2 Reproduction and Variation

Question 1

diploid cell

Answer 1

cell with a double set of chromosomes as in body cells

Question 2

gamete

Answer 2

sex cell

Question 3

anther

Answer 3

organ which produces male gametes (pollen) in flowering plants

Question 4

ovary

Answer 4

organ which produces eggs (ova) in animals

Question 5

ovary

Answer 5

organ in flowering plants which contains ovules (female gametes)

Question 6

testis

Answer 6

organ in animals which produces sperm (male gametes)

Question 7

haploid cell

Answer 7

cell with a single set of chromosomes as in gametes

Question 8

zygote

Answer 8

diploid cell produced when haploid gametes are fertilised

Question 9

fertilisation

Answer 9

fusion of the nuclei of 2 haploid gametes to make a diploid zygote

Question 10

discrete variation

Answer 10

variation where individuals are in definite groups e.g. gender, tongue rolling

Question 11

continuous variation

Answer 11

variation where individuals vary along a range with most around average e.g. height, number of young in a litter

Question 12

phenotype

Answer 12

physical characteristics e.g. colour of fur

Question 13

genotype

Answer 13

set of genes possessed by an organism e.g RR, Rr or rr

Question 14

single gene inheritance

Answer 14

where a characteristic is determined by one gene usually leading to discrete variation

Question 15

polygenic inheritance

Answer 15

where a characteristic is determined by several genes usually leading to continuous variation

Question 16

dominant

Answer 16

a characteristic which only needs one copy of the gene to be shown (usually represented by a capital letter)

Question 17

recessive

Answer 17

a characteristic which needs 2 copies of the gene to be shown otherwise the dominant copy masks it e.g. rr

Question 18

homozygous

Answer 18

a genotype with 2 copies the same for a gene e.g. RR or rr

Question 19

heterozygous

Answer 19

a genotype with 2 different copies of a gene e.g. Rr