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Flashcards in Mitosis And Meiosis Deck (35):
1

What is a p arm?

Short arm of chromatid

2

What is the q arm?

Long arm of chromatid

3

What is a telomere?

Repeated sequences at each end of a chromosome or chromatid

4

What is a centromere?

Repetitive sequence that links sister chromatids

5

What are the positions of centromeres called?

Metacentric- middle
Submetacentric
Afrocentric
Telcentric- top

6

How are chromosomes grouped?

According to size and shaped
In groups A-G

7

What is mitosis?

Cell division in somatic cells
Produces two identical daughter cells

8

What tissues is mitosis necessary for?

Epidermis
Mucosae
Bone marrow
Spermatogonia

9

What occurs in prophase?

Spindle fibres appear
chromosomes condense
Nuclear membrane breaks down

10

What occurs in prometaphase?

Spindle fibres attach to chromosomes
Chromosomes condense

11

What happens in metaphase?

Chromosomes align at the equator

12

What happens at anaphase?

Centromeres divide
Sister chromatids move to opposite poles

13

What happens in telophase?

Nuclear membrane reforms
Spindle fibres disappear
Chromosomes decondense

14

What happens in cytokinesis?

Cytoplasm divides
2 genetically identical daughter cells form

15

What are alleles?

Different forms of the same gene

16

Where are chromosomes during interphase?

Chromosome territories

17

What alleles do sister chromosomes have?

The same

18

What is meiosis?

Cell division for germ line cells
Produces 4 non-identical cells
Haploid
One round of replication and two rounds of division
Egg and sperm produced

19

What occurs in prophase I?

Nuclear membrane breaks down
Chromosomes condense
Crossing over occurs

20

What occurs in metaphase I?

Pairs of homologous chromosomes move to the equator of the cell

21

What occurs in Anaphase I?

Homologous chromosomes move to opposite poles of the cell

22

What occurs in telophase I?

Chromosomes gather at poles of the cell

23

What occurs in prophase II?

New spindle forms

24

What occurs in metaphase II?

Chromosomes line up at the equator

25

What happens in anaphase II?

Centromeres divide and chromatids move to opposite poles of the cell

26

What happens in telophase II?

Nuclear envelope reforms

27

How does genetic diversity occur?

Random assortment of chromosomes
Crossing over of genetic material

28

What is spermatogenesis?

Cell division to produce male gametes
1 cell (spermatocyte)- 4 sperm
Takes around 60 days

29

What is oogenesis?

Cell division to produce female gametes
1 cell (oocyte) - 1 egg and 3 polar bodies
Takes 12-50 years

30

What are the consequences of missegregation in meiosis?

Third of miscarriages
Infertility
Mental retardation

31

What is non-dysfunction at anaphase?

Where the incorrect number of chromosomes is moved to each pole
1 cell gets 2 chromosomes
1 cell gets 0 chromosomes
Leads to aneuploidy

32

What is the format to describe a karyotype?

Chromosome number, sex complement and structural changes separated by commas
E.g. 47, XY, +21
Male with trisomy 21

33

What does mitotic dysfunction in first post zygote can division lead to?

One with less chromosomes Usually lost unless involved X

34

If non disjunction occurs in later cell divisions

Leads to mosaic karyotype

35

What is mosaicism?

Presence of two or more cell lines in an individual