Biology Exam 4

Which of the following statements correctly compares transcription in prokaryotes and eukaryotes?

Bacteria have one type of RNA polymerase, whereas eukaryotes have at least three

Which of the following statements correctly defines the process of gene expression?

Gene expression is the process by which DNA directs the synthesis of proteins

The genetic code is essentially the same for all organisms. Based on this information, one can logically assume which of the following statements to be correct?

A gene from an organism can theoretically be expressed by any other organism

Which of the following statements best describes the termination of transcription in bacteria?

RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.

Which of the following processes only occurs in eukaryotic gene expression?

A poly-A tail is added to the 3’end of an mRNA, and a cap is added to the 5’ end.

The nitrogenous base adenine is found in all members of which of the following groups of molecules?

ATP, RNA, and DNA

A particular triplet of bases in the template strand of DNA is 5’-AGT-3’. The corresponding codon for the mRNA transcribed is

3’-UCA-5’

In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA known as pre-mRNA?

RNA polymerase II

Garrod hypothesized that inherited diseases such as alkaptonuria, the inability to metabolize the chemical alkapton, occur because

genes dictate the production of specific enzymes, and affected individuals have gene defects that cause them to lack certain enzymes

What is a ribozyme?

An RNA with enzymatic activity

Which of the following statements best describes the function of the TATA box in eukaryotic promoters?

It is the recognition site for a specific transcription factor

A eukaryotic mutation upstream of a particular gene has been identified that changes the sequence of the TATA box to GATA. How would you predict that this mutation would. Affect the transcription of this gene?

Transcription factor binding would be reduced or eliminated, and transcription of the gene would decrease dramatically

Which of the following statements correctly describes alternative RNA splicing?

It can allow the production of different proteins products from a single mRNA

Which of the following is a function of a poly-A tail in mRNA?

It helps protect the mRNA from degradation by hydrolytic enzymes

Transcription in eukaryotes requires which of the following in addition to RNA polymerase?

Several transcription factors

How do small RNA’s in the spliceosome initiate the splicing of the pre-mRNA?

By base pairing to specific sites along the intron

A eukaryotic transcription unit that is 8000 nucleotides long may use 1200 nucleotides to make a protein consisting of approximately 400 amino acids. Which of the following statements best explains this fact?

Many noncoding stretches of nucleotides are present in eukaryotic DNA

A part of the promoter, called the TATA box, is said to be highly conversed in many different organisms through evolution. Which of the following correctly describes why this is the case?

Any mutation in the sequence is selected against

In which direction does RNA polymerase move along the DNA?

3’ to 5’ along the template strand

Some people who have had a herpesvirus-mediated cold sore or genital sore may have flare ups for the rest of their life. Why does this occur?

Copies of the herpesvirus genome remaining as mini-chromosomes in some host cell nuclei

Which of the following processes can be effective in preventing the onset of viral infection in humans?

Getting vaccinated

Why do RNA viruses tend to have unusually high rats of mutation?

Replication of their genomes does not involve correcting errors in genome replication

How do antiviral drugs help treat viral infections?

They interfere with viral replication

Which of the following nucleic acids make(s) up viral genomes?

DNA or RNA

Which of the following statements correctly describes viruses?

They cannot reproduce without a host cell

Which of the following statements correctly describes one characteristics of the lytic cycle of viral replication?

A large number of phases are released at a time

Which of th following statements correctly describes the lysogenic cycle of lambda phage?

The phage genome replicates along with the host genome

Which of the following responses correctly lists the order of events in a generalized viral replicative cycle?

The virus enters the cell, host enzymes replicate the viral genome, enzymes transcribe the viral genome into mRNA

Which of the following statements correctly describes adenoviruses?

They contain DNA surrounded by a capsid

Which of the following characteristics determine a virus’s host range?

The proteins on its surface and that of the host

Which of the following statements correctly describes the most probable fate of a newly emerging virus that causes high mortality in its host?

The newly emerging virus will die out rather quickly or will mutate to be far less lethal

Which of the following statements correctly describes one difference between vertical and horizontal transmission of plant viruses?

Vertical transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant

Which of the following statements accurately describes plant virus infections?

They spread via the plasmodesmata

A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell. Contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. Which of the following would be expected to occur?

The plants would develop the typical symptoms of TMV infection

Which of the following series of events reflects what we know about how the flu virus moves between species?

An animal as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates and is passed to a new species such as a bird, and the virus mutates and can be transmitted to humans.

Which viruses have single-stranded RNA that acts as a template for DNA synthesis?

Retroviruses

Which of the following statements correctly describes the best predictor of how much damage a virus causes?

Ability of the infected cell to undergo normal cell division

Most molecular biologists think that viruses originated from naked bits of cellular nucleic acid. Which of the following observations supports this theory?

Viral genomes are usually similar to the genome of the host cell

What is metgenomics?

Sequencing DNA from group of species rom the same ecosystem

What is proteomics?

The study of the full protein set encoded by a genome

What is bioinformatics?

The application of computational methods to the storage and the analysis of biological data

A microarray known as GeneChip, with most of the human protein-coding genetic sequences, has been developed to aid in the study of human cancer by comparing gene sequences and patterns of gene expression in cancer cells with those in normal cells. What kind of information might be gleaned from this GeneChip to aid in cancer presentation?

Data that could alert patients to what kind of cancer they were likely to acquire

What characteristic of short tandem repeat DNA makes it useful for DNA fingerprinting?

The number of repeats varies widely from person to person or animal to animal

In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. Why is this the case??

Nonidentical genes produce different versions of globing during development

Unequal crossing over during prophase 1 can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, called hemoglobin lepore, exists in the human population. Hemoglobin Lepore has a deleted series of amino acids If this mutated form was caused by unequal crossing over, what would be an expected consequence?

There should also be persons who hemoglobin contains two copies of the series of amino acids that is deleted in hemoglobin Lepore.

Genetic variation among humans is relatively small when compared to other species. Where in the human genome does most of the diversity occur?

In single nucleotide-polymorphisms

Fragments of DNA have been extracted from the remnants of extinct woolly mammoths, amplified, and sequenced. How might these fragments be used now?

They may help us understand the evolutionary relationships among members of related organisms

Most molecular biologists think that viruses originated. From naked bits of cellular nucleic acid. Which of the following observations supports this theory?

Viral genomes are usually similar to the genome of the host cell.

Which of the following genomic components can be duplicated in a genome?

DNA sequences, chromosomes, or set of chromosomes

When’d does exon shuffling occur?

During meiotic recombination

Which of the following statement most correctly describes the whole-genome shotgun approach for sequencing a genome?

Cloning fragments from many copes of an entire chromosome, sequence in the fragments, and then ordering the sequences.

Which of the following statements correctly describes a multigene family?

It is made up of genes whose sequences are very similar and that probably arose by duplication

How do transposable elements contribute to a genome evolution?

They carry entire genes or individual exons to new locations

A recent study compared the Homo sapiens genome with that of Neanderthals. The results of the study indicated that there was a mixing of the two genomes at some period in evolutionary history. What data were discovered that suggested this conclusion?

A number of modern H. Sapiens with Neanderthal sequences were observed.

What might be the most reasonable approach to determine the probable function of a particular sequence of DNA in humans?

Look for a reasonably identical sequence in another species, prepare a knockout of this sequence in that species, and look for the consequences.

In most eukaryotes, only about 1.5% of the genome codes for proteins. What types of sequences made up the rest of the genome?

Gene-related regulatory sequences

Which of the following statements provides a correct representation oof gene density?

Humans have approximately 21000 genes in 3000 Mb.

Why might the cricket genome have 11 times as many base pairs as that of drosphila melanogaster?

Crickets must have more noncoding DNA