Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ESA 1 > MGD > Flashcards

MGD Flashcards

1
Q

Explain allosteric regulation of enzymes

A

The binding of a substance to a point other than the active site to stimulate or depress the activity of the enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What substances increase and decrease PFK activity?

A

Increase - AMP

Decrease - Citrate and ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Generally, explain the action of kinase and phosphorylase enzymes

A

Kinase enzymes add phosphate to make a chemical more reactive whereas phosphorylase enzymes take off a phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are endogenous inhibitors?

A

These are substances produced by the body to competitively inhibit an enzyme to regulate its activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the three stages of transcription?

A

Initiation - TATA box is found at -30
Elongation - reading the DNA from 5’ to 3’ and making the sequence from 3’ to 5’
Termination - creation of a 5’ cap and a polyA tail at 3’ end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the coding and template strand of DNA?

A

Terminology used in transcription process
Coding - has the same code as the mRNA created
Template - has the opposite bases to the mRNA because of base pairing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give the substrate for translation

A

Amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Give the substrate for transcription

A

Deoxynucleotide triphosphates (dNTPs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give the enzyme for transcription

A

RNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Give the enzyme for translation

A

Ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Give the function of tRNA

A

Has an anticodon to the mRNA bases and is bound to the specific amino acid that the mRNA codon codes for

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What enzyme binds tRNA to an amino acid?

A

tRNA synthetase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What amino acid is always found at the start of a protein sequence?

A

Methionine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give the function of peptidyl transferase

A

In translation, this enzyme elongates the peptide sequence by bringing the next tRNA to the mRNA codon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is euchromatin?

A

The genetic material within the nucleus that can be accessed and expressed. Stains a light colour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is heterochromatin?

A

The densely packed genetic material that cannot be expressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain the basis of the ‘beads on a string’ formation

A

The negatively charged sugar phosphate backbone is coiled round a series of positively charged histone proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a solenoid fibre?

A

The coiling of the ‘beads on a string’ into one continuous, 70nm fibre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What base does adenine bind to?

A

Thymine - “a tea for two” meaning by two hydrogen bonds

Cytosine and guanine bind by three hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Give the purine and pyramidine bases

A

Purine - adenine and guanine “pure silver”

Pyramidine - cytosine and thymine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What creates the polarity of the sugar phosphate backbone?

A

Phosphate at the 5’ end and hydroxyl at the 3’ end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Outline the PCR process

A

Existing DNA heated to 95°C to break hydrogen bonds
DNA primers added to line up to exposed strands
Cooled again to allow primers to bind
Taq polymerase then elongates the primer to create a new DNA strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is blotting?

A

Electrophoresis + fluorescent probe to highlight the divisions created by the electrophoresis process. Southern blotting for DNA, Northern for RNA and Western for proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is protein gel electrophoresis?

A

Filtering of proteins based on size, shape and charge. Proteins applied to a porous gel and a charge is set up. Proteins migrate toward their opposite charge but the gel restricts movement of the large proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is SDS-PAGE?

A

Extension of the protein electrophoresis process except addition of a solution breaks all disulphides bridges and makes all proteins negatively charged so filtering is based only on size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Explain isoelectric focusing

A

Separation of proteins based on isoelectric point. Proteins will stop at their isoelectric point

27
Q

What is the conglomeration of isoelectric focusing and SDS PAGE called?

A

2D PAGE. A system to better separate proteins

28
Q

Explain the process of ELISA

A

Determining the concentration of a specific antibody.
Antigen lines container
Unknown antibody quantity is added (solution washed)
Enzyme-linked antibody added (solution washed)
Substrate added and conversion rate measured
(Production rate is directly proportional to unknown antibody conc)

29
Q

Define aneuploidy

A

Where the DNA from one chromosome is added to another so that one is deficient and another has excess. No overall change in genetic material

30
Q

Define polyploidy

A

More than two chromosomes present as in trisomy 21 (down’s)

31
Q

Give the function of helicase

A

Unwinding the DNA strand during replication

32
Q

Give the function of DNA polymerase

A

This creates the new strands from the templates when replicating DNA. Reads in the 5’ to 3’ and creates the new strand from 3’ to 5’

33
Q

What are Okazaki fragments?

A

The strands in DNA replication are read from 5’ to 3’ but one strand is at 3’ to 5’ so DNA polymerase does this strands in short sections, known as Okazaki fragments

34
Q

Give the function of ligase enzyme

A

Ligase joins together the Okazaki fragments on the lagging strand in DNA replication to give a continuous strand

35
Q

What happens at prophase?

A

Dissolution of the nucleolus and formation of two poles in the cell

36
Q

What happens in metaphase?

A

Formation of spindle fibres from the poles which attach to the centromeres of the chromosomes

37
Q

What happens in anaphase?

A

Pulling apart of the chromosomes to either pole so that it is now divided into two daughter chromosomes

38
Q

What happens in telophase?

A

The formation of the new nucleolus followed by separation of the cytoplasms (cytokinesis) into two distinct cells.

39
Q

How is diversity created in meiosis?

A

Random assortment of chromosomes in metaphase I

Crossing over of material at the chiasmata at prometaphase I

40
Q

Define Vmax

A

The maximum rate at which product is produced by an enzyme

41
Q

What is Km?

A

The substrate concentration that gives half of the Vmax. This is a measure of affinity of the enzyme to its substrate

42
Q

How are Km and Vmax affected in competitive inhibition?

A

Km increases (affinity decreases) and Vmax is unaffected

43
Q

How are Vmax and Km affected in non-competitive inhibition?

A

Km is unaffected but Vmax will decrease

44
Q

Explain how amino acids show stereoisomerism

A

The central carbon atom can have two different formations for the four bonds that connect to it. This is optical isomerism or enantiomers

45
Q

Define pK

A

The pH at which a substance becomes protonated. Strong acids will need a very low pH to become protonated because they have a strong tendency to donate a proton

46
Q

Define isoelectric point

A

The pH at which a chemical has no overall net charge

47
Q

Describe the primary structure of proteins

A

A string of amino acids in sequence held together by peptide bonds

48
Q

Describe the secondary structure of proteins

A

The creation of beta pleated sheets and alpha helices with hydrogen bonding and the original peptide bonds

49
Q

Describe the structure of alpha helices

A

Right handed turn structure with 3.6 amino acids per turn

Pitch of 0.54nm - rise in height per full turn

50
Q

Describe the tertiary structure of proteins

A

3D folding of the secondary structure

Bonding is peptide, hydrogen, ionic, van der Waals forces and disulphide bridges

51
Q

Describe the quaternary structure of proteins

A

Association of more than one tertiary protein to create a large protein e.g. Haemoglobin (globular) and collagen (fibrous)

52
Q

Give the difference between adult and foetal haemoglobin

A

Foetal has two alpha subunits and two gamma subunits as opposed to two alpha and two beta in adults

53
Q

Give the basis for the sigmoid curve for oxygen uptake by haemoglobin

A

This is due to co-operative binding of haemoglobin, whereby it is more likely to take up subsequent oxygen molecules once it has taken up the first

54
Q

Describe the dissociation pattern of myoglobin

A

Hyperbolic curve to give oxygen as a dump at low partial pressures

55
Q

Describe the difference between beta and alpha thalassaemia

A

Beta thalassaemia is a defect in the beta subunits of haemoglobin and will present after birth. Fatal.
Alpha is a defect of the alpha subunits and will be present before birth but have a higher affinity for oxygen and so breathlessness and stunted growth are common

56
Q

Give the pathophysiology of sickle cell anaemia

A

Mutation of glutamate to valine in the beta subunit of haemoglobin. Valine is hydrophobic and so creates a sticky pocket which is susceptible to lysis

57
Q

Give a description of complementation in inheritance patterns

A

More than one gene codes for the same phenotype as in albinism

58
Q

Give and describe the two forms of single nucleotide polymorphism (SNPs)

A

Transitions - purine to purine or pyramidine to pyramidine

Transversions - purine to pyramidine or vice versa

59
Q

What is the commonest cause for single nucleotide polymorphism (SNPs)?

A

Radiation

60
Q

Give the four types of mutation that a single nucleotide polymorphism (SNPs) can cause

A

Missense - different amino acid coded for
Nonsense - creation of a stop codon
Silent - no change to amino acid sequence

61
Q

Explain the basis for frameshift mutations

A

The open reading frame is changed due to insertion or deletion of nucleotides. Most commonly caused by slippage, where a base loops out of the template strand.

62
Q

What is tautomeric shift?

A

Where a proton transiently moves so that the wrong base pair is made by DNA polymerase e.g. cytosine binds to adenine

63
Q

Give the two types of genetic repair

A

Mismatch - removal of one base and replacement with correct one
Excision - removal of a defective strand of DNA and insertion of the correct one

ESA 1 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions