Chapter 14

Question 1

6 basic methods

Answer 1

1. replication of DNA
2. locating nucleotide sequences
3. cutting and joining sections of DNA
4. seperating pieces of DNA
5. pasting DNA into an organism
6. sequencing sections of DNA

Question 2

replication of DNA

Answer 2

polymerse chain reaction (PCR)
under normal conditions a nuber of enzymes are required for replication
PCR uses one enzyme: a heat resistance form of DNA polymerse

Question 3

hot springs contain

Answer 3

organisms with enzymes that can withstand high temps

Question 4

heat is used to

Answer 4

sperate strands of DNA

hydrogen bond - heat to 90 C- single strand DNA - cool double stranded DNA

Question 5

primers

Answer 5

short DNA strands - required to start copying

Question 6

heat resistance DNA polymerse

Answer 6

synthesizes new strands from unpolymerized nucleotides

Question 7

steps in PCR

Answer 7

sample DNA, primers, DNA polymerse, and nucelotides are combined
1. heat strands to sperate
2. cool to allow binding of primer and sythesis of new strands
3. repeat
each step doubles the amount of DNA

Question 8

cutting and joining DNA

Answer 8

restriction enzymes: 
cut DNA into fragments 
naturally found in bacteria 
probably used by to cut viral DNA 
in techological applications, DNA samples must be removed from a cell

Question 9

restiction sites

Answer 9

ech enzyme cuts DNA at specific nucleotide sequences
cut is not directly across strand - leaving sticky ends
complimentary sticky ends form hydrogen bonds

Question 10

joining sections of DNA

Answer 10

DNA ligase: bonds the phosphate of one nucleotide to the sugar of another nueclotide

Question 11

NEW* the cas 9 emzyme

Answer 11

uses a RNA sequence to find and cut DNA
can cut DNA at nay nucleotide sequence
can be introduced to a livng cell to make a DNA cut

Question 12

combining DNA from different organisms

Answer 12

cut with the SAME restiction enzyme

Question 13

combining DNA from different organisms

Answer 13

1. DNA from each organism must be cut with the same restiction enzymes
2. DNA from each organism is mixed, allowing H bonds to form between sticky ends
3. DNA ligase bonds sugar/ phosphate backbones

Question 14

pasting DNA into organisms

Answer 14

3 methods: only covering 1
plasmids
2. virususes ( not covered)
3. mechanical methods (not covered)

Question 15

plasmid vectors

Answer 15

plasmids have same restrictins sites as those found on chromosomal DNA
bacteria naturally take up plasmids from the environment
soem plasmids can intergrate into eukaryotic genomes

Question 16

plasmid vectors ex

Answer 16

placing human genes into bacteria to produce human protiens

1. extract plamid from bactria and DNA from human
2. cut with same restriction emzymes
3. mix samples, add ligase
4. place plasmid back in bactria. select cells that produce gene product

Question 17

plamid introduced into cultured plant cells

Answer 17

plasmid have a gene that allows it to become part of a plant chromosome

Question 18

separating pieces of DNA

Answer 18

gel electrophoresis
DNA has a neg charge and can therefor be drawn to a pos charge
small DNA fragments move more quickly to pos charge than larger fragments

Question 19

procedure gel electrophoresis

Answer 19

1. mixure of DNA placed on gel
2. electric current is applied cross the gel
3. DNA sperates by size
4. DNA is stained
   uses: indentify organisms
   sperating and locating genes
   sequencing DNA

Question 20

determining the nucelotide sequence of a sction of DNA

Answer 20

sequencing uses of PCR and two types of nueclotides

1. normal nucleotides
2. modified nucleotides:
   - different dyes are attached to nucleotides with different bases
   - sugars cannot bind to a phosphate (stops PCR)

Question 21

locating nucleotide sequences

Answer 21

probes: known sequences of single stranded, radioactive or fluorescent DNA

Question 22

locating sequences steps:

Answer 22

1. sample DNA is seperated into single stands and attached to the surface
2. probe is added to the sample
   probe binds iwth comlimentry strands
3. sample washed to remove unbound probes
4. prescence of probe detected

Question 23

uses for probes

Answer 23

1. detect a sequence in an organism:
   - allele of interest (known mutation)
   - presence of a mirco organism in diease idenification
2. genetic mapping. combined with gel electrophoresis

Question 24

restriction fragment anaylsis

Answer 24

examines size distrubution of DNA fragements (restriction fragments) cut by restiction enzymes
size of fragments is determined by distance between restriction sites

Question 25

mutations in restiction sites create

Answer 25

different size DNA fragaments (bands)

Question 26

uses

Answer 26

1. identify carriers of alleles associated geentic disorders (especially recessive alleles)
2. DNA fingerpriting: indentify indivduals within a population

Question 27

restriction fragement anaylsis ex)

Answer 27

mutation that causes sickle cell anemia can be identified with restiction enzyme
this only works if the mutation resulting in a new alleles is part of a restiction site

Question 28

human DNA fingerprinting

Answer 28

examines regions of DNA that areL
non coding
highly variable
repeated
doesnt rely on mutations to restiction sites
allele- # of repeats (a different size of DNA fragment)
average number of alleles in the population is uusally about 30
throughout the chrosmosome there are many locations with repeats
each location with a repeat can be examined using restiction fragment anaylsis

Question 29

human DNA fingerprinting procedure

Answer 29

uses restiction fragments and probes

1. DNA sample is amplified using PCR
2. sample is cut with restirction enzymes
3. fragments are sperated by gel electrophoresis
4. DNA seprated into single strands and bound to a surface
5. probes are used to find fragments with repeated sequence

Question 30

testing identity

Answer 30

to test for the identity of indivduals, more than one location of repeated DNA is compared between samples

Question 31

parental testing

Answer 31

bands (alleles) found in a child must be present in one or both parents
if the mother doesnt havea band the child posses, it must be in the father

Question 32

genetically modified organisms (GMOs)

Answer 32

organisms that have had their genomes artifically modified
2 types of mofications
modification of exisiting genomes
trangenic organisms

Question 33

modification of existing genomes

Answer 33

ex) flavor savr tomatoes

have a gene responsible for fruit softening silenced

Question 34

transgenic organisms

Answer 34

organisms with genes from two or more species
ex) 1. round up ready crops:
have a gene from bacteria making them resistant to “round up”
2. Bt crops:
genes from bacteria make them toxic to insects

Question 35

using genetic technology to treat genetic disorders

Answer 35

1. supply missing gene product
   working copies of genes inserted into other organisms to produce gene product
   ex) human insulin is produced from E.coli bacteria

Question 36

gene therapy

Answer 36

place normal in a vector
infect cells
normal gene becomes part of cells chromosome
inject modified cells back into patient
extract cells from patient with abnormal allele