meiosis

Question 1

asexual reproduction

Answer 1

Produces clones (genetically identical)
Single parent
Little variation in population, only through mutations
Fast and energy efficient

Question 2

sexual reproduction

Answer 2

Meiosis produces gametes (sex cells)
2 parents: male/female
Lots of variation/diversity
Slower and energy consumptive

Question 3

genes

Answer 3

segments of DNA that code for basic units of heredity

Question 4

how do offspring acquire genes from parents?

Answer 4

inheriting chromosomes

Question 5

Somatic (body) cell

Answer 5

2n = 46 chromosomes
Each pair of homologous chromosomes includes 1 chromosome from each parent

Question 6

autosomes

Answer 6

22 pairs of chromosomes that do not determine sex

Question 7

sex chromosomes

Answer 7

X and Y

Question 8

female chromosome pair

Answer 8

XX

Question 9

male chromosome pair

Answer 9

XY

Question 10

gametes chromosomes (and egg and sperm)

Answer 10

(n=23): 22 autosomes + 1 sex chromosome
Egg: 22 + X
Sperm: 22 + X or 22 + Y

Question 11

meiosis =

Answer 11

reduction division

Question 12

how many times do cells divide during meiosis

Answer 12

twice

Question 13

result of meiosis

Answer 13

4 daughter cells, each with half as many chromosomes as parent cell

Question 14

meiosis basic phases

Answer 14

meiosis I (1st division)
interphase
prophase I
metaphase I
anaphase I
telophase I and cytokinesis
meiosis II (2nd division)
prophase II
metaphase II
anaphase II
telophase II

Question 15

what is the purpose of meiosis I

Answer 15

1st division

Question 16

what is the purpose of meiosis II

Answer 16

creates gametes

Question 17

interphase

Answer 17

chromosomes replicate

Question 18

prophase I

Answer 18

Synapsis: homologous chromosomes pair up
Tetrad = 4 sister chromatids
Crossing over at the chiasmata

Question 19

metaphase I

Answer 19

tetrads line up

Question 20

anaphase I

Answer 20

pairs of homologous chromosomes separate
(Sister chromatids still attached by centromere)

Question 21

Telophase I & Cytokinesis:

Answer 21

Haploid set of chromosomes in each cell
Each chromosome = 2 sister chromatids
Some species: chromatin & nucleus reforms

Question 22

prophase II

Answer 22

No interphase
No crossing over
Spindle forms

Question 23

metaphase II

Answer 23

Chromosomes line up

Question 24

anaphase II

Answer 24

sister chromatids seprate

Question 25

telophase II

Answer 25

4 haploid cells Nuclei reappear Each daughter cell genetically unique

Question 26

events unique to meiosis I

Answer 26

Prophase I: Synapsis and crossing over Metaphase I: pairs of homologous chromosomes line up on metaphase plate Anaphase I: homologous pairs separate 🡪 sister chromatids still attached at centromere

Question 27

crossing over

Answer 27

Exchange genetic material Recombinant chromosomes

Question 28

sources of genetic information

Answer 28

independent assortment of chromosomes crossing over random fertilization

Question 29

Independent Assortment of Chromosomes

Answer 29

Random orientation of homologous pairs in Metaphase I number of possible combinations when chromosomes assort independently = 2n 223= 8.4 million possible combinations to create a gamete

Question 30

Random Fertilization

Answer 30

Any sperm + Any egg 2^23 x 2^23 = 70 trillion combinations!

Question 31

similarity between mitosis and meiosis

Answer 31

both are divisions of cell nucleus

Question 32

mitosis

Answer 32

Somatic cells 1 division 2 diploid daughter cells Clones From zygote to death Purpose: growth and repair No synapsis, crossing over

Question 33

meiosis

Answer 33

Gametes 2 divisions 4 haploid daughter cells Genetically different-less than 1 in 8 million alike Females before birth follicles are formed. Mature ova released beginning puberty Purpose: Reproduction

Question 34

Karyotype

Answer 34

a picture of an organism’s complete set of chromosomes

Question 35

how are karyotype's arranged

Answer 35

from largest 🡪 smallest pair

Question 36

purpose of karyotypes

Answer 36

used to determine genetic abnormalities

Question 37

can cancer cells have abnormal chromosomes?

Answer 37

yes, abnormal NUMBER of chromosomes

Question 38

HeLa Cells

Answer 38

Oldest and most commonly used human cell line Cervical cancer cells taken from Henrietta Lacks

Question 39

HeLa Cells are an active version of

Answer 39

temomerase

Question 40

do HeLa Cells die

Answer 40

no, not even after a few divisions

Question 41

what are HeLa Cells used in research for

Answer 41

Develop vaccine for polio, cancer, AIDS, virus, radiation research

Question 42

in HeLa Cells, it was estimated that

Answer 42

cells produced in culture exceeded # cells in Henrietta’s body

Question 43

ethical concerns about HeLa Cells

Answer 43

Controversy: Cells harvested without patient consent “Discarded tissues can be commercialized” – sold for profit Genome published in 2013 without family’s consent “The Immortal Life of Henrietta Lacks” by Rebecca Skloot

Question 44

life cycle

Answer 44

reproductive history of organism, from conception 🡪 production of own offspring

Question 45

what processes alternate in sexual life cycles?

Answer 45

fertilization and meiosis

Question 46

fertilization

Answer 46

combine gametes (sperm + egg) Fertilized egg = zygote (2n) Zygote divides by mitosis to make multicellular diploid organism