Genetics

Question 1

uses of mitosis

Answer 1

growth and repair

Question 2

stages of cell cycle

Answer 2

Interphase:
- G phase 1 (cell grows in size and synthesizes mRNA and protein that are required for DNA synthesis plus gets the function of cell type)
- Synthesis (DNA replicates)
- G phase 2 (more Growth and makes stuff for mitosis)
Mitosis
Cytokinesis (actual split)

Question 3

prophase

Answer 3

nucleus membrane has disappeared and DNA unwinds and condenses into chromosomes consisting of 2 sister chromatids

Question 4

metaphase

Answer 4

chromosomes line up at the equator of the cell and spindle fibres form and become visible

Question 5

anaphase

Answer 5

each pair of chromosomes is separated into two identical, independent chromosomes

Question 6

telophase

Answer 6

a nuclear membrane forms around each set of chromosomes to separate the nuclear DNA from the cytoplasm. The chromosomes begin to uncoil, which makes them diffuse and less compact

Question 7

cytokenesis

Answer 7

divides the cytoplasm of the parental cell into two daughter cells.

Question 8

uses of meiosis

Answer 8

Forms the gametes(sex cell) that only has 23 chromosomes(half the information) as meiosis has 1 interphase but 2 metaphases forming 4 gametes it allows for each gamete to be unique due to the genetic shuffling

Question 9

people who discovered DNA

Answer 9

Rosalind Franklin and Maurice Wilkins found it was a double helix
James Watson and Francis Circk discovered 3D structure

Question 10

3 bits of DNA

Answer 10

Deoxyribose sugar
Phosphate bond
Nitrogenous base (A=T. C≡G)

Question 11

steps of protien synthesis

Answer 11

• DNA unzipped and a complementary mRNA is formed (T is replaced with U)
• mRNA moves from nucleus to cytoplasm and attaches to a ribosome
• for every 3 bases (a codon) one complementary tRNa lines up with the mRNA sequence
• tRNA molecules transport specific amino acids to the ribosome
• chain of several hundred amino acids in the correct order according to the original DNA is then made. This is called a polypeptide

Question 12

causes of mutations

Answer 12

• radiations
• chemicals in foods
• carcinogens in general
• random error in copying DNA

Question 13

effects of muations

Answer 13

can be harmless as codes for same or extremely similar amino acid or occurs in the”junk DNA” / non coding DNA
can be harmful- ie genetic diseases or cancer or no longer being able to synthesize certain nutrients
can be helpful : being more resistant to malaria (when successful leads to evolution

Question 14

types of mutations

Answer 14

insertion
deletion
substitution

Question 15

Human genome project

Answer 15

aims:
- identify genetic diseases and treat them better (have identified 4000 genes so far)
- help identify history and migration patterns
- personalised medicine (recommend better preventative action and identify targets of drugs more effectively)

Question 16

possible issues that could arise from Human genome project

Answer 16

• health insurance companies could change rates or deny service to people more at risk for certain diseases
• eugenics
• lack of genetic diversity
• breeding a “perfect” race

Question 17

genotype

Answer 17

persons genes
can be heterozygous or homozygous

Question 18

phenotype

Answer 18

characteristic presented

Question 19

allel

Answer 19

different form of a gene

Question 20

polydactyly

Answer 20

dominant - extra finger

Question 21

cystic fibrosis

Answer 21

chlorine path doesn’t work co mucus is thicker and harder to move out of lungs causing frequent lung infection- recessive

Question 22

Embryo screening

Answer 22

DNA isolated from embryo
fluorescent probe mixed with embryo DNA
Probe binds to DNA
UV light shone to look for allels with gene disorders

Question 23

disadvantages of embryo screening

Answer 23

Not used embryos may be destroyed (ethical)
could screen for gender (ethical)
Information goes to health insurance (ethical)
costs alot of money (economic)

Question 24

advantages of embryo screening

Answer 24

carefully monitored in the UK
May not have immediate life threatening consequences

Question 25

variation factors

Answer 25

Environmental genetic

Question 26

types of variation

Answer 26

continuous (e.g hair colour) discontinuous (e.g blood type)

Question 27

why does genetic variation happen

Answer 27

meiosis sexual reproduction genetic mutation

Question 28

lamark

Answer 28

thought repeated strain would cause changes in an organism and those changes would pass down to offspring (doesn't work cuz your genes didn't change)

Question 29

darwin

Answer 29

animals with favorable characteristic are more likely to survive the selection pressure of the environment and hence are more likely to have many offspring to inherit the characteristic (this called natural selection) over time allele becomes more frequent in the population causing it to have evolved over time