7B- meiosis

Question 1

What are the 2 types of cells in multicelluar organisms

Answer 1

somatic cells and germ cells

Question 2

somatic cells

Answer 2

diploid cells produced during mitosis that are identical to the parent cell eg. skin cells, muscle cells and nerve cells

Question 3

Germ cells

Answer 3

haploid cells that are produced during meiosis that are not identical to the parent cell eg. gametes

Question 4

meiosis

Answer 4

sexual production of cells to produce 4 not identical daughter cells

Question 5

how many copies of each chromsome will be in a gamete

Answer 5

1 copy

Question 6

what happens when 2 gametes fuse in meiosis

Answer 6

2 copies of each chromosme develop inisde of a zygote

Question 7

compare meiosis and mitosis

Answer 7

meiosis:
1.Involves rearrangement of alleles to create a variation
2.Produces 4 genetically unique daughter cells
3.Daughter cells contain half the number of chromosomes (n) of the parent cell

Mitosis:
1.Does not involve recombination of alleles
2.Two identical daughter cells are produced
3.Daughters cells contain the same number of chromosomes (2n) as the parent cell

Question 8

why is meiosis called reduction divsion

Answer 8

meiosis is called reducation division because it reduces the number of chromsomes from 2n of the somatic cell to half(n)

Question 9

what are the 2 divisions of meiosis

Answer 9

meiosis I
meiosis II

Question 10

what is meoisis I, what process are involved in this

Answer 10

a diploid cell is spilt into 2 geneitically different haploid cells

The process involves
Prophase I
Metaphase I
Anaphase I
Telophase I

Question 11

what occurs during meosis I to creater variaton

Answer 11

crossing over and independent assortments—–explain these processes in more detail

Question 12

what is crossing over in meiosis

Answer 12

During prophase I, the same types of chromsomes are lined up to to create recombination chromatids thus creating a genetic variation

Question 13

What is independent assortment in meiosis

Answer 13

During metaphase I, homologus chromsomes arrange along the equator of the cell and results in the random splitting of chromsomes thus creating genetic variation

Question 14

Stages of meiosis

Answer 14

1. Interphase I
   2.Prophase I
   3.Metaphase I
2. Anapahse I
3. Telophase I
4. Prophase II
5. Metaphase II
6. Anapahse II
7. Telophase II
8. Cytokenisis

Question 15

Interphase I

Answer 15

cell grows and duplicates all chromsomes in preparation for cell division

Question 16

Prophase I

Answer 16

The nuclear memrbane breaks down as chromsomes condense and line up in a homogolous pair

Question 17

Metaphase I

Answer 17

Spindle fibres fully form and attach to the centromere of each chromsome
homologus chromsomes align along the metpahase plate

Question 18

Anaphase I

Answer 18

homologous chromsomes are pulled by spindle fibres from the centromere to opposite sides of the cell

homolohus pairs spilt

Question 19

Telophase I

Answer 19

1.chromatin decondenses

2.nucela envelope starts to reappear

3.clevaeg furrow forms

4.2 new cells walls and cell membranes found

5.cell undergoes cytokinesis

Question 20

Prophase II

Answer 20

1.the 2 cells are prepared for another diviison,

2. the nulcear memrbae begins to break dwon, the chromsomes condense,centrioles produce spindle fibres

Question 21

metapahse II

Answer 21

each chromeosme lines up along the metphase plate of the cell as microtubules from opposite poles of the cell prepare to pull the chromosmes apart

Question 22

Anapahse II

Answer 22

sister chromaiids are now seperated ad pulled towards opposite poles of the cell by microtubules whcih are attached at each centromere

dna spilts

Question 23

Telophase II

Answer 23

with indivual chromatids now at each pole of the cell, sperate nuclear mememrbane beign to form around eahc set as the chromeosmes begin to decondense and unravel

Question 24

when do errors occur during meiosis

Answer 24

when a pair of chromosomes fail to split or separate at anaphase causing either two copies to be present on one gamete, OR a copy of the chromosome is missing

Question 25

cytokensis

Answer 25

division of cytoplasm to form 2 new cells

Question 26

purpose of sexual reproduction

Answer 26

to increase genetic diveristy

Question 27

purpose of meiosis

Answer 27

to enable seuxal reproduction to happen without an icnrease of the number of chormsomes in an indiviudal

Question 28

interkensiis

Answer 28

period of rest mebetwene meiosis I and meiosis II

Question 29

Gameotgensisi

Answer 29

after meosiis haploid cells furhter develop to become gametes either sperm(spermatogneisis) or eggs(oogneisis

Question 30

how mmany chormomes and chromatids atthe end of meiosis I and meoiss II

Answer 30

meosis I is 23 chromomes 46 chormatids

mecoosis II 23 chormomes 23 chroamtids

Question 31

lugon city is an endemic place for malaria
1) why is that homozygous dominant (in sickle cell anemia) less advantageous than heterozygous recessive in Lugon city

2) why is that in a place with no mosquitoes, homozygous dominant trait is better

Answer 31

people with heterozogous reccsive is more advatnageous for maralria because they produce both sickle cells and normal cells, this means that when malaria infects the cells and changes its shape, the immune systemcan quicjly identify the sickle shaped RBC that haeve been infected, thus creating more resistance to malaria,

-malaria struggles to grow in a sickle cell trait

whereas, homogous dominant means that no normal cells aare prpdocued so it takes longer for the immine system to identify which redbloodcells have been infected because their all sickle shaped

What is the anser for question 2??

Question 32

co

codominance

Answer 32

2 allelels are fully expressed and dominant

Question 33

2) why is that in a place with no mosquitoes, homozygous dominant trait is better

Answer 33

if they arehomziosu domiant that is better because they dont need to be resistance agaisnt malaria