MMSC490 Exam 1 (Quiz Questions)

Chapters 1, 2, 4, and 5 Practice Quiz Questions

Why is it thought that regulatory elements occur in clusters?

Allows the interaction of multiple transcription factors

In 1995, the first complete genome of ................. was sequenced by Dr. Craig Venter.

Haemophilus influenzae

The experimental inactivation of a gene by homologous recombination with an inactive mutant to assess function of the normal genes in intact organisms is often referred to as what type of experiment?

Knockout

The human genome is estimated to contain about ................... genes.

20,000–25,000

n 2010, scientists developed a series of overlapping oligonucleotides that extended a full 1.08 million base pairs and used it to develop the first complete organism using a synthetic genome. The newly created cells had normal growth and morphology.
In addition to the synthetic genome, why did the investigators also included a gene that confers resistance to tetracycline?

The tetracycline resistance gene allows the selection of only the cells that are resistant to tetracycline and thus cells that survive selection carry the novel synthetic genome.

The large-scale project call ENCODE used RNA-seq to characterize all RNAs in 147 human cell types. The surprise result from analysis of the data revealed that even though there is only 1% of the genome that encodes for protein, as much as .............% of the genome is actually transcribed.

50

Which statement below best explains why there are 64 possible codons?

There are only four nucleotides and with a triplet code, the total number of possibilities would be 43.

The simplest eukaryotic genome is found in

Saccharomyces cerevisiae.

Mass spectrometers are used to

identify proteins by mass/ratio peptide analysis as part of proteomic procedures.

The Arabidopsis genome, like many plant genomes, contains more genes than many animals. This is due largely to

gene duplication

Surprisingly, after sequencing many different species, what organism stands out as having the largest number of genes?

apple

Stretches of sequenced nucleotides that code for polypeptides are recognized by the

absence of chain-terminating codons.

In the upstream promoter of some human genes, a regulatory sequence of eight nucleotides, TGACGTCA, has been shown to regulate a number of cAMP responsive genes. Based on this knowledge, you conduct a genome search and identify 250 of these identical sequences that occur. Could you then conclude that these sequences coincide with genes that are cAMP responsive?

No, because this is a sequence that in the context of 3 billion base pairs would occur fairly regularly, and may or may not be associated with a gene.

Which of the following best defines systems biology?

The computational overlay of data from both genomic and proteomic experiments

Potential protein-coding regions of genomic DNA containing long stretches of nucleotide sequences that can encode polypeptides and contain no stop codons are called

open-reading frames.

Which of the following would not necessarily be part of a cellular signaling network?

Synthetic genetic toggle switches

Five percent of the genome is conserved among all mammals, yet only ~1% directly encodes proteins. What is the likely role for the remaining 4%?

Regulation of expression for the 1% that encodes proteins

Mass spectrometers are used to

identify proteins by mass/ratio peptide analysis as part of proteomic procedures.

Which of the following methods would utilize an antibody that recognizes cellular proteins to investigate protein–protein interactions?

Immunoprecipitation

Analysis of the H. influenza and E. coli genomes revealed that ................ % of the genomes encodes for protein.

90

The new field of science called ................... lies at the interface between biology and computer science. It is focused on developing the computational methods needed to extract useful biological information from the sequence of billions of bases of DNA.

bioinformatics

What is a common method for testing blood samples of athletes for the presence of performance enhancing drugs?

Mass spectrometry

There are more distinct proteins in eukaryotic cells than there are number of genes. Which of the following best explain this?

Many genes can give rise to multiple RNAs through alternate splicing.

What is best described as an engineering approach to understanding and manipulating biological systems?

Synthetic biology

Consider two signaling pathways: A-B-C-D-E and 1-2-3-4-5-6-7. Which of the following responses would be representative of a feedforward relay?

B stimulates E

In RNA interference experiments, siRNAs homologous to known mRNAs inhibit expression of the proteins by what mechanism?

They form double-stranded RNA molecules that get degraded in the cytoplasm.

Consider a hypothetical signaling pathway where the initiating signal is A, the terminal response is E, and there are three intermediate components, B, C, and D, such that the complete pathway is A-B-C-D-E. Experimentally, you determine that E acts to simulate A. This is an example of

positive feedback.

Which of the following methods revealed that there were many more RNAs transcribed that are accounted for by the protein-coding genes in human cells?

RNA-seq

What percent of genes are similar between mice, rats, and humans?

90

The human genome contains approximately ................ billion base pairs.

3

Analysis of the H. influenza and E. coli genomes revealed that ................ % of the genomes encodes for protein.

90

The first eukaryotic genome to be completely sequenced was

the yeast Saccharomyces cerevisiae.

Analysis of the first bacterial genome to be sequenced, H. influenzae, revealed .................. rRNA genes, ............... different tRNA genes, and ........... potential protein-coding genes.

6; 54; 1,743

Which of the following methods revealed that there were many more RNAs transcribed that are accounted for by the protein-coding genes in human cells?

RNA-seq

Mass spectrometry has determined that which of the following cellular structure has the largest number of unique proteins?

Plasma membrane

To sequence the human genome, the International Human Genome Sequencing Consortium

used BAC clones as substrates for sequencing.

Which of the following would be used to express a human protein in E. coli?

An expression plasmid containing cDNA made from the mRNA for the protein

The CRISPR/Cas system has revolutionized the efficiency at which scientists can experimentally induce a mutation in a gene to investigate the functional role of the protein it encodes. Which of the following is not a critical component needed in the CRISPR/Cas system?

Access to target mRNA

Reverse transcriptase is an enzyme that catalyzes ………. synthesis.

RNA-directed DNA

A codon is a

sequence of three nucleotides on an mRNA that binds to specific tRNAs.

In Meselson and Stahl’s experiment, cells were grown in media containing 15N in place of 14N, and then the cells’ DNA was separated by equilibrium centrifugation. This experiment demonstrated that DNA

replication is semiconservative.

The experimental introduction of DNA into eukaryotic cells is called

transfection

Mutations may be introduced into selected genes of living cells by

homologous recombination with an altered cloned gene.

Eggs and sperm are

haploid

To identify, in a sample, the protein against which you have an antibody, the best technique to use would be ……….. blotting.

Western

When introduced into living cells, antisense RNA molecules bind

to complementary mRNA sequences and block protein synthesis.

Which of the following would be used to clone intact pieces of human DNA that are 400 kb pairs long?

Yeast artificial chromosomes

DNA replicates

semiconservatively

The technique by which a particular nucleic acid sequence is localized with labeled probes within a cell, tissue, or isolated chromosome is called ……….. hybridization.

in situ

DNA is a double helix with ………..base pairs per complete turn of the helix.

10

Proteins are composed of polymers of amino acids. How many different amino acids are there?

20

The first enzymatic step in making a cDNA uses which of the following?

Reverse transcriptase

DNA was identified as the genetic material in experiments done by

Avery, MacLeod, and McCarty.

The technique by which fragments of DNA are separated by gel electrophoresis, denatured, blotted on nitrocellulose paper, labeled with a complementary radioactive probe, and detected by autoradiography is called ………… blotting.

Southern

A dominant negative mutant is typically one that

produces a protein that interferes with the function of the protein produced by the normal gene.

Vectors for expressing a eukaryotic protein in a bacterium must contain which of the following?

Origin of replication

In RNA interference, expression of a gene is most effectively inhibited by injection of

double-stranded RNA.

Animal cells and most cells of higher plants are

diploid

When thymidine and adenosine interact within the DNA molecule, they form

two hydrogen bonds.

SDS-polyacrylamide gel electrophoresis (SDS-PAGE) separates proteins on the basis of which of the following?

Size

RNA molecules that serve as templates for protein synthesis are called ……….. RNAs.

messenger

The most common method of DNA sequencing is based on premature termination of DNA synthesis by inclusion of

dideoxynucleotides

The restriction enzyme NotI recognizes a specific DNA sequence of eight base pairs and cleaves at that site. Statistically, in any genome there should be one NotI recognition site for every ……….. base pairs.

4^8

Transgenic mice are usually produced by

injecting DNA containing the gene into the pronucleus of a fertilized egg.

George Beadle and Edward Tatum provided clear evidence that genes specified the structure for enzymes in a series of experiments on the

fungus Neurospora.

In the base pairing within a DNA double helix,

A pairs with T and G pairs with C.

Heat-denatured DNA will renature when cooled to about

65C.

Deduction of the structure of DNA was based on a series of key X-ray crystallographic studies done by

Wilkins and Franklin.

Our fundamental knowledge about mutation, genetic linkage, and the relationships between genes and chromosomes was acquired largely from experiments on the

fruit fly Drosophila.

A bacterial artificial chromosome is a vector

derived from a plasmid with an origin of replication.

Expression of a human protein in a bacterial cell is best done with human

cDNA in a bacterial expression vector.

To clone genes, a plasmid vector should contain a(n)

All of the above

Nucleic acid hybridization is the

formation of a double-stranded molecule from the interaction of two complementary-sequence single-stranded molecules.

Which of the following methods would be used to determine if treatment of a cell culture with a drug led to an increased expression of mRNA?

Northern

Restriction endonucleases are enzymes that

cleave DNA only at specific sequences.

How many different RNA triplets specify amino acids?

61

Taq polymerase is used in the polymerase chain reaction because it

is stable at high temperatures.

Sphingomyelin contains two hydrocarbon chains linked to

serine

In the primary structure of a protein, amino acids are joined together by .......... bonds.

peptide

Which of the following is not a basic amino acid?

Glutamine

Cholesterol, a membrane lipid in animals, has a chemical structure similar to

estradiol

Which of the following are involved in forming the tertiary structure of proteins?

All of the above

Which of the following store most chemical energy per unit weight?

Lipids

Complementary base pairs form .......... bonds to direct replication of DNA.

hydrogen

Lipids play a major role in cells as

All of the above

Introducing a double bond into a fatty acid has the effect of putting a(n) .......... into the conformation of the molecule.

kink

The unique properties of different membranes are primarily a function of their

proteins

An amphipathic molecule is

part water-soluble and part water-insoluble.

Fatty acids are stored in fat droplets in the form of

triacylglycerols

In polysaccharides, sugars are linked together by means of .......... bonds.

glycosidic

Sugars can cyclize if they contain .......... or more carbons.

five

Which of the following is not one of the four major classes of organic molecules in the cell?

Water

Common factors affecting the fluidity of a membrane include

All of the above

In the fluid mosaic model of biological membrane structure, transmembrane proteins are

embedded nearly randomly in the lipid bilayer.

The scientist who first determined the complete amino acid sequence of a protein (insulin) was

Frederick Sanger.

Proteins can be covalently modified by the addition of phosphate groups to all but which of the following amino acids?

Arginine

Proteins are polymers of how many different amino acids?

20

Which of the following is not one of the ways in which DNA differs from RNA?

DNA can form hydrogen bonds with complementary sequences.

Lipids with unsaturated fatty acids

increase the fluidity of membranes.

Nucleotides have an important function in cells as

All of the above