MGD

Question 1

What is sickle cell anaemia? What is its pattern of inheritance?

Answer 1

Autosomal recessive

Glutamate to valine substitute. Results in sickle cell RBC

Question 2

What is beta and alpha thalassaemia? Which one can result in still birth?

Answer 2

beta - decreased or absent beta chains in Hb.

alpha - Decreased or absent alpha chains in Hb.

alpha

Question 3

How are blood clots broken down? What promotes clot breakdown?

Answer 3

Blood clots broken down by Plasmin.

Plasminogen converted to plasmin, promoted by t-Pa and streptokinase.

Question 4

What are the 5 phases of mitosis?

Answer 4

1. Prophase
2. pro-metaphase
3. metaphase
4. anaphase
5. telophase

Question 5

How is genetic diversity achieved during meiosis?

Answer 5

Independent assorment of chromosomes

Crossing over

Question 6

Describe the process of transription

Answer 6

Initiation - TATA box recognised and RNA polymerase recruited

Elongation

Termination - Methyl guanine cap added to 5’ end. 3’ end is polyadenylated

Splicing - introns removed and exons remain

Question 7

Describe the process of translation

Answer 7

1. mRNA binds to ribosome
2. met-tRNA binds to P site.
3. AA bound tRNA binds to A site and Met forms peptide bond using peptidyl transferase
4. Process continues until peptide forms.
5. Stop codon reached. Peptide released.

Question 8

Why does a vitamin C deficiency result in Scurvy?

Answer 8

vit c vital cofactor to prolyl hydroxylase.

prolyl hydroxylase hydroxylates prolines in collagen.

Question 9

How are proteins transpored to the nucleus?

Answer 9

• Protein must contain NLS.
• Binds to importin and translocated to nucleus
• Importin binds to Ran and is recycled.

Question 10

How are proteins targetted to lysosomes?

Answer 10

1. Must have Mannose 6 phosphate signal
2. M6P attaches to M6P receptors on golgi and taken to lysosome
3. Acidc env of lysosome causes detachment. Receptor recycled.

Question 11

How are proteins retained in the ER?

Answer 11

KDEL sequence which attaches to receptors in Golgi network to return it to the ER

Question 12

What is western, southern and northern blotting used for?

Answer 12

SNOW DROP

Southern - DNA

Northern - RNA

Western - Proteins

Question 13

How would you separate proteins according to molecular weight?

Answer 13

SDS-PAGE

Question 14

How would you separate proteins based on pI?

Answer 14

Isoelectric focussing

Question 15

How would you separate proteins based on both weight and pI?

Answer 15

2D-PAGE

Question 16

How would you assess the concentration of a particular protein in a solution?

Answer 16

ELISA

Ab attaches to Protein attached to bottom of test tube. Then antibody attached to enzyme.

Question 17

Define aneuploidy and polyploidy

Answer 17

polyploidy - an addition of entire set of chromosomes

Aneuploidy - not a multiplication of haploid number

Question 18

Define balanced and unbalanced changes in chromosomes

Answer 18

Balanced - no missing or extra info

Question 19

give properties of an alpha helix

Answer 19

0.54nm pitch, 3.6 AAs per turn Right handed

Question 20

where does detox occur in cells

Answer 20

golgi and ER

Question 21

in what circumstances is a zwitterion deprotonated

Answer 21

pH>pKa

therefore if pka is low, strong acid.

Question 22

what is pI

Answer 22

pH at which protein has no charge

Question 23

when does 2,3- BPG increase

Answer 23

high altitude and at high metabolism tissues

Question 24

what feature of binding does myoglobin display

Answer 24

hypoerbolic

Question 25

what is PFK activated and inhibited by

Answer 25

activated - AMP, F-2,6-BP inhibtied - ATP, citrate, H+

Question 26

what is a purine and pyrimidine

Answer 26

purine - CUT - 2 rings pyrimidine - AG - 1 ring

Question 27

explain initiation, elongation and termination of translation

Answer 27

initiation - 40S binds to 5' cap. Methionine tRNA binds. 60S binds elongation - new tRNA at A site. Peptide transferase to A site. tRNA at P goes to E site. termination - stop codon. peptide chian released

Question 28

where are pre and post signals cleaved

Answer 28

pre - ER post - golgi

Question 29

what is I cell diseae

Answer 29

No M6P addition for lysosyme proteins. Proteins present in blood

Question 30

what is restriction analysis useful for

Answer 30

Size of DNA, mutations, DNA fingerprinting, gene cloning

Question 31

what is a heterochromatin and euchromatin

Answer 31

hetero - tightly packed eu - loosely packed

Question 32

what are ring chromosomes, isochromosomes, and robertsonian translocations//

Answer 32

ring - formed by loss of telomeres iso - 2 non identical chromosomes made of P+P and q+q arms robertsonian - q+q arms and loss of pp

Question 33

what are transversion, transition, nonsense, missense mutations

Answer 33

transversion - purine to pyrimidine or vice versea transition - purine to purine. or pyrimidine to pyrimidine nonsense - AA to stop codon missense - AA to diff AA

Question 34

what is nucleotide excision and base excision and mismatch repair

Answer 34

nucleotide - \<30 base repaired. UV damage base - 1-5 bases. Oxidative damage mismatch - incorrect BP excised and repaired

Question 35

what is pattern of inheritance of DMD

Answer 35

x linked recessive

Question 36

symptoms of galactokinase deficiency and transferase deficiency

Answer 36

galactokinase - cataracts, galacosturia transferase - hepatomegaly, jaundice

Question 37

symptoms of hyperammonemia

Answer 37

reacts with alpha ketoglutarate in TCA cycle so lethargy, acidosis so vomiting, coma, irritability

Question 38

what is type 1 and 2b hyperlipoproteinemias and how treat

Answer 38

type 1 - lipoprotein lipase defect 2b - ldl receptor defect treat with statins

Question 39

how treat addisonian crisis

Answer 39

IV cortisol