B2.7 Mitosis and Meiosis

Question 1

What are the stages of mitosis? [5]

Answer 1

1) Prophase
2) Metaphase
3) Anaphase
4) Telephase
5) Interphase

Question 2

Explain what happens during each phase of mitosis

Answer 2

1) Chromosomes are replicated (sister chromatids)
2) Centromere are produced either side
3) They meet in the centre and attach using spindle fibres
4) They split apart
5) Two new cells are formed

Question 3

Where does mitosis occur? And where does meiosis occur?

Answer 3

Mitosis = all over the body 
Meiosis = sex organs

Question 4

How many divisions are there in mitosis? And how many divisions are there meiosis?

Answer 4

Mitosis = once 
Meiosis = twice

Question 5

What does mitosis create? And what does meiosis create?

Answer 5

Mitosis = body cells 
Meiosis = gametes

Question 6

What is the number of chromosomes in mitosis? And what is the number of chromosomes in meiosis?

Answer 6

Mitosis = 46 (diploid) 
Meiosis = 23 (haploid)

Question 7

How many cells does mitosis produce? And how many cells does meiosis produce?

Answer 7

Mitosis = 2 cells 
Meiosis = 4 cells

Question 8

What is the function of mitosis? And what is the function of meiosis?

Answer 8

Mitosis = growth and repair, cellular reproduction
Meiosis = sexual reproduction

Question 9

Define what a stem cell is

Answer 9

A not yet specialised cell, it replicates many times and has the potential to become different cells

Question 10

Define haploid

Answer 10

Half the DNA, gametes have haploid chromosomes

Question 11

Define diploid

Answer 11

All the DNA, zygotes have al the DNA

Question 12

Give information about the disease Polydactyly [3]

Answer 12

• Extra fingers and toes
• Dominant allele of the gene
• One parent carries it

Question 13

Give information about Cystic fibrosis [6]

Answer 13

• Faulty gene in glands that secrete
• Thick secretions of mucus
• Both parents carry it
• Causes liver failure, diabetes and infections
• Traps pathogens
• Causes infertility and malabsorption

Question 14

Where are stem cells found? [4]

Answer 14

• Bone marrow
• The brain
• In the blood
• Embryos

Question 15

What are the two types of stem cells?

Answer 15

1) Adult stem cells

2) Embryotic stem cells

Question 16

What can stem cells be used for and why?

Answer 16

Treating sickness as they can be easily turned into specialised cells which can slow down the process of the illness

Question 17

What specifically can stem cells be used for?

Answer 17

treating and replacing organs and tissues

Question 18

Give ethnic reasons to why people might agree or disagree with embryotic stem cells

Answer 18

Scientists = using embryos is better as there are more stem cells to work with

Religious people = People are just having a baby for stem cells and the embryo has the right to live

Question 19

Define heterozygous

Answer 19

Where two alleles are different

Question 20

Define homozygous

Answer 20

Same gene from both parents in the zygote

Question 21

Define allele

Answer 21

Represents different variations of the gene

Different forms of the same gene

Question 22

define dominant

Answer 22

A trait that overrides recessive genes (shown with a capital letter)

Question 23

Define recessive

Answer 23

A trait that is hidden by the dominant. Two is needed to show characteristics

Question 24

Define genotype

Answer 24

genes you have inherited

Question 25

What are the advantages of genetic screening? [4]

Answer 25

• Choice to keep the baby or have an abortion
• Reduces people with the disease
• Prepares people emotionally and financially
• Reduces health care costs overtime

Question 26

What are the disadvantages of genetic screening? [4]

Answer 26

• Encourages abortion
• Puts embryo at risk, miscarriage
• May cause harm to the mother
• Very expensive