chapter 10 - DNA

Question 1

James Watson and Francis Crick discovered

Answer 1

Developed DNA model and double helix structure in 1953

Question 2

Rosalind Franklin discovery

Answer 2

Took first pictures of DNA

Question 3

what is DNA

Answer 3

Code of genetic information

Question 4

where is DNA found

Answer 4

nucleus

Question 5

DNA helps code for

Answer 5

proteins

Question 6

proteins give us

Answer 6

uniqueness

Question 7

gene definition

Answer 7

fundamental unit of heredity

Question 8

how many chromosomes does a person have?

Answer 8

46 total
23 pairs, 1 from each parent

Question 9

chromosomes are found in the form of

Answer 9

wound up DNA

Question 10

double helix

Answer 10

2 coiled strands of DNA

Question 11

what are DNA strands made of?

Answer 11

nucleotides

Question 12

nucleotide made of

Answer 12

5-carbon sugar (deoxyribose), phosphate group, nitrogenous base

Question 13

4 base pairs of DNA and their pairing

Answer 13

adenine and thymine
cytosine and guanine

Question 14

coding DNA

Answer 14

Codes for unique proteins

Question 15

what percentage of DNA is coding DNA?

Answer 15

5%

Question 16

what percentage of DNA is non-coding DNA?

Answer 16

95%

Question 17

what does non-coding DNA code for?

Answer 17

nothing

Question 18

what type of DNA is best for forensic identification? why?

Answer 18

non-coding DNA, contains tandem repeats that would be specific to each person

Question 19

what is DNA replication

Answer 19

Making new DNA from existing DNA
Making more copies

Question 20

how does DNA replication work?

Answer 20

1. DNA helicase separates DNA strands by breaking Hydrogen bonds
2. replication fork forms gaps in DNA ligase
3. DNA polymerase adds complementary nucleotides to each DNA strand
4. covalent bonds form along sugar-phosphate backbone
5. DNA polymerase falls off
6. replication is complete

Question 21

what does the replication fork look like

Answer 21

Y

Question 22

purpose of DNA fingerprinting

Answer 22

Establishes a link between biological evidence and a suspect

Question 23

uses for DNA fingerprinting

Answer 23

Evidence in court
Body identification
Blood relative identification
Cures for disease

Question 24

3 main technologies of DNA typing

Answer 24

RFLP
PCR
STR

Question 25

what does RFLP stand for

Answer 25

Restriction Fragment Length Polymorphisms

Question 26

what does PCR stand for

Answer 26

polymerase chain reaction

Question 27

what does STR stand for

Answer 27

short tandem repeats

Question 28

when was RFLP used

Answer 28

1985-mid 90s

Question 29

polymorphisms definition

Answer 29

variations of DNA sequences between individuals

Question 30

4 basic steps of RFLP

Answer 30

Isolate→ separating the DNA from the cell Cut→use restriction enzymes to cut Separate/Sort→ use gel electrophoresis Analyze→ looking for specific allele patterns

Question 31

what happens in the 1st step of RFLP?

Answer 31

isolation and extraction Break open cells→grind them and add a detergent solution Add salt→ (sodium chloride) - remove proteins bound to the DNA Precipitate DNA→ add cold alcohol

Question 32

what happens in the 2nd step of RFLP?

Answer 32

Cut Restriction enzymes (bacterial cells) cut DNA Looks for specific DNA sequence (tandem repeats)

Question 33

what happens in step 3 of RFLP

Answer 33

Gel Electrophoresis Load DNA into gel wells Add electrical current Molecules sort by size Banding pattern

Question 34

what happens in the 4th step of RFLP?

Answer 34

Radioactive markers are added Bind to DNA

Question 35

3 outcomes of RFLP

Answer 35

match excluded inconclusive

Question 36

DNA match definition

Answer 36

DNA profile appears the same

Question 37

DNA exclusion definition

Answer 37

samples originated from different sources

Question 38

DNA inconclusive definition

Answer 38

doesn't support a conclusion

Question 39

what is PCR designed to do

Answer 39

Designed to copy or multiply strands of DNA

Question 40

when is PCR used

Answer 40

when there is limited evidence

Question 41

how much DNA can you get from a single speck of blood?

Answer 41

MILLIONS

Question 42

primer definition

Answer 42

short segments of DNA

Question 43

how does PCR work (4 steps)

Answer 43

Heat DNA→ causes separation of DNA strands Cool and add a primer→ allows DNA segments to find their base pair Add DNA polymerase and free nucleotides→ causes DNA to rebuild Heat to 75 C for completion

Question 44

advantages of PCR

Answer 44

Yields more than 1 billion copies quick short strands anything can have DNA on it

Question 45

how many cycles of PCR usually happens

Answer 45

28-32

Question 46

how long does 1 cycle of PCR take

Answer 46

2 min

Question 47

why are shorter strands of DNA more advantageous in PCR?

Answer 47

they are less susceptible to degradation

Question 48

what is STR

Answer 48

Short sequences that repeat themselves in a DNA molecule

Question 49

how long is an STR

Answer 49

3-7 bases in length; less than 450 bases long

Question 50

where are STR located

Answer 50

chromosomes (loci)

Question 51

what type of DNA testing is the most successful? why?

Answer 51

STR, large numbers in the human genome

Question 52

how does STR work?

Answer 52

Extract the gene from the sample→ STR TH01→ A-A-T-G; 7 variants found→ 5-11 repeats Amplify the sample using PCR Separate by electrophoresis Examine the distance the STR migrates to determine the number of times TH01 repeats Each person has two STR types for TH01—one inherited from each parent

Question 53

how are the results of STR shown?

Answer 53

peaks on a graph each represents the size of a DNA fragment the possible alleles are numbered for each loci

Question 54

multiplexing definition

Answer 54

the more STR’s characterized, the smaller the percentage of population they can come from

Question 55

2 forms of sex identification in STR

Answer 55

Amelogenin gene Y-STR's

Question 56

Amelogenin gene

Answer 56

found on x and y chromosome Shorter by 6 bases on the X chromosome Males= 2 bands; females= 1 band

Question 57

Y-STR's

Answer 57

only found on Y chromosome

Question 58

advantages of STR

Answer 58

only requires a small amount of DNA greater discrimination of results less susceptible to degradation less time to run

Question 59

how much DNA do you need for STR

Answer 59

18 cells