Lab 7

Question 1

what is biotechnology

Answer 1

it is the use of organisms or their components (e.g. DNA, proteins) to make or modify products useful to humans

Question 2

what is modern biotechnology

Answer 2

it has been developed since the 1970s and specifically refers to the manipulation of DNA invitro

Question 3

what does modern biotechnology permit

Answer 3

the alteration of specific DNA sequences as well as the transfer of genes between organisms which enabled revolutonary advances in the field of forensics, medicine, ag, polution control and evolutonary biology

Question 4

what is the structure of DNA like

Answer 4

-large double stranded double helix
-each strand is composed of nucleotides
-each nucleotide is composed of 3 parts
-within each of the two strands of DNA nucloetides are joined by covalent phosphodiester bonds
-between the two strands of DNA, H bonds are formed between complementry N bases ( A+T C+G)

Question 5

what is the 3 parts a nucletide is composed of

Answer 5

-nitrognous base
-sugar (deoxyribose)
-phosphate group which is - charged

Question 6

what is the central dogma

Answer 6

-the flow of info from DNA to RNA
-info that is encoded in the DNA is transcribed into a complementry RNA copy. the RNA copy is translated into a sequence of amino acids which are the building blocks of proteins

Question 7

what does forensic refer to

Answer 7

the use of scientific methods in a wide array of legal or investigation situations

Question 8

what is forensic biology

Answer 8

it is an that area of science that deals with DNA from body tissues and fluids

Question 9

what must biological samples collected for DNA contain

Answer 9

it must contain nucleated cells

Question 10

what are suitable nucleated cells

Answer 10

bodily fluids (saliva, blood, semen, vaginal secrtrations, urine), hair folecles, skin, organs, bones

Question 11

what are the most common types of biological samples obtained from

Answer 11

blood, hair, or buccal (cheek) cells

Question 12

can all blood contain DNA

Answer 12

blood contains 4 components—RBC, WBC, plateletes, and plasma. in mammals mature RBC alone are not suitable for DNA extraction. they lack nuclei and organelles whereas WBC are nucleated

Question 13

how is DNA extracted from the nuclei of the cells in a sample

Answer 13

extraction is accomplished by chemically lysing (breaking open) the cells and the nuclei to liberate the DNA which is then chemically precipitated out of solution

Question 14

why are sports drinks used as a medium for collecting intact banana cells

Answer 14

because it is isotonic to the inside of the banana cell

Question 15

when extracting DNA why do we add alcohol

Answer 15

DNA is highly soluble in water but insoluble in alcohol therefor DNA ppts out in solution into the ethanol layer

Question 16

what is polymerased chain reaction

Answer 16

it is a process that rapidly makes identical copies of DNA sequences

Question 17

why would you need to use polymerase chain reaction for an investigation

Answer 17

often only small biological samples are available to invesigators. much less required for investigations. the numerous copies of spicific DNA sequences can then be used in subsequent analysis

Question 18

what DNA is the polymerase chain reaction usually used for

Answer 18

it is used to copy a particular DNA sequence of intrest (e.g a ene) for comparison, rather then the entire DNA complement

Question 19

what are the 4 ingredience needed for polymerase chain reaction

Answer 19

-DNA extract
-each of the 4 deoxyribosenucleotide triphosphates (dNTPs: DATP, dCTP, dGTP, dTTP) these are the building blocks used to produce the copies of DNA
-primers—short segments of synthetic DNA necessary for the initiation of DNA replication
-DNA polymerase (taq polymerase) a heat soluble enzy,e that elonglates the DNA chain by adding dNTPs to the primers
-the ingredience are combined and the solution is placed in a thermal cycler, an automated system that maintains a series of temperatures for specified periods.

Question 20

what are the 3 steps of a PCR cycle

Answer 20

-denaterization of DNA (heat to seperate the two strands of the DNA double helix)
-annealing of primers (cool so that primers can bond to the single strands of DNA
-extension of primers (heat allow DNA polymerase (Taq) to add dNTPs to the end of the primers

Question 21

what is the result at the end of each PCR cycle

Answer 21

the DNA sequence specified by the primers in doubled in quantity which results in an exponental increase. therefore the end resule of numerous consecutive cycles is billions of identical copied of the same specific DNA sequence. this rapid selective amplification is complete within hours

Question 22

what does restriction fragment analysis allow

Answer 22

it enables an indirect comparison of nucleotide sequences in different DNA samples through the use of restriction enzymes which “cut” DNA within different DNA within specific recognition sequences/restriction sites

Question 23

what are restriction fragments

Answer 23

for eample restriction enzyme ecori recognizes and cuts DNA within the nitrogenous base sequence GAATTC. the resulting lengths of DNA are what is called restriction fragments

Question 24

for restriction fragments what cant determine genetically different people

Answer 24

since alleles of genes very in their nucleotide sequences they may similarly very in the number of potential restriction sites contained within those sequences. differences in the number of restriction sites yield restriction fragments that differ both in number and the size in genetically different individuals

Question 25

what is the first step used in restriction fragment analysis

Answer 25

it is a restriction digest

Question 26

what is restriction digest processfor fragment analysis

Answer 26

a restriction enzyme is added to the PCR product and the solution is placed in an incubator. the enzyme cuts the DNA in the PCR product into specific fragment sizes and numbers, depending on the number of restriction sites present

Question 27

what is the second step in restriction fragment analysis

Answer 27

gel electrophoresis

Question 28

how does the gel electrophoresis procedure in restriction fragment analysis work

Answer 28

it is a process that allows is to separate the restriction fragments based upon molecular size differences in size of the DNA fragments

Question 29

what is the gel electrophoresis in restriction fragment analysis made form

Answer 29

-agarose (a polysaccaride derived from algae)
-the gel is submerged in a chamber containing salt water which conducts electricity

Question 30

what happens in gel electrophoresis once all the samples of DNA have been loaded. what are the mechanics

Answer 30

electrodes are attached to both ends of the chamber and a current is applied. the DNA which is - charged due to its phosphate backbone migrate towards the + electrode. the gel is a porous matrix which slows the movement of DNA fragments. larger DNA fragments cannot pass through the matrix of the gel as easily as smaller frangments so they do not travel as far

Question 31

what are the odds of individuals having identical patters of restriction enzymes

Answer 31

between 1 and 100,000 and 1 in one billion

Question 32

what is recombinant DNA

Answer 32

when DNA from two different sources (i.g two species) is combined into one molecule

Question 33

what things has recombinant DNA been engineered to facilitate the manufacture of

Answer 33

-numerous of medically and agriculturally important proteins
-also been used to produce crops that are resistant to herbicides, pest and diseases

Question 34

what is a genetically modified organism

Answer 34

an organsim that acquired genes through any artificial process, including recombinant DNA technology