Terms For Genetics

Question 1

Continuous variation

Answer 1

Wide range of characteristics varying between two extremes
-Polygenic: lots of genes work together
-Line graph or histogram

Question 2

Discrete variation

Answer 2

Small number of distinct groups
-Single gene inheritance
-Bar graph

Question 3

Gamete

Answer 3

Sex cell

Question 4

Gene

Answer 4

-Control certain characteristics
-Small sections of DNA which code for proteins

Question 5

Alleles

Answer 5

Different forms of the same gene for a particular characteristic

Question 6

Genotypes

Answer 6

The genes inherited by an organism for a particular characteristic

Question 7

Phenotypes

Answer 7

The physical appearance of a characteristic

Question 8

Dominant

Answer 8

An allele that is always expressed (masks recessive alleles)

Question 9

Recessive

Answer 9

Need 2 recessive alleles to be expressed (masked by dominant alleles)

Question 10

True breeding

Answer 10

A homozygous organism/individual so they can only pass on one type of allele for a particular characteristic

Question 11

Homozygous

Answer 11

An organism that has two alleles that are the same

Question 12

Heterozygous

Answer 12

An organism that has two alleles that are different

Question 13

Monohybrid cross

Answer 13

A cross involving 1 charactericstic
-two true breeding individuals are mated together
-All the F1 are heterozygous for the gene

Question 14

Variation

Answer 14

All the differences that exist between members of the same species

Question 15

Why may predicted rations not be achieved?

Answer 15

-fusion of gametes (fertilisation) is a random process involving an element of chance

-the sample size, ie number of offspring produced, is often too small