meiosis

Question 1

asexual reproduction

Answer 1

based on mitotic division of the nucleus

Question 2

Unicellular (asexual)

Answer 2

reproduce itself

Question 3

multicellular (asexual)

Answer 3

for a new individual but offspring is a clone

Question 4

sexual reproduction

Answer 4

not identical to parents

-genetic contribution form 2 parents

Question 5

how are gametes produced?

Answer 5

by meiosis

gametes and offspring are genetically different

Question 6

somatic cells

Answer 6

body cells not specialized for reproduction

• contain homologous pairs of chromosomes
• each parent contributes on homolog

Question 7

Gametes contain

Answer 7

one set of chromosomes

Question 8

haploid:

Answer 8

=n= number of chromosomes

Question 9

fertilization:

Answer 9

two haploid gametes fuse to form and Diploid zygote (2n)

Question 10

why sexual reproduction

Answer 10

allows random selection of half the diploid chromosome set- forms a haploid gamete that fuses with another to make a diploid cell.

Question 11

karyotype:

Answer 11

number, shapes, and sizes of the metaphase chromosomes in a cell

Question 12

Meiosis consists of two nuclear divisions but

Answer 12

Dna is replicated only once.

Question 13

the function of meiosis

Answer 13

• reduce the chromosome number from diploid to haploid
• ensure that each haploid has a complete set of chromosomes
• generates diversity among the products

Question 14

Meiotic division:

Answer 14

reduces the chromosome number

Question 15

meiosis I

Answer 15

homologous pairs of chromosomes come together and pair along their entire lengths

Question 16

After metaphase I…

Answer 16

the homologous pairs separate, but the individual chromosomes made up of sister chromatids remains together

Question 17

Prophase I

Answer 17

• homologous chromosomes pair: synapsis.
• -four chromatids of each homologous pair form a tetrad
• chromosomes cross over
• new combo of genes

Question 18

Metaphase I

Answer 18

chromosomes are at the equatorial plate: homologous pairs are held together by chiasmata

Question 19

Anaphase I

Answer 19

• homologous chromosomes separate

- daughter nuclei contain only one set of chromosomes (two chromatids)

Question 20

what does independent assortment promote?

Answer 20

diversity

Question 21

Telophase I

Answer 21

occurs in some organisms:

• nuclear envelope reaggregates, followed by an interphase called interkinesis
• in other organisms, meiosis II begins immediately

Question 22

Meiosis II:

Answer 22

similar to mitotic division

-chromosomes are not identical

Question 23

nondisjunction:

Answer 23

when homologous pairs fail to separate at anaphase I; sister chromatids fail to separate, or homologous chromosomes may not remain together

Question 24

aneuploidy

Answer 24

chromosomes lacking or present in excess

Question 25

translocation

Answer 25

piece of chromosome breaks off and attaches to another chromosomes

Question 26

trisomy 21 in humans- 3 copies of chromosome21 =

Answer 26

downs

Question 27

Polyploids:

Answer 27

extra whole set of chromosome - this abnormally in itself does not prevent mitosis

Question 28

triplets are

Answer 28

3n

Question 29

tetraploids are

Answer 29

4n

Question 30

mitosis in unimpaired..

Answer 30

meiosis is problematic

Question 31

necrosis-

Answer 31

cell damaged or starved for o2 or nutrients - swells and bursts

Question 32

apoptosis:

Answer 32

genetically programmed cell death