AP Bio Ch. 20 Study Guide

Name: ID:

Email:

True/False
Indicate whether the statement is true or false.

Interactive question 20.4 A Does the following statement answer the question?
By amplifying the gene prior to cloning, the later task of identifying clones carrying the desired gene is simplified.

Interactive question 20.4 B Does the following statement answer the question?
There is a limit to the number of accurate copies that can be made due to the accumulation of relatively rare copying errors. Large quantities of a gene are better prepared by DNA cloning in cells.

Multiple Choice
Identify the choice that best completes the statement or answers the question.

Interactive question 20.1
Which of the following DNA sequences would most likely function as a restriction site for a restriction enzyme?

CAGCAG
GTCGTC

GTGCTG
CACGAC

GAATTC
CTTAAG

Interactive question 20.7
What is a likely cause of these developmental failures?

a.	DNA methylation and histone acetylation help to regulate gene expression.
b.	An adult cell must have epigenetic changes in its chromatin reprogrammed in order to support normal gene expression during development.
c.	The DNA of many cloned embryos has been found to be improperly methylated.
d.	The DNA of many cloned embryos has been found to have uneven strands after repeated rounds of DNA copying.
e.	all of the following are causes
f.	none of the following are causes

Interactive question 20.8
Which of the following are practical considerations in human gene therapy?

a.	to assure that proper control mechanisms are present so that the gene is expressed at the proper time
b.	to assure that proper control mechanisms are present so that the gene is expressed in the proper place
c.	to assure that proper control mechanisms are present so that the gene is expressed to the proper degree
d.	insertion of a therapeutic gene must not harm other cell functions
e.	we could influence the genetic makeup of future generations
f.	all of these are practical and ethical considerations
g.	none of these are practical and ethical considerations

Matching

Interactive question 20.2

cDNA library

genomic library

This library contains copies of DNA segments from the entire genome. Thus, all genes should be represented, along with the regulatory sequences and introns.

This library allows you to sequence only the exons of a gene, and also indicates which genes are expressed either in different cell types or at different stages of development in the same cell type.

Interactive question 20.3 Part 1
Identify components a-j

a.	complementary sticky ends	f.	amp^R (ampicillin resistance) gene
b.	bacterial plasmid	g.	lacZ gene
c.	recombinant plasmids	h.	plate with ampicillin and X-gal
d.	restriction site	i.	human DNA fragments
e.	recombinant bacteria	j.	gene of interest

10.

11.

12.

13.

14.

15.

16.

17.

Interactive question 20.3 Part 2
Put the following steps in order

a.	Plate bacteria on agar containing ampicillin and X-gal.
b.	Both plasmid and DNA are cut with the same restriction enzyme. Single cut in plasmid disrupts lacZ gene; multiple fragments of human DNA form.
c.	Cells containing recombinant plasmids are identified by their ability to grow in the presence of the antibiotic and by their white color. Blue colonies contain plasmids that resealed and thus have a functioning lacZ gene. Identify clones carrying the gene of interest with a nucleic acid probe.
d.	Recombinant plasmids transform bacteria with mutation in their lacZ gene.
e.	Plasmids are obtained and human DNA is isolated.
f.	Fragments are mixed and some foreign fragments base-pair with plasmid. DNA ligase seals ends.

18.

Step 1

19.

Step 2

20.

Step 3

21.

Step 4

22.

Step 5

23.

Step 6

Interactive question 20.5
List the lab steps in order to produce the autoradiography (Southern blotting)

a.	restriction enzyme treatment of samples
b.	autoradiography
c.	gel electrophoresis
d.	hybridization with radioactive probe
e.	DNA transfer by blotting onto membrane
f.	Suspect 1
g.	Suspect 2

24.

Step 1

25.

Step 2

26.

Step 3

27.

Step 4

28.

Step 5

29.

Which suspect committed the bloody crime?

Interactive question 20.6

a.	Researchers analyzed the phenotypes of the worms that develop with each lacking gene and classified most of the genes into a few functional groups.
b.	As in RT-PCR, mRNA is isolated from different tissues, and cDNA is made and labeled with fluorescent dye. The cDNA is applied to a microarray (single stranded DNA fragments of the genes of an organism arranged in a grid). The different cDNA will hybridize with the genes that were expressed in the tissue. The intensity with which the hybridize spots fluoresce indicates the relative amount of mRNA that was in the tissue.
c.	The mRNA from different tissue samples could be isolated. Reverse transcriptase would be used to make cDNA of all the mRNA, and PCR using specific primers could amplify only the gene of interest. Running the samples on a gel would show bands only in the tissues that were expressing the gene. RT-PCR
d.	If similar sequences occue in known genes in other species, the function of a gene may be inferred.

30.

What are some of the benefits of determining the nucleotide sequence of a gene of unknown function?

31.

Describe a recent research method you could use to identify the tissues in which a particular gene is expressed.

32.

Describe a research method that enables you to compare both which genes are expressed and what their relative rates of expression are in several tissues.

33.

In one study, RNAi was used to prevent the expression, one gene at a time, of 86% of the genes in early nematode embryos. What did this allow researchers to do?

Structure Your Knowledge #1
3 answers for each

an agricultural application

a medical application

34.

diagnosis of genetic and infectious diseases

35.

treatment of genetic disorders or other diseases

36.

improvement of the genomes of agriculture plants and animals to improve quality and yield

37.

production of insulin, human growth factor, TPA, and other useful products

38.

“pharm” animals to produce pharmaceutical proteins

39.

development of plant varieties that have genes for resistance to diseases, herbicides, and insects

Structure Your Knowledge #2 Brief Description

a.	Polymerase chain reaction: DNA is mixed with heat resistant DNA polymerase, nucleotides, and primers having complementary sequences for targeted DNA section and repeatedly heated to separate, cooled to pair with primers and replicate.
b.	Changes introduced in sequence of a cloned gene; mutated gene is inserted into a cell; phenotype of mutant is studied.
c.	Bacterial enzymes that cut DNA at restriction sites, creating sticky ends that can base pair with other fragments.
d.	Radioactively or fluorescently labeled single-stranded DNA or mRNA used to base pair with complementary sequence of DNA or RNA.
e.	Single-stranded DNA fragments are incubated with four nucleotides, DNA polymerase, and four labeled dideoxy nucleotides that interrupt synthesis; samples separated by size, sequence of nucleotides read from sequence of fluorescent tags. New automated techniques now used.
f.	mRNA is isolated; cDNA is synthesized by reverse transcriptase and DNA polymerase; cDNA is amplified using primers specific for the gene; gel elctrophoresis shows band in samples which had mRNA from that gene.
g.	mRNA isolated from cell is treated with reverse transcriptase to produce a complementary DNA strand, and then a double stranded DNA gene, minus introns and control regions.
h.	Double-stranded RNAs that match a gene sequence are inserted into cell; they trigger breakdown or block translation of that gene’s mRNA.
i.	DNA fragments separated by gel electrophoresis, transferred by blotting onto paper, labeled probe added, rinsed, autoradiography.
j.	Mixture of molecules applied to to gel in electric field; molecules separate, moving at different rates due to charges and sizes.
k.	Fluorescently labeled cDNA is made from a cell’s mRNA and applied to a DNA microarray of single stranded DNA from many different genes attached to a glass grid. The intensity and location of fluorescence indicates gene expression in the cell.

40.

restriction enzymes

41.

Gel electrophoresis

42.

cDNA

43.

nucleic acid probe

44.

Southern blotting

45.

DNA sequencing

46.

PCR

47.

DNA microassay

48.

RT-PCR

49.

in vitro mutagenesis

50.

RNA interference (RNAi)

Structure Your Knowledge #2
Some Uses in DNA Technology

a.	determine nucleotide sequence
b.	make recombinant DNA, form restriction fragments used for many other techniques
c.	technique for determining function of a gene
d.	analyze DNA; genetic profile
e.	creates genes that are easier to clone in bacteria; produces library of genes that are expressed in cell
f.	determine whether a particular gene is expressed in a sample
g.	rapidly produce multiple copies of a gene or section of DNA in vitro
h.	separate restriction fragments into pattern of distinct bands; fragments can be removed from gel and retain activity or can be identified with probes
i.	test thousands of genes simultaneously to compare gene expression in different tissues or at different developmental stages or conditions
j.	silence the expression of genes to study their functions and interactions between genes
k.	locate gene in clone of bacteria; identify bands on gels; DNA microassay; diagnose infectious diseases

51.