Lesson 2 - Mutations

Question 1

meaning translocation

Answer 1

a mutation in which part of one chromosome breaks off and rejoins to another completely different chromosome. It may be balanced, if 2 parts of the chromosome effectively swap, or it may be unbalanced if a piece simply breaks off one chromosome and joins another

Question 2

meaning sex chromosomes

Answer 2

chromosomes that carry the information that determines the sex of the individual

Question 3

which chromosomes do human females have

Answer 3

XX

Question 4

which chromosomes do human males have

Answer 4

XY

Question 5

meaning non-disjunction

Answer 5

the process that occurs when members of a pair of chromosomes fail to separate during reduction division of meiosis, resulting in one gamete with 2 copies of a chromosome and one gamete with no copies of that chromosome

Question 6

meaning monosomy

Answer 6

when only one member of a pair of chromosomes is present in a cell

Question 7

meaning polysomy

Answer 7

when a cell contains 3 or more rather than 2 chromosomes of a particular type

Question 8

meaning aneuploidy

Answer 8

when a cell contains too few or too many chromosomes

Question 9

meaning mutation rate

Answer 9

the rate at which mutations naturally occur

Question 10

meaning mutagens

Answer 10

chemicals known to increase the rate of mutation

Question 11

how are people with down’s syndrome formed

Answer 11

when there is non-disjunction of chromosome 21 sperm/ ovum. After fertilisation, the zygote have polysome, with 3 copies of chromosome 21

Question 12

what are the symptoms of down’s syndrome

Answer 12

heart abnormalities, learning difficulties, lack fo muscle tone, visual problems