chapter 3 final review

Promoters of many genes have mostly adenines and thymines. What is the most likely reason for this high proportion of adenines and thymines?

This is the region where template and nontemplate strands separate, and A-T base pairs require less energy to separate than G-C base pairs.

Which statement explains why rRNAs are the most abundant type of RNA in a mammalian cell?

rRNAs are an integral part of ribosomes, and it takes millions of ribosomes to translate all the proteins required for a cell's functions.

Translation is the process by which:

ribosomes synthesize protein from information in an RNA molecule

What is the order of processes that support the central dogma?

DNA replication, transcription, translation

In a nucleotide, the base is attached to the sugar at the:

1' carbon.

Imagine you have discovered a new species of bacteria. To begin your investigation of this organism, you run an assay on the total nucleotide content of the bacterial DNA. If the cytosine content of DNA from the bacterial cells is 40%, what is the adenine content?

10%

In a DNA strand, successive nucleotides are linked by:

3'-5' phosphodiester bonds.

In a messenger RNA, the cap is present at the:

5' end

An RNA transcript is synthesized in which direction?

5' to 3'

In a nucleotide, the phosphate is attached to the sugar at the:

5′ carbon.

A template DNA strand contains the sequence 5′-ATGCTGAC-3′. The corresponding sequence in the RNA transcript is:

5′-GUCAGCAU-3′.

In the DNA sequence, the top strand is the template strand.5'-GTAGCCGATAAT-3'3'-CATCGGCTATTA-5'If the base pair G-C (in bold) is changed to T-A, what would the resulting nucleotide be in the mRNA?

A

Which statement is true of DNA?

A purine always forms a complementary base pair with a pyrimidine.

Which choice correctly describes the complementary base pairing of adenine in both DNA and RNA?

Adenine pairs with thymine in DNA and with uracil in RNA.

Which one of the features distinguishes RNA from DNA?

DNA has thymine as one of its bases, whereas RNA has uracil.

What is the central dogma?

DNA is transcribed into RNA, which is translated into protein.

The central dogma of molecular biology states that information flows from

DNA to RNA to protein

Imagine that a eukaryotic cell carries a mutation that causes the poly(A) tail to rarely be added to the primary transcripts. What would be the result of such a mutation?

The primary transcript would likely be less stable, and its transport from the nucleus to the cytoplasm would be affected.

In eukaryotes, among the possible errors listed, which would make an mRNA less stable?

Either the 5' cap was not added or the poly(A) tail was not formed.

Which one of the options represents a standard Watson-Crick base pair interaction?

G-C

Which statement is true regarding primary transcripts?

In prokaryotes, primary transcripts are synonymous with mRNA

In an RNA world:

RNA functions in information storage and also performs catalysis.

Transcription is sometimes described as a process in which RNA is "copied" from the template strand of DNA. This statement is potentially misleading because:

RNA nucleotides contain ribose and so cannot be an exact copy of DNA, the RNA transcript and the DNA template strand are antiparallel, RNA molecules contain uracil instead of thymine, the RNA transcript has a complementary sequence of bases to the template strand.

What is the name of the enzyme complex that forms at the start of transcription?

RNA polymerase

Which example correctly lists the components necessary for eukaryotic transcription?

RNA polymerase, general transcription factors, DNA, and RNA nucleotides

RNA splicing is a component of:

RNA processing.

If you made a change in the promoter sequence in the DNA that inactivates the promoter, what would happen at the RNA level?

The RNA polymerase would not be able to recognize and bind the DNA, so no RNA would be made.

What would happen if an enhancer sequence were mutated so that its binding partner was always bound and recruiting the RNA polymerase complex?

Transcription would occur continuously.

Transcription and translation differ in prokaryotes versus eukaryotes in which of these ways?

Translation of prokaryotic mRNA can occur as the mRNA is being transcribed, which is not possible in eukaryotes.

In a deoxyribonucleotide, what chemical group is found at the 2' carbon of the sugar component?

a hydrogen

Which choice is a component of a nucleotide?

a nitrogen-containing base, a five-carbon sugar ,one or more phosphate groups

Transcription continues until:

a terminator sequence is encountered.

RNA processing consists of the:

addition of a poly(A) sequence, addition of a cap, removal of introns.

The RNA base uracil pairs with

adenine.

An intron is:

an RNA sequence that is removed during the processing of an RNA molecule in the nucleus

In eukaryotes, the messenger RNA consists of:

an RNA transcript with cap added, introns removed, and poly(A) sequence added

The attraction of nonpolar flat nitrogenous ring structures of a nucleotide, leading to the exclusion of water and stability of DNA, is referred to as:

base stacking interactions.

The poly(A) sequence that is added to RNA during processing:

helps prevent rapid breakdown of the messenger RNA.

Alternative splicing allows for:

different polypeptides to be made from a single gene.

Alternative splicing means that:

different spliced forms contain different combinations of exons

In eukaryotes, where do activator proteins bind?

enhancers

RNA processing occurs in:

eukaryotes only

In messenger RNA, the protein-coding sequence is present in:

exons

All RNA is translated to generate proteins true or false?

false

All introns have identical lengths and sequences. true or false?

false

During transcription of a given protein-coding gene, both strands are used as template. True or false?

false

Muscle cells make different proteins than nerve cells because they have different sequences of DNA. true or false?

false

The number of proteins produced by protein coding genes in the human genome is less than the number of protein coding genes. true or false

false

The same strand in a DNA double helix is used as the template strand for transcription of every gene in a given chromosome true or false?

false

RNA catalysis means that RNA can:

function like an enzyme.

Ribose differs from deoxyribose in that a ribose:

has an extra hydroxyl group.

In a messenger RNA, the cap is needed to:

initiate translation.

Which of the mRNA modifications is common in human cells?

intron removal and exon joining, alternative splicing, 5' cap addition, 3' poly(A) tail addition

Which type of post-transcriptional modification is common in eukaryotes?

intron removal, polyadenylation, 5' cap addition, polyadenylation and intron removal

Select the answer option that arranges the components in order from smallest to largest.

nucleoside, nucleotide, gene, genome

RNA processing occurs in the:

nucleus

In a double-stranded DNA molecule, the strands are said to be antiparallel because:

one strand runs in 5' to 3' direction and the other in 3' to 5'.

Transcription starts at a(n):

promoter

In eukaryotes, where do general transcription initiation factors bind?

promoters

Which RNA type is the most abundant in mammalian cells?

rRNA

Transcription ends at a:

terminator

In the DNA sequence 5'-TGAC -3', the phosphodiester linkage between the guanine and the adenine connects

the 3' end of the guanine to the 5' end of the adenine.

In double-stranded DNA, the amount of A equals that of T and the amount of C equals that of G because:

the strands have complementary sequences of bases

Transcription of RNA from DNA in eukaryotes requires:

transcription factors, activator proteins, RNA polymerase, a promoter sequence

In which cellular process is RNA involved?

transcription, transcription and translation, splicing, translation

When DNA or genetic information is passed between bacteria (and bacteria take up this material from their surrounding environment), this process is referred to as:

transformation.

A template strand of DNA and a newly transcribed RNA molecule are antiparallel. true or false?

true

An exon is considered a "coding sequence" of DNA, and its information is retained in the processed mRNA within a cell. true or false?

true

In eukaryotes, transcription is located in the nucleus, and translation takes place in the cytoplasm. true or false?

true

In the sequence 5'-AGGCCT-3', an available phosphate group would be found at the nucleotide labeled "A." True or false?

true

Transcriptional activator proteins bind to a specific DNA sequence referred to as an enhancer true or false?

true

Whichever DNA strand is transcribed, the RNA polymerase reads the template strand from 3' to 5'. true or false?

true

in a long double-stranded DNA molecule containing the genetic information for many genes, the template strand for one gene may be the nontemplate strand for another gene at a different region of the DNA. true or false?

true

Which nucleotide base pairs with adenine in an RNA molecule?

uracil