14 - Meiosis

Question 1

Heredity

Answer 1

the transmission of traits from one generation to the next

Question 2

Gametes

Answer 2

Reproductive cells, such as sperm and eggs

Question 3

Somatic cells

Answer 3

All body cells EXCEPT reproductive cells (gametes)

Question 4

Asexual reproduction

Answer 4

A single individual (like yeast or amoeba) is the sole parent and passes copies of all its genes to its offspring WITHOUT the fusion of gametes

Question 5

Sexual production

Answer 5

Two parents give rise to offspring that have unique combinations of genes inherited from the two parents

Question 6

Sex chromosomes

Answer 6

X and Y chromosomes

Question 7

Autosomes

Answer 7

chromosomes that are not involved in determining a person’s sex

Question 8

Ploidy

Answer 8

refers to the number of sets of chromosomes in a cell

Question 9

Diploid

Answer 9

any cell with two chromosomes sets (2n)

Question 10

Haploid

Answer 10

single set of chromosomes (n)

Question 11

Zygote

Answer 11

resulting fertilized egg, diploid cell

Question 12

Fertilization

Answer 12

the union of gametes, culminating in fusion of their nuclei

Question 13

Meiosis

Answer 13

special type of cell division that produces cells with half the chromosome of the parent cell. Occurs in cells of testes and ovaries in humans

Question 14

Meiosis 1

Answer 14

Homologs are separated

Question 15

Prophase 1

Answer 15

Duplicated homologous chromosomes pair up and exchange segments (2n=6)

Question 16

Metaphase 1

Answer 16

chromosomes line up by homologous pairs

Question 17

Anaphase 1

Answer 17

The two homologous chromosomes of each pair separate

Question 18

Telophase 1 and cytokinesis

Answer 18

Two haploid cells form; each chromosome still consists of two sister chromatids

Question 19

Meiosis 2

Answer 19

sister chromatids are separated

Question 20

prophase 2

Answer 20

• spindle apparatus forms
• chromosomes, each still composed of two chromatids associated at the centromere. are moved by MTs toward metaphase 2 plate

Question 21

Metaphase 2

Answer 21

• chromosomes align at metaphase plate
• due to crossover in meiosis 1, sister chromatids are not genetically identical
• kinetochores of the sister chromatids attach to MTs from opposite poles, preparing for their separation

Question 22

Anaphase 2

Answer 22

Breakdown of proteins holding sister chromatids together at centromere allows chromatids to separate and move toward opposite poles
- each chromatid has now become an individual chromosome

Question 23

Telophase 2

Answer 23

• nuclei form, chromsomes begin decondensing and cytokinesis occurs
• four daughter cells are produced, each with a haploid set of (unduplicated chromosomes)
• Four daughter cells are genetically distinct from one another and from the parent cell

Question 24

Chromosomes

Answer 24

structures that carry genetic information

Question 25

Sister chromatids

Answer 25

joined copies of the original chromosome

Question 26

Homologous chromosomes

Answer 26

(or homologs) are pairs of chromosomes that have the same genes in the same order, but they may have different versions of those genes

Question 27

Duplicated chromosomes

Answer 27

chromosomes that have been copied to prepare for cell division

Question 28

Chromatin

Answer 28

material consisting of DNA and proteins; visible in a dividing cell as individual condensed chromosomes

Question 29

Crossing over

Answer 29

is a process that happens during meiosis where homologous chromosomes exchange pieces of genetic material

Question 30

Synapsis

Answer 30

the process during meiosis where homologous chromosomes pair up tightly

Question 31

Chiasmata

Answer 31

(singular, chiasma) where crossovers have occurs

Question 32

Independent assortment

Answer 32

is a process during meiosis where the pairs of homologous chromosomes are randomly distributed to the daughter cells

Question 33

Random fertilization

Answer 33

refers to the idea that any sperm cell can fertilize any egg cell

Question 34

Nondisjunction

Answer 34

a mishap, in which the members of a pair of homologous chromosomes do not move apart properly during meiosis 1 or sister chromatids fail to separate during meiosis 2

Question 35

Aneuploidy

Answer 35

an abnormal chromosome number

Question 36

Monosomy

Answer 36

(2n-1) a type of aneuploidy where a cell is missing one chromosome from a pair. Turner syndrome is a cause of this.

Question 37

Trisomy

Answer 37

(2n+1), a condition where a cell has an extra chromosome, resulting in 3 copies instead of 2. This can lead to down syndrome.