Chapter 9

Which of the following are directly needed in order for translation to occur?

- mRNA - tRNA - rRna - amino acids

Which of the following statements about tRNA is TRUE?

No tRNA can recognize a stop codon.

Which of the following best describes translation?

RNA -> protein

Please select all of the characteristics of DNA to test your understanding of its chemical structure.

- Deoxyribose sugar - Phosphate group - Nitrogenous bases

Mutant bacteria may be detected by utilizing

- selective media - replica plating - differential media

Please match the viruses with the statements that most accurately describe them, to test your understanding of DNA and RNA viruses.

1. dsDNA virus - herpesvirus 2. retrovirus - HIV 3. ssRNA virus - poliovirus

Please match the types of transduction to the statements that most accurately describe them, to test your understanding of the basic processes involved in transduction.

1. random fragments of disintegrating host DNA are taken up by the phage during assembly - generalized transduction 2. highly specific part of the host genome is regularly incorporated into the virus - specialized transduction

Please match the types of RNA with the statements that most accurately describe them to test your understanding of the different types of RNA and their basic functions in genetic expression.

1. transcribed version of a structural gene or genes in DNA - messenger RNA 2. contains the anticodon and an amino acid binding site - transfer RNA 3. forms a complex cellular structure that contributes to the process of translation - ribosomal RNA

Which of the following DNA sequences is complementary to 5' TAGAC 3'?

5' GTCTA 3'

Which of the following combinations are correctly matched?

70S - ribosome

A certain polypeptide is 100 amino acids in length. During translation of this polypeptide, how many amino acids entered through the A site of the ribosome?

99

According to Chargaff's rule, which of the following statements about double-stranded DNA is NOT true?

A + T = C + G

Translation is terminated when a stop codon is presented at the

A site.

Which of the following is a characteristic of double-stranded DNA? 0.34 nanometers per base pair 10 base pairs per turn 2 nanometers in width All of these choices are correct.

All of these choices are correct.

Which of the following best describes transcription?

DNA -> RNA

RNA primers are removed by the action of the enzyme

DNA polymerase I.

The enzyme that travels along the leading strand assembling new nucleotides on a growing new strand of DNA is

DNA polymerase.

T/F: Before DNA replication can occur, the OH bonds between the strands must be broken.

False

T/F: DNA pol III can initiate DNA synthesis.

False

T/F: Elongation of the polypeptide chain is terminated when a stop codon enters the P site of the ribosome.

False

T/F: In a repressible operon, excess product acts as a corepressor to increase transcription of the operon.

False

T/F: In the presence of tryptophan, transcription of the trp operon is on.

False

T/F: One DNA strand is used as the template to make two new strands of DNA.

False

T/F: One reason mutations are so problematic is that bacterial cells have no ability to repair a mutation once it has occurred.

False

T/F: The accuracy of DNA replication is important because mutations in the DNA are always detrimental to the survival of an organism.

False

T/F: The completed polypeptide is released from the tRNA that is in the E site.

False

T/F: The genomes of bacteria cells, eukaryotic cells, and viruses are all about the same size.

False

T/F: The newly-synthesized strand of DNA has exactly the same base sequence as that of its template strand.

False

T/F: The products of protein synthesis are exclusively enzymes and enzyme products.

False

T/F: The sequence for protein synthesis is translation, then transcription.

False

T/F: The sex pilus is found on the F- cell.

False

T/F: The terminator of a gene is located upstream of the coding region.

False

T/F: Unwinding of the DNA during transcription is the result of the activity of a helicase enzyme downstream of the RNA polymerase.

False

Which of the following DNA molecules is the most stable?

GCGTGCAC CGCACGTG G and C are held together by three hydrogen bonds while A and T pair using only two hydrogen bonds, making a GC bond more stable

Which of the following is correct regarding sigma factor?

It recognizes the promoter region.

The enzyme that accomplishes transcription is termed

RNA polymerase.

Which of the following occurs as the ribosome shifts down the mRNA by a distance of one codon?

The tRNA that was in the A site moves into the P site.

T/F: A structural gene encodes the information for a specific protein.

True

T/F: A transposon can move from the host DNA to a plasmid.

True

T/F: After DNA replication two identical DNA molecules are formed.

True

T/F: All viruses require the use of host cell ribosomes and host cell tRNA to translate viral mRNA into viral proteins.

True

T/F: DNA is the blueprint that indicates which kinds of proteins to make and how to make them.

True

T/F: DNA mutations are passed on to a cell's progeny.

True

T/F: The amino acid sequence of a protein determines its shape and specific function.

True

T/F: The lac operon is normally in an off mode and does not initiate enzyme synthesis when the appropriate substrate is absent.

True

T/F: The polycistronic mRNA is transcribed from the lac operon when lactose is present in the cell.

True

T/F: Translation termination concludes with the dissociation of the two ribosomal subunits and mRNA from each other.

True

Which of the following is not true about transposons?

are able to leave the host genome via a vector

Nucleotides are the building blocks of

both DNA and RNA.

A mutation that causes a change in a single nucleotide in DNA

changes the corresponding nucleotide in mRNA, resulting in a different codon.

Which of the following is NOT a result of transposon activity in bacteria?

correction of ultraviolet radiation mutations

The genetic material in bacteria is

double-stranded DNA.

Semi-conservative replication of DNA means

each DNA made contains one old strand and one new strand of DNA.

In DNA replication

each strand replicates in a different direction.

The trp operon consists of ________ structural gene(s).

five

Which of the following occurs first in transcription?

formation of a holoenzyme

The ______ is the sum total of genetic material in a cell.

genome

The enzyme that unwinds a segment of the DNA molecule is

helicase

When one bacterium donates DNA to another bacterium, a type of genetic recombination known as _________ has occurred.

horizontal gene transfer

HFr refers to a cell that has

integrated the F plasmid into its genome.

The lac repressor binds to what site within the lac operon?

lacO

Genetic ______ and the variations they produce result in population changes and thus, evolution.

mutations

For DNA viruses, the virus cycle occurs in the ____________, whereas the virus cycle for RNA viruses occurs in the ___________.

nucleus; cytoplasm

In the process of specialized transduction

only a few specific genes from one bacterial cell are transferred to the second bacterial host by a phage.

In specialized transduction

only bacterial genes near the site of integration of the phage DNA can be transduced.

A(n) _______ is a section of prokaryotic DNA that contains one or more genes along with a corresponding operator to control transcription.

operon

DNA replication begins at a specific site called the

origin.

The correct structure of DNA components can be presented as

phosphate-sugar-base.

Extra pieces of DNA found in bacteria are called ______________.

plasmids

The transcription enzyme first attaches to the ________ of the gene.

promoter

The protein that promotes translation termination is called

release factor.

Retroviruses, such as the human immunodeficiency virus (HIV), carry their genetic information as RNA and convert it to DNA using the enzyme

reverse transcriptase.

DNA replication is said to be

semi-conservative.

The donor chromosome is transferred as

single-stranded DNA.

The Rho protein is involved in the _____ stage of transcription.

termination

F+ refers to a cell containing

the F plasmid.

The enzyme _____________ is responsible for compacting the DNA molecule in prokaryotes.

topoisomerase

The acceptance by a bacterial cell of small DNA fragments from the surrounding environment is termed ________.

transformation

Transposons are

transported by plasmids.

Which of the following is NOT a nitrogen base found in DNA?

uracil