Cells

Front 1

Klinefelter syndrome

Back 1

2 many chromosomes, has an extra X chromosome so XXY

Occurs in males

Front 2

Epistasis

Back 2

1 gene influences the expression of another gene

Front 3

Phectrophy

Back 3

Single gene with multiple phenotypic effects

Front 4

Polyogenic

Back 4

Phenotype is controlled by multiple genes

Front 5

Linked genes

Back 5

Tend to be inherited together (located close together) on some chromosome

Front 6

Complete linkage

Back 6

Always inherited together (very closely located)

Front 7

Incomplete linkage

Back 7

Genes are on the same chromosomes but can be separate during crossing over

Front 8

Polyploidy

Back 8

Multiple sets of chromosome

Front 9

Genotype

Back 9

Genetic make up/ set of alleles

Front 10

Phenotypes

Back 10

What a gene looks like

Front 11

Mendells laws

Back 11

1. Law of segregation - 2 alleles for each gene separate

2. Law of independent assortment - alleles of different genes assort independently

Front 12

Di-hybrid

Back 12

Mating of 2 individuals who have 1 trait

RRYY x rryy (9:3:3:1)

Front 13

Monohybrid Cross

Back 13

Mating of 2 individuals who have 1 trait

Pp x Pp (phenotype 3:1)

Front 14

Purpose of test crosses

Back 14

To determine an unknown genotype at an organism (PP + Rr)

Front 15

Non-disjunction

Back 15

When chromosomes fail to separate or chromatids didn't separate at the appropriate time

Front 16

Method of test cross

Back 16

Cross the unknown with homozygous recessive to produce offspring- observe offspring

Front 17

Incomplete Dominance

Back 17

Phenotype is an intermediate

(e.g. white flower x red flower = pink flower)

Front 18

Co-dominance

Back 18

Phenotypes exists side by side with an organism

Front 19

How many copies of lethal genes of needed to kill someone?

Back 19

2 copies of the lethal genes

Front 20

Multiple alleles

Back 20

Same genes have more than 2 alleles

(e.g ABO Blood types)

Front 21

X inactivation

Back 21

Inactivate an X chromosome XX toxic becoming highly condensed as a barr body

Front 22

Difference between deletion, duplication, inversion and translocation

Back 22

Deletion- removal of a chromosomes segment

Duplication- repetition of a chromosome segment

Inversion - reversal of a chromosome segment

Translation - relocation of a chromosome segment

-reciprocal - Both exchange fragment

-non-reciprocal - chromosome transfer segments without receiving one in return

Front 23

Lejuene syndrome

Back 23

Deletion of tip of short arm of chromosome

Front 24

Williams-Beuven Syndrome

Back 24

Deletion of chromosome 7

Front 25

Philadelphia translation

Back 25

+ (9-22)

translocation

Front 26

Duchenne muscular dystrophy

Back 26

+(x-21)

translocation

Front 27

Famial down syndrome

Back 27

+ (4-21)

translocation

Front 28

Independent assortment

Back 28

Genes on separate chromosomes which line up in an alternative arrangement (occurs before the end of meiosis 1)

Front 29

Complete linkage

Back 29

When alleles for 2 genes cannot be separated as they are on the same chromosome (very rare as they can be separated during crossing over)

Front 30

Incomplete linkage

Back 30

When 4 possible gametes can be produced due to an unequal ratio (the distance between 2 genes can be used to calculate the ratios)

Front 31

Recombinants

Back 31

After crossing over a combo of alleles occur that is ot found in the parental types ( more parental types than recombinants)

Front 32

How does distance affect likelihood of gene separation?

Back 32

The further apart 2 genes are on a chromosome, the greater the chance that they will be separated during crossing over

Front 33

Calculate the number of map units between genes

Back 33

total number of recombinant gametes /

total number of both parental and recombinant gametes

x100

Front 34

Equilibrium

Back 34

When the gene frequency and genotypes in a population remain the same from one generation to the next

(p^2) + 2pq + (q^2) = 1

Front 35

5 assumptions made by the hardy-Weinberg principle

Back 35

1. Infinite population

2. No mutations

3. No fitness differences among genotypes

4. No migration (so no new genes introduced or removed from population)

5. Random mating allowed to occur

Front 36

Huntington disease

Back 36

Inheritance of a mutated copy of the Huntington gene which has a triplet repeat expansion (encodes fro more CAG repeats)

Front 37

PCR

Back 37

Denaturing - separation of double helix

Annealing - hydrogen bonding of the primers

Extension - DNA polymerase adds nucleotides

Front 38

Difference between somatic and germline mutations

Back 38

Somatic are acquired

Germline are inherited through gametes

Front 39

4 types of mutations

Back 39

1. Frameshift

2. Nonsense

3. Missense

4. Triplet repeat expansion

Front 40

Difference between monogenic and polygenic mutations with examples

Back 40

Monogenic- mutation in 1 gene (e.g. CF, Huntington, haemophilia a&b)

Polygenic - several genes acting together or have environmental factors interacting with the genes (e.g. asthma, diabetes - lack of exercise and diet can interact with genes and turn them on)

Front 41

Locus

Back 41

position of gene allele

Front 42

Difference between Metacentric, acrocentric, telocentric and submetacentric?

Back 42

Metacentric - centromere in centre

Acrocentric - centromere almost at the end

Telocentric - Not in humans but centromere is at the very end

Submetacentric - centromere at one end

Front 43

Downs Syndrome

Back 43

3 chromosome 21's

Mothers over 45 have a 40% chance

Occurs due to non-disjunction

Front 44

2 ways that non-disjunction can occur

Back 44

1. 1st division of meiosis 1:homologous chromosomes fail to go to the 2 daughter cells, all go to one

2. Meiosis 2: 4 daughter cells, 2 normal, N+1 and N-1

Front 45

Turner syndrome

Back 45

Only have 1X chromosome

Front 46

Atavism

Back 46

a trait that appears to disappear from a population and then reappears

Front 47

Sex determination

Back 47

For some species, temp can be a contributing factor

Front 48

Gene pool

Back 48

Total aggregate of genes and alleles in a population at one time

Front 49

Random Genetic drift

Back 49

Random change in allele frequency

Front 50

Bottleneck effect

Back 50

Population dramatically reduced due to an event, resulting in a massively reduced gene pool

Front 51

Founder effect

Back 51

New population forms with only a fraction of genetic diversity hence not being representative of the original population

Front 52

Stabilising selection

Back 52

-Reduces variation but does not change the mean

- medium individuals are favoured and extremes filtered out

Front 53

Directional selection

Back 53

-Favours one extreme

- Shifts the mean in a particular direction

Front 54

Disruptive Selection

Back 54

-Favours the 2 extremes producing 2 peaks

- medium individuals are reduced

Front 55

Sexual selection

Back 55

Females choose male mate depending on appearance (even if they are less suited tot their enviro, males will develop certain features to attract mates)

Front 56

Frequency dependent selection

Back 56

Higher frequency species does worse, so they become less frequent

In the next generation it will have swopped, the opposite will be in a higher frequency and therefore will do worse

Front 57

Geographic distribution of genetic variation

Back 57

The gradual transition/ genetic shift with a variable such as temperature with frost resistance

Front 58

4 requirements for natural selection

Back 58

1. Variation

2. Inheritance

3. Selection (some variants reproduces and pass on certain traits more than others)

4. Time (successful variants accumulate over time)

Front 59

Silent Mutations

Back 59

They have no effect on the phenotype, they often occur in the non-coding regions such as the intergonic region and introns

Front 60

Missense Mutations

Back 60

Change in the amino acid which can alter the proteins ability to function

Front 61

Frameshift Mutation

Back 61

Either through insertion or deletion of base pairs resulting a complete change in the amino acid from that point

Front 62

Nonsense Mutations

Back 62

Base change resulting in the formation of a stop codon, resulting in the early termination of the polypeptide

Front 63

Triplet repeat expansion

Back 63

Some genes contain repeats of a triplet, sometimes causing catastrophic expansion, resulting in a change in protein function or destabilising a chromosome

Front 64

Advantages and disadvantages of using mice

Back 64

Advantages:

-Share many biological functions

- same size genomes and genes in roughly the same order

- similar immune system

- fast breeding

Disadvantages:

- physiologically different from humans

- ethical concerns

Front 65

Embryonic development

Back 65

Embryos begin as a small number of totipotent cells. Progressive restriction of cell fate until terminally differentiated and can only give rise to same type of cells

Front 66

Totipotent

Back 66

A cell able to give rise to all types of cells via cell division

Front 67

Pluripotent

Back 67

Can only give rise to a few types of cell

Front 68

Gene therapy

Back 68

Altering the genetic code of an individuals cell, to correct single gene disorders

Normal allele is inserted into the cells of the affected tissue

Best applied to stem cells as skin cells will eventually die and fall off

Corrected stem cells keep dividing and pass on the corrected gene to all progeny

Front 69

Phylogenetic trees

Back 69

Traces the relationship between species, the more closely related species are closer together on the tree diagram

Multiple sequences come from each patient

Front 70

Multiple HIV viruses within individuals

Back 70

HIV virus within individuals is more closely related than that of different individuals due to mutations that occur during reverse transcription