genetics (definitions)

Question 1

haploid

Answer 1

a eukaryotic cell or organism containing only one complete set of chromosomes

Question 2

diploid

Answer 2

a eukaryotic cell or organism containing two complete sets of chromosomes

Question 3

gene

Answer 3

a length of DNA that codes for a particular polypeptide or protein

Question 4

allele

Answer 4

one of two or more alternative nucleotide sequences at a single gene locus; alleles are variant forms of genes

Question 5

locus

Answer 5

the position on the chromosomes where a gene occurs; alleles of the same gene occupy the same locus

Question 6

genotype

Answer 6

the alleles that an organism carries (present in every cell)

Question 7

phenotype

Answer 7

the appearance of the organism; the way in which the genotype of the organism is expressed

Question 8

homozygous

Answer 8

a genotype in which the two alleles of the gene are the same (eg HH, hh)

Question 9

heterozygous

Answer 9

a genotype in which the two alleles of the gene are different (eg Hh)

Question 10

dominant allele

Answer 10

an allele with a phenotype that is expressed even when present with an allele that is recessive to it

Question 11

recessive allele

Answer 11

an allele with a phenotype that is not expressed when an allele that is dominant to it is present

Question 12

codominant allele

Answer 12

alleles that are both expressed if they are present together in a heterozygous person