Biology Exam 4

Does RNA polymerase move in a set direction along a strand of DNA during transcription

Yes, the RNA polymerase moves in a direction that reads the bases of the DNA sequence from the 3' end toward the 5' end.

The letter A indicates _____.

a DNA double helix

During RNA processing a(n) _____ is added to the 3' end of the RNA.

a long string of adenine nucleotides

Polypeptides are assembled from _____.

amino acids

The attachment of a free amino acid to a specific RNA molecule is the key step in

charging of tRNA

Predict how a drug that inhibits histone deacetylase will alter gene expression.

chromatin would stay decondensed; transcription would be prolonged; amount of protein would increase

In eukaryotes, the most direct result of the chromosome organization shown in Figure 19.2 is that __________. See Section 19.2 (Page) .

chromosomes are coiled to occupy a much smaller volume

Translation occurs in the _____.

cytoplasm

PFK

cytoplasm only

The RNA segments joined to one another by spliceosomes are _____.

exons

The completed mRNA contains the gene's ___ joined together in the correct order.

exons

. A ___ mutation occurs when a single base-pair substitution results in the formation of a stop codon and early termination of translation.

nonsense

Why do loss of function mutations in p53 often lead to mutations in other genes? See Section 19.6 (Page) .

p53 normally functions as a tumor suppressor to stop the cell cycle after DNA damage occurs.

Enzyme complexes that break down protein are called _____.

proteasomes

Protein-phosphorylating enzymes' role in the regulation of gene expression involves _____.

protein activation

The nuclear membrane's role in the regulation of gene expression involves _____.

regulating the transport of mRNA to the cytoplasm

A substitution in the third base of a codon that does not change the amino acid specified is called a ___ mutation.

silent

Spliceosomes are composed of _____.

small RNAs and proteins

Molecular complexes called ____carry out RNA splicing in the nucleus.

spliceosomes

In a process called , non-coding regions of the RNA transcript are removed.

splicing

What is this an image of?

supercoils

Both DNA polymerases and RNA polymerases create new strands of nucleotides that are complementary to one strand of a DNA molecule. However, DNA polymerases and RNA polymerases differ in some important ways.

the base sequence of the gene's promoter

What is the cellular destination of the majority of proteins that are translated on free ribosomes?

the cytoplasm

During transcription, in which direction is (1) RNA synthesized and in which direction is (2) the DNA template "read"? See Section 17.1 (Page) .

(1) 5'—>3' (2) 3'—>5'

Which three statements correctly describe the processing that takes place before a mature mRNA exits the nucleus

-Noncoding sequences called introns are spliced out by molecular complexes called spliceosomes. -A cap consisting of a modified guanine nucleotide is added to the 5' end of the pre-mRNA. -A poly-A tail (50-250 adenine nucleotides) is added to the 3' end of the pre-mRNA.

Which of the following statements correctly describe the role of transcription factors in the initiation of transcription? Select all that apply.

-Some transcription factors bind to both strands of the DNA, whereas others bind specifically to either the template or coding strand -Binding of a transcription factor to DNA requires a specific sequence of bases in the DNA binding region -Some transcription factors must bind to the promoter before RNA polymerase II can bind.

Which two statements correctly describe the template and/or coding strands

-The template and coding strands are always antiparallel; that is, if one strand has its 3' end on the left and its 5' end on the right, the other strand has the opposite orientation. -During transcription, the DNA bases on the template strand are paired with their complementary RNA bases to form the RNA transcript.

Which of the following statements are true about these two types of proteins? Select all that apply.

-Transport between the membranes and compartments of the endomembrane system, including the plasma membrane, is via small vesicles that bud from one compartment and fuse with the next. -Both types of proteins are translated on ribosomes that are bound to the ER. -Proteins to be secreted are released from the cell when the vesicles containing them fuse with the plasma membrane.

Which of the following mutations would result in a frameshift mutation? Select all that apply.

-insertion of a single nucleotide in the coding region of a gene -deletion of two sequential nucleotides in the coding region of the gene

Which three statements correctly describe the role that mRNA plays in protein synthesis in eukaryotes?

-mRNA carries genetic information from the nucleus to the cytoplasm. -mRNA is produced only after the steps of RNA processing -mRNA is the template for protein synthesis in translation

transcription/RNA processing

-pre-mRNA -sn RNA -mRNA

Which two statements correctly describe the roles of tRNA and rRNA in protein synthesis?

-rRNA is the major structural component of ribosomes and is involved in binding both mRNA and tRNAs. -tRNAs implement the genetic code, translating information from a sequence of nucleotides to the sequence of amino acids that make up a protein.

translation

-tRNA -rRNA

How many different Martian codons are possible if the codon length is 4 bases

16

Where would RNA polymerase attach?

A

Why is RNA interference aptly named? See Section 19.4 (Page) .

Both the miRNA that does the interfering and the mRNA that is destroyed are RNA.

Which statement correctly describes where cytoplasmic and secreted proteins are synthesized?

Cytoplasmic proteins are synthesized on free ribosomes, whereas secreted proteins are synthesized on ribosomes bound to the rough ER.

insulin

ER to Golgi to outside cell

Individuals who inherit mutations in p53 would be expected to have what symptoms? See Section 19.6 (Page) .

Higher likelihood of developing various types of cancer

One way that gene regulation in eukaryotic and prokaryotic cells is similar is: See Section 19.5 (Page) .

In both types of cell, the primary mechanism to regulate gene expression is at the level of transcriptional regulation.

Why is it that bacterial ribosomes can begin translation before mRNA synthesis is completed, but eukaryotic ribosomes cannot? See Section 17.3 (Page) .

In prokaryotes, transcription and translation take place in the cytoplasm.

How is a mutation in a bacterial cell that deletes three base pairs 10 base pairs upstream from the +1 site likely to affect transcription and why? See Section 17.1 (Page) .

Initiation will be inhibited because sigma cannot bind to the promoter.

The nucleotide shown below is called cordycepin triphosphate. It is a natural product of a fungus that is used in traditional medicines.

It lacks a 3' OHOH.

What level of transcription would you predict for a gene whose promoter is heavily methylated? See Section 19.2 (Page) .

Low transcription

Based on this information, what is the minimum size of a codon for these hypothetical Martian life-forms

N = x y

How could alternative splicing allow two different species with the same number of genes to produce vastly different numbers of proteins? See Section 19.4 (Page) .

One species could produce many different mRNA from each of their genes while another only produces one or a few.

not used in protein synthesis

RNA primers

The final RNA template for protein synthesis in eukaryotes is different from the RNA that was produced from the DNA template because of

RNA processing

What is the function of a spliceosome?

RNA processing

What name is given to the process in which pre-mRNA is edited into mRNA?

RNA processing

In addition to splicing, additional modifications at the 5' and 3' end are required to generate a mature mRNA. What is the significance of these modifications? See Section 17.2 (Page) .

These modifications allow the mRNA to be recognized by the protein synthesis machinery and protect it from degradation.

Which statement is most accurate concerning how gene expression in eukaryotes compares with that in bacteria? See Section 19.3 (Page) .

The number of proteins that controls transcription is much greater in eukaryotes.

The letter C indicates _____.

histones

Regions of the RNA transcript that contain non-coding bases are called___ . These regions are not present in the mRNA that leaves the nucleus.

introns

What is this an image of?

loops

RNA processing converts the RNA transcript into _____.

mRNA

A gene-regulation strategy that is unique to eukaryotic cells is __________. See Section 19.1 (Page) .

mRNA processing

The substitution of one base-pair for another can cause a ___ mutation that results in a single amino acid change in the protein.

missense

During RNA processing a(n) _____ is added to the 5' end of the RNA.

modified guanine nucleotide

In eukaryotes, the size of the primary transcript is generally ________ the gene in the template DNA strand. See Section 17.2 (Page) .

the same length as

In eukaryotes, what allows only certain genes to be expressed in certain types of cells?

the set of regulatory transcription factors

The formation of a strand of RNA that is complementary to one strand of the nuclear DNA is called

transcription

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?

transcription

In ___, the nucleotide sequence of a piece of RNA is converted into a sequence of amino acids in a polypeptide.

translation

MicroRNAs control gene expression at the level of _______. See Section 19.4 (Page) .

translation

What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?

translation