MEIOSIS - MAIN TERMS

Question 1

HOMOLOGOUS CHROMOSOME PAIR

Answer 1

when one pair comes from the mother and the other comes from the father
ensures organism has the characteristics of both parents

Question 2

KARYOTYPE

Answer 2

the complete diploid set of chromosomes within a somatic cell of an organism

Question 3

MITOSIS

Answer 3

the division of somatic cells, and helps with growth, repair of damaged tissues and asexual reproduction
two daughter cells produced

Question 4

CROSSING OVER

Answer 4

• hom chro arrange in pairs
• bivalent forms
• sister chromatids visible
• crossing over and exchange of segments occur
• hom chro pair after

Question 5

PURPOSE OF MEIOSIS

Answer 5

the formation of sex cells/gametes in the sex organs of animals

Question 6

GAMETOGENESIS

Answer 6

gamete formation

Question 7

SPERMATOGENESIS

Answer 7

sperm formation

Question 8

OOGENESIS

Answer 8

egg formation

Question 9

REDUCTION DIVISION

Answer 9

meiosis, bc diploid chromosome no. is reduced to haploid

Question 10

IMPORTANCE OF MEIOSIS

Answer 10

• diploid chromosome number is halved to prevent chromosomes from doubling w each gen
• leads to genetic variation
• prod spores in plants and gametes in animals

Question 11

GENETIC VARIATION

Answer 11

differences that occur as a result of diff gene combinations between organisms of a species

Question 12

DIFF GENE COMBOS ARE OBTAINED BY

Answer 12

crossing over
random assortment of chro on the equator
random fertilization

Question 13

ABNORMAL MEIOSIS

Answer 13

when meiosis does no proceed as normal, resulting in a change in no or structure of chromosomes

Question 14

ANEUPLOIDY

Answer 14

when there are extra or missing chromosomes in a cell

Question 15

DOWN SYNDROME

Answer 15

when there are 47 chromosomes instead of 46, because chromosome pair no 21 does not separate during Anaphase 1

Question 16

DOWN SYN CHARACTERISTICS

Answer 16

• small almond shaped eyes
• large tongue
• flat forehead, nose bridge

Question 17

SIMILARITIES

Answer 17

both cell division processes
both require DNA rep during Interphase
both have PMAT

Question 18

DIFFERENCES

Answer 18

no variation in Mit (identical dau cells)
variation in Mei (by crossing over)

two dau cells in Mit, four dau cells in Mei

no crossing over in Mit, yes in Mei

Question 19

CHROMOSOME

Answer 19

occur in the nucleus of every living cell

Question 20

CHROMOSOME STRUCTURE

Answer 20

DNA molecule wrapped around proteins (histones)

Question 21

GENE

Answer 21

DNA segment that controls a particular inherited characteristic

Question 22

diploid chromosome number

Answer 22

2n

double set of chromosomes

Question 23

GAMETES

Answer 23

sex cells
egg / sperm
one set of chromosomes

Question 24

zygote

Answer 24

formed when the egg and sperm fuse

two sets of chromosomes

Question 25

human karyotype

Answer 25

22 pairs of autosomes and one pair of gonosomes 46 (dip chro num)\ ie.) 44 + XX - female 44 + XY - male

Question 26

INTERPHASE

Answer 26

the period between two consecutive cell divisions | when cell DNA replication and cell growth take place

Question 27

prophase of Mit

Answer 27

``` chromatin net shortens and thickens to become visible as chromosomes nucl mem and nucleolus disappear centrosome duplic centrioles move to opp poles spindle fibres develop ```

Question 28

metaphase of Mit

Answer 28

chromosomes position in a single row on the equator | spindle fibers attach to centromeres

Question 29

anaphase of Mit

Answer 29

each centremere divides into two chromatids separate and move to opposite poles now known as daughter chromosomes cytokinesis begins

Question 30

telophase of Mit

Answer 30

``` daughter chro position at poles spindle fibers disappear nuc mem and nuclelous form cytokinesis two identical daughter cells are formed ```

Question 31

meiosis defintion

Answer 31

a reduction division where the chromosome number of each cell is halved, from dip to hap

Question 32

first meiotic division

Answer 32

chro number is halved and genetic material is changed

Question 33

second meiotic divison

Answer 33

proceeds like normal mitosis where chromatids/daughter chro separate

Question 34

polyploidy

Answer 34

the condition where there are more than two sets of chromosomes in a cell, more common in plants