Chapter 9 Meiosis

Question 0

sex cells also referred to as

Answer 0

germ cells
half cells (haploids)
2 haploids = diploid

Question 1

Meiosis

Answer 1

Cell division in sexual reproductive cells

• process of Halving the chromosomes
• Also known as germ cells= “early cells”

Question 2

sexual life cycle in animals

Answer 2

1. Male and female are diploids (2n)
2. Mom dad give their egg (mom) and sperm (dad) are haploid with 1/2 the chromosomes of “regular” somatic cells
3. Egg and sperm fertilization to create a Zygote (diploid) 2n
4. Mitosis occurs for zygote to create a human adult

Question 3

gamete cells and chiasma (crossing over)

Answer 3

occurs in prophase I
2 non sister chromotids of homologous chromosomes (diploids) cross over genetic info to make a Hybrid
Adds diversity

Question 4

differences between Mitosis vs Meiosis

Answer 4

Mitosis= to repair, regrow, regenerate new cells
- only a diploid cell can repair DNA damage

Meiosis= to halve chromosomes so there is not too much DNA in organism
must have 46 chromosomes (23 pairs) 23 haploids
too much or too little DNA will cause abnormalities like Down syndrome or cancer

Question 5

Asexual reproduction = not sexual

Answer 5

• Prokaryotes only divide through mitosis binary fission not meiosis
• protists are simple eukar. ex algae no sex reproduction unless stressed
• fungi and non flowering plants us Asexual reproduction

Question 6

synapsis

Answer 6

occurs only in meiosis

- during prophase I: homologous chromos. join together to create tetrads (group of 4 chromotids)

Question 7

Phases of Meiosis

Answer 7

Interphase
Meiosis I =                  Meiosis II
Prophase I                  Prophase II
Metaphase I               Metaphase II
Anaphase I                 Anaphase II
Telophase I                 Telophase II
                                    Cytokinesis

Question 8

Interphase

Answer 8

DNA replicates

Question 9

Prophase I

Answer 9

1. nuclear envelope disintegrates
2. centrioles move to opposite poles
3. spindle fibers form
4. DNA chromosomes condense from chromatin form
5. Crossing over (chiasma) of genetic info

Question 10

metaphase I

Answer 10

1. tetrads line up along cell equator

2. spindle fibers attach to centromeres

Question 11

anaphase I

Answer 11

1. centromeres break apart and homologous chromosomes separate (sister chromotids are still attached)
2. cytokinesis begins

Question 12

telophase I

Answer 12

1. chromosomes decondense back into chromatin form

2. 2 nuclear envelopes form around each haploid daughter cells

Question 13

Prophase II

Answer 13

1. centrioles form toward poles on opposite ends of cell
2. nuc. env dissolves
3. spindle fibers form
4. dna condensed to chromosomes

Question 14

metaphase II

Answer 14

1. sister chromotids line up along cell equator

2. spindle fibers attach to centromeres

Question 15

anaphase II

Answer 15

1. centromeres break and sister chromotids seperate
2. chromotids move to centrioles at end of poles
3. cytokinesis begins

Question 16

telophase II

Answer 16

1. chromosomes decondense to chromatin form
2. 4 nuclear envelopes form around each (4) haploid daughter cells
3. cytokinesis complete