Mutations (Inheritance)

Question 1

What does polymorphic mean?

Answer 1

occurrence of 2 or more clearly different forms or alternative phenotypes in the population of a species

Question 2

What causes a mutation or makes a mutation more likely?

Answer 2

errors in DNA replication, exposure to mutagens (e.g. radiation), viral infection, alleles providing different phenotypes

Question 3

What is natural selection?

Answer 3

certain characteristics are more useful for survival in a species, so these are more likely to reproduce and pass on this gene

Question 4

In a DNA sequence what is a substition?

Answer 4

it is a direct swap of base sequences

Question 5

In a DNA sequence what is a insertion?

Answer 5

a base sequence is added, this causes a frame shift

Question 6

In a DNA sequence what is a deletion?

Answer 6

a base sequence is removed, this causes a frame shift

Question 7

In a DNA sequence what is an inversion?

Answer 7

Where in a sequence of 3 bases that code for an amino acid they are the same bases but occur in a different order

Question 8

Compare rates of mutation in Orangutans, Bacteria, and Peas

Answer 8

Rates of mutation across all organisms are slow, However because bacteria reproduce at a fast rate they have the highest rate of mutations because they are more likely to occur with increased reproduction. Because of this peas have next slowest and Orangutans have the slowest.

Question 9

What do mutagens do? examples?

Answer 9

Mutagens increase rate of mutation (DOES NOT CAUSE MUTATIONS) e.g ionising radiation, chemicals in smoking

Question 10

What are carcinogens?

Answer 10

mutagens that result in a cancer

Question 11

How does a tumour form?

Answer 11

mutated cells that are not destroyed by the immune system divide to produce many clones containing the mutation which then grow out of control

Question 12

What does Benign mean?

Answer 12

tumour stays in one place, uncontrolled division in one area

Question 13

What does Malignant mean?

Answer 13

travel in blood/lymph and will cause uncontrolled division in many areas so multiple tumours form

Question 14

What causes sickle-cell anaemia?

Answer 14

a mutation in the haemoglobin-beta gene found on chromosome 11 which create sickle-shaped red blood cells

Question 15

What are symptoms of sickle-cell anaemia?

Answer 15

anaemia, Swelling of hands and feet, episodes of pain, frequent infections, delayed growth or puberty, vision problems

Question 16

What causes down syndrome?

Answer 16

people with down syndrome have an extra copy of chromosome 21 also called trisonomy 21 - they have 3 copies instead of 2, replication of this cell will always have an extra chromosome

Question 17

what are the symptoms of down syndrome?

Answer 17

A flattened face (especially bridge of nose), Almond-shaped eyes that slant up, A short neck, small ears, a tongue that tends to stick out of the mouth, tiny white spots on the iris of the eye, small hands and feet, a single line across the palm of the hand (palmar crease), small pinky fingers (sometimes curve towards the thumb, poor muscle tone or lose joints, shorter in height than as children and adults.

Question 18

What are some of the effects of down syndrome?

Answer 18

slow growth, slow muscle development, intermediate to moderate learning, short life expectancy, heart and cardiac problems.