1.4 Genes and Phenotypic Expression

Question 1

What are the two key parts that play a role in determing what genes are expressed

Answer 1

Cell differnetiation and Day to changes (e.g. environmental conditions may increase the expression of certain gene products when neded

Question 2

Explain cell differentiation

Answer 2

cells all begin as identical clons able to become any type of cell, then differentation occurs, making the cells specific, with more genes expressed that are suited to their purpose

Question 3

What causes differences between our cells

Answer 3

The differences are brought about by the types of proteins each different type of cells produces.

Question 4

What is it called when a gene makes a protein

Answer 4

Gene expression

Question 5

Why do different cell types produce different proteins

Answer 5

Due to genes in their DNA being turned on and off

Question 6

Are some genes expressed constantly in all cells?

Answer 6

Yes - e.g. genes involved in cellular respiration

Question 7

Will all genes be expressed in all cell types?

Answer 7

No

Question 8

Does the rate at which genes are expressed vary?

Answer 8

Yes

Question 9

What two things cause gene regulation (rate at which genese are expressed)

Answer 9

DNA methylation and histone modification

Question 10

Why does DNA methylation and histone modification impact gene regulatio

Answer 10

They both cause changes in the coiling of DNA around a histone

Question 11

What is Chromatin in simple terms

Answer 11

A double stranded helical structure of DNA

Question 12

DNA is complexed with histones to form ……..

Answer 12

Nucleosomes

Question 13

Coiling DNA around histones allows the gene to be….

Answer 13

either expressed or not expressed

Question 14

What does a tighter wrap of the DNA around a histone result in

Answer 14

It restricts the ability for the gene to be expressed, hence reducing the amount of gene product produced

Question 15

What does a looser wrap of the DNA around a histone result in

Answer 15

Results in the DNA more likely to be expressed

Question 16

Does DNA wrap differently around histones for different cells?

Answer 16

Yes - this reults in differences as to which genes are expressed

Question 17

What is DNA methylation

Answer 17

A process in which methyl groups are added to the DNA molecule

Question 18

What does DNA methylation achieve?

Answer 18

DNA methylation can change the activity of a DNA segment without changing the sequence

Question 19

When located in a gene promoter, what does DNA methylation typically do?

Answer 19

Typically acts to repress gene transcription

Question 20

What can methyl groups added to the DNA promote?

Answer 20

The attachement of proteins to the DNA (such as histones, leading to wrapping and inaccessibility of that section)

Question 21

What is one way methylation alters transcription

Answer 21

the Methylation of CpG islands way prevent or enhance the binding of regulatory transcription factors to the promoter region

Question 22

What happens when CpG-binding proteins bind methylated sequences

Answer 22

Transcription is inbited

Question 23

What other protein does methyl Cpg-binding protein recruit to convert the cromatin to a closed conformation

Answer 23

Histone deacetylase

Question 24

What does the methylation of DNA and histones cause

Answer 24

causes nucleosomes to pack tightly together, meaning transcription factors cannot bind to the DNa and genes can not be expressed

Question 25

What is the result of histone acetylation

Answer 25

Loose packing of the nucleosomes, meaning transcription factors cen bind to the DNA and genes are expressed

Question 26

what is epigenetics

Answer 26

The study of changes to the DNA that ocur after differentiation has occured. E.g. differeneces in how gene expression occurs,

Question 27

What is epigenetics NOT the study of

Answer 27

Mutations

Question 28

Give one example of epigenetics

Answer 28

The wrapping or methylation of the DNA sequence

Question 29

Is there evidence to suggest lifetsyle choices can lead to these changes?

Answer 29

Yes

Question 30

What can a high fat diet cause

Answer 30

Certain genes to be over-methylated, leading to a reduction in expression

Question 31

What could a reduction in expression of a certain gene caused by over-methylation lead to

Answer 31

Majpr problems as your cell may not be able to express that gene and make required proteins or reduce the rate at which it’s expressed, leading to a significant impact in overall health

Question 32

If certain genes aren;t expressed due to epigenetics, what could happen?

Answer 32

Processes that organisms have inplace to manage diseases could potentially be limited/stopped/hindered

Question 33

Give an example of what could happen if an important cell is hyper-methylated

Answer 33

If genes that suppress tumour formation due to being hyper-methylated due to environemental or other factors, it is more likley that a tumur will form and cause cancer

Question 34

Epigenetic mechanisms are essential for normal development and …

Answer 34

maintenance of tissue specific gene-expression patterns in mammals.

Question 35

What can the disruption of epigenetic proccecesses lead to

Answer 35

altered gene function and malignant cellular transformation

Question 36

The intiation and progression of cancer, traditionally seen as a gentic disease, is now realised to involve…

Answer 36

Epigentic abnormalities as well as genetic alterations

Question 37

The reversible nature of epigenetic aberrations has led to the emergence of

Answer 37

Epigenetic therapy, which is already making progress with the recent FDA approval of three epigenetic drugs for cancer treatment

Question 38

There is some evidence to suggest that epigenetic changes can be passed onto the next generation. What does this mean?

Answer 38

children could inherit the negative impacts of a parent’s diet/life choices