Lab Chapters 9

Question 1

A gene is

Answer 1

piece of DNA which provides the instructions for making (codes for) a protein

Question 2

Genetic transformation involves

Answer 2

insertion of a gene into an organism in order to modify a particular trait or, perhaps, provide the organism with a wholly new trait

Question 3

How can genetic transformation be used in bioremediation

Answer 3

bacteria can be genetically transformed with genes enabling them to digest oil spills

Question 4

What is the source for GFP?

Answer 4

Jellyfish aequorea victoria

Question 5

In this activity, you will be moving moving genes from one organism to another using

Answer 5

plasmid DNA (small circular pieces of DNA)

Question 6

True or false: In addition to their circular genome, bacteria generally possess one or more plasmids

Answer 6

True

Question 7

How do plasmids contribute to bacteria survival?

Answer 7

Plasmids contain genes for traits that may be beneficial to bacterial survival. In nature, bacteria can transfer plasmids back and forth allowing them to share these beneficial genes. This natural mechanism allows bacteria to adapt to new environments. The recent occurrence of bacterial resis-tance to antibiotics is due to the transmission of plasmids

Question 8

The bio-rad PGLO plasmid encodes for two genes. What are they?

Answer 8

GFP and a gene resistant to ampicillin

Question 9

The gene regulation system PGLO encodes for is unique because

Answer 9

pGLO also incorporates a special gene regulation system (an inducible promoter), which can be used to control expression of the fluorescent protein in transformed cells

Question 10

The gene for GFP can be switched on in transformed cells by adding

Answer 10

The sugar arabinose

Question 11

Selection for cells that have been transformed with pGLO DNA is accomplished by

Answer 11

Growth on antibiotic plates

Question 12

The promoter that controls the expression of the ampicillin resistance gene is always active , unlike

Answer 12

The promoter controlling GFP expression

Question 13

When viewed under ultraviolet light, transformed cells will appear ___ on plates not containing arabinose, and _____ when arabinose is included in the nutrient agar medium.

Answer 13

white (wild-type phenotype)
fluorescent green

Question 14

To move the pGLO plasmid DNA through the cell membrane you will:

Answer 14

1. Use a transformation solution of CaCl2
   (calcium chloride). 2. Carry out a procedure referred to as heat shock.

Question 15

For transformed cells to grow in the presence of ampicillin you must:

Answer 15

Provide them with nutrients and a short incubation period to begin expressing their newly acquired genes before you transfer them to a medium that contains ampicillin.

Question 16

The act of transformation is intended to

Answer 16

introduce the plasmid DNA into the E. coli cells and provide an environment for the cells to express their newly acquired genes.

Question 17

The heat shock water bath is set at ___C for ___seconds

Answer 17

42C
50sec

Question 18

The stack of plates should be placed ____ before being placed in a 37C incubator overnight

Answer 18

Upside down

Question 19

There are approxi-mately ? genes in the human genome.

Answer 19

25,000

Question 20

TorF: in most cases, it is correct to say that each gene codes for a unique polypeptide: one gene, one polypeptide.

Answer 20

True

Question 21

Organisms regulate expression of their genes and ultimately the amounts and kinds of proteins present within their cells for a myriad of reasons, including

Answer 21

developmental changes, cellular specialization, and adaptation to the environment

Question 22

TorF:Gene regulation not only allows for adaptation to differing conditions, but also prevents wasteful overproduction of unneeded proteins which would put the organism at a competi-tive disadvantage

Answer 22

True

Question 23

What is the purpose of a promoter?

Answer 23

Regulation of the expression of proteins often occurs at the level of transcription from DNA into RNA. This regulation takes place at a very specific location on the DNA template, called a promoter, where RNA polymerase sits down on the DNA and begins transcription of the gene.

Question 24

What is the purpose of a promoter?

Answer 24

Regulation of the expression of proteins often occurs at the level of transcription from DNA into RNA. This regulation takes place at a very specific location on the DNA template, called a promoter, where RNA polymerase sits down on the DNA and begins transcription of the gene.

Question 25

What are operons

Answer 25

In bacteria, groups of related genes are often clustered together and transcribed into RNA from one promoter. These clusters of genes controlled by a single promoter are called operons.

Question 26

The three genes (araB, araA, and araD) that code for three digestive enzymes involved in the breakdown of arabinose are clustered together in what is known as the

Answer 26

Arabinose operon

Question 27

Production of these three proteins (araB, araA, and araD) is dependent upon the initiation of transcrip-tion from a

Answer 27

single promoter, PBAD
.

Question 28

Transcrip-tion of araB, araA, and araD requires

Answer 28

requires the simultaneous
presence of RNA polymerase, araC, a transcription factor that binds DNA and facilitates transcription, and arabinose

Question 29

When arabinose is present in the environment, bacteria

Answer 29

take it up.

Question 30

Once inside the bacteria, the arabinose interacts directly with the araC protein which is bound to the DNA at the beginning of the arabinose operon. The interaction causes araC to

Answer 30

change its shape which in turn promotes (actually helps) the binding of RNA polymerase and the three genes araB, A, and D, are transcribed.

Question 31

In the absence of arabinose the araC

Answer 31

returns to its original inactive shape and transcription is shut off

Question 32

TorF: the DNA code of the pGLO plasmid has been engineered to incorporate aspects of the arabinose operon

Answer 32

True

Question 33

the presence of arabinose, araC protein promotes the binding of RNA polymerase and GFP is produced. Why?

Answer 33

Both the promoter (PBAD
) and the araC gene are present. However, the
genes which code for arabinose catabolism, araB, A, and D, have been replaced by the single gene which codes for GFP

Question 34

the absence of arabinose, araC no longer facilitates the binding of RNA polymerase and the GFP gene is

Answer 34

not transcribed.

Question 35

When GFP is not made, bacteria colonies will appear to have

Answer 35

a wild-type (natural) phenotype—of white colonies with no fluorescence