definitions

Question 1

trait

Answer 1

a characteristic feature of an organism
(run in families predictably, controlled by one or more genes)

Question 2

genotype

Answer 2

the genetic variant present at a given location in the genome
(variations = alleles)

Question 3

phenotype

Answer 3

an individual’s observable traits
(determined by interactions between genotype and the environment)

Question 4

chromosome

Answer 4

a structure composed of DNA and proteins that bears genetic information

Question 5

gene

Answer 5

a section of DNA that codes for a polypeptide or RNA

Question 6

gene locus

Answer 6

a specific location of a gene along a chromosome

Question 7

alleles

Answer 7

different molecular forms of the same gene
(may be many alleles at a locus)

Question 8

ploidy

Answer 8

the number of copies of a genome an organism has
(haploid, diploid, etc.

Question 9

cell cycle

Answer 9

phases a cell passes through to produce daughter cells by cell division

Question 10

euploid

Answer 10

having the appropriate number of chromosomes

Question 11

aneuploid

Answer 11

having an inappropriate number of chromosomes

Question 12

monosomy

Answer 12

having the loss of 1 chromosome

Question 13

trisomy

Answer 13

having an extra chromosome

Question 14

monohybrid crosses

Answer 14

cross parental varieties with contrasting traits for a single character

Question 15

homozygous

Answer 15

two alleles that are the same

Question 16

heterozygous

Answer 16

two different alleles

Question 17

chimera

Answer 17

an individual who has cells from two different sources, violating typical inheritance patterns

Question 18

chimera

Answer 18

an individual who has cells from two different sources, violating typical inheritance patterns

Question 19

wild type

Answer 19

an allele that is common and thought of as the ‘default’ phenotype

Question 20

mutant alleles

Answer 20

all other alleles but the wild type

Question 21

polymorphic

Answer 21

a gene with multiple alleles

Question 22

pleiotropic allele

Answer 22

has multiple phenotypic effects

Question 23

epistasis

Answer 23

when phenotypic expression of one gene is influenced by the products of other genes

Question 24

penetrance

Answer 24

proportion of individuals with a genotype that develop the expected phenotype

Question 25

expressivity

Answer 25

the degree to which a phenotype is expressed in an individual

Question 26

qualitative traits

Answer 26

have discrete qualities often controlled by alleles at a single locus

Question 27

quantitative traits

Answer 27

show continuous variation which is influenced by genes at many loci as well as the environment

Question 28

homogametic sex

Answer 28

has two copies of the gene

Question 29

heterogametic sex

Answer 29

has one copy of the gene

Question 30

hemizygous

Answer 30

a gene that is present in a single copy in an otherwise diploid individual

Question 31

semi conservative replication

Answer 31

each parent strand of DNA is a template, new molecules have one old and one new strand

Question 32

DNA helicase

Answer 32

enzyme used to ‘unzip’ DNA

Question 33

primase

Answer 33

enzyme synthesises short RNA strand primer that binds to the unzipped DNA

Question 34

DNA polymerase

Answer 34

starts at primer site and begins elongation

Question 35

telomeres

Answer 35

repetitive sequences that bind proteins and prevent the DNA repair system from recognising chromosome ends as breaks

Question 36

crossing over

Answer 36

exchange of genetic material between non sister chromatids

Question 37

independent assortment of alleles

Answer 37

matter of chance how homologous chromosomes line up in anaphase I and which ones go to which daughter cell

Question 38

nondisjunction

Answer 38

pairs of homologous chromosomes / sister chromatids fail to separate during meiosis

Question 39

metastasis

Answer 39

cancer begins in one part of the body before spreading to other areas

Question 40

acquired mutations (spontaneous)

Answer 40

arise during an individual’s lifetime due to environmental impacts or age

Question 41

germline mutations (hereditary cancer)

Answer 41

inherited mutations from either the sperm or egg

Question 42

oncogenes

Answer 42

mutated genes that have the potential to cause cancer

Question 43

tumour suppressor genes

Answer 43

normally limit how much a cell can grow (regulation)