3 Genetics

Question 1

Allele

Answer 1

One of a number of alternative forms of a gene that can occupy a given gene locus on a chromosome. They differ from one another by one or only a few bases.

Question 2

Chromosome

Answer 2

Single long molecule of DNA, associate with protein, that carries the genes in linear order.

Question 3

Co-dominant

Answer 3

Pairs of alleles that both affect the phenotype when present in the heterozygous state.

Question 4

Dominant

Answer 4

An allele that has the same effect on the phenotype when in either the homozygous or heterozygous state.

Question 5

F1

Answer 5

first generation

Question 6

F2

Answer 6

second generation

Question 7

Gamete

Answer 7

General name for haploid sex cells, eggs, sperm cells and pollen grains.

Question 8

Gene

Answer 8

The basic unit of inheritance by which hereditary characteristics are transmitted from parent to off-springs. Section of DNA which codes for a specific characteristic.

Question 9

Genotype

Answer 9

The alleles possessed by an organism.

Question 10

Heterogametic

Answer 10

The gender that has two different sex chromosomes in the pair, XY. This is the male.

Question 11

Heterozygous

Answer 11

Having two different alleles at a gene locus.

Question 12

Homogametic

Answer 12

The gender that has an identical pair of sex chromosomes, XX. This is the female.

Question 13

Homologous

Answer 13

Chromosomes in a diploid cell which contain the same sequence of genes but are derived from different parents.

Question 14

Homozygous

Answer 14

Having two identical alleles at a gene locus.

Question 15

Locus

Answer 15

The specific position on a homologous chromosome of a gene.

Question 16

Monohybrid Cross

Answer 16

A genetic cross involving only one characteristic.

Question 17

Phenotype

Answer 17

The characteristics of an organism.

Question 18

Pure breeding

Answer 18

Having a homozygous genotype. Usually used to describe a dominant phenotype.

Question 19

Recessive

Answer 19

An allele that only has an effect on the phenotype when it is in the homozygous state.

Question 20

Sex chromosomes

Answer 20

The pair of chromosomes that control the sex or gender of the individual. In mammals and some other organisms these are the X and Y chromosomes.

Question 21

Sex linkage

Answer 21

The pattern of inheritance characteristic of genes located on the sex (X) chromosomes.

Question 22

Test Cross

Answer 22

Using a homozygous recessive to test a phenotypically dominant phenotype to determine if it is heterozygous or homozygous.

Question 23

Autosomes

Answer 23

The chromosomes other than sex chromosomes.

Question 24

Diploid

Answer 24

pairs of chromosome called homologous pairs

Question 25

Haploid

Answer 25

one chromosome from each homologous pair.

Question 26

Mutations

Answer 26

random changes in base sequence of DNA which give rise to new alleles.

Question 27

Genome

Answer 27

The whole of the genetic information of an organism

Question 28

Genome Size

Answer 28

The total length of DNA in an organism.

Question 29

The Human Genome Project

Answer 29

Determines the entire base sequence of all the human chromosomes

Question 30

Sickle Cell Anemia

Answer 30

Caused by a mutation in on of the haemoglobin genes. An amino acid GLUTANIC has been substituted by VALINE.

Question 31

Causes of mutations

Answer 31

Ionising radiation, X-rays, UV light and genic chemicals

Question 32

PCR

Answer 32

Polymerase Chain Reaction copies and amplifies small samples of DNA. Only specific section is amplified through the use of a primer which binds to the complementary regions of DNA.

Question 33

Restriction endonucleases

Answer 33

group of enzymes that recognise very specific sequences of DNA and cut both of the DNA stands at this point.

Question 34

Requirements for gene transfer 4

Answer 34

1- the insulin gene 2- a plasmid 3- a host bacterium (E.coli) 4- 4 enzymes

Question 35

Gene transfer (7)

Answer 35

1- plasmid cut with restriction enzymes to produce sticky ends 2- add insulin gene 3- join loose ends with ligase 4- recombinant plasmid- contains the plasmid genes plus the human insulin gene 5- insert into bacterium 6- bacterium cultured in large vat 7- filtered and purified: human insulin

Question 36

GMOs

Answer 36

genetic code is (nearly) universal so it can be transferred between organisms

Question 37

Benefits of GM

Answer 37

increase production- greater yield | resistant to a specific pest/ external element

Question 38

Risks of GM

Answer 38

developing resistance spread of antibiotic resistance mutations

Question 39

Risks of GM

Answer 39

developing resistance spread of antibiotic resistance mutations

Question 40

Clone

Answer 40

a group of cells or organisms that are genetically identical because they have come from a single parent.

Question 41

Cloning

Answer 41

naturally occurring- plants: cuttings/runners | animals- done after IVF: zygote divides and each will develop into an embryo

Question 42

SCNT 3

Answer 42

Somatic Cell Nuclear Transfer used to clone adult animals. 1- removes nucleus from body cell 2- transplant nucleus into enucleated egg cell 3- egg cell behaves like zygotes and develop into mature frogs

Question 43

Carrier

Answer 43

an individual that has a recessive allele of a gene.

Question 44

Pure/ true breeding

Answer 44

a parent where the dominant phenotype is homozygous.

Question 45

Pure/ true breeding

Answer 45

a parent where the dominant phenotype is homozygous.

Question 46

Mendel

Answer 46

pea-plant

Question 47

most gametes producing cells

Answer 47

are diploid

Question 48

alleles are in pairs

Answer 48

in pairs

Question 49

gametes are produced by

Answer 49

meiosis

Question 50

gametes are

Answer 50

haploid and contain one allele from a pair

Question 51

fusion of haploid gametes to form the zygote

Answer 51

restores the diploid number

Question 52

random fertilisation

Answer 52

mixes alleles

Question 53

Huntingdon's

Answer 53

dominant

Question 54

Haemophilia

Answer 54

chromosome X- recessive

Question 55

Colour blindness

Answer 55

chromosome X- recessive

Question 56

Cystic fibrosis

Answer 56

Recessive

Question 57

Test Cross

Answer 57

to test whether a dominant phenotype is homozygous or heterozygous and ALWAYS crossed with the HOMOZYGOUS RECESSIVE