Bio Definitions

Question 1

Genotype

Answer 1

The genetic constitution of an organism

Question 2

Phenotype

Answer 2

Observable characteristics determined by its genotype and its interactions with the environment

Question 3

Co dominant

Answer 3

Both alleles are expressed and contribute to phenotype

Question 4

Dominant

Answer 4

Allel is always expressed and contributes to phenotype

Question 5

Recessive

Answer 5

Alleles that is only expressed if homozygous then will contribute to phenotype

Question 6

Sex linkage

Answer 6

A genes whose locus is on the X chromosome

Question 7

Monohybrid

Answer 7

A genetic inheritance cross of a characteristic determined by one gene
Assumes 3:1 ratio

Question 8

Dihybrid cross

Answer 8

A genetic inheritance cross for a characteristic determined by 2 genes
Assumes 9:3:3:1 ratio

Question 9

Chi squared test

Answer 9

To see if difference between observed and expected value are significantly different in categorical data

Question 10

Gene pool

Answer 10

All the genes / alleles in a population

Question 11

Loci/locus

Answer 11

Position of allele on chromosome

Question 12

Diploid

Answer 12

Pair of homologous chromosomes

Question 13

Haploid

Answer 13

One set of chromosomes

Question 14

What does Hardy Weinberg predict?

Answer 14

Frequency of alleles of a particular gene will stay constant over many generations providing no mutation, large populations, migration, selection, random mating

Question 15

Why named model organism is good for studying
genetics

Answer 15

Small size so simple nutrient medium so less cost
Reproduce quickly so many generations can be studied
Large number of eggs so improved reliability

Question 16

why would recessive sex-linked
diseases/phenotypes be more
common in XY than XX

Answer 16

XX need 2 recessive alleles

Question 17

Why may a genetic cross
give different phenotypic
ratios to what is expected?

Answer 17

Epistasis
Random fusion of gametes
Small sample size

Question 18

Evidence for allele being recessive?

Answer 18

Parents are heterozygous, and therefore carriers of recessive allele, can both pass recessive allele to child making them affected/recessive
phenotype as homozygous

Question 19

Evidence for X linked disease/trait being recessive

Answer 19

Mum passes on X chromosome with recessive chromosome to son

Question 20

Evidence for allele not being on X chromosome?

Answer 20

Look for homozygous recessive daughter and dad with dominant allele on X chromosomes

Look for homozygous recessive mother and dominant phenotypes son

Question 21

Autosomal linkage

Answer 21

Genes are on the same homologous pair of chromosomes (not the sex chomosomes)

Question 22

Epistasis

Answer 22

When one gene affects the expression of another gene within the phenotype

Question 23

Allele

Answer 23

Different versions of genes