3b: Inheritance (not all)

Question 1

Genes

Answer 1

Live in different forms called alleles- give different inherited characteristics

Question 2

Dominant allele

Recessive allele

Answer 2

Only 1 copy of allele is necessary for characteristics to be shown

2 copies of allele necessary

Question 3

Homozygous

Heterozygous

Answer 3

2 identical alleles

2 different alleles

Question 4

DNA molecule

Answer 4

Two strand coiled to form double helix
Strands linked by paired bases: adenine with thymine, cytosine with guanine

AT
CG

Question 5

Codominance

Answer 5

Both alleles contributing to phenotype- both characteristics present at the same time

Question 6

Meiosis

Answer 6

Produces four cells- each with half number (23) of chromosomes- results in formation of generically different haploid gametes

New cells not genetically identical

Happens in ovaries and testes, 2 rounds of division (no interphase in second round)

Question 7

Diploid and haploid number of chromosomes

Answer 7

46 and 23

Question 8

Mutation

Answer 8

Change in order of bases in DNA (change in genetic code)

Question 9

Mutagen

Answer 9

Agent that causes mutation: ionising radiation and chemicals in tobacco

Question 10

Mitosis

Answer 10

Growth, repair, cloning and asexual reproduction
Whole body
Same number of chromosomes 46
Genetically identical

Question 11

Phenotype

Answer 11

Characteristic

Question 12

Genotype

Answer 12

The alleles present in cell nucleus