MEIOSIS - MAIN TERMS Flashcards

1
Q

HOMOLOGOUS CHROMOSOME PAIR

A

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

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2
Q

KARYOTYPE

A

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

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3
Q

MITOSIS

A

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

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4
Q

CROSSING OVER

A
  • hom chro arrange in pairs
  • bivalent forms
  • sister chromatids visible
  • crossing over and exchange of segments occur
  • hom chro pair after
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5
Q

PURPOSE OF MEIOSIS

A

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

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6
Q

GAMETOGENESIS

A

gamete formation

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7
Q

SPERMATOGENESIS

A

sperm formation

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8
Q

OOGENESIS

A

egg formation

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9
Q

REDUCTION DIVISION

A

meiosis, bc diploid chromosome no. is reduced to haploid

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10
Q

IMPORTANCE OF MEIOSIS

A
  • 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
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11
Q

GENETIC VARIATION

A

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

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12
Q

DIFF GENE COMBOS ARE OBTAINED BY

A

crossing over
random assortment of chro on the equator
random fertilization

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13
Q

ABNORMAL MEIOSIS

A

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

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14
Q

ANEUPLOIDY

A

when there are extra or missing chromosomes in a cell

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15
Q

DOWN SYNDROME

A

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

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16
Q

DOWN SYN CHARACTERISTICS

A
  • small almond shaped eyes
  • large tongue
  • flat forehead, nose bridge
17
Q

SIMILARITIES

A

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

18
Q

DIFFERENCES

A

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

19
Q

CHROMOSOME

A

occur in the nucleus of every living cell

20
Q

CHROMOSOME STRUCTURE

A

DNA molecule wrapped around proteins (histones)

21
Q

GENE

A

DNA segment that controls a particular inherited characteristic

22
Q

diploid chromosome number

A

2n

double set of chromosomes

23
Q

GAMETES

A

sex cells
egg / sperm
one set of chromosomes

24
Q

zygote

A

formed when the egg and sperm fuse

two sets of chromosomes

25
Q

human karyotype

A

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

26
Q

INTERPHASE

A

the period between two consecutive cell divisions

when cell DNA replication and cell growth take place

27
Q

prophase of Mit

A
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
28
Q

metaphase of Mit

A

chromosomes position in a single row on the equator

spindle fibers attach to centromeres

29
Q

anaphase of Mit

A

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

30
Q

telophase of Mit

A
daughter chro position at poles
spindle fibers disappear
nuc mem and nuclelous form
cytokinesis
two identical daughter cells are formed
31
Q

meiosis defintion

A

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

32
Q

first meiotic division

A

chro number is halved and genetic material is changed

33
Q

second meiotic divison

A

proceeds like normal mitosis where chromatids/daughter chro separate

34
Q

polyploidy

A

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