Review questions for Trends in Biotechnology



Review questions for Trends in Biotechnology

The real exam will be much shorter.

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Please look at these quizzes:

• Animation and Quiz

•

• The review problem is at

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The review problem is at



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Also please make sure you know the words from the first 3 chapters in the word list



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These questions are from different websites. If you go to the site you will be able to check the answers.



Choose the best answer

2

When Hershey and Chase differentially tagged the DNA and proteins of bacteriophages and allowed them to infect bacteria, what did the viruses transfer to the bacteria?

A) radioactive phosphorus and sulfur

B) radioactive sulfur

C) DNA

D) Both b and c are correct.

3

If one strand of a DNA molecule has the base sequence ATTGCAT, its complementary strand will have the sequence

A) ATTGCAT

B) TAACGTA

C) GCCATGC

D) CGGTACG

4

DNA is made up of building blocks called

A) proteins.

B) bases.

C) nucleotides.

D) deoxyribose.

5

X-ray diffraction experiments conducted by _____________ led to the determination of the structure of DNA.

A) Francis Crick

B) James Watson

C) Erwin Chargaff

D) Rosalind Franklin

6

Meselson and Stahl proved that

A) DNA is the genetic material.

B) DNA is made from nucleotides.

C) DNA replicates in a semiconservative manner.

D) DNA is a double helix held together with base-pairing.

7

DNA polymerase III can only add nucleotides to an existing chain, so _________________ is required.

A) an RNA primer

B) DNA polymerase I

C) helicase

D) a DNA primer

8

Okazaki fragments are

A) synthesized in the 3' to 5' direction.

B) found on the lagging strand.

C) found on the leading strand.

D) assembled as continuous replication.

9

Beadle and Tatum's experiment showed that each enzyme is specified by a single

A) chromosome.

B) gene.

C) nucleotide.

D) mutation.



1

The bases of RNA are the same as those of DNA with the exception that RNA contains

A) cysteine instead of cytosine.

B) uracil instead of thymine.

C) cytosine instead of guanine.

D) uracil instead of adenine.

2

Which one of the following is not a type of RNA?

A) nRNA (nuclear RNA)

B) mRNA (messenger RNA)

C) rRNA (ribosomal RNA)

D) tRNA (transfer RNA)

3

Each amino acid in a protein is specified by

A) several genes.

B) a promoter.

C) an mRNA molecule.

D) a codon.

4

The three-nucleotide codon system can be arranged into ______________ combinations.

A) 16

B) 20

C) 64

D) 128

5

The TATA box in eukaryotes is a

A) core promoter.

B) - 35 sequence.

C) - 10 sequence.

D) 5' cap.

6

The site where RNA polymerase attaches to the DNA molecule to start the formation of RNA is called a(n)

A) promoter.

B) exon.

C) intron.

D) GC hairpin.

7

When mRNA leaves the cell's nucleus, it next becomes associated with

A) proteins.

B) a ribosome.

C) tRNA.

D) RNA polymerase.

8

If an mRNA codon reads UAC, its complementary anticodon will be

A) TUC.

B) ATG.

C) AUG.

D) CAG.

9

The nucleotide sequences on DNA that actually have information encoding a sequence of amino acids are

A) introns.

B) exons.

C) UAA.

D) UGA.

10

Which of the following statements is correct about prokaryotic gene expression?

A) Prokaryotic mRNAs must have introns spliced out.

B) Prokaryotic mRNAs are often translated before transcription is complete.

C) Prokaryotic mRNAs contain the transcript of only one gene.

D) All of these statements are correct.



1

Cutting certain genes out of molecules of DNA requires the use of special

A) degrading nucleases.

B) restriction endonucleases.

C) eukaryotic enzymes.

D) viral enzymes.

3

In Cohen and Boyer's recombinant DNA experiments, restriction endonucleases were used to

A) isolate fragments of cloned bacterial plasmids.

B) isolate fragments of frog DNA that contained an rRNA gene.

C) cleave the bacterial plasmid.

D) All of these are correct.



7

In addition to coding sequences, our genome contains

A) noncoding DNA within genes (i.e., introns)

B) structural DNA involved in telomeres and centromeres.

C) simple repetitive DNA.

D) DNA from transposable elements that have jumped around in the genome.

E) All of these are present in genomic DNA.



1

In order to ensure he had pure-breeding plants for his experiments, Mendel

Need a Hint?

A) cross-fertilized each variety with each other.

B) let each variety self-fertilize for several generations.

C) removed the female parts of the plants.

D) removed the male parts of the plants.

2

When two parents are crossed, the offspring are referred to as the

Need a Hint?

A) recessives.

B) testcross.

C) F1 generation.

D) F2 generation.

3

A cross between two individuals results in a ratio of 9:3:3:1 for four possible phenotypes. This is an example of a

Need a Hint?

A) dihybrid cross.

B) monohybrid cross.

C) testcross.

D) none of these.

4

Human height shows a continuous variation from the very short to the very tall. Height is most likely controlled by

Need a Hint?

A) epistatic genes.

B) environmental factors.

C) sex-linked genes.

D) multiple genes.

5

In the human ABO blood grouping, the four basic blood types are type A, type B, type AB, and type O. The blood proteins A and B are

Need a Hint?

A) simple dominant and recessive traits.

B) incomplete dominant traits.

C) codominant traits.

D) sex-linked traits.



1

The transforming agent was identified as DNA by

A) Griffith.

B) Avery.

C) Hershey and Chase.

D) Watson and Crick.

2

If a DNA molecule contains 20% A, approximately what percentage of G is present?

A) 20%

B) 40%

C) 30%

D) 60%

3

DNA replication is

A) semiconservative.

B) conservative.

C) dispersive.

D) semidispersive.

4

In the Meselson and Stahl experiment, what percentage of the DNA is labeled with light nitrogen after three generations of replication.

A) 25%

B) 50%

C) 75%

D) 100%

5

Enzymes called ____ catalyze the formation of covalent bonds that hold together the sugar-phosphate backbone of the DNA molecule.

A) helicases

B) DNA polymerases

C) RNA polymerases

D) ligases

6

Replication proceeds in a ____ to _____ direction.

A) 3' to 3'

B) 3' to 5'

C) 5' to 3'

D) 5' to 5'

7

Which strand below would make the sequence 5' AAACGCTT 3' a double stranded DNA molecule?

A) 5' TTTGCGAA 3'

B) 5' UUUGCGUU 3'

C) 5' AAGCGUUU 3'

D) 5' AAGCGTTT 3'

8

How many DNA bases make up the human genome?

A) 3 thousand

B) 3 million

C) 3 billion

D) 30 billion

9

Considering DNA replication along the 5' to 3' template strand, what event takes place first?

A) DNA polymerase begins adding RNA nucleotides

B) DNA polymerase begins adding DNA nucleotides

C) primase adds an RNA primer

D) primase removes the 5' phosphate

10

If Hershey and Chase found S35 in progeny phages rather than P32, their experiment would have demonstrated that

A) proteins contain phosphorus.

B) DNA contains sulfur.

C) phage DNA enters the host cell.

D) phage protein enters the host cell.

11

DNA structure was proposed by

A) Griffith.

B) Chargaff.

C) Avery.

D) Watson and Crick.

12

Energy is required to break the hydrogen bonds holding the bases together. Which pair will be the most difficult to separate?

A) A - T

B) C - G

C) A - C

D) G - T

13

A scientist isolates a cell line characterized by unusual cell division. In these cells, only small fragments of DNA are found. A defective ____ enzyme may be responsible.

A) DNA polymerase

B) ligase

C) primase

D) exonuclease

14

If a nucleic acid is found to contain 20% A and 20% T, the molecule is probably

A) single-stranded DNA.

B) double-stranded DNA.

C) single-stranded RNA.

D) double-stranded RNA.

15

The number of amplified pieces of DNA equals ____ after five cycles of PCR.

A) 5

B) 10

C) 25

D) 32

16

Is it possible to use PCR to produce many copies of all DNA of one chromosome?

A) yes, if the correct primers are available

B) yes, if the telomeres are present

C) no, PCR cannot copy DNA, only RNA

D) no, PCR copies short sequences of DNA only

17

If DNA polymerase could add bases in the 3' to 5' direction, there would be no need for

A) DNA ligase.

B) Okazaki fragments.

C) helicase.

D) PCR.

18

Which of the following is not a component of a chromosome?

A) histone proteins

B) DNA polymerase

C) RNA

D) chromosomes contain all of the above



1

The process of copying a gene's DNA sequence into a sequence of RNA is called

A) replication.

B) transcription.

C) translation.

D) PCR.

2

The transcribing enzyme is

A) ligase.

B) DNA polymerase.

C) RNA polymerase.

D) amino-acyl transferase.

3

Which molecule contains the genetic code?

A) DNA

B) mRNA

C) tRNA

D) rRNA

4

Transcription occurs along a ____ template forming an mRNA in the ____ direction.

A) 5' to 3'; 5' to 3'

B) 5' to 3'; 3' to 5'

C) 3' to 5'; 5' to 3'

D) 3' to 5'; 3' to 5'

5

Which of the statements below is false?

A) The genetic code is overlapping.

B) The genetic code is universal.

C) Degenerate codons specify the same amino acids.

D) The genetic code is triplet.

6

The first mRNA codon to specify an amino acid is always

A) TAC.

B) UAA.

C) UAG.

D) AUG.

7

The amino acid sequence of a polypeptide chain comprises the ____ structure of the protein.

A) primary

B) secondary

C) tertiary

D) quaternary

8

Transfer RNA's bind during translation by the

A) codon.

B) anticodon.

C) template.

9

Of the ____ different possible codons, ____ specify amino acids and ____ signal stop.

A) 20, 17, 3

B) 180, 20, 60

C) 64, 61, 3

D) 61, 60, 1

10

RNA contains which bases?

A) adenine, thymine, guanine, cytosine, uracil

B) adenine, thymine, guanine, cytosine

C) thymine, guanine, cytosine, uracil

D) adenine, guanine, cytosine, uracil

11

Which of the following statements is true regarding introns?

A) Introns are the parts of mRNA that are translated.

B) Introns have no function.

C) In general, human genes have fewer introns than genes of other organisms.

D) Introns may be involved in exon shuffling.

12

Which mode of information transfer usually does not occur?

A) DNA to DNA

B) DNA to RNA

C) DNA to protein

D) all occur in a working cell

13

A geneticist isolates a gene for a specific trait under study. She also isolates the corresponding mRNA. Upon comparison, the mRNA is found to contain 1,000 fewer bases than the DNA sequence. Did the geneticist isolate the wrong DNA?

A) yes, mRNA is made from a DNA template and should be the same length as the gene sequence

B) yes, the mRNA should contain more bases than the DNA sequence because bases flanking the gene are also transcribed

C) no, the final mRNA contains only exons, the introns were removed

D) no, the mRNA was partially degraded after it was transcribed

14

The effort to decipher the genetic code was led by ____ who was awarded a Nobel Prize for his work.

A) Nirenberg

B) Lederberg

C) Watson

D) Crick

15

A DNA strand with the sequence AACGTAACG is transcribed. What is the sequence of the mRNA molecule synthesized?

A) AACGTAACG

B) UUGCAUUGC

C) AACGUAACG

D) TTGCATTGC

16

What sequence on the template strand of DNA corresponds to the first amino acid inserted into a protein?

A) TAC

B) UAA

C) UAG

D) AUG

17

Which of the following is an example of the degeneracy of the genetic code?

A) a given amino acid has more than one codon

B) each codon specifies more than one amino acid

C) the first two bases specify the amino acid

D) the genetic code is not degenerate

18

Proteomics

A) is another term for genomics in humans.

B) is the study of the collection of proteins produced in a particular cell.

C) is the study of proteins produced by a particular gene.

D) proves that a single gene codes for only one protein.

19

The template strand of DNA for one gene may be the coding strand of DNA for another gene.

A) True

B) False

20

Which of the following statements is true regarding transposons?

A) They are sequences of mRNA that can move around in the genome.

B) They exist in corn, but are not found in the human genome.

C) They are the most abundant type of repeat in the genome.

D) All of the above are true regarding transposons.

21

Transcription and translation of a gene composed of 30 nucleotides would form a protein containing no more than ___ amino acids.

A) 10

B) 15

C) 60

D) 90



1 . Which one of the following lists the four bases contained in DNA? [Hint]

guanine, pyroline, thymine, uracil

adenine, guanine, uracil, thymine

adenine, guanine, purine, thymine

cytosine, guanine, thymine, uracil

adenine, guanine, cytosine, thymine

2 . Which one of the following describes a nucleotide most completely? (10.2) [Hint]

a sugar and a pyrimidine

nitrogen base, a sugar, and a phosphate group

a sugar and a purine

nitrogen base and a sugar only

a sugar and a phosphate group only

3 . What technique was most helpful to Watson and Crick? [Hint]

X-ray crystallography

cloned DNA

radioactive labeling

electrophoresis

transgenic animals

4 . For DNA _____. [Hint]

the ratio of A to C is close to 1:1 and the ratio of G to T is close to 1:1

the ratio of A to G is close to 1:1 and the ratio of T to C is close to 1:1

A + G > T + C

A + T = G + C

the ratio of A to T is close to 1:1 and the ratio of G to C is close to 1:1

5 . One strand of a DNA molecule has the base sequence ATAGGT. The complementary base sequence on the other strand of DNA will be _____. [Hint]

TGGAUA

ATAGGT

TATCCA

TGGATA

UAUCCA

6 . The two sugar-phosphate strands of a DNA molecule are joined to each other by _____. [Hint]

5' —> 3' deoxyribose and phosphate bonds

ionic bonds between guanine and cytosine

covalent bonds between carbon atoms in deoxyribose molecules

hydrogen bonds between nucleotide bases

covalent bonds between nitrogen atoms in adenine and in thymine

7 . Which one of the following is NOT true about double-stranded DNA? [Hint]

It is helical.

It contains hydrogen bonds.

The two strands are said to be complementary.

Adenine and uracil are present in equal amounts.

The strands run in opposite directions.

8 . The information in DNA is contained in _____. [Hint]

the sequence of nucleotides along the length of one strand of the DNA molecule

the sequence of amino acids that make up the DNA molecule

the type of sugars used in making the DNA molecule

the variation in the structure of nucleotides that make up the DNA molecule

all of these

9 . Which one of the following statements does NOT apply to the Watson-Crick model for DNA? [Hint]

The two strands of the DNA helix are upside down with respect to each other.

The purines (double rings) base pair with the pyrimidines (single rings).

The nitrogenous bases are attached to the deoxyribose molecules.

The framework of the helix consists of sugar-phosphate units of the nucleotides.

The two strands of the helix are held together by covalent bonds.

10 . The statement that each new molecule of DNA contains one parental and one newly synthesized strand of DNA refers to _____. [Hint]

the de novo synthesis of DNA

the one gene–one enzyme hypothesis

transcription

a model of DNA replication

the formation of replication bubbles

11 . During the replication of DNA molecules _____. [Hint]

the cell undergoes mitosis

both strands of a molecule act as templates

only one strand of the molecule acts as a template

the reaction is catalyzed by RNA polymerase

errors never occur

12 . Two new strands of DNA molecules grow as bases are added by the enzyme _____. [Hint]

DNA polymerase

bacterial duplicating complex

RNA polymerase

DNA replicase

polynucleotidase

13 . Monomers for the synthesis of DNA are called _____. [Hint]

disaccharides

nucleotides

amino acids

monosaccharides

fatty acids

14 . A gene is usually _____. [Hint]

the same thing as a chromosome

made by a ribosome

the information for making a polypeptide

made of RNA

made of protein

15 . Which one of the following is NOT associated with RNA? [Hint]

phosphates

a sugar

uracil

single-strandedness

thymine

16 . When messenger RNA (mRNA) is being made, the RNA base ____ always pairs with the base _____ in DNA. [Hint]

U ... T

T ... G

T ... A

A ... U

U ... A

17 . The DNA code is CGT. What messenger RNA is made from this? [Hint]

CTA

ATU

GCA

UCG

TCU

18 . Information is transferred from the nucleus to the cytoplasm of eukaryotic cells in the form of _____. [Hint]

nucleic acids

sterols

lipids

carbohydrates

proteins

19 . A particular ____ carry the information for making a specific polypeptide, but ____ can be used to make any polypeptide. [Hint]

gene and mRNA ... a ribosome and tRNA

gene and ribosome ... tRNA and mRNA

tRNA and ribosome ... a gene and mRNA

ribosome and mRNA ... a gene and tRNA

gene and tRNA ... a ribosome and mRNA

20 . The number of nucleotide bases "read" together on the mRNA to designate each amino acid is __________; this unit is called a __________. [Hint]

2 ... anticodon

3... codon

2 ... dipeptide

1 ... amino acid

3 ... triose

21 . Which one of the following statements is true? [Hint]

Each gene codes for three proteins.

Each DNA base codes for three amino acids.

It takes three genes to code for one protein.

Each amino acid in a protein is coded for by three bases in the DNA.

Each triplet has many different meanings.

22 . During the transcription of a given portion of a DNA molecule _____. [Hint]

mRNA is synthesized on only one of the chains

half of the mRNA is synthesized on half of one chain; then the other half of the mRNA is made on the other half of the DNA

mRNA is synthesized on both chains of the DNA molecule, but first on one side and then the other

any of the above patterns may be found

mRNA is synthesized on both chains of the DNA molecule at once

23 . One strand of a DNA molecule has the following sequence: 3'-AGTACAAACTATCCACCGTC-5'. In order for transcription to occur in that strand, there would have to be a specific recognition sequence, called a(n) __________, to the left of the DNA sequence indicated. [Hint]

promoter

intron

exon

codon

centromere

24 . At one point as a cell carried out its day-to-day activities, the nucleotides GAT were paired with the nucleotides CUA. This pairing occurred _____. [Hint]

in a double-stranded DNA molecule

it is impossible to say, given this information

during transcription

when an mRNA codon paired with a tRNA anticodon

during translation

25 . What is the proper order of the following events in the expression of a eukaryotic gene?

translation

RNA processing

transcription

[Hint]

2, 3, 1

2, 3, 1

1, 2, 3

3, 2, 1

1, 2, 3

26 . A terminator in mRNA synthesis is _____. [Hint]

a specific nucleotide sequence in DNA that signals a stop to transcription

none of the above

A character played by Arnold Schwarzenegger

a molecule of tRNA that recognizes a stop codon

an enzyme whose specific function is to stop synthesis

27 . Which one of the following catalyzes the linkage between nucleotides to form RNA? [Hint]

tRNA

RNA polymerase

RNA ligase

reverse transcriptase

RNA

28 . In transcription, _____. [Hint]

only one DNA strand is used as a template for the synthesis of RNA

all of the above

none of the above

RNA nucleotides are used

the DNA promoter region acts as an initial binding site for RNA polymerase

29 . A cell biologist found that two different proteins with largely different structures were translated from two different mRNAs. These mRNAs, however, were transcribed from the same gene in the cell nucleus. Which mechanism below could best account for this? [Hint]

The gene could be transcribed in different directions.

Exons from the same gene could be spliced in different ways to make different mRNAs.

A mutation might have altered the gene.

The two proteins have different functions in the cell.

Different systems of DNA unpacking could result in two different mRNAs.

30 . Usually, in eukaryotic genes _____. [Hint]

introns are not transcribed

both introns and exons are transcribed, but the RNA transcribed from them does not leave the nucleus

exons are transcribed, but the RNA transcribed from introns does not leave the nucleus

exons are not transcribed

exons and introns are transcribed, and the RNA transcribed from them leaves the nucleus

31 . Which one of the following statements correctly describes mRNA processing in eukaryotes? [Hint]

Introns are cut out and transported to the ribosomes.

Introns are cut out and the resulting exons are spliced together.

Exons are cut out and transported to smooth endoplasmic reticulum.

Introns are cut out and spliced together at the end of the mRNA.

Exons are cut out and the introns are spliced together.

32 . A mutation in a DNA sequence is likely to have NO effect on phenotype if the mutation _____. [Hint]

changes a stop codon to a codon specifying an amino acid

substantially changes the structure of an enzyme

occurs in an intron

forms a new stop codon

prevents the initiation of transcription of the DNA sequence that codes for ATP synthase

33 . In a eukaryotic cell, transcription takes place _____. [Hint]

in the nucleus

on the cell membrane

in the rough endoplasmic reticulum

on free ribosomes

in the cytoplasm

34 . The function of tRNA during protein synthesis is to _____. [Hint]

deliver amino acids to their proper site during protein synthesis

process mRNA

attach mRNA to the small subunit of the ribosome

transcribe mRNA

guide ribosome subunits out of the nucleus through nuclear pores

35 . During translation in a eukaryotic cell _____. [Hint]

polypeptides are synthesized at ribosomes, according to instructions carried by mRNA

ribosomes move into the nucleus

French cells are able to speak to German cells

mRNA is synthesized by the bonding of free nucleotides to the bases on the template strand of DNA

tRNA carries amino acid molecules to the nucleus, where they are added to a growing polypeptide chain

36 . Which one of the following processes does NOT take place in the nucleus? [Hint]

assembly of ribosomes

removal of introns from RNA

transcription

translation

replication of DNA

37 . During translation, amino acid chain elongation occurs until _____. [Hint]

no further amino acids are needed by the cell

the ribosome encounters "stop" codons

all tRNAs are empty

the polypeptide is long enough

the ribosome runs off the end of the mRNA strand

38 . A virus infects a cell and randomly inserts many short segments of DNA containing a stop codon throughout the organism's chromosomes. This will probably cause _____. [Hint]

the DNA to break up into thousands of short segments

manufactured proteins to be short and defective

all of the above

incorrect pairing between mRNA codons and amino acids

no bad effects, as long as the stop codons are not also inserted into tRNA

39 . During the process of translation, ____ matches an mRNA codon with the proper amino acid. [Hint]

DNA polymerase

transfer RNA

a ribosome

ATP

messenger RNA

40 . A sequence of pictures of polypeptide synthesis shows a ribosome holding two transfer RNAs. One tRNA has a polypeptide chain attached to it; the other tRNA has a single amino acid attached to it. What does the next picture show? [Hint]

The amino acid moves over and bonds to the polypeptide chain.

The tRNA with the polypeptide chain leaves the ribosome.

The tRNA with the single amino acid leaves the ribosome.

The polypeptide chain moves over and bonds to the single amino acid.

A third tRNA with an amino acid joins the pair on the ribosome.

41 . Which summary of protein synthesis is correct? [Hint]

DNA leaves the nucleus, goes to a ribosome, and catalyzes the polymerization of amino acids in a protein.

Transfer RNAs line up on a ribosome, and amino acids bind to them with hydrogen bonds.

None of the above.

Messenger RNA is made on a DNA template, and then amino-acid-bearing transfer RNAs line up on it in through codon-anticodon pairing.

DNA exchanges its thymine units with uracil in polymerase. This activates polymerase, and it starts joining amino acids together.

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