gene therapy

Question 1

Define genetic mutations

Answer 1

Changes in the nucleotide sequence of the DNA

Question 2

Name 4 examples of spontaneous mutations

Answer 2

Replication error
Tautomerization
Deamination
Depurination

Question 3

Name 6 examples of induced mutations

Answer 3

Intercalating agents
Base analogues
Deaminating agents
Alkylating agents
Oxidising agent
Radiation

Question 4

Replication errors
Some repetitive regions cause slippage and insertion of more repeats.
Can this be repaired?

Answer 4

NO

Question 5

What is a replication error

Can it be repaired?

Answer 5

Normal replication introduces the wrong base once every 10^10 base pairs
Good chance it will get repaired

Question 6

What is Tautomerization?

Answer 6

DNA bases can convert between forms altering the Hydrogen bonds

Question 7

The tautomerization example of Amino to Imino is for what bases?

Answer 7

A or C

Question 8

The tautomerization example of Keto to enol is for what bases?

Answer 8

G or T

Question 9

What is deamination?

Answer 9

A bases looses an amino group

Question 10

How many conversions of C to U happen per cell per day?

Answer 10

100

Question 11

How many conversions of A to G happen per cell per day?

Answer 11

1

Question 12

Which deamination can be repaired?

Answer 12

C A G can be repaired

T CANNOT BE REPAIRED

Question 13

Define depurination

Answer 13

Cleavage of base-sugar bond on A or G is removed. So in replication the base pair is guessed

Question 14

How many Purine glycosidic bonds are hydrolysed per cell per day

Answer 14

~10,000 purine glycosidic bonds

hydrolyse/cell/day

Question 15

What are intercalating agents?

Answer 15

Insert themselves between bases

Question 16

What is the results of base analogues?

Answer 16

Incorporated into DNA more prone t automeric shifts

Question 17

What are alkylating agents?

Answer 17

Add alkyl groups to nucleobases

Question 18

Name 2 examples of alkylating agents

Answer 18

Nitrosamines

Methyl Bromide

Question 19

Can alkylation be repaired?

Answer 19

YES

Question 20

What does Alkylation speed up?

Answer 20

Depurination

Question 21

What are deaminating agents?

Answer 21

Remove amino groups far quicker than spontaneous deamination

Question 22

Name 3 examples of deaminating agents

Answer 22

Nitrous acid
Nitrosamine
Nitrate
Nitrite

Question 23

What mutagen causes the most mutations?

Answer 23

oxidising agents

Question 24

Name an example of an oxidising agent

Answer 24

Superoxide ion O2-

hence H2o2

Question 25

What are inborn errors of mutation?

Answer 25

``` A class of genetic disease involving altered metabolic function, eg mutation in a single gene encoding a metabolic enzyme ```

Question 26

What are 3 types of metabolic disorders

Answer 26

Anabolic catabolic Storage

Question 27

What type of metabolic disorder is Phenylketonuria?

Answer 27

Catabolic

Question 28

Where is the gene mutation to cause Phenylketonuria? | Is it recessive or dominant?

Answer 28

Autosome 12 | recessive

Question 29

What enzyme is affected by a mutation in the Phenylketonuria?

Answer 29

Phenylalanine Hydroxylase

Question 30

What does the phenylketonuria cause?

Answer 30

Inability to metabolise the essential amino acid Phenylalanine. So excess phenyl-ketones in the urine and it builds up in the blood mental retardation organ damage unusal posture

Question 31

What percentages of the classic PKU point mutations are in ____ part of the PAH gene intron/exon splice site coding region promotor

Answer 31

40% in intron/exon splice site 20% of mutations in coding region 40% in promoter

Question 32

What is the normal result to increase Phe?

Answer 32

PAH enzyme converts Phe to Tyr

Question 33

When does PKU mannifest? | What are the results for the sufferer?

Answer 33

``` Manifests after birth 1 in 20,000 newborns 5IQ lost /month Death by 20/30 years Must be put on low Phe diet ```

Question 34

How many types of glycogen storage disease? | Is it dominant or recessive

Answer 34

14 different types | recessive

Question 35

What is the problem caused by glycogen storage disease

Answer 35

Inability to convert glycogen to glucose Enlarged liver Hypoglycaemia

Question 36

What are the 4 enzymes involved in glycogen breakdown

Answer 36

Glycogen phosphorylase Glycogen debranching enzyme Phosphoglucomutase Glucose 6 Phosphatase

Question 37

What causes Glycogen storage disease 1 - von Gierke disease

Answer 37

Phosphorylated glucose produced by glycogen breakdown is not readily transported out of cells The liver contains glucose 6 phosphatase which cleaves glucose 6 phosphate into free glucose Glucose 6 phosphatase is deficient in von Gierke disease

Question 38

What causes Glycogen storage disease V - McArdle disease? Which chromosome is this on?

Answer 38

The muscle glycogen phosphorylase is absent. Myophosphorylase (PYGM) on chromosome 11.

Question 39

How many different mutations in the gene

Answer 39

33 different mutations throughout the gene. 1 in 100,000 20/30 yrs old.

Question 40

What are the results of McArdle diease?

Answer 40

Muscle weakness and cramps Ability to perform strenuous exercise is limited Shows that utilisation of muscle glycogen is not essential for life

Question 41

Can Familial hyperchlestrolaemia be treated?

Answer 41

Only the heterozygous form with statins Decreased production of LDL cholesterol. Produces more receptors.