V L4: Protein markers in Forensics

Question 1

what are polypeptide polymers?

Answer 1

proteins

Question 2

what are the building blocks for proteins?

Answer 2

amino acids

Question 3

what do amino acids contain?

Answer 3

chiral carbon with 4 groups attached

Question 4

How do amino acids differ?

Answer 4

• size
• charge
• chemical properties

Question 5

what does an amino acid sequence determine?

Answer 5

determines protein conformation

Question 6

what are the four levels of structure?

Answer 6

primer
secondary
tertiary
quaternary

Question 7

The information contained in the genes in the DNA is transcribed into _____ and the _____ contained in the mRNA are translated into an _____ ______ _______.

Answer 7

mRNA
codons
amino acid sequence

Question 8

whats a codon?

Answer 8

3 consecutive nucleotides

Question 9

antibodies bind to?

Answer 9

antigens

Question 10

what are ANTIBODIES?

Answer 10

proteins that circulate in the blood, are made by the immune system in response to an invasion by antigens.

Question 11

what is an ANTIGEN?

Answer 11

substance (usually foreign) capable of reacting with an antibody. A foreign substance that can elicit antibody formation is known as an immunogen

Question 12

Binding of antigen-antibody is specific to the _____ of the antigen and the _____ site of the antibody. The complex formed is ______.

Answer 12

epitope
binding
reversible

Question 13

what shape is an antibody?

Answer 13

Y shaped protein

Question 14

How many chains does an antibody have?

Answer 14

4 amino acid residue chains

Question 15

what type of chains does an antibody have?

Answer 15

2 heavy

2 light

Question 16

what are the antigen binding sites on an antibody?

Answer 16

Complementarity determining regions

Question 17

what are the 5 classes of antibodies?

Answer 17

IgG, IgA, IgM, IgD, and IgE

Question 18

what are the 2 types of antibodies?

Answer 18

Polyclonal and monoclonal antibodies

Question 19

whats another word for a specific type of antigen ?

Answer 19

immunogen

Question 20

An immunogen contains a small portion known as an ______ which is recognised by an antibody.

Answer 20

epitope

Question 21

whats it called when theres more than one epitope on an immunogen ?

Answer 21

multivalent

Question 22

what can a epitope do?

Answer 22

elicit product of its own antibody

Question 23

who discovered the ABO system ?

Answer 23

Landsteiner 1901

Question 24

How many blood types are there, what are they?

Answer 24

4 
A
AB
B
O

Question 25

what sugar does O allele have?

Answer 25

no extra sugar

Question 26

what sugar does A allele have?

Answer 26

N-acetylgalactosamine

Question 27

what sugar does a B allele have?

Answer 27

galactose

Question 28

what antibodies does blood type A have?

Answer 28

A

Question 29

what antibodies does blood type B have?

Answer 29

B

Question 30

what antibodies does blood type AB have?

Answer 30

A and B

Question 31

what antibodies does blood type O have?

Answer 31

none

Question 32

The ABO gene is on what chromosome?

Answer 32

9

Question 33

A and B alleles are ______

Answer 33

codominant

Question 34

If you know the blood type of the parents, can you figure out the possible genotypes of the children?

Answer 34

yes

Question 35

How big is the ABO locus?

Answer 35

18kb in size with 7 exons

Question 36

The DNA sequence of A and B alleles differ by what?

Answer 36

7 single nucleotide substitutions

Question 37

___ of the ____ SNP's translate into different amino acids

Answer 37

4 7

Question 38

what are the 4 SNPs that translate into different amino acids?

Answer 38

R176G G235S L266M G268A

Question 39

what amino acid residue is most important in determining if it will be A-trsnferase or B-transferase?

Answer 39

266 and 268

Question 40

what are some ABO typing Advantages ?

Answer 40

Cheap and simple to perform | other markers increases accuracy

Question 41

what are some ABO typing limitations?

Answer 41

Highly sensitive and specific relatively little individual discrimination

Question 42

whats a polymorphic gene?

Answer 42

A gene is said to be polymorphic if more than one allele occupies that gene's locus within a population, leads to abnormal protein.

Question 43

Allele frequencies vary between ?

Answer 43

ethnic groups

Question 44

what are isoenzymes?

Answer 44

same enzyme reaction, different amino acid sequence

Question 45

Name 6 Isoenzymes?

Answer 45

``` Phosphoglucomutase (PGM) Esterase D (EsD) Adenosine deaminase (ADA) Erythrocyte acid phosphatase (EAP) Adenylate kinase (AK) Glyoxalase (GLO) ```

Question 46

when was Phosphoglucomutase described?

Answer 46

1960s

Question 47

where is Phosphoglucomutase encoded?

Answer 47

Encoded at the PGM1 locus at chromosome 1

Question 48

whats the abbreviation for Phosphoglucomutase?

Answer 48

PGM

Question 49

Where can PGM be found?

Answer 49

PGM can also be found in semen

Question 50

what cases is PGM good for?

Answer 50

sexual assault cases

Question 51

PGM subgroups that can be detected by what?

Answer 51

isoelectric focusing

Question 52

what does Haemoglobin consist of?

Answer 52

consists of 2 α chains and 2 β chains

Question 53

when is feta Hb used?

Answer 53

cases of infantside and concealed birth

Question 54

Sickle cell Hb links too?

Answer 54

ethnic origin

Question 55

what 2 major isoenzymes are found in Human α-amylases?

Answer 55

Human salivary α-amylase (HSA). | Human pancreatic α-amylase (HPA)

Question 56

Identification of saliva is based on the detection of ?

Answer 56

HSA

Question 57

what is used for the detection of HSA?

Answer 57

primary binding assays Immunochromatographic assays enzyme linked immunosorbent assay (ELISA) techniques.

Question 58

what used when characterising proteins?

Answer 58

``` Centrifugation (differential/rate-zonal) SDS-PAGE Liquid Chromatography Antibody assays Mass spectrometry ```

Question 59

Sodium Dodecyl Sulphate (SDS)Polyacrylamide Gel Electrophoresis (PAGE)

Answer 59

1. Β-MEOH breaks down the disulfide bridges 2. SDS/heat unfolds the subunits of the protein 3. Negatively charged linearised peptides are sieved through a gel mesh under an electric field 4. Smaller peptides travel faster towards the + electrode than larger peptides. 5. A size marker is run alongside samples

Question 60

what's Liquid chromatography?

Answer 60

Protein fractionation through porous matrix within a column

Question 61

How does liquid chromatography work?

Answer 61

Proteins interact differently with different matrices and differ in time spent bound to the matrix

Question 62

what is Western blotting also knows as?

Answer 62

immunoblotting

Question 63

Specific proteins can be identified after SDS-PAGE separation using a labelled _____.

Answer 63

antibody

Question 64

How does western blotting work?

Answer 64

1. blot proteins from the gel onto a sheet of nitrocellulose paper or nylon membrane using an electric field 2. Soak membrane in solution with the labelled antibody.