Mutations & Gene Expression

Question 1

What is a mutation?

Answer 1

a change to the base sequence of DNA

Question 2

What is a mutagenic agent?

Answer 2

a substance which increase the rate of mutations

Question 3

What are the 6 types of mutations?

Answer 3

1. substitution
2. deletion
3. addition
4. duplication
5. inversion
6. translocation

Question 4

What is a substitution mutation?

Answer 4

one or more bases swapped for another

Question 5

What is a deletion mutation?

Answer 5

one or more bases are removed
causes a frameshift

Question 6

What is an addition mutation?

Answer 6

-one or more bases are added
-frameshift to the right

Question 7

What is a duplication mutation?

Answer 7

-one or more bases duplicated

Question 8

What in an inversion mutation?

Answer 8

a group of bases gets separated from the sequence and re-joins in the same position but inverted

Question 9

What is translocation of bases?

Answer 9

a group of bases gets separated from the DNA sequence & attaches to a different chromosome

Question 10

What type of mutation often has the biggest effect?

Answer 10

translocation

Question 11

What are the two reasons why a mutation might not cause a change in the amino acid sequence?

Answer 11

-degenerate nature of code
-a mutation could occur in the intron

Question 12

What are the 4 types of stem cells?

Answer 12

1. Totipotent
2. Pluripotent
3. Multipotent
4. Unipotent

Question 13

What are totipotent stem cells?

Answer 13

they can differentiate into any type of cell

Question 14

What are pluripotent stem cells?
And where are they found?

Answer 14

they can differentiate into any type of cell apart from placental cells
found in embryos

Question 15

What are multipotent stem cells?
And are they embryonic/adult?

Answer 15

can differentiate into a limited type of cell
-found in adults

Question 16

What are unipotent stem cells?

Answer 16

can differentiate into one type of cell

Question 17

What are the 4 sources of stem cells?

Answer 17

-embryonic
-umbilical cord
-placental
-adult

Question 18

How do stem cells become specialised?

Answer 18

-when replicating, they only transcribe and translate certain parts of their DNA
-only certain genes are expressed
-proteins produced
-determine cell structure / processes

Question 19

What are cardiomyocytes?

Answer 19

heart muscle cells

Question 20

What does iPS stand for?

Answer 20

induced pluripotent cells

Question 21

What is iPS?

Answer 21

when specialised adult body cells (unipotent) are made to express certain transcription factors
Which makes the cells pluripotent

Question 22

What could stem cells be used for in medicine?

Answer 22

-spinal cord injuries (nerve cells)
-heart disease (heart tissue)
-organ transplants

Question 23

What is the rate of transcription controlled by?

Answer 23

transcription factors

Question 24

What type of biological molecules are transcription factors?

Answer 24

proteins

Question 25

What are the 2 types of transcription factor?

Answer 25

activator repressor

Question 26

What is the promoter region?

Answer 26

-a short section of DNA -at the start of a gene -that the RNA polymerase binds to

Question 27

What is the enzyme responsible for synthesising mRNA from DNA ?

Answer 27

RNA polymerase

Question 28

How do activators work?

Answer 28

-moves from cytoplasm to nucleus -binds to the promoter region -RNA polymerase binds to activator, binding it to DNA strand -gene is transcribed

Question 29

How do repressors work?

Answer 29

-moves from cytoplasm to nucleus -binds to promoter region -prevent RNA polymerase from binding -stopping transcription

Question 30

What type of hormone is oestrogen?

Answer 30

steroid hormone

Question 31

What does oestrogen have to form to act as a TF?

Answer 31

forms an oestrogen oestrogen receptor complex

Question 32

What happens when an OORC is formed?

Answer 32

-the complex changes shape -becomes an active TF (activator) -can now enter the nucleus

Question 33

What is the definition of epigenetics?

Answer 33

Heritable changes in gene function without changes to base sequence of DNA (Changes may due to lifestyle, stress, diet)