Topic 9 Meiosis

Question 1

Meiosis

Answer 1

A special type of cell division that can produce sperm and egg cells (gametes)
* Produces non-identical daughter cells

Question 2

Heredity

Answer 2

is the transmission of traits from one
generation to the next

Question 3

Variation

Answer 3

is demonstrated by the differences in appearance that offspring show from parents and siblings

Question 4

Genetics

Answer 4

is the scientific study of heredity and variation

Question 5

genes

Answer 5

are the units of heredity and are made up of segments of DNA

Question 6

Locus (plural, loci)

Answer 6

• a genes specific position along a chromosome

Question 7

somatic cells

Answer 7

23 pairs, 46 total
Non-reproductive cells
* Two sets of chromosomes
* Diploid

Question 8

karyotype

Answer 8

ordered display of the pairs of chromosomes from a cell

Question 9

asexual reproduction:

Answer 9

single, individual passes all of its genes to its offspring without the fusion of gametes

Question 10

clone

Answer 10

genetically identical to parent cell

Question 11

sexual reproduction

Answer 11

two parents give rise to offspring that have unique combo of genes inherited from two parents

Question 12

gametes

Answer 12

• reproductive cells, sperm and egg
• haploid
• egg sex chromosome is x
• sperm can be either x or y

Question 13

sex chromosomes

Answer 13

called x and y
rest are called autosomes

Question 14

Aneuploidy

Answer 14

abnormal amount of chromosomes

Question 15

Sets of Chromosomes in a Cell

Answer 15

Thetwochromosomesineachpairarecalled homologous chromosomes, or homologs

Question 15

homologous chromosomes

Answer 15

same length and shape carry similar genes
- each pair contains one chromosome from eahc parent

Question 16

diploid cell

Answer 16

two sets of chromosomes
- 2n= 46

Question 16

A life cycle

Answer 16

the generation to generation sequence of stages in reproductive history of an organism

Question 17

fertilization

Answer 17

union of gametes

Question 18

fertalized egg

Answer 18

called zygote
- has one set of chromosomes from each parent cell
- produces somatic cells by mitosis and develops into an adult

Question 19

Behavior of Chromosome Sets in the Human Life Cycle

Answer 19

• at sexual maturity, ovaries and testes produce haploid gametes through meiosis
• gametes are only haploid in animal cells
• only diploid cells can undergo meiosis

Question 20

meiosis cell divisions

Answer 20

meiosis I and II
- the two divisions result in four daughter cells rather than 2
- each daughter cell has onlky half as many chromosomes as parent cell

Question 21

Events unique to meiosis, occurring in meiosis I

Answer 21

Synapsis and crossing over in prophase I:
- homologous physically connect and exhange genes
- create chiasmata

homologous pairs at the metaphase plate

separateion of homologs during anaphase 1

telophase 1 creates two haploid cells, each chromosomes still consists of two sister chromatids

Question 22

mitosis II

Answer 22

• very similar to mitosis
• sister chromotids will separate
• 4 haploid daughter cells

Question 23

Results of Meiosis

Answer 23

• Chromosomes duplicate before meiosis
• Pairs of homologs and crossover at chiasma allows for genetic recombination
• The chromatids are sorted into four haploid daughter cells

Question 24

Comparing mitosis and meiosis

Answer 24

• Mitosis:
• Conserves the number of chromosome sets
• Produces cells that are genetically identical to the parent cell
• Meiosis:
• Reduces the number of chromosomes sets from two (diploid) to one (haploid) * Produces cells that differ genetically from each other and from the parent cell
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