Biology Quiz 3

Sort the following in the order that they occur in gene expression (earliest to latest) in a eukaryote:

Transcription factors bind to the promoter RNA Polymerase II binds to DNA Introns are removed tRNA binds to the A site Proteins are glycosylated

A scientist begins with a concentration of 10 nM DNA. At the end of 5 cycles of PCR, what will be the concentration of the gene that he/she is amplifying?

320 10 * 2^5

If the DNA sequence (template strand) that encodes for a particular amino acid is 3'-GTA-5', what will be the sequence of the anticodon on the tRNA?

5' - AUG - 3'

What codon does the anticodon 5'-CGA-3' recognize? Write in the 5' to 3' direction.

5' - UCG - 3'

Which chemical groups are added to histones to change them from positively charged to neutrally charged?

Acetyl

Sort the following in first to last in a cycle of the polymerase chain reaction.

Denature by heat Anneal by cooling Synthesis/polymerase extends chain

To what regions do activators bind?

Enhancers and promoters

In a codon of mRNA, which base pair (first, second, or third) is most crucial in determining the amino acid that it codes for?

First

If the DNA sequence (template strand) that encodes for a particular amino acid is 3'-GTA-5', what amino acid does this code for?

Histidine (His)

Which of the following is NOT required for the polymerase chain reaction (PCR)?

Ligase

What type of mutation leads to premature termination of a peptide sequence?

Nonsense mutation

A blot that transfers DNA from a gel to a filter membrane is called a ___ blot.

Southern blot

What will happen in the lac operon (an inducible system!) if there is a mutation in the regulatory gene promoter (pi) such that RNA Polymerase fails to bind to pi?

The cell will always produce the enzymes involved in lactose metabolism, even if lactose is absent.

1) Which of the following does not occur in eukaryotes after mRNA is transcribed? a. Binding of RNA polymerase II to the promoter b. Capping of the 5' end c. Addition of a poly A tail to the 3' end d. Splicing out of the introns e. Transport to the cytosol

a. Binding of RNA polymerase II to the promoter

1) To what regions do activators bind? a. Enhancers b. Promoters c. Silencers

a. Enhancers

1) Which of the following is NOT true of RNA processing in eukaryotes? a. Exons are excised and hydrolyzed before mRNA moves out of the nucleus. b. The existence of exons and introns may facilitate crossing over between regions of a gene that code for polypeptide domains. c. Ribozymes function in RNA splicing d. RNA splicing may be catalyzed by spliceosomes. e. An initial RNA transcript is much longer than the final RNA molecule that may leave the nucleus.

a. Exons are excised and hydrolyzed before mRNA moves out of the nucleus.

12. A single hair is found at the scene of a crime. Which technology would you use first to determine if the hair could have come from a certain suspect? a. PCR b. DNA sequencing c. DNA fingerprinting d. Probing e. Antisense RNA

a. PCR

3. What is the coding strand? a. The DNA strand whose base sequence is identical to the base sequence of the RNA transcript produced (although with thymine replaced by uracil). b. The single-stranded RNA molecule that is transcribed from the DNA. c. The DNA strand that contains codons that are matched with anticodons of tRNA during transcription. d. The region of a chromosome that contains a gene.

a. The DNA strand whose base sequence is identical to the base sequence of the RNA transcript produced (although with thymine replaced by uracil).

1. The manufacture of new proteins is termed ________, and the production of a messenger RNA corresponding to a specific gene is called ________. a. Translation; transcription b. Termination; translation c. Transcription; translation d. Transfer; translation

a. Translation; transcription

11) E. coli cells that have taken up the plasmid WITH foreign DNA will be ______ to ampicillin and _____ to tetracycline. a. resistant; sensitive b. sensitive; resistant c. resistant; resistant d. sensitive; sensitive

a. resistant; sensitive

1) The most efficient means of regulating protein synthesis is by a. selective blocking of transcription. b. translation of the mRNA. c. inhibition of the protein. d. degradation of the protein. e. transcription of the gene.

a. selective blocking of transcription.

1) Which chemical groups are added to histones to change them from positively charged to neutrally charged? a. Thiol b. Acetyl c. Butyl d. Phosphate

b. Acetyl

6. Which of the following best explains how a point mutation can lead to a nonsense mutation? a. Changing a single base has no effect on the protein b. Changing a single base leads to a premature termination of translation c. Changing a single base within a codon from an A to a C d. The addition or deletion of a base alters the reading frame for the gene

b. Changing a single base leads to a premature termination of translation

1) True or false? Exons are removed and introns are spliced together to form the mature mRNA. a. True b. False

b. False

11. Hybridization: a. Replicates the library onto a piece of filter paper. b. Identifies specific DNAs or RNAs by renaturing with a fluorescently labeled probe. c. Genomic library selection. d. Transformation of plasmid DNA. e. Is the term describing the bond formation facilitated by DNA ligase.

b. Identifies specific DNAs or RNAs by renaturing with a fluorescently labeled probe

8. A sample from the lab reveals that mRNA extracted from the nucleus appears much longer than a mature mRNA. Why might this be? a. mRNA is made as a duplicate within the nucleus and only exports half of itself to the cytoplasm. b. Introns have been removed. c. Mature mRNA is supercoiled and only appears shorter than the primary transcript. d. Chemical bonds tighten during export to the cytoplasm, causing the mRNA to shrink. e. Exons form a lariat and are cut by a splicesome.

b. Introns have been removed.

1) A paleontologist has recovered a bit of tissue from the 400-year-old preserved skin of an extinct dodo. He would like to compare DNA from the sample with DNA from living birds. Which of the following would be most useful for increasing the amount of DNA available for testing? a. RFLP analysis b. PCR c. Electroporation d. Gel electrophoresis

b. PCR

10. A mixture of DNA of two different sizes (2 kilobases and 4 kilobases) are analyzed with agarose gel electrophoresis. Upon viewing the gel, you would expect to see: a. The 4 kb size of DNA to run farther on the gel in a smear because it is bigger and will impede the smaller piece to move. b. The 2 kb size of DNA to run farther on the gel because it is smaller and can more easily be moved through the agarose polymer. c. Both sizes of DNA to appear at the same distance on the gel because of DNA interactions. d. The 2kb size to run slower on the gel because there are fewer phosphates to contribute to contribute to the electrical charge responsible for moving the DNA. e. None of the above.

b. The 2 kb size of DNA to run farther on the gel because it is smaller and can more easily be moved through the agarose polymer.

9. In the lac operon, the repressor protein binds to _____ to inhibit transcription. a. The promoter b. The operator c. The CAP site d. The enhancer e. Lactose

b. The operator

1) DNA fingerprinting is used a. to provide a means of identifying identical DNA sequences. b. as a forensics tool to provide evidence in a criminal case. c. to identify genetic diseases. d. to sequence fragments of DNA. e. for all of the above.

b. as a forensics tool to provide evidence in a criminal case.

15. The ultimate origin of genetic variation is a. genetic drift. b. mutation. c. natural selection. d. a founder effect. e. nonrandom mating

b. mutation.

Initiation

begins with binding at the promoter

1) Which of the following sequences along a double-stranded DNA molecule may be recognized as a cutting site for a particular restriction enzyme? a. 5'-AAGG-3' 3'-TTCC-5' b. 5'-AGTC-3' 3'-TCAG-5' c. 5'-GGCC-3' 3'-CCGG-5' d. 5'-ACCA-3' 3'-TGGT-5'

c. 5'-GGCC-3' 3'-CCGG-5'

2. Each amino acid in a protein is specified by - a. Multiple genes b. A promoter c. A codon d. A molecule of mRNA

c. A codon

1) Eukaryotic protein-encoding genes differ from their prokaryotic counterparts in that eukaryotic genes a. Are double-stranded b. Are present in only a single copy c. Contain introns d. Have a promoter e. Transcribe mRNA

c. Contain introns

13. In order, the steps of PCR are: a. Denaturing, annealing, and termination b. Annealing, synthesis, and denaturing c. Denaturing, annealing, synthesis d. Synthesis, annealing, termination e. Denaturing, amplification, synthesis

c. Denaturing, annealing, synthesis

1) Which statement about selective gene transcription in eukaryotes is NOT true? a. Different classes of RNA polymerase transcribe different parts of the genome. b. Transcription requires transcription factors. c. Genes are usually transcribed in groups called operons. d. Both positive and negative regulation occur. e. Many proteins bind at the promoter.

c. Genes are usually transcribed in groups called operons.

1) The bonds between the anticodon of a tRNA molecule and the complementary codon of mRNA are a. Catalyzed by peptidyl transferase b. Formed by the input of energy from ATP c. Hydrogen bonds that form while the codon is in the A site d. Catalyzed by aminoacyl-tRNA synthetase e. Covalent bonds formed with energy from GTP

c. Hydrogen bonds that form while the codon is in the A site

1) _____ groups added to histone proteins cause the DNA to become more tightly packed whereas _____ groups added to histone proteins cause the DNA to become less tightly packed. a. Phosphate; methyl b. Methyl; phosphate c. Methyl; acetyl d. Acetyl; phosphate e. Acetyl; methyl

c. Methyl; acetyl

1) In eukaryotic cells, promoters are a. transcribed. b. transcribed and translated. c. neither transcribed nor translated. d. transcribed and then removed. e. sequences of RNA that are spliced out.

c. neither transcribed nor translated.

10) E. coli cells that have taken up the plasmid only (no foreign DNA inserted) will be ______ to ampicillin and _____ to tetracycline. a. resistant; sensitive b. sensitive; resistant c. resistant; resistant d. sensitive; sensitive

c. resistant; resistant

4. An anticodon would be found on which of the following types of RNA? a. snRNA b. mRNA c. tRNA d. rRNA

c. tRNA

1) Type II restriction endonucleases are useful because a. they degrade DNA from the 5' end b. they cleave the DNA at random locations c. they cleave the DNA at specific sequences d. they only cleave modified DNA

c. they cleave the DNA at specific sequences

1) Using the genetic code, identify a possible sequence of nucleotides in the DNA that would code for the polypeptide sequence Phe-Pro-Lys (shown is 3'à5' direction of template strand). a. AAA-GGG-UUU b. TTC-CCC-AAG c. TTT-CCA-AAA d. AAG-GGC-TTC e. UUU-CCC-AAA

d. AAG-GGC-TTC

14. "Golden rice" was created by a. manipulating the genome of a commonly-grown agricultural species of plant. b. introduction of DNA from both prokaryotes and other eukaryotes not closely related to the rice plant. c. a public facility, and distributed without commercial restraints. d. All of the above. e. None of the above.

d. All of the above.

1) Regulatory proteins (aka DNA binding proteins) interact with DNA by - a. Unwinding the helix and changing the pattern of base pairing b. Interacting with the sugar-phosphate backbone of the double helix c. Unwinding the helix and disrupting base pairing d. Binding to the major groove of the double helix and interacting with base pairs

d. Binding to the major groove of the double helix and interacting with base pairs

7. Regulatory proteins interact with DNA by - a. Unwinding the helix and changing the pattern of base pairing b. Interacting with the sugar-phosphate backbone of the double helix c. Unwinding the helix and disrupting base pairing d. Binding to the major groove of the double helix and interacting with base pairs

d. Binding to the major groove of the double helix and interacting with base pairs

5. The job of a ribosome during translation can best be described as - a. Targeting proteins to the rough endoplasmic reticulum b. Determining the sequence of amino acids c. Carrying amino acids to the mRNA d. Catalyzing peptide bond formation between amino acids

d. Catalyzing peptide bond formation between amino acids

1) Beadle and Tatum discovered several classes of Neurospora mutants that were able to grow on minimal medium with arginine added. Class I mutants were also able to grow on medium (no arginine) supplemented with either ornithine or citrulline, whereas class II mutants could grow on citrulline medium but not on ornithine medium. The metabolic pathway of arginine synthesis is as follows: Precursor -> Ornithine -> Citrulline -> Arginine A B C From these growth results, they could conclude that a. One gene codes for the entire metabolic pathway b. The genetic code of DNA is a triplet code c. Class I mutants have their mutations later in the nucleotide chain than do class II mutants, and thus have more functional enzymes d. Class I mutants have a nonfunctional enzyme at step A, and class II mutants have a nonfunctional enzyme at step B e. Class I mutants have a nonfunctional enzyme at step B, and class II mutants have a nonfunctional enzyme at step C

d. Class I mutants have a nonfunctional enzyme at step A, and class II mutants have a nonfunctional enzyme at step B

1) Which of the following is NOT true of a codon? a. It consists of three nucleotides b. It may code for the same amino acid as another codon does c. It never codes for more than one amino acid d. It extends from one end of a tRNA molecule It is the basic unit of the genetic code

d. It extends from one end of a tRNA molecule It is the basic unit of the genetic code

1) Refer to the diagram below. What will happen if there is a mutation in the z gene (structural gene for beta-galactosidase)? a. Lactose will be synthesized constitutively b. Lactose will be metabolized constitutively c. Lactose will never be synthesized d. Lactose will never be metabolized

d. Lactose will never be metabolized

12) E. coli cells that have NOT taken up any plasmid will be ______ to ampicillin and _____ to tetracycline. a. resistant; sensitive b. sensitive; resistant c. resistant; resistant d. sensitive; sensitive

d. sensitive; sensitive

1) Which of the following mutations would be most likely to have a harmful effect on an organism? a. A base-pair substitution b. A deletion of three consecutive bases near the middle of the gene c. A single base deletion near the middle of an intron d. A single base deletion close to the end of the coding sequence e. A single base insertion near the start of the coding sequence

e. A single base insertion near the start of the coding sequence

1) Control of gene expression in eukaryotes includes all of the following except a. Alternative splicing of RNA transcripts b. Binding of proteins to DNA c. Transcription factors d. Feedback inhibition of enzyme activity by allosteric control e. DNA methylation

e. DNA methylation

1) RFLP analysis is being used as evidence to link suspects with blood and tissues found at crime scenes. DNA fingerprints look something like supermarket bar codes. The pattern of bars in a DNA fingerprint shows a. The order of bases in a particular gene b. The individual's genotype c. The order of genes along particular chromosomes d. The presence of dominant or recessive alleles for particular traits e. The presence of certain DNA fragments

e. The presence of certain DNA fragments

___ are spliced together to form a mature mRNA from a pre-mRNA.

exons

Start site

first base to be transcribed

Poly(A) Tail

placed on the 3' end of the transcript

Guanine cap

placed on the 5' end of the transcript

RNA polymerase binds to a ___ to initiate __.

promoter;transcription