7D- nature vs nurture

Question 1

environment

Answer 1

the conditions and resources external to an organism with which that organism typically interacts

Question 2

proportionate heritability

Answer 2

the amount of phenotypic variation that can be explained by genes in a given population

Question 3

epigenetics

Answer 3

changes to an organisms phenotype resulting from modifications to gene expression

Question 4

gene expression

Answer 4

the process of reading the information stored within a gene to create a functional product, typically a protein

Question 5

transcription

Answer 5

the process whereby a sequence of DNA is used to produce a complementary sequence of mRNA

Question 6

translation

Answer 6

the process whereby an mRNA sequence is used to produce a protein

Question 7

DNA methylation

Answer 7

the process by which methyl (-CH3) groups are added to particular nucleotides in a DNA segment so as to modify the expression of a gene

Question 8

somatically heritable

Answer 8

genetic traits or alterations to a cell which are inherited by daughter cells during the course of regular mitotic cell division

Question 9

what is an organisms phenotype explained by

Answer 9

partly by genes and partly by environmental factors

Question 10

what does proportionate heritability tell us

Answer 10

an organisms phenotype can be entirely due to the environment (dying hair) or genes can play the main role in phenotype determination (blood type)

Question 11

how do environmental factors impact phenotype

Answer 11

they will typically act in ways that influence the performance of an organisms proteins. they modify the functions of proteins rather than affecting the creation of the proteins themselves

Question 12

what is transcription and translation

Answer 12

transcription involves reading and copying out a gene sequence from a DNA molecule. the copy- mRNA- moves out of the nucleus to ribosomes in the cytosol or on the RER for translatoin
translation is where the mRNA instructs the ribosome how to build the specific protein for which the DNA sequence codes

Question 13

what is the process of gene expression

Answer 13

DNA -transcription> copy of gene (mRNA) -translation> protein

Question 14

what does epigenetics alter

Answer 14

they alter the process of transcription.

Question 15

how can epigenetics regulate expression

Answer 15

they can increase or decrease the amount of transcription of a particular gene and therefore alter the amount of protein produced. epigenetics regulate the expression of specific proteins, which changes growth and development

Question 16

show how the presence or absence of an epigenetic factor can produce a different genotype

Answer 16

epigenetic factor X present → gene Z turned on → protein produced → phenotype A
epigenetic factor X present → gene Z turned off → protein not produced → phenotype B

Question 17

what are 2 types of epigenetic changes

Answer 17

DNA methylation and histone modification

Question 18

what is DNA methylation

Answer 18

methyl groups attach to nucleotides within the DNA sequence of a particular gene
they then alter levels of gene expression, typically by silencing it

Question 19

what is DNA demethylation

Answer 19

removal of methyl groups from a DNA sequence
gene is expressed

Question 20

what is histone modification

Answer 20

when histone methyltransferases HMT join methyl groups to histone tails and modify how tightly a DNA molecule is wrapped aruond it
if the DNA is condensed tighter around the histone, it makes it more difficult for genes to be transcribed and less likely to be expressed
if the DNA is less tightly packed, it is easier to transcribe and more likely to be expressed

Question 21

what are methyl groups like

Answer 21

they are like a light switch. when they attach to parts of our DNA sequence, they tell our cells to read or to not read this section, which in turn means that the associated proteins aren’t created

Question 22

what is the importance of epigenetics

Answer 22

helping to control cell differentiation → despite containing the same DNA, not all of the cells inside an organism are the same. different cell types are regulated largely by epigenetic mechanisms that turn off unneeded genes and promote expression of required genes
provide an environment response mechanism→ epigenetic modifications act as a rapid feedback mechanism by which an organism can respond to changes in their environment. the genes for these proteins are stimulated by high temperatures to demethylate, activating transcription and ensuring more of these useful proteins are synthesised

Question 23

are epigenetics heritable

Answer 23

they are somatically heritable although some epigenetic changes may also be passed onto offspring during reproduction

Question 24

why do identical twins become increasingly different as they age

Answer 24

genes are being switched on or off by exposure to different environmental factors, but these are being passed onto new cells as they grow and regenerate- somatically heritable