Exam #2

What molecule indirectly provides energy for translation

ATP

Which is false when comparing DNA and RNA?

Both are composed of the same types of nucleotides

Which relationship about nucleotide composition in DNA is correct?

C+A=G+T

Which of the following is not an accurate description of a checkpoint that controls the progression of the cell cycle?

Cytokinesis involves the formation if cleavage furrow to separate cells

Which molecule is responsible for separating double-stranded DNA into single strands?

DNA helicase

Which is not a critical factor for DNA replication of the leading strand?

DNA ligase

During DNA replication, proteins that are important for separating the DNA strands and allowing movement of the replication fork include each of these except

DNA polymerase

Which produces short sequences of RNA which allows polymerase to synthesize a new strand of DNA?

DNA primase

A strand of DNA is composed of nucleotide bases, sulfate groups, and sugars

False

If there is 28% adenine then there must be 28% cytosine for the DNA composition of a particular organism

False

Leigh syndrome is a human disease that is characterized by mental impairment and progressive loss of movement abilities. People with Leigh syndrome have a mutation in one of several genes that encode the proteins needed for the electron transport chain. What effect would these mutations have on the function of the cell?

Fewer ATP molecules would be produced by ATP synthase than usual

Which statement about tRNA is FALSE?

Functional tRNAs have been spliced by splicesomes

Which statement accurately describes transcription by RNA polymerase?

It is possible for one RNA polymerase to transcribe one strand of DNA in the 5' to 3' direction and another RNA polymerase to transcribe the complementary strand of DNA in the 5' to 3' direction, producing two different transcripts

Which statement about DNA replication is incorrect?

It is powered by hydrolysis of ATP

When does the small ribosomal subunit bind to the transitional complex in eukaryotic cells?

It is the first component to bind to the mRNA

Why must the life cycle of sexually reproducing species alternate between haploid and diploid stages?

Meiosis must occur at some point in the life cycle to prevent a doubling of chromosomes in each generation

The following mRNA transcript would result in which polypeptide sequence? 5' ACU UUC ACU AUG UUU UUA UCC UCC ACU CCU UGA 3'

Met-Phe-Leu-Ser-Ser-Thr-Pro

Which of the following statements about the structure or composition of DNA is false?

The amount of thymine closely approximates that of guanine within a particular organism

If a DNA template strand has a sequence of 3' TACAATGTAGCC 5', the RNA produced from it will be which sequence?

5' AUGUUACAUCGG 3'

The process by which haploid cells are produced from diploid cells is called

meiosis

Beginning with the simplest level of structure, which order of organization of genetic material is correct?

nucleotide, double helix, strand, chromosome, genome

The building blocks of DNA are

nucleotides

Bacteria are grown in ^15 N (heavy) medium and then transferred to ^14 N (light) medium and are allowed to replicate for 2 generations. The DNA is subsequently isolated and centrifuged in a CsCl2 gradient to yield what type of gradient bands?

one light and one half-heavy band

The amino acids of a growing polypeptide chain are held together by what kind of bond during the elongation stage of translation?

peptide

The nucleotides within DNA are composed of a

phosphate group, deoxyribose sugar, nitrogenous base

In a single stand of DNA, nucleotides are connected by what type of bond?

phosphodiester

In a eukaryotic cell, the direct product of transcription is

pre-mRNA

Transcription begins near a site in the DNA called the

promoter

What is NOT involved in translation?

protein polymerase

Because more than one codon can specify the same amino acid, the genetic code is said to be

redundant

Which of the following are used by the cell to recognize the stop codon and terminate translation?

release factors

What is not a protein involved in DNA replication?

replication fork

Which is involved in replicating the lagging stand of DNA but is not involved in leading stand DNA replication?

ribosome

The mechanism of DNA replication is

semiconservative

What serves as the "translator" or intermediary between an mRNA codon and an amino acid (ie, what interacts with the mRNA and brings the amino acid to the ribosome)?

tRNA

Which statement about the 5' cap and mRNA processing is TRUE?

the addition of a 5' cap to mRNA occurs while the pre-mRNA is being made

When considering the complexity of genetic material, two strands of DNA are twisted to form a double helix

true

Which statement about RNA processing in eukaryotes is INCORRECT?

The excision of introns from pre-mRNA is the only modification required to produce a mature mRNA

What is the function of the poly A tail?

The poly A tail increases mRNA stability in eukaryotes by protecting it from hydrolysis, catalyzed by a protease, in the cytosol

Which statement about the mRNA start codon is INCORRECT?

The start codon is usually GGA

The term N-terminus refers to the presence of what functional group at one of the ends of the polypeptide?

amino group

What enzyme catalyzes the attachment of amino acids to tRNA molecules?

aminoacyl-tRNA synthase

Consider a diploid species where n=5. If an individual of this species was found to have 11 chromosomes, it would be categorized as

aneuploid

You prepare the first ever karyotype of an endangered species of frog. Upon examination you find that all the chromosomes are meta metacentric. This is going to make it difficult to identify

both p and q arms of the chromosomes

Which of the following is not a part of the mitotic spindle apparatus in plants?

centrioles

The formation of the bivalent during meiosis

contributes to the genetic diversity of a species

Eukaryotic ribosomes most often function in the

cytosol

The process of transcription and translation are collectively known as

gene expression

Which feature of DNA represents the highest (or most complex) level of structure?

genome

Which purine base forms 3 hydrogen bonds when binding its complementary nucleotide base?

guanine

The major way that meiosis II differs from mitosis is that

in meiosis II, the cells are haploid

Intervening sequences that are transcribed, but not translated into protein are called

introns

Which statement about RNA polymerase in bacteria is INCORRECT?

it catalyzes the addition of nucleotides to the 5' end of a growing RNA strand

Which molecule catalyzes covalent bond formation between fragments of DNA?

ligase

The actions of DNA helicase and DNA topoisomerase both promote the unwinding and uncoiling of DNA

True

Which of the following statements about the cell cycle is correct?

When the S phase of the cell cycle is finished, a cell has twice as much DNA as it did during the G1 phase

Without the work of Rosalind Franklin, Watson and Crick would not have known

Which nucleotides could pair together, how many strands of DNA made up the molecule, the shape of the molecule, and the width of the molecule

During crossing over in meiosis. an unequal exchange of genetic material occurs. This would most likely produce

a deficiency in one homologoue and a duplication in the other homologue

An mRNA sequence is 5' AUG GGC ACU CAU ACU UAA 3'. How many distinct aminoacyl-tRNA synthetases are required to translate the mRNA sequence?

4

What protein synthesizes messenger RNA in eukaryotes?

RNA polymerase II

Which is not a result of DNA polymerase III function?

Removal of RNA primers

Place the following events of mitosis in the correct order

Sister chromatids begin to condense, Nuclear membrane breaks up, sister chromatids align on the metaphase plate, sister chromatids separate, cleavage furrow forms

Which of the following statements is false concerning sister chromatids?

Sister chromatids separate during anaphase I of meiosis

DNA polymerase can be described as an enzyme that

adds nucleotides to the 3' end of a growing DNA strand

All of these nucleotide bases are pyrimidines except?

adenine

A unit of DNA sequence that is transcribed into RNA and ultimately results in the formation of a functional protein product is called a

gene

Which part of a gene contains the information that specifies an amino acid sequence?

transcribed region

The process that produces mRNA from DNA is called

transcription

What protein communicates to RNA polymerase to begin to transcribe genes?

transcription factors

Consider an organism whose diploid karyotype shows it to have a total of 60 chromosomes. How many chromosomes would be contained in the sperm of this organism?

30

How many replication forks are there at an origin of replication?

2

A DNA specimen that contains 30% guanine has ______ thymine

20%

Humans have ___ pairs of autosomes

22

Humans have ___ pairs of chromosomes

23

How many nucleotides make up a single codon?

3

Which statement describes a reason ribosomal genes are useful for comparing evolutionary relationships among organisms?

All organisms possess these genes and they can be compared with each other

What process enables a single gene to encode two or more polypeptides that are different in their amino acid sequence?

Alternative splicing (exon shuffling)

What was one of the pieces of evidence most critical to the discovery of DNA structure?

An X-ray diffraction pattern suggesting double helix shape

Which statement about DNA is false?

One chromosome is made up of many DNA molecules

Bacteria are grown in ^15 N (heavy) medium and then transferred to ^14 N (light) medium and are allowed to replicate for 1 generation. The DNA is subsequently isolated and centrifuged in a CsCl2 gradient to yield what type of gradient bands?

One half-heavy (between light and heavy) band

Why is there a need to produce Okazaki fragments on the lagging strand but not on the leading strand of DNA?

The two parental strands of DNA are anti parallel and DNA polymerase makes DNA in the 5' to 3' direction only

DNA is a double helix structure whose strands are held together by hydrogen bonds with A to T and C to G base pairing

True

At the end of meiosis I

the cells are haploid and the homologous pairs are in separate cells

Cytogenetics is

the field of genetics that involves the microscopic examination of chromosomes and cell division

In a haploid dominant species

the multicellular organism is haploid, and only the zygote is diploid

Which of these proteins is not matched with the correct function?

topoisomerase -> separates double-stranded DNA into single strands