Chapter 13

Question 1

recombinant DNA technology

Answer 1

is technology used by scientists to combine genes from different organisms or species

Question 2

plasmids

Answer 2

small, circular DNA molecules that are separate from the much larger bacterial chromosome

Question 3

how do biologists use plasmids?

Answer 3

to move genes into bacteria

Question 4

restriction enzyme

Answer 4

“cuts” a DNA molecule into fragments at specific points

Question 5

how do bacterial cells reproduce and make a clone/identical copies of a desired gene?

Answer 5

1) the restriction enzyme “cuts” a DNA molecule into fragments at specific points
2) Another enzyme “pastes” a fragment carrying a particular gene into a plasmid
3) Then the plasmid is put back into a bacterial cell. Then when the bacterial cell reproduces, it creates clones/identical copies, of the desired gene

Question 6

genomic library

Answer 6

the complete collection of cloned DNA fragments from an organism

Question 7

nucleic acid probe

Answer 7

a molecule that has been labeled with radioactivity, making it easy to detect

Question 8

Genetically Modified Organism (GMO)

Answer 8

any organism that has acquired one of more genes by artificial means

Question 9

transgenic

Answer 9

if the new genetic material came from a different species

Question 10

how do u genetically modify a plant?

Answer 10

researchers inset a plasmid containing the desired gene into a plant cell

Question 11

how do u genetically modify a mammal?

Answer 11

the desired gene is inserted j to a fertilized egg. the egg is then returned to a female animals body

Question 12

how can plants be cloned?

Answer 12

from cuttings

Question 13

how can animals be cloned?

Answer 13

replacing the nucleus of an egg cell with another cell’s nucleus

Question 14

polymerase chain reaction (PCR)

Answer 14

a technique that makes billions of identical DNA molecules in just a few short hours. it is used to produce large enough samples of DNA for further analysis

Question 15

Gel electrophoresis

Answer 15

a technique for sorting DNA fragments by length

Question 16

Genetic markers

Answer 16

particular stretches of DNA that vary from person to person

Question 17

DNA fingerprint

Answer 17

each persons DNA fragments produce a particular pattern of banding

Question 18

operon

prokaryotes

Answer 18

a cluster of genes along with its two control sequences

Question 19

promoter

prokaryotes

Answer 19

(one control sequence) is a binding site for an enzyme needed in DNA transcription

Question 20

operator

prokaryotes

Answer 20

(one control sequence) switches the promoter on and off

Question 21

repressor

(prokaryotes)

Answer 21

a protein that turns the operator off by binding to it

Question 22

gene expression

eukaryotic cells

Answer 22

the transcription and translation of genes into proteins

Question 23

transcription factors

eukaryotic cells

Answer 23

are proteins that regulate promoter sequences. told by chemical signals in the cell.

Question 24

cellular differentiation

Answer 24

when individual cells become more specialized in structure and function as the organism develops

Question 25

stem cells

Answer 25

cells that remain able to differentiate into various other types of cells

Question 26

Homeotic genes

Answer 26

are master control genes that produce proteins that regulate the expression of other genes

Question 27

biotechnology

Answer 27

the use of organisms to perform tasks for humans

Question 28

what is one way that recombinant DNA technology can benefit farmers?

Answer 28

using this technology, a gene that provides resistance to specific weed-killing chemicals has been developed. When farmers use chemicals, they kill weeds withou killing crops

Question 29

how can recombinant DNA technology be used to treat the disease diabetes?

Answer 29

using this technology, scientists can insert the human gene that directs the production of human insulin into the bacterium E Coli, which can produce large quantities of human insulin, insulin is used to treat diabetes

Question 30

what is the role of the restriction enzyme?

Answer 30

they can recognize a specific base sequence in DNA, attach themselves to the DNA, and cut the two nucleotide strands

Question 31

why do scientists keep a set of restiction enzymes?

Answer 31

because they can cut DNA where they want, eliminate a gene, and replace it with another

Question 32

why might scientists want to insert a new gene into bacteria?

Answer 32

bacteria reproduce rapidly and could make many copies of a new gene. Bacteria could also produce large quantities of a gene product

Question 33

what is the role of the DNA ligase?

Answer 33

DNA ligase pastes the sticky ends to a new complementary sequence

Question 34

why did the scientists first chose to clone a mouse with brown fur, but the egg from a mouse with white fur?

Answer 34

they could tell by the fur of the newborn if the brown mouse was cloned

Question 35

what is the role of heat in the first step of PCR?

Answer 35

heat breaks the hydrogen bonds between the complimentary DNA strands, allowing the strands to separate

Question 36

when there is no lactose, what prevents EColi from producing lactose-processing enzymes?

Answer 36

the repressor binds to the operator and prevents RNA polymerase from starting the process of transcription and translation

Question 37

what is the role of the RNA polymerase?

Answer 37

RNA polymerase is the enzyme that copies the DNA code into RNA

Question 38

why is it important for the Ecoli to turn on and off the enzyme making machinery?

Answer 38

to conserve energy; it's a bad strategy for the organisms to produce a very "expensive" set of proteins if they are not needed