Cell division (paper 2) TOPIC 1 & 6

Question 1

.what do most cells in the human body contain

Answer 1

a nucleus

Question 2

what does a nucleus contain

Answer 2

the genetic meterial of the cell

Question 3

what is the genetic chemical in the nucleus called

Answer 3

DNA

Question 4

what is DNA arranged into

Answer 4

structures call chromosomes

Question 5

what is a chromosome

Answer 5

a coiled molecule of DNA carrying different genes

Question 6

what is a the term for a body cell

Answer 6

somatic cell

Question 7

how are chromosomes found in somatic cells

Answer 7

in pairs

Question 8

why are chromosomes found in pairs

Answer 8

because each pair is inherited from the person’s mother and one from their father

Question 9

how many chromosomes do humans contain

Answer 9

46 chromosomes in 23 pairs

Question 10

what is the haploid number and what is it for a human

Answer 10

the number of pairs of chromosomes
23 pairs in a human

Question 11

what is the diploid number and what is it for humans

Answer 11

the number of chromosoms in a cell
46 chromosomes

Question 12

what are gametes

Answer 12

sex cells

Question 13

what is the female sex cell

Answer 13

an ovum

Question 14

what is the male sex cell

Answer 14

sperm

Question 15

what is the word for the picture of chromosomes when removed from a nucleus and arranged in order

Answer 15

a karyogram or karyotype

Question 16

what are karyograms/karyotypes used for

Answer 16

to determine the sex of an individual and diagnose genetic disorders

Question 17

how can you tell if an individual is female

Answer 17

they will have 2 x chromosomes

Question 18

how can you tell if an individual is male

Answer 18

they will have one x chromosome and one y chromosome

Question 19

how are new cells made

Answer 19

by the proccess mitosis

Question 20

define mitosis

Answer 20

the growth and repair of tissues

Question 21

what is the cell cycle

Answer 21

the series of stages which somatic cells divide in

Question 22

what happens in stage one of the cell cycle for mitosis (interphase)

Answer 22

• cell increases in size
• the DNA is replicated
• the number of organelles is doubled

Question 23

what happens in the second stage of the cell cycle for mitosis (prophase)

Answer 23

• the chromosomes condense in the middle of the cell
• half the chromosomes are pulled to one pole of the cell
• two nuclei are formed
• cell is split to form 2 genetically identical daughter cells

Question 24

what is the longest stage of mitosis

Answer 24

when the cell grows and replicated their DNA and increases the sub-cellular structures (the first stage)

Question 25

what do genes do

Answer 25

they carry the instructions to control a characteristic

Question 26

what is binary fission

Answer 26

the method of asexual reproduction which single-cell organisms use to create a copy of themselves

Question 27

in binary fission are plasmids equally shared between the daughter cells? explain?

Answer 27

No - the plasmids are shared randomly, but one loop of DNA goes to one daughter cell and the other to the other daughter cell

Question 28

what happens in the process of binary fission

Answer 28

- Cell replicates DNA - cell grows - cell wall forms and cell membrane invaginates - daughter cells formed

Question 29

what type of cells conduct binary fission

Answer 29

prokaryotic

Question 30

what is meiosis used for

Answer 30

the formation of gametes

Question 31

what is similar in the processes mitosis and meiosis

Answer 31

DNA is duplicated before cell division in both

Question 32

mitosis? meiosis? which produces genetically identicel cells and which produces genetically unique cells

Answer 32

genetically identicle cells - mitosis genetically unique cells - meiosis

Question 33

mitosis? meiosis? results in haploid cells or diploid cells

Answer 33

diploid = mitosis haploid = meiosis

Question 34

mitosis? meiosis? occurs only at certian times of life cycle or takes place throughout lifetime

Answer 34

occurs throughout lifetime = mitosis occurs at certain times of lifecycle = meiosis

Question 35

mitosis? meiosis? involved in asexual or sexual reproducution

Answer 35

asexulal reproduction = mitosis sexual reproduction = meiosis

Question 36

what is a stem cell

Answer 36

an undifferentiated cell

Question 37

what is the function of a stem cell

Answer 37

they can differentiate to become different types of specialised cells

Question 38

what are the three different types of stem cells

Answer 38

- embryonic - adult - plant

Question 39

what is different for stem cells in animals comapred to plants

Answer 39

in animals little to no growth takes place, the same type of cells are made. in plants they are able to differentiate trhoguhtout their lives (known as meristem cells)

Question 40

what is the name given to the stem cells in plants which are undifferentated

Answer 40

meristem cells

Question 41

how are embryonic stell cells formed

Answer 41

after a sperm cell and egg fuse to form a zygote, that cell divides to form an embryo. the inner cells of this ball are embryonic stem cells

Question 42

give an example of an adult stem cell

Answer 42

bone marrow

Question 43

what are adult stem cells described as

Answer 43

multipotent stem cells

Question 44

what are embryonic stem cells described as

Answer 44

totipotent stem cells

Question 45

where are the meristem cells found in plants

Answer 45

at the tips of roots and shoots

Question 46

what are the ethical againsts and fors in stem cell research

Answer 46

+they are treating and curing patients +wasted embryos from fertilisation are being used -they think its a potential life -embryos cannot consent -think time and money should be used to find an alternative solution

Question 47

what are the two types of reproduction

Answer 47

- asexual - sexual

Question 48

evalutate asexual reproduction

Answer 48

- involves mitosis (or buimary fission in bacteria) - involves only one patient - does not involve fusion of gametes - does not result in mixing genetic info - produces genetical identical offspring

Question 49

how can plants reproduce asexually

Answer 49

using the process vegetative reproduction

Question 50

what type of production is in animalas

Answer 50

sexual

Question 51

define sexual reproduction

Answer 51

the mixing of genetic information which leads to variety in the offspring - the offspring are genetically different to both parents

Question 52

what are the male gametes called

Answer 52

sperm

Question 53

what are the female gametes called

Answer 53

ova

Question 54

which cell division process does the formation of the gametes involve

Answer 54

meiosis

Question 55

how many chromosomes does each gamete contain

Answer 55

the haploid number of chromosomes (half)

Question 56

describe fertilisation

Answer 56

- the ovum and sperm fuse together - results in single zygote cell (has full number of chromosmes) - zygote develops into the embryo

Question 57

what type of plants does sexual reproduction occur in

Answer 57

flowering plants

Question 58

what is the reproductive organ of any flowering plant

Answer 58

the flower

Question 59

what is the male gamete in plants

Answer 59

the stamen (anther and filament) which contain the pollen

Question 60

what is the female gamete in plants

Answer 60

the carple (stigma, style and ovary) which contains the ocules

Question 61

what happens during pollination

Answer 61

the pollen is transferred from the anther to the stigma

Question 62

what happens when a cell divides to form gametes

Answer 62

- copies of the genetic info is made - cell divides twice to form 4 gametes - each have a haploid number of chromosomes - all gametes are genetically different from each other

Question 63

whtat are the advantages of sexual reproduction

Answer 63

- genetically varied = survival advantage if change occurs - natural selection sped up by selective breeding

Question 64

what are the advantages of asexual reproduction

Answer 64

- only one parent needed - more time and energy efficient

Question 65

give some examples of organisms that use BOTH sexual and asexual reproduction

Answer 65

- malaria parasite (protist) - fungi - strawberry plant - daffodils

Question 66

how does the malaria parasite reproduce

Answer 66

sexually - when inside the mosquito asexually - when inside the human

Question 67

how does fungi reproduce

Answer 67

sexually - releases spores sexually asexually - releases spores asexually

Question 68

how does the strawberry plant reproduce

Answer 68

sexually - produces gametes in flowers asexually - produce runners

Question 69

Describe mitosis

Answer 69

Cell increases in size and dna replicates One set of chromosomes get pulled to each pole of the cell Cell membrane and cytoplasm divide into genetically identical cells