Mastering Bio – Flashcards

In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and _____ of the last nucleotide in the polymer. A. a nitrogen from the nitrogen-containing base B. the 5' phosphate C. the 3' OH D. C6

The first step in the replication of DNA is catalyzed by _____. primase helicase ligase single-strand binding protein DNA polymerase

The action of helicase creates _____. A. DNA fragments and replication forks B. replication forks and replication bubbles C. primers and DNA fragments D. DNA fragments and replication bubbles E. primers and replication bubbles

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments? A. DNA polymerase can assemble DNA only in the 5' to 3' direction B. it is more efficient than assembling complete new strands C. the replication forks block the formation of longer strands D. only short DNA sequences can extend off the RNA primers E. DNA polymerase can assemble DNA only in the 3' to 5' direction

What catalyzes DNA synthesis? A. Primer B. Replication fork C. dNTPs D. DNA polymerase

Which of the following statements about DNA synthesis is true? A. Nucleotides are added in a random fashion to single-stranded DNA. B. As DNA polymerase moves along the template strand, each new nucleotide provides a 5' hydroxyl group for the next reaction to occur. C. DNA polymerase adds dNTP monomers in the 3' to 5' direction. D. Primers are short sequences that allow the initiation of DNA synthesis.

True or false? Single-stranded DNA molecules are said to be antiparallel when they are lined up next to each other but oriented in opposite directions.

Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base? A. One of the daughter cells, but not the other, would have radioactive DNA. B. All four bases of the DNA would be radioactive. C. DNA in both daughter cells would be radioactive. D. Neither of the two daughter cells would be radioactive.

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' C C T A G G C (T) G C A A T C C 5' An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence? A. 5' G C C U A G G 3' B. 5' A C G T T A G G 3' C. 5' A C G U U A G G 3' D. 5' G C C T A G G 3'

A new DNA strand elongates only in the 5' to 3' direction because _____. A. replication must progress toward the replication fork B. the polarity of the DNA molecule prevents addition of nucleotides at the 3' end C. DNA polymerase begins adding nucleotides at the 5' end of the template D. DNA polymerase can add nucleotides only to the free 3' end

Researchers found E. coli that had mutation rates one hundred times higher than normal. Which of the following is the most likely cause of these results? A. The proofreading mechanism of DNA polymerase was not working properly. B. The single-stranded binding proteins were malfunctioning. C. The DNA polymerase was unable to add bases to the 3' end of the growing nucleic acid chain. D. There were one or more mismatches in the RNA primer.

Which of the following is most critical for the association between histones and DNA? A. Histones are small proteins. B. Histones are highly conserved (that is, histones are very similar in every eukaryote). C. Histones are positively charged. D. There are at least five different histone proteins in every eukaryote.

You can tell which end is the 3' end by the presence of a hydroxyl (-OH) group. DNA polymerase III can only add nucleotides to the 3' end of a new DNA strand. Because the two parental DNA strands of a double helix are antiparallel (go from 3' to 5' in opposite directions), the direction that DNA pol III moves on each strand emerging from a single replication fork must also be opposite. part D diagram

What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA? RNA processing gene expression polypeptide formation transcription translation

What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein? RNA processing gene expression polypeptide formation transcription translation

What name is given to the process in which pre-mRNA is edited into mRNA? RNA processing gene expression polypeptide formation transcription translation

Polypeptides are assembled from _____. hexoses glycerol nucleotides proteins amino acids

RNA processing converts the RNA transcript into _____. a protein DNA a eukaryotic cell mRNA a polypeptide

The flow of information in a cell proceeds in what sequence? A. from DNA to RNA to protein B. from DNA to protein to RNA C. from RNA to protein to DNA D. from protein to RNA to DNA E. from RNA to DNA to protein

A codon consists of _____ bases and specifies which _____ will be inserted into the polypeptide chain. three ... amino acid four ... fatty acid two ... nucleotide four ... amino acid three ... nucleotide

In the process of transcription, _____. RNA is synthesized proteins are synthesized DNA is replicated mRNA attaches to ribosomes

What is the process called that converts the genetic information stored in DNA to an RNA copy? Translocation Replication Translation Transcription

Which of the following statements best describes the promoter of a protein-coding gene? A. The promoter is a site at which only RNA polymerase will bind. B. The promoter is a nontranscribed region of a gene. C. The promoter is a site found on RNA polymerase. D. The promoter is part of the RNA molecule itself.

What determines which base is to be added to an RNA strand during transcription? A.The order of the chemical groups in the backbone of the RNA molecule B. The previous base C. Base pairing between the DNA template strand and the RNA nucleotides D. Base pairing between the two DNA strands

What happens to RNA polymerase II after it has completed transcription of a gene? A. It is degraded. B. It is free to bind to another promoter and begin transcription. C. It begins transcribing the next gene on the chromosome. D. It joins with another RNA polymerase to carry out transcription.

The direction of synthesis of an RNA transcript is _____. 1' —> 5' 5' —> 3' 1' —> 3' 3' —> 5' 2' —> 4'

What enzyme catalyzes the attachment of an amino acid to tRNA? aminoacyl-tRNA synthetase rubisco dextrinase argininosuccinate lyase nuclease

What is transcription

In humans, the hormone testosterone enters cells and binds to specific proteins, which in turn bind to specific sites on the cells' DNA. These proteins probably act to do what? A. cause mutations in the DNA B. unwind the DNA so that its genes can be transcribed C. help RNA polymerase transcribe certain genes D. promote recombination E. alter the pattern of DNA splicing

It is possible for a cell to make proteins that last for months; hemoglobin in red blood cells is a good example. However, many proteins are not this long-lasting; they may be degraded in days, hours, or even minutes. What is the advantage of short-lived proteins? A. Short-lived proteins enable the cells to control their activities precisely and efficiently. B. Cells lack the raw materials to make most of the proteins they need. C. Most proteins are used only once. D. Long-lasting proteins are likely to make the cell cancerous. Most cells have a short life span.

The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called _____. RNA interference RNA obstruction RNA disposal RNA blocking

Which of the following best describes siRNA? A. a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits B. a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor C. a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns D. a double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA

How do master regulatory genes function in cell differentiation? A. The transcription factors they produce coordinately control related genes. B.They may produce proteins that stimulate production of more of the master regulatory gene. C. They are often capable of changing some fully differentiated cells of different types into their particular cell type. D. They produce proteins that act as transcription factors to produce proteins specific to the function of the particular cell type. E. All of the above.

How do cells become differentiated? A. Different genes are expressed so that different proteins are produced. B. They differentiate through the process of mitosis. C. Paternal effect genes begin the process of differentiation by providing positional information. D. Some cells contain maternal chromosomes and some contain paternal chromosomes. E. The DNA in each cell changes so that the appropriate proteins are produced.

A cell is considered to be differentiated when it _____. loses connections to the surrounding cells appears to be different from the surrounding cells replicates by the process of mitosis produces proteins specific to a particular cell type

Imagine that you've isolated a yeast mutant that contains histones resistant to acetylation. What phenotype do you predict for this mutant? A. The mutant will require galactose for growth. B. The mutant will show low levels of gene expression. C. The mutant will grow rapidly. D. The mutant will show high levels of gene expression.

The primary difference between enhancers and promoter-proximal elements is that enhancers _____. A. enhance transcription; promoter-proximal elements inhibit transcription B. are DNA sequences; promoter-proximal elements are proteins C. are transcription factors; promoter-proximal elements are DNA sequences D. are at considerable distances from the promoter; promoter-proximal elements are close to the promoter

The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different _____. sets of regulatory proteins regulatory sequences promoters genes

Gene expression is often assayed by measuring the level of mRNA produced from a gene. If one is interested in knowing the amount of a final active gene product, a potential problem of this method is that it ignores the possibility of _____. alternative splicing chromatin condensation control transcriptional control translational control

Not long ago, it was believed that a count of the number of protein-coding genes would provide a count of the number of proteins produced in any given eukaryotic species. This is incorrect, largely due to the discovery of widespread _____. chromatin condensation control alternative splicing translational control transcriptional control

One way to detect alternative splicing of transcripts from a given gene is to _____. A. compare the sequences of different mRNAs made from the given gene B. measure the relative rates of transcription of the given gene compared to that of a gene known to be constitutively spliced C. compare the DNA sequence of the given gene to that of a similar gene in a related organism D. compare the sequences of different primary transcripts made from the given gene

Which of the following supports the argument that viruses are nonliving? Their DNA does not encode proteins. They are not cellular. They have RNA rather than DNA. They do not evolve.

How do prions, which are misfolded proteins, infect organisms? A. Prions enter brain cells through the lymphatic system and make copies of themselves. B. Prions recruit ribosomes to make more copies of the wrong form of the protein. C. Prions only arise through spontaneous mutation. They are not transmissible. D. Prions enter brain cells and cause normal forms of the protein to refold into the prion form. E. None of the above.

Which of the following processes within viral replication is the greatest source of genetic variation in RNA virus populations? A. Capsid proteins from the host cell can replace the viral capsid. B. Viral RNA is translated by host cell ribosomes. C. Transcription from the host cell RNA polymerase introduces numerous mutations. D. High mutation rate due to lack of proofreading of RNA genome replication errors.

By what mechanism might transposons contribute to gene duplication? A. Transposons may lead to slippage of DNA polymerase during DNA replication. B. Transposons may promote unequal crossing over during meiosis. C. Transposon insertion may disrupt an exon. D. Transposons cause failure of chromosomes to segregate during mitosis. E. Transposons may promote accidents in meiosis, leading to polyploidy.

Exon shuffling occurs during _____. meiotic recombination translation DNA replication splicing of DNA

When gene duplication occurs to its ultimate extent by doubling all genes in a genome, what has occurred? creation of a polyploid creation of a diploid creation of a gene cluster pseudogene creation

Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces? 1. capsules 2. endospores 3. fimbriae 4. plasmids 5. flagella