Genotypes and phenotypes

Question 1

genotype

Answer 1

it describes an organism’s complete set of genes eg. Bb, BB

Question 2

Phenotype

Answer 2

the observal features, traits or outward expressions of a gene eg. brown eyes

Question 3

Dominant genotype

Answer 3

repersented by a capital letter and usually expressed in a heterozogous individaul.

Question 4

Reccesive genotype, what is it masked by

Answer 4

rerpesnteed by a lowercase letter,usually masked by the dominant trait in a thereotzogus indivulda eg for blue eyes B is domiant in Bb

Question 5

when is the recessive genotype expressed

Answer 5

shown if two alleles are expressed for exmaple bb in blueeyes

Question 6

heterozogous

Answer 6

When two different alleles are inherited.
For example, Bb (Brown eyes)

Question 7

homozogous

Answer 7

Two identical alleles from their mother and father.
For example, BB (brown eyes) or bb (blue eyes)

Question 8

Codominance

Codominance

Answer 8

both alleles are dominant and are expressed in the genoype of anindivual eg blood type

Question 9

when does codominance occur

Answer 9

when both alleles from the genotype are fully expressed in the phenotype of a heterozygous individual.

Question 10

incomplete domiance

Answer 10

Incomplete dominance occurs when neither allele from the genotype is fully expressed, resulting in a ‘blending’ of traits eg. for flowers an example of incmoplete domaince is C^r C^w

Question 11

how is the sex of an indiivudal determeidn

Answer 11

is determined by what sex chromosome is contained within the egg and sperm at fertilization.

Question 12

what determines the gender of an indiivudal

Answer 12

The sperm determines the sex of the offspring as males can produce sperm containing either X or Y chromsome whereas females can onlyproduce gametes containing X chromsomes

Question 13

Sex linked inheritance are either inherited from and what does sex inheritnace include

Answer 13

X or Y chromosome

colour blindness, haemophilia, baldness.

Question 14

Why do more men have disorders linked to sex linked inhertiane

Answer 14

Since males only have one X chromosome, they are unable to mask the recessive trait, so therefore are expressed.

Question 15

what factors can influence genotyeps

Answer 15

the environemnt can dramatically effect the way genes express themselves in genotypes eg. if you were raised in a place where you lacked essiental nutrients and were manlourished then your frame and bone structure will be smaller and weaker than someone who grew up well off and noursihed.

Question 16

Proportionate heritability

Proportionate heritability

Answer 16

is Where an organism’s phenotype is explained partially by genes and partially by environmental factors

Question 17

example of Proportionate heritability

Answer 17

the colour hydrangeas are dependent o the PH of the soil they are produced in

eg. putting alkaline soil will cause the flower to become pink whereas acidicifc soil will cause the flower to become blue and basic soil will cause the flower to become purple

Question 18

An example of how the enviornment effects phenotype in refercne to point colouring

Answer 18

Tyrosinase is an enzyme that is repsonsible for melanin production, himalayoan rabbits are homozngous fora rescessive allele of the tyrosiane gene, therefore their born with white fur but when exposed to colder envornmrents they are partially black.

Question 19

epigenticis

Answer 19

the study of heritable phenotypes changes that do not involve alterations in the DNA nucleotide sequences

Question 20

examples of epigentic mechanissms

Answer 20

methylation of histones which tell the cell decrease/slowly down gene transcription, thus decreasing gene expression

Acetylation of histones which tells the cell to increase/quickening gene transcpriton/quickening thus increasing gene expression

Question 21

why does having sickle cell anemia protect you from malaria

Answer 21

1.INCREASED MALARIA RESISTANCE AS IMMUNE SYSTEM IS ABLE TO IDNEITYF WHICH CELLS HAVE BEEN AFFECTED BY MALARIA QUICKER

2.harder for malaria to grow

Question 22

differienate betwene homologous chromsoomes and sister chromatids

Answer 22

homologous chromeomse are a pair of chormoems wiht the same lenght and size, gene and gene loci and have the same centromre position, wheras sister chromatids are 2 chromomes held togheter by a centromeree

Question 23

what is meant by sex linked inheritance

Question 24

what stage are chromomes visible

Answer 24

prophase

Question 25

d

synapisis

Answer 25

pairing of homologus chromomes to allow genes to swap-fusion ofgenes–process that allows crossing over to occur

Question 26

compare what kind of cell is produced during meiosis to mitosis

Answer 26

meioiss-gametes
mtipsis-somatic cells

Question 27

nature vs nurture

Question 28

how epignetics work

Answer 28

The environment changes the way that the genotypes are expressed but does not change the sequence of the DNA.

Question 29

differnce between genetics and epigentics

Answer 29

epignecites does not alter DNA nucleotide sequence

Question 30

wh

why does methalyation of histones decrease gene transcritpion but aceytlation of histones increase gene transcirption

Answer 30

HISTONE MODIFICATION -> Methylation of the histone tails will cause increased wrapping of the DNA around the histones causing silencing of the dna

actyheltiaton of hitsiones–opposite

Question 31

wh

why are epigentics important

Answer 31

it allows usto respond to the enviornemnt around us and adapt to it which increases our chances of survival

Question 32

is there somatic transmission in epigentics

Answer 32

it is somatically hertiabble and someepigentic changes may be passed onto offspring.