Biology 190 Exam 1 Study Materials - University of Nevada, Las Vegas (UNLV)

Polypeptide

A polypeptide is a chain of amino acids that have been linked together by dehydration reactions.

When a protein is denatured why does it lose its functionality?

Denaturation breaks the weak bonds, such as hydrogen bonds and van der Waals interactions that hold the protein in its three-dimensional shape.

A nucleotide is made of what components?

A nitrogenous base, a phosphate group, and a pentose sugar

Which of the following is an organic molecule?

O2, CH4, NaCl, Ne, H2O

Which of the following functional groups is present in all amino acids?

amine-NH2 and carboxyl-COOH

The sex hormones estrogen, progesterone, and testosterone belong to which class of macromolecules?

Lipids

What are properties of hydrocarbons?

Hydrophobic, nonpolar, and a good source of stored energy

In what polysaccharide form do plants store glucose to be available later as an energy source?

Starch

The overall three-dimensional shape of a single polypeptide is called the

Tertiary

Protein molecules are polymers (chains) of

amino acid molecules

The lipids that form the main structural component of cell membranes are

Phospholipids

Cellulose is a made of many

polymer; glucose molecules

The alpha helix and beta pleated sheet represent which level of protein structure?

The secondary structure

Which of the following is a polymer?

Cellulose, a plant cell wall component

The unwinding of DNA at the replication fork causes twisting and strain in the DNA ahead of the fork, which is relieved by an enzyme called

topoisomerase

The rate of elongation of a DNA strand in prokaryotes is __________ the rate in eukaryotes.

much faster than

Which of the following lists is in order from the entity with the smallest genome to the entity with the largest genome?

Virus, bacteria, eukaryote

Which of the following statements concerning the structure of DNA is correct?

Adenine forms two hydrogen bonds with thymine; guanine forms three hydrogen bonds with cytosine.

Chargaff found that in DNA samples,

the ratio of A to T is close to 1:1 and the ratio of G to C is close to 1:1

The role of DNA polymerases in DNA replication is to __________.

attach free nucleotides to the new DNA strand

Which of the following statements about origins of replication is correct?

All of the listed responses are correct.

The overall error rate in a completed DNA molecule is approximately

one error per 10,000,000,000 nucleotides

The incorporation of an incorrect base into a DNA molecule during replication

can be repaired by the mismatch repair system

Once the DNA at the replication fork is unwound by helicases, what prevents the two strands from coming back together to re-form a double helix?

Single-strand binding proteins bind the unwound DNA and prevent the double helix from re-forming.

Who is credited with discovering the structure of the DNA double helix?

Watson and Crick

The two strands of a DNA double helix are antiparallel. This means that

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

What is the major difference between bacterial chromosomes and eukaryotic chromosomes?

Bacteria have a single circular chromosome, whereas eukaryotes have several linear chromosomes.

What enzyme joins Okazaki fragments?

DNA ligase

During Griffith's experiments with Streptococcus pneumoniae in mice, material from __________ bacteria transformed __________ bacteria.

heat-killed virulent; living nonvirulent

Which of the following components is required for DNA replication?

RNA primers

One strand of a double-stranded DNA molecule has the base sequence 5'-ATAGGT-3'. The complementary base sequence on the other strand of DNA will be 3'-__________-5'.

TATCCA

In DNA, the two purines are __________, and the two pyrimidines are __________.

adenine and guanine; cytosine and thymine

DNA polymerase adds nucleotides to the __________ of the leading strands and to the __________ of the lagging strands (Okazaki fragments).

3' end; 3' end

A ribozyme is __________.

an RNA molecule that functions as an enzyme

A stretch of bacterial DNA 600 nucleotides long can code at most for a polypeptide of how many amino acids?

200

Transcription involves the transfer of information from __________.

DNA to RNA

A nucleotide deletion early in the coding sequence of a gene would most likely result in __________.

All of the listed choices are correct.

The type of mutation responsible for sickle-cell anemia is __________.

both a point mutation and a nucleotide-pair substitution

There are how many types of bacterial RNA polymerase?

One

Which enzyme synthesizes tRNA?

RNA polymerase

RNA polymerase __________.

moves along the template strand of DNA, elongating an RNA molecule in a 5′ → 3′ direction

Which of the following is transcribed and then translated to form a protein product?

A gene for a transcription factor

Which of the following is true of transcription factors?

All of the listed responses are correct.

If the 5′ → 3′ nucleotide sequence on the nontemplate DNA strand is CAT, what is the corresponding codon on mRNA?

CAU

Which of the following is not transcribed from DNA?

Promoter

How is the template strand for a particular gene determined?

It is established by the presence of the promoter.

Which binding site on a ribosome holds a tRNA attached to a growing polypeptide chain?

P site

Which of the following is true of RNA processing?

Assemblies of protein and small RNAs, called spliceosomes, may catalyze splicing.

Which of the following is not involved in the formation of a eukaryotic transcription initiation complex?

Small RNA molecules

A signal peptide __________.

is the first 20 or so amino acids of a protein destined for a membrane location or for secretion from the cell

Which of the following is not part of the translation initiation complex?

TATA box

Transfer RNA __________.

binds to its specific amino acid in the active site of an aminoacyl-tRNA synthetase