Answer 3

Male and female gametes form an embryo

Question 4

Fission

Answer 4

An animal clones of itself without embryonic development

Question 5

What are advantages of fission

Answer 5

Avoid costs associated with both finding a mate and mating itself
= Risks of predation, aggression from conspecifics, energy costs

Question 6

Disadvantages of fission

Answer 6

Lack of genetic diversity puts the whole population at risk w/natural selection

Question 7

Advantages of Parthenogenesis

Answer 7

-Avoid costs associated with finding a compatible mate: search costs in low density of another sex
-Could introduce new chromosome structure with homologous recomb.
-Some forms can introduce the opposite sex within the population (WZ)

Question 8

Disadvantages of Parthenogenesis

Answer 8

Still does not increase diversity from parent

Question 9

What are gametes

Answer 9

female eggs (ova) and male sperm

Question 10

All cells have a pair of each what

Answer 10

Chromosome type (one from each parent), except for gametes which have one of each chromosome type

Question 11

Advantages of sexual reproduction

Answer 11

-Genetic diversity allows beneficial mutations to
come together in the same individual, enhancing adaptation
-Genetic diversity reduces occurrences of harmful mutations and increases occurrences of resistance to pathogens and parasites

Question 12

Disadvantages of sexual reproduction

Answer 12

Costs associated with finding a mate and mating:
risks of predation, aggression from conspecifics,
energy costs

Question 13

Mitosis undergoes 1 round of separation to generate 2 diploid (2N) daughter cells, in what organisms does this take place and what type of cells

Answer 13

in multicellular organisms = somatic cells

Question 14

How many rounds of separation does meiosis undergo and what does it generate

Answer 14

2 rounds of separation, generates 4 haploid cells called gametes

Question 15

In meiosis I, homologous chromosomes align, recombine, and separate from each other, how is this different than mitosis?

Answer 15

All chromosomes align independently in mitosis

Question 16

In meiosis II, sister chromatids are then separated from each other, how is this different than mitosis

Answer 16

Mitosis is 1N

Question 17

The physical structure of homologous chromosomes being linked by cohesins =

Answer 17

the synaptonemal complex

Question 18

Chiasma can form along any region of homology, what is this called?

Answer 18

Homologous recombination

Question 19

Each chiasma represents what

Answer 19

Individual crossovers

Question 20

Recombination may occur multiple times between two homologs, usually how many times?

Answer 20

2-3 times per pair

Question 21

What does mendels law of segregation say?

Answer 21

Each parental gamete
contributes 1 and only 1 allele for
a particular gene to its offspring

Question 22

During gamete formation, what do maternal and paternal alleles do?

Answer 22

Seperate from one another

Question 23

What does mendels law of independent assortment say

Answer 23

During gamete formation, alleles for different traits segregate independently of one another (they’re on different homologous chromosomes)

Question 24

Does meiosis support mendels law of idependent assortment?

Answer 24

Meiosis supports this “law” because maternal and paternal chromosomes are not inherited together

Question 25

When is mendels law of independent assortment best observed?

Answer 25

when assessing different alleles of unrelated genes IF these genes are not IMMEDIATELY next to each other
* Also easier to see if they don’t involve multiple alleles and have simple either/or sets of phenotypes

Question 26

What does meiosis generate and how?

Answer 26

Genetic diversity with independent assortment and homologous recombination

Question 27

Offspring produced by sexual reproduction therefore substantially increase the genetic diversity of the population and minimizes threats to the population due to the process of what?

Answer 27

Natural selection

Question 28

What holds sister chromatids together during DNA replication

Answer 28

Cohesin proteins

Question 29

What type of protein degrade cohesion and allow the chromatids to separate once all chromatids are attached to microtubules

Answer 29

Separase proteins

Question 30

Microtubules attach to a protein complex called what

Answer 30

A kinetochore

Question 31

Kinetochore microtubule depolymerization leads to chromatids aligning in the center of the cell during what phase

Answer 31

metaphase

Question 32

What happens in cytokinesis?

Answer 32

-Polar microtubules push ends of the cell away from each other
- Actin and myosin filaments constrict around the center of the cell (a contractile ring)
- A cleavage furrow forms & ring splits the cell
-Plant cells use Golgi-derived vesicles to instead form a phragmoplast, creating a cell wall/plate
-Mitochondria and chloroplasts in high numbers and separate randomly
-ER is split; each half goes to one daughter cell
-Golgi is fragmented and pulled to each pole; Golgi fragments reform the Golgi in new cells
-Other organelles are inherited randomly

Question 33

What happens during interphase

Answer 33

-G1 – the cell prepares for DNA synthesis
* S – DNA synthesis occurs
* G2 – the cell prepares for cell division
* A cell that is not in the cell cycle is said to be in G0

Question 34

M – nuclear and cell division occurs during what

Answer 34

Mitosis

Question 35

If chromosomes are not properly attached to spindles, what happens?

Answer 35

APC/C is inhibited and will not activate cyclins needed to complete M

Question 36

If DNA replication is incomplete or there is DNA damage, what happens? Cdc25 will not activate Cdks for entering M

Question 37

If DNA damage is prolonged, p53 ubiquitylation by MDM2 is insufficient, p53 transcribes p21, p21 blocks CDKs, and p53 may trigger what?

Answer 37

apoptosis