Mitosis and Meiosis tonight

Question 1

mitosis vs meiosis key points

Answer 1

mitosis vs meiosis
1 division vs 2 division
daughter cells genetically identical vs genetically different
2 cells produced vs 4 cells produced
diploid to diploid/ haploid to haploid vs diploid to haploid
Same number of chromosomes vs half the number of chromosomes
meiosis only - separation of homologous chromosomes
crossing over
indenpendent segregation

Question 2

meiosis def

Answer 2

produces daughter cells that are genetically different from each other

Question 3

independent assortment/ segregation

Answer 3

alleles of 2 to more diff gene get sorted into gametes independently of one another

Question 4

compare and contrast mitosis and meisois (6marks)

Answer 4

both - PMAT (phrophase, metaphase, anaphase, telophase)
- contraction of spindle fibres seperates chromatids or chromsomes
- chromosomes line up at equator of cell and there is movement towards poles
- process ends with cytokinesis/ new cell is produced
- DNA must be copied during interphase

Mitosis
- genetically identical daughter cells
- individual chromosomes line up at equatoe in metaphase
- no idependent segregation
- no bivalents and crossing over
- diploid cells produced
- 2 daughter cells

Meiosis
- genetically different daughter cells
- homologous pairs line up at equator in metaphase 1
- independent segregation of homologous chromosomes
- Bivalents form- crossing over occurs
- Haploid cells produced
- 4 daughter cells

Question 5

Describe and explain the arrangement of genetic material in prophase:

Answer 5

1- Chromosomes visible
2- still condensing
3- chromosomes arranged randomly/ not lined up
4- Because no spindles

Question 6

Meiosis key words (6marker)

Answer 6

A
2- divisions - meiosis 1, meios 2

DNA Replication in late interphase

Seperation of homologous chromosoemes - 1st division

Seperation of sister chromatids - 2nd division

produce 4 haploid cells

Question 7

cell cycle

Answer 7

the process of interphase, mitosis and cytokinesis

Question 8

Prophase

Answer 8

The chromosomes thicken and condense, becoming visible. The nuclear envelope breaks down

Question 9

Metaphase

Answer 9

The chromosomes align in the centre of the cell. Spindle fibres begin to attach to each sister chromatid

Question 10

Anaphase

Answer 10

The sister chromatids are pulled apart to opposite poles of the cell. The centromeres divide in two and move to opposite poles of the cell, pulled by microtubules

Question 11

Telophase

Answer 11

The start of the cell division where the spindle fibres disintergrate and the nucleolus reforms

Question 12

Cytokinesis

Answer 12

The process by which the cell splits into two at the end of mitosis, forming a new nuclear envelope and plasma membrane
(dividing cytoplasm follows nuclear division)

Question 13

Chromatid

Answer 13

Half a chromosome

Question 14

Homologous Chromosomes

Answer 14

Identical chromosome

Question 15

Centromere

Answer 15

The central region of a chromosome that holds the two chromatids together

Question 16

Mitosis

Answer 16

The process that produces two daughter cells and have the same number of chromosomes as the parent cell

Question 17

binary fusion

Answer 17

The process of cell division in prokaryotic cell

Question 18

First Stage of Binary Fission

Answer 18

The circular DNA replicates, both copies attach to the cell membrane. The plasmid also replicates

Question 19

Second Stage of Binary Fission

Answer 19

The cell membrane grows between the replicated DNA and begins to pinch inwards which splits the cytoplasm in two. The new cell wall forms, forming the complete daughter cells (identical)
each with single copy of circular DNA and variable copies of plasmids

Question 20

The Importance of Mitosis

Answer 20

Used for growth, repair and reproduction

Question 21

Outline prophase

Answer 21

Chromosomes become more visible, thicken.
2. Centrioles move to opposite ends of the cell (poles).
3. Spindle fibres develop from each of the centrioles (spindle apparatus).

Question 22

Outline Interphase

Answer 22

Precedes Mitosis

1. Cell is not dividing.
2. Considerable cellular activity - replication of DNA, two copies on centromere.

Question 23

Outline Metaphase

Answer 23

centrosomes reach opposite poles
1. Chromosomes seen to be made up of two chromatids.
2. Microtubules attach to centromere - chromosomes pulled to the cell equator where they line up.
spindle fibres extend from centrosomes

Question 24

Outline Anaphase

Answer 24

1. Centromeres divide, separating each pair of sister chromatids.
2. Chromatids pulled to their respective poles as spindles contract, centromeres first - v-shaped. (now called chromosomes)

Question 25

Outline Telophase

Answer 25

1. Chromosomes reach their respective poles and then uncoil, become long and thin again - chromosomes again. 2. Spindle fibres disintegrate; nuclear envelope and nucleolus reform. 3. Cytoplasm divides in cytokinesis.

Question 26

Outline the process of Binary Fission

Answer 26

How prokaryotic cells divide: 1. Circular DNA molecule replicates, and both copies attach to the cell membrane. 2. Plasmids also replicate. 3. Cell membrane begins to grow between the two DNA molecules and begins to pinch inwards - dividing cytoplasm in two. 4. New cell wall forms between the DNA molecules, dividing the original cell into two identical daughter cells - each with a copy of the circular DNA and a variable number of copies of the plasmids.

Question 27

Outline how viruses replicate Acellular, non-living, so do not undergo cell division.

Answer 27

1. Attach to host cell with the attachment proteins on their surface. 2. Inject nucleic acid into host cell. 3. Viral nucleic acid then hijacks the cell's machinery and codes for metabolic processes to produce viral components - nucleic acid, enzymes, structural proteins, which are then assembled into new viruses.

Question 28

Crossing over

Answer 28

between homologous pairs - chromatid break during mitosis and reform to the chromatid of its homologous chromosome so that its alleles are exchanged

Question 29

what creates genetic variation in daughter cells

Answer 29

crossing over in late prophase 1 and independent segregation of chromatids in anaphase 11

Question 30

what is independent segregation

Answer 30

segregation of chromosomes - alleles of 2 or more diff genes get sorted into gametes independent of one another - homologous chromosomes line up in random orientation

Question 31

meisois stages

Answer 31

x2 stages

Question 32

meiosis reproduction

Answer 32

sexual

Question 33

mitosis produces

Answer 33

produces genetically identical parent cells - same number of chromosomes as parent cells

Question 34

cell division in prokaryotic cells ...

Answer 34

binary fusion

Question 35

cell division in eukaryotic cells..

Answer 35

mitosis and meiosis

Question 36

cytokenesis key points

Answer 36

forms two genetically identical daughter cells animal: contractile ring and cleavage furrow plant: cell plate formed

Question 37

cell cycle x3 stages

Answer 37

interphase nuclear divison cytokinesis

Question 38

cancer cells

Answer 38

uncontrolled cell division - damage to the genes that regulate mitosis and cell cycle

Question 39

eukaryotic cells process

Answer 39

cell cycle

Question 40

mitosis is a

Answer 40

controlled process

Question 41

interphase processes

Answer 41

no division occurs x3 stages DNA replication

Question 42

x3 stages of interphase

Answer 42

g1 phase: cell growth, signal received for cell to divide s phase: synthesis of DNA g2 phase- further cell growth, error checking of newly synthesised DNA