MCBG

Question 1

Metabolism definition

Answer 1

Metabolism is the set of processes which derive
energy and raw materials from food stuffs and use
them to support repair, growth and activity of the
tissues of the body to sustain life

Question 2

Work the body does

Answer 2

Biosynthetic work - synthesis of cellular components

Transport work - membranes : maintaining gradients

Mechanical work - muscle contraction

Electrical work - nerve impulse conduction

Osmotic work - in the kidneys

Question 3

Creatine

Answer 3

Energy can be stored in creatine phosphate by creatine kinase. When ATP is high creatine phosphate is produced.
When ATP is low creatine phosphate is broken down to from creatine and ATP.

Question 4

Creatinine

Answer 4

Creatinine is a breakdown product of creatine and creatine phosphate.
Excreted via the kidneys
The excretion is proportional to muscle mass of the individual - in urine

Question 5

Features of triacylglycerols

Answer 5

They are hydrophobic, stored in anhydrous form

Utilised during starvation

Question 6

Fat mobilisation from adipose

Answer 6

Hormone sensitive lipase breaks down triacylglcerol into fatty acids and glycerol in high levels of glucagon.

Question 7

Features of fatty acids

Answer 7

Can be saturated or unsaturated

Amphipathic

Question 8

Where does fatty acid catabolism occur

Answer 8

Mitochondria

Question 9

Carnitine shuttle

Answer 9

Acyl-CoA is converted to acyl carnitine via CAT1
It then transported into the matrix of the mitochondria via the carnitine shuttle transporter
It is then converted back into acyl-CoA by CAT2.

Question 10

Glycerol metabolism

Answer 10

Occurs in the liver

Glycerol to glycerol phosphate where it can re enter glycolysis as DHAP producing NADH.

Question 11

Ketones produced in the body

Answer 11

Acetoacetate
Acetone
Beta hydroxybutyrate

Question 12

Where are ketone bodies produced

Answer 12

Liver mitochondria

Question 13

In a fed state when insulin is high what happens to levels of ketone bodies

Answer 13

The levels are decreased and cholesterol is produced by stimulating HMG-CoA reductase

Question 14

Ketone body features

Answer 14

Water soluble
Acetoacetate is strong organic acid which can cause ketoacidosis
Volatile acetone may be excreted via the lungs - smelt on breath.

Question 15

Replication stress can lead to

Answer 15

Replication machinery defects
Fork slippage
Defects in response pathway

Question 16

Responses to DNA damage and replication stress

Answer 16

DNA repair

Apoptosis

Question 17

Base excision repair

Answer 17

Deamination

Replacing uracil with the correct DNA complementary bas pair.

Question 18

Nucleotide excision repair

Answer 18

A dimer is formed and detected.
The surrounding DNA and dimer are opened and removed.
New complementary base nucleotides are replaced.

Question 19

Mismatch repair

Answer 19

The wrong complementary nucleotide is removed with a section of DNA. The missing patch is then replaced and sealed.

Question 20

Single strand break

Answer 20

Template from other stand is used to replace the lost DNA nucleotides
Not error free but not error prone

Question 21

Double strand repair - non homologous end joining

Answer 21

Error prone
The ends of the chains are joined.
Always ends in a mutation

Question 22

Double strand breakage - homologous directed repair

Answer 22

It uses the other chain of DNA.

Question 23

Mitotic non disjunction

Answer 23

Missegregation of chromosomes leads to aneuploidy

Question 24

How is genetic variation created in meiosis

Answer 24

Crossing over in prophase 1

Random assortment in metaphase 1

Question 25

Meiotic non disjunction

Answer 25

Missegregation of chromosomes leads to aneuploidy in gametes which can cause monosomy and trisomy in zygotes

Question 26

Genotype definition

Answer 26

The DNA sequence of an individual which determines the specific characteristics of that person

Question 27

Phenotype definition

Answer 27

An individual’s observable characteristics directly influenced by the genotype and the environment.

Question 28

Gene

Answer 28

A section of DNA that codes for a protein

Question 29

Allele

Answer 29

A version or variant of the gene

Question 30

Mitochondrial disease inheritance

Answer 30

Mitochondria come from the oocyte and therefore are passed on from your mother

Question 31

Polygenic inheritance

Answer 31

More than one gene can be involved in producing a phenotype.

Question 32

Mutation definition

Answer 32

A change in the nucleotide sequence of DNA

Question 33

Transition mutations

Answer 33

Change to same type of base | Purine to purine

Question 34

Transversion mutation

Answer 34

Change to different type of base | Purine to pyrimidine

Question 35

Missense / non-synonymous

Answer 35

Changes the gene product

Question 36

Mutations affecting the regulatory sequences

Answer 36

Change in the amount of gene product

Question 37

Frameshift or mutation of stop codon

Answer 37

Changes polypeptide length

Question 38

Silent or neutral mutations

Answer 38

Do not have an effect

Question 39

Fork slippage

Answer 39

Trinucleotide expansion such as in Huntington’s disease

Question 40

Polyploidy

Answer 40

Gain of haploid set of chromosomes

Question 41

Aneuploidy

Answer 41

Loss or gain of whole chromosome | Caused by meiotic non disjunction

Question 42

Mosaicism

Answer 42

Presence of 2 or more cell lines in an individual

Question 43

Reciprocal translocation

Answer 43

Sections of DNA on non-homologous chromosomes are exchanged If the affected chromosomes are passed on together no DNA is lost and the patient is unaffected If one affected chromosome is passed on with an unaffected chromosome then DNA is lost and the patient is affected This could lead to genetic defects and miscarriages

Question 44

Robertsonian translocation

Answer 44

2 acrocentric chromosomes fuse If the affected chromosome is passed on by itself the patient is unaffected. However if the affected chromosome is passed on with an unaffected chromosome aneuploidy occurs.

Question 45

Southern Blotting

Answer 45

DNA fragments are added to agarose gel for electrophoresis. It is then transferred to a more stable and firm nitrocellulose sheet by blotting. DNA fluorescent probes are added and hybridisation occurs creating an image.

Question 46

Microarrays

Answer 46

Allow analysis of 1000s of genes simultaneously

Question 47

FISH

Answer 47

DNA probes for DNA sequences are created and added | Mutated chromosomes will light up if the DNA probe binds

Question 48

SDS PAGE

Answer 48

Separates proteins based on their size 3D structure is broken down by ionic detergent Large proteins move slower

Question 49

Requirements for gel electrophoresis

Answer 49

Gel Buffer Power supply Stain

Question 50

Sanger sequencing

Answer 50

Use of dideoxynucleotides to terminate DNA elongation This causes segments of DNA to form DNA molecules of increasing size are produced They are separated out by capillary electrophoresis The fluorescently labelled nucleotides are then detected.

Question 51

Agarose gel electrophoresis

Answer 51

DNA is visualised by staining with ethium bromide DNA samples placed in wells and move across gel towards the positive electrode Smallest fragments move the quickest

Question 52

PCR

Answer 52

DNA is heated and denatured DNA primers are added and annealed DNA is cooled and renatures The final product contains the forward and reverse primers

Question 53

Why is PCR used

Answer 53

To amplify a specific DNA fragment

Question 54

Reverse transcriptase PCR

Answer 54

This is used to determine if a gene is expressed