Bio (genetics)

Question 1

Allele

Answer 1

Different forms of a gene due to slightly different order of bases e.g brows eyes/blue eyes

Question 2

Allele frequency

Answer 2

is a measure of the relative frequency of an allele on a genetic locus in a population

Question 3

Asexual reproduction

Answer 3

Reproduction incolving only one parent. doesnt produce genetic variation

Question 4

Chiasma

Answer 4

point of contact, the physical link, between two (non-sister) chromatids belonging to homologous chromosomes during crossing over

Question 5

Co-dominance

Answer 5

heterozygous individuals have a phenotype that shows the phenotype of both parents

Question 6

Complete dominance

Answer 6

A form of dominance in heterozygous condition where in the allele that is regarded as dominant completely masks the effect of the allele that is recessive

Question 7

crossing over

Answer 7

occurs during meiosis, when the homologous chromosomes line up at the equator, sometimes they tangle, snap and extange genetic information

Question 8

Diploid

Answer 8

a cell or an organisim consisting of two sets of chromosomes: usually, one set from the mother and another set from the farther

Question 9

Evolution

Answer 9

is the change in the characteristics of a species over several generations and relies on the process of natural selection

Question 10

Fertilisation

Answer 10

A process in sexual reproduction that involves the union of male (sperm)
and female (ovum) gametes (each with a single, haploid set of
chromosomes) to produce a diploid zygote

Question 11

Fi

Answer 11

The parental generation (P) is the first set of parents crossed. The F1 (first
filial) generation consists of all the offspring from the parents

Question 12

Founder effect

Answer 12

Is the loss of genetic variation that occurs when a new population is
established by a very small number of individuals from a larger
population.

Question 13

Gamete

Answer 13

sex cell of an organism e.g. sperm, egg, pollen or ova

Question 14

Gametic cells

Answer 14

Sex cells, e.g. sperm, egg, pollen and ova, cells with half the chromosome
number. If a mutation occurs in one of these cells and that cell results in
a zygote, all cells in the offspring will have that mutation

Question 15

Gene

Answer 15

a length of DNA that holds the instructions for a characteristic

Question 16

Gene pool

Answer 16

Refers to the total number of genes of every indevidual in a population

Question 17

Genetic diversity

Answer 17

The total number of genetic characteristics in the genetic makeup of a species

Question 18

Genetic drift

Answer 18

is the change in the frequency of an existing gene variant (allele) in a
population due to random chance alone and not natural selection.

Question 19

Genotype

Answer 19

the genetic makeup of the organism

Question 20

Haploid

Answer 20

when a cell has half the usual number of chromosomes

Question 21

Heterozygous

Answer 21

Different forms of the allele are present in the genotype e.g. Hh

Question 22

Homologous chromosomes

Answer 22

Chromosome pairs (one from each parent) that are similar in length,
gene position, and centromere location. They contain. The position of the genes on each homologous chromosome is the same. However, the genes may contain different alleles.

Question 23

Homozygous

Answer 23

the same form of the allele is present in the genotype e.g. HH or hh

Question 24

Incomplete dominance

Answer 24

Heterozygous indeviduals have a phenotype that is intermediate between the two homozygous phenotypes (like a bland)

Question 25

Independent assortment

Answer 25

The way the homologous chromosomes line up at the equator maternal
and paternal, is completely random

Question 26

Lethal genes

Answer 26

Alleles that produce a gene product that kills the offspring (must have two coppies of the allele)

Question 27

Linked genes

Answer 27

Genes located on the same chromosome that tend to be inherited together

Question 28

Meiosis

Answer 28

The type of cell division which produces gametes

Question 29

Migration

Answer 29

Migration (sometimes called gene flow) refers to the movement of individuals from one population to the other

Question 30

Multiple alleles

Answer 30

Multiple alleles occur with genes that have more than two different alleles. An individual will only have two of the alleles in its genotype.
e.g. Human blood types, complete dominance, and co-dominance

Question 31

why is genetic variation important?

Answer 31

means that populations have the ability to adapt to changes in their environment over generations.

Question 32

Mutation

Answer 32

A permanent change in the bases on the DNA. it is the only way of creating new alleles

Question 33

Natural selection

Answer 33

Selection presure on the whole population, wening out the unfit genes meaning the fitter genes will be passed down into further generations

Question 34

Pedigree chart

Answer 34

is a diagram that depicts the biological relationships between an organism and its ancestors

Question 35

Phenotype

Answer 35

The physical appearance of the organism

Question 36

Population bottleneck

Answer 36

Is an event that drastically reduces the size of a population, may becaused by various events, such as an environmental disaster. The population bottleneck produces a decrease in the gene pool of the population because many alleles, or gene variants, that were present in the original population are lost

Question 37

Pure breeding

Answer 37

A group of identical indeviduals that only produce one type of gamete due to the fact they are homozygous

Question 38

Segregation

Answer 38

the process that occurs during meiosis where pairs of alleles are separated when the homologous chromosomes split

Question 39

selective presure

Answer 39

The selective pressure means that animals that don’t have these characteristics are less likely to survive and reproduce due to natural selection.

Question 40

Sexual reproduction

Answer 40

reproduction involving two parents. Produces genetic variation

Question 41

Somatic cells

Answer 41

body cells

Question 42

Test cross

Answer 42

A genetic cross between a homozygous recessive individual and a corresponding suspected heterozygote to determine the genotype of the latter.

Question 43

Sexual selection

Answer 43

indeviduals dont breed randomly. they choose mates based off preferable characteristics meaning overtime those traits will become more common and prominant within a gene pool.

Question 44

why is genetic variation important to a population/species

Answer 44

to insure the population doesnt die out

Question 45

why are mutations considered the ultimate source of variation

Answer 45

because mutation is the only source of new alleles

Question 46

How are natural selection and sexual selection different

Answer 46

sexual selection is usually just for females where natural selection effects the whole population

Question 47

Genetic drift

Answer 47

Genetic drift refers to the change in allele frequencies in populations due to chance, not selection. It can cause alleles to become “fixed” (when only one allele remains) or to become “lost” (when an allele is totally absent from a population).

Question 48

Founder effect

Answer 48

small group of organisims from original population migrate to a different place and are isolated. not a representation of the total gene pool

Question 49

Why is gene flow important for populations/species

Answer 49

to keep the population strong

Question 50

what does founder effect and bottleneck effect have in common

Answer 50

both a form of genetic flow. change in the gene pool by chance involving a small gene pool