B6 - Genetics and Evolution

Question 1

What do these terms mean
a) DNA

Answer 1

DNA - The genetic material which makes up chromosomes and genes

Question 2

What do these terms mean
a) Double Helix

Answer 2

Double Helix - the shape of DNA - 2 twisted polymers

Question 3

What do these terms mean
a) Chromosome

Answer 3

Chromosome - A long stand on DNA. One chromosome can contain thousands of genes

Question 4

What do these terms mean
a) Gene

Answer 4

Gene - A section of DNA coding for one characteristic . There can be hundreds of genes on one chromosome

Question 5

What do these terms mean
a) Asexual reproduction

Answer 5

Asexual reproduction - Reproduction which only requires one organism.

Offspring are genetically identical to the parent

Question 6

In sexual reproduction, why are the offspring different to the parents?

Answer 6

The offspring share half the DNA with each parent.

They are not genetically identical to either parent.

Question 7

What are the genetic differences between men and women?

Answer 7

Men = XY

Women = XX

Question 8

Draw a punnet square to show the inheritance of the sex chromosomes in males and females

Answer 8

Question 9

What is genetic variation?

Give some examples

Answer 9

Differences caused by the inheritance of different genes

e.g. eye colour / Blood Group / ear lobes etc

Question 10

What is environmental variation?

Give some examples

Answer 10

Environmental Variation is caused by the choices we make and the way we live our lives - we were NOT born with them

e.g. Tattoo / Scar / Piercings

Question 11

What are mutations?

Answer 11

Mutations - Changes in DNA

These often have no effect, but can sometimes have a positive or a negative effect

Question 12

In Cystic Fibrosis

a) Dominant or Recessive
b) Symptoms
c) Treatment

Answer 12

Cystic Fibrosis is

a) Recessive - both parents much carry and pass on the recessive gene
b) Affects the cell membranes - causing build up of mucus in the lungs
- The pancreas does not release all digestive enzymes
c) Phsiotherpy to remove mucus from the lungs (reduce chest infections)

Tablets containing enzymes are taken before eating

Question 13

In Polydactyly

a) Dominant or Recessive
b) Symptoms
c) Treatment

Answer 13

Polydactyly is

a) Dominant - only one parent needs to pass on the gene
b) Symptoms - extra fingers and toes
c) Extra fingers can be surgically removed

Question 14

Explain these terms in genetics

a) Dominant
b) Recessive

Answer 14

Dominant - Likely to be shown

Recessive - less likely to be shown

Question 15

What does the term ‘carrier’ mean in genetics?

Answer 15

Someone who has the recessive gene but does not have any symptoms

A carrier does not have the symptoms but can pass the recessive gene on

Question 16

Give 2 examples of how we use selective breeding in agriculture (farming)

Answer 16

Breeding cattle with better characteristics for producing meat e.g. larger size / more milk

Crops which are disease resistant

Breeding crops with better yields e.g. apple trees that yeild (grow) more fruit

Question 17

How would you breed the whitest sheep?

Answer 17

Selective breeding

Take the whitest male, and whitest female and breed them together

Question 18

What are the disadvanges to selective breeding?

Answer 18

More chance of breeding in negative characteristics along with good

Reduces the ‘gene pool’ (selection of Alleles) which can mean less immunity to disease

Question 19

What is the genetic engineering?

Answer 19

Taking the genes from one organism and inserting them into another

e.g. human gene for insulin inserted in bacterial DNA so bacteria make insulin for treating diabetes

Question 20

How is genetic enegineering used?

Answer 20

Genetic egineering is taking the genes from one organism and inserting them into another

e.g. human gene for insulin inserted in bacterial DNA so bacteria make insulin for treating diabetes

Question 21

What are the ethical concerns surrounding genetic engineering?

Answer 21

• It can be hard to predict how changing an animals DNA will effect the animal
• Many genetically modified (engineered) embryos don’t survive
• Some genetically modified animals suffer from health problems

GM Crops

• Possible reduced flowers which could effect insect population
• Lack of understanding of how GM crops may affect humans when they eat them

Question 22

What is the theory of evolution by natural selection?

Answer 22

• All organisms show variation
• Some variations give an advantage
• They are more likely to survive
• More likely to breed/reproduce
• Pass on ‘good’ genes to the offspring
• Eventally a new species evolve - evolution