DNA

Question 1

The 4 nucleotides

Answer 1

Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)

Question 2

Number of chromosomes within the average human cell

Answer 2

46

Question 3

Genes

Answer 3

Sections in the chromosomes that code for special functions in inheritance or in the development of an embryo after conception

Question 4

Homozygous

Answer 4

Having two of the same allele at any given locus

Question 5

Heterozygous

Answer 5

Have two different alleles at any given locus

Question 6

Allele

Answer 6

Different forms of a particular gene at a particular locus

Question 7

Phenotype

Answer 7

Observed characteristic expressed by the gene

Question 8

Genotype

Answer 8

Alleles that make up a gene

Question 9

Two types of variability in alleles

Answer 9

Sequence polymorphisms

Length polymorphisms

Question 10

SNP

Answer 10

Single nucleotide polymorphisms (type of sequence polymorphism)

Question 11

Tandem repeats

Answer 11

Base pair sequence repeats that occur next to each other without any intervening base pairs
Ex. ATC-ATC-ATC-ATC

Question 12

VNTR

Answer 12

Variable number of tandem repeats- variation in the number of repeats occurs from one individual to the next at a particular locus

Question 13

Population genetics

Answer 13

Determination of the frequencies with which particular genetic markers occur

Question 14

Product Rule

Answer 14

Technique of multiplying probabilities together (pop gen)

Question 15

First DNA typing method

Answer 15

Restriction fragment length polymorphism (RFLP)

Question 16

RFLP

Answer 16

Restriction fragment length polymorphism- typing method where restriction enzymes are used to isolate small fragments of DNA called mini satellites or VNTRs

Question 17

PCR

Answer 17

Polymerase chain reaction- technique used to increase the amount of DNA through amplification

Question 18

STR

Answer 18

Short tandem repeats

Question 19

Hypervariable

Answer 19

Having a large number of alleles

Question 20

Southern Blot

Answer 20

Method of transferring DNA fragments to a nylon membrane after separation through electrophoresis

Question 21

Probe hybridization

Answer 21

Technique used to visualize VNTRs after southern blots, uses radioactively labeled probes of short strands of DNA that are complementary to the core-repeating units of the VNTRs

Question 22

Three steps of PCR

Answer 22

1. Denaturation
2. Annealing
3. Extension

Question 23

Thermal cycler

Answer 23

Apparatus used for PCR, capable of achieving and maintaining preset temperatures very precisely

Question 24

Ingredients in a PCR tube

Answer 24

DNA sample, reaction buffer, polymerase enzyme, nucleotides

Question 25

Taq

Answer 25

DNA polymerase enzyme commonly used in the USA Heat stable 5' to 3' polymerase activity Has 5' to 3' exonuclease activity Does NOT have 3' to 5' exo proof reading

Question 26

PCR Step 1

Answer 26

Denaturation- Heated to 94 degrees C. Double stranded DNA denatures, resulting in single-stranded DNA

Question 27

PCR Step 2

Answer 27

Annealing/primer hybridization- primers are attached to each of the separated strands, done at 60 degrees

Question 28

Primers

Answer 28

Short strands of synthetic DNA attached during the annealing step that mark the starting points for addition of new bases to complete the reproduction of each strand

Question 29

PCR Step 3

Answer 29

Extension- 72 degrees C- under the influence of Taq polymerase, nucleotides are added to the primer one by one

Question 30

Number of PCR cycles before double stranded target sequences exist

Answer 30

3

Question 31

Direction of DNA synthesis

Answer 31

5' --> 3'

Question 32

Typical number of PCR cycles

Answer 32

28-32

Question 33

Advantages of STRs

Answer 33

High variability in the population Small size makes them less sensitive to DNA degradation Many to choose from

Question 34

Allelic ladders

Answer 34

Strands of DNA made up of all common alleles present at each STR locus, used for calibration

Question 35

Amelogenin

Answer 35

Locus used to determine sex. Not an STR

Question 36

HV1 and HV2

Answer 36

The two hyper variable regions in mtDNA

Question 37

Approximate length of mtDNA

Answer 37

16.5k base pairs

Question 38

Number of genes coded for in mtDNA

Answer 38

37

Question 39

Nucelotides

Answer 39

Pentose + phosphoric acid group + nitrogenous base

Question 40

Nucleosides

Answer 40

Sugar + nitrogenous base

Question 41

Normal confirmation of DNA

Answer 41

B DNA- right handed helix, 10.5 pb per turn

Question 42

Advantages of PCR

Answer 42

Amp can be done on samples containing very small amounts of DNA and degraded DNA Relatively rapid and simple Can serve as a starting point for the detection of virtually any kind of variation to be found in the genome Multiplex mode- simultaneous amplification reactions Small amount required allows portions of evidence samples to be set aside for repeat testing

Question 43

Controls in PCR Reaction

Answer 43

- DNA extraction blank - Positive amplification control - Negative amplification control

Question 44

DNA extraction blank

Answer 44

Detects contamination during extraction

Question 45

Positive amplification control

Answer 45

Shows that master mix and thermal cycler functioned correctly

Question 46

Negative amplification control

Answer 46

Detects contamination occurring at time of PCR set up

Question 47

Progressivity

Answer 47

Avg # of nucleotides added before the enzyme dissociates from the DNA