Unit 8 - The control of gene expression

Question 1

Types of mutations

Answer 1

Substitution
Deletion
Addition
Duplication
Inversion
Translocation

Question 2

Why don’t all mutations affect the order of amino acids

Answer 2

Because Dna is degenerate

Question 3

Why do additions, duplications and deletions have a higher chance of causing mutation?

Answer 3

They cause a frame shift which affects more codons

Question 4

3 ways that mutagenic agents can cause mutation

Answer 4

Act as a base
Alter bases
Changing structure of DNA

Question 5

Features of benign tumours

Answer 5

Non cancerous
Slow growing
Cannot form metastases

Question 6

Features of malignant tumours

Answer 6

Grow rapidly
Form metastases
Travel using blood/ lymphatic system

Question 7

Features of tumour cells

Answer 7

Irregular in shape
Larger nucleus
Don’t produce full proteome
Dont respond to growth- regulating processes
Divide more frequently than other cells

Question 8

Features of tumour cells

Answer 8

Irregular in shape
Larger nucleus
Don’t produce full proteome
Dont respond to growth- regulating processes
Divide more frequently than other cells

Question 9

Two types of factors that increase risk of cancer

Answer 9

Environmental factors
Genetic factors

Question 10

Two types of factors that increase risk of cancer

Answer 10

Environmental factors
Genetic factors

Question 11

What are stem cells

Answer 11

An unspecialised cell which can multiply indefinitely and can differentiate to become a specialised cell

Question 12

4 types of stem cells

Answer 12

Totipotent
Pluripotent
Multipotent
Unipotent

Question 13

What can stem cells be used to treat?

Answer 13

Spinal cord injuries
Heart disease and damage
Bladder conditions
Respiratory diseases
Organ transplants

Question 14

3 sources of stem cells

Answer 14

Adult stem cells (Bone marrow)
Embryonic stem cells (Embryos 4-5 days old)
Induced pluripotent (Specialised cells which have been treated)

Question 15

Ethical issues with embryonic stem cells

Answer 15

It is destruction of an embryo which could become a fetus
At the moment of fertilisation the induvidual has the right to life
Adult stem cells ar not as useful as embryonic stem cells
Some induced pluripotent stem cells may be rejected by the body

Question 16

Steps for oestrogen promoting transcription of genes

Answer 16

• Oestrogen binds to a transcription factor forming an oestrogen- oestrogen receptor complex
• This activates the transcription factor
• This then binds to the promoter region of the gene
• This allows RNA polymarase to bind and transcription to occur

Question 17

Types of interfering molecules

Answer 17

SiRNA
miRNA

Question 18

Which is more complementary to the DNA- miRNA or siRNA

Answer 18

siRNA

Question 19

How does siRNA work

Answer 19

Associates with proteins which cut the DNA when siRNA binds

Question 20

How does miRNA work?

Answer 20

Associates with proteins which block transcription when miRNA binds

Question 21

How does methlation affect transcription?

Answer 21

Decreases transcription of gene

Question 22

How dooes acetylation offect transcription?

Answer 22

Increases transcription of gene.

Question 23

Why is ot harder to translate the genome of complex organisms?

Answer 23

• They have large sections of non- coding DNA
• ## They have large complex regultory genes

Question 24

Why use newer sequencing methods?

Answer 24

• Less labour intensive
• Cheaper
• Can be done on a much larger scale

Question 25

methods of isolating genes

Answer 25

Using reverse transcriptase to produce CDNA Using restriction endonuclease enzymes Gene machine

Question 26

Methods of gene amplification

Answer 26

In vivo- gene inserted into a vector- vector inserted into host cell In vitro- using PCR

Question 27

Methods of identification of transgenic host cells

Answer 27

Marker genes

Question 28

Types of gene mutations

Answer 28

Addition Deletion Substitution Inversion Duplication Translocation

Question 29

Step 3- Identification of transformed organisms

Answer 29

- Marker genes inserted at same time as gene being replicated - Host cells grown on agar plates - Marker gene can code for antibiotic resistance - Colonies which survive in antibiotic are grown (replica plating)

Question 30

Two types of gene therapy

Answer 30

Somatic therapy- Body cells Germ line therapy- Sex cells

Question 31

Uses of screening using DNA probes and hybridisation

Answer 31

Identifies heritable conditions Determines how a patient will respond to specific drugs To identify health risks

Question 32

Using electrophoresis to compare DNA of samples

Answer 32

- DNA cut - Using restriction endonuclease - Use electrophoresis - Separate according to length - Add absorbent paper to make them visible (southern blotting) - Make single-stranded by heating/ using alkali - Apply radioactive probe and use autoradiography - Different tandem repeats= different length

Question 33

Uses of genetic fingerprinting

Answer 33

- Determine genetic relationships - Determine genetic variability within a population - Determine culprit in forensic science - Medical diagnosis - Animal and plant breeding

Question 34

Uses of human genome project

Answer 34

- Aids the understanding of gene function and interaction - Scientists can identify genes which are linked to cancer - Identified genes related to Alzheimers

Question 35

Medical uses of Identifying genes

Answer 35

Identifying dangerous alleles which have been inherited

Question 36

General uses of identifying genes

Answer 36

Checking parents of child Selective breeding Forensic science in crime

Question 37

Application of genome projects

Answer 37

Genetic screening for inherited diseases Developing medical treatments for genetic diseases

Question 38

What are primers and what do they do?

Answer 38

Single-stranded DNA Mark beginning and end of DNA being amplified

Question 39

What is a vector

Answer 39

Carrier of DNA/ gene into another cell

Question 40

Steps in PCR

Answer 40

Temperature is increased to 95 degrees to split DNA into single strands Temperature then cooled to 55 degrees to allow primers to anneal Heated again to 72 degrees which is optimum temperature for DNA polymerase to replicate DNA

Question 41

In what direction do strands move in electrophoresis

Answer 41

From negative to positive electrode

Question 42

What can DNA hybridisation be used for

Answer 42

Screen for heritable conditions Check potential drug responses Check for health risks