BSC Module 6

Select all of the following organisms that have introns in their primary mRNA transcripts.

animals eukaryotes archaea

Select all of the following that are actions of the enzyme RNA polymerase.

attach to the promoter on DNA build an mRNA chain unzip the DNA to expose the template strand

All of the genetic material that is within a cell is called its

genome.

A(n) _______ mutation is one that occurs in the cells that give rise to sperm or egg.

germline

A ribosome is composed of

rRNA and proteins

A mutation that causes an mRNA nucleotide to change from GGC to GGA is a ______ mutation.

silent

What role does DNA play in the cell?

store genetic information

A(n) ______ mutation is caused by the replacement of one nucleotide with another.

substitution

The promoter is a sequence on the ______ that signals the start of a gene.

template strand of DNA

At the beginning of transcription, RNA polymerase binds to

the promoter

In the 1950s, the biochemist Erwin Chargaff found that in DNA, the amount of the nucleotide base _________, adenine always equals the amount of the nucleotide base , and the amount of the nucleotide base cytosine always equals the amount of the nucleotide base _________.

thymine; guanine

Arrange the events of transcription in the order that they occur, beginning with the first event at the top.

1. RNA polymerase binds to the gene's promoter. 2.RNA polymerase moves down the template strand, producing a complementary RNA molecule. 3.RNA polymerase separates from the DNA and the newly synthesized RNA is released.

Place these translation initiation and elongation events in order from the first step at the top to the last step at the bottom.

1. The 5' end of mRNA molecule binds with the small ribosomal subunit. 2. The first tRNA binds to the start codon on the mRNA molecule. 3. The large ribosomal subunit binds to the small ribosomal subunit. 4. The second tRNA molecule binds to the second codon on the mRNA molecule. 5. A covalent bond is formed between the two amino acids. 6. The ribosome releases an empty tRNA.

Which scientist showed that the amount of the base guanine in a DNA molecule equals the amount of the base cytosine in a DNA molecule?

Chargaff

Hershey and Chase showed that the part of a virus that could enter bacterial cells and cause the production of more viruses was

DNA

The information that each cell needs to produce proteins is stored in a molecule called

DNA

Select all the statements about nucleotides that are accurate.

DNA always contains the same sugar in its nucleotides. They are composed of a sugar, a nitrogen-containing base, and one or more phosphorus-containing groups.

Match the following scientists with their contribution to the discovery of the structure of DNA. Instructions

Erwin Chargaff: Determined that DNA contains equal amounts of adenine and thymine and of guanine and cytosine. Maurice Wilkins and Rosalind Franklin: Used X-ray diffraction to determine the three-dimensional shape of the DNA molecule. James Watson and Francis Crick: Used the known ratios of nucleotides along with the X-ray diffraction data to build a ball-and-stick model of the DNA double helix.

______ are portions of mRNA that get spliced together to form mature mRNA prior to translation.

Exons

Select all of the correct statements regarding the results of Frederick Griffith's 1928 experiment involving Streptococcus pneumoniae.

Live S strains caused pneumonia in mice. Heat-killed S strains mixed with live R strains caused pneumonia in mice.

__________ in DNA may arise spontaneously as errors in replication, or they can be induced by external agents, like chemicals and radiation.

Mutations

Select all of the following that are true about codons.

They are composed of three mRNA bases. They correspond to one amino acid.

True or false: A mutation that occurs in a sperm cell has the potential of being passed on to the next generation.

True

What scientists worked out the double helical structure of DNA using a ball-and-stick model?

Watson and Crick

The ______ pattern generated by Wilkins and Franklin revealed that DNA was comprised of a regular repeating structure of building blocks.

X-ray diffraction

The term genome refers to

all the genetic material in an organism's cell

A variant of a gene is referred to as a(n)

allele

Mutations can lead to genetic variability because they create new ________, or variants of genes

alleles

What represents Chargaff's discovery about the amounts of the nitrogenous bases A, G, C, and T in the DNA molecule?

amount of A = amount of T; amount of G = amount of C

On a tRNA molecule, the ________ is a three-base sequence that is complementary to and binds to an mRNA codon during translation.

anticodon

What 3-base site of a tRNA molecule is complementary to an mRNA codon?

anticodon

Select all of the following that are true about frameshift mutations.

can be caused by the deletion of two nucleotides can be caused by the addition of one nucleotide disrupts the codon reading frame likely to change the amino acid sequence

Select all of the following agents or processes that can cause mutations.

chemical mutagens some forms of radiation errors in DNA replication

In an RNA molecule, a(n) ______ is a genetic "code word" that corresponds to one amino acid.

codon

The genetic code specifies what amino acid is matched to each three-nucleotide ______ in the mRNA.

codon

DNA has a ______ helical structure consisting of two intertwining strands of ______.

double; nucleotides

What are coding regions of eukaryotic mRNA that are translated?

exons

In the Hershey and Chase experiment, radioactively-labeled sulfur was found in the ______ within one test tube, while radioactively-labeled phosphorus was found in the ______ within the other test tube, indicating that ______ was the genetic material.

fluid; bacterial cells; DNA

After translation is complete, the newly synthesized polypeptide must ______, as determined by some regions of the amino acid chain.

fold into its functional shape

The ______ describes the correspondence of three-nucleotide codons to specific amino acids or directions for starting and stopping translation.

genetic code

Match the following steps of transcription with their descriptions. Instructions

initiation RNA polymerase binds to the gene's promoter. elongation RNA polymerase moves down the template strand, adding nucleotides and producing a complementary RNA molecule. termination RNA polymerase separates from the DNA and the newly synthesized RNA is released.

In eukaryotes, a part of an mRNA molecule that is removed before translation is called a(n)

intron

When Griffith mixed together live strain R bacteria and heat-killed S bacteria and injected them into mice, the mice died, and ______ bacteria were isolated from the mice, indicating that something could pass between cells and transform them.

live S strain

During production of a protein, the information encoded in a DNA base sequence is transcribed to produce a molecule of ______, which is then processed and translated to produce the sequence of ________acids in a protein.

mRNA; amino

In transcription, the genetic information in DNA is copied into a(n) ______ molecule, and in translation, the "message" in an mRNA molecule is translated into a(n) ______ sequence.

mRNA; amino acid

During the elongation stage of translation, the ribosome exposes codons on the ______ one at a time; each codon determines what ______ will bring its attached amino acid to the ribosome to be added to the polypeptide chain.

mRNA; tRNA

A change in a protein-encoding DNA sequence or a regulatory DNA sequence, such as an enhancer, is called a(n)

mutation

A(n)________ is a change in a cell's DNA sequence.

mutation

Subunits called ______ are the building blocks of nucleic acids, as determined by scientists by about 1930.

nucleotides

What describes a substitution mutation?

one DNA base is replaced with another

RNA ______ is the enzyme that builds the RNA chain during transcription.

polymerase

Enzymes and chaperone proteins assist in ______ that takes place after translation is complete.

polypeptide folding

In the "central dogma," information flows from DNA to RNA to

proteins

A complex of rRNA and proteins called a(n) is the physical location of protein synthesis.

ribosome

A substitution mutation is said to be ______ if the mutated gene encodes the same protein as the original gene version.

silent

In his experiments with S. pneumoniae bacteria and mice, Frederich Griffith found that

something in heat-killed S bacteria could transform type R bacteria

Wilkins and Franklin performed X-ray diffraction that revealed details about

the three-dimensional shape of the DNA molecule

In a frameshift mutation, nucleotides are added or deleted in any number other than a multiple of

three

In the "central dogma" describing the flow of genetic information from DNA to protein, DNA is copied to RNA in a process called ________, and the information in RNA is used to direct the synthesis of a protein in a process called __________.

transcription; translation