Bio Exam #2

which statement correctly describes mutation and their repairs a. DNA polymerase makes very few mistakes during dna replication b. DNA polymerase can correct mistakes during DNA replication c. mutations only occur during DNA replication d. DNA polymerase can easily copy damaged dna e. repair enzymes can fix a mutation after the altered DNA strand has been replicated

b. DNA polymerase can correct mistakes during dna replication

enzymes increase the rate of a given reaction by lowering _____ energy a. kinetic b. activation c. thermal d. potential e. chemical bond

b. activation

allosteric regulation controls reaction rate by a. producing excess substrates b. binding regulatory molecules at a sire other than the active site c. changing in the temperature of the system d. binding regulatory molecules to the active site e. alternately oxidizing and reducing the substrate

b. binding regulatory molecules at a site other than the active site

the 'natural' use of restriction enzymes by bacteria is to a. integrate viral DNA b. destroy viral DNA c. repair "sticky ends" d. copy the bacteria genes e. clone DNA

b. destroy viral DNA

during the production of recombinant DNA, _____ seals the gaps between hybridized DNA fragments a. dna polymerase b. dna ligase c. rna polymerase d. ribosomes e. dna repair enzymes

b. dna ligase

an organisms complete set of genetic material is its a. proteome b. genome c. dna library d. probe e. transcriptome

b. genome

an enzyme found inside a human cell a. can catalyze many different reactions by binding to various substrates b. helps bring reactants to the transition state c. can catalyze endergonic reactions only d. rarely requires cofactors e, works optimally at temperature below 37degrees C

b. helps bring reactants to the transitions state

during endergonic reactions, reactants with _____ free energy are converted to molecules with ____ free energy; therefore, they require a net input of energy in order to proceed a. more, less b. less, more c. zero, low d. high levels of, no e. potential, kinetic

b. less, more

what serves as the template for the production of cDNA a. dna b. mrna c. rRNA d. trna e. protein

b. mrna

the removal of electrons from a compound is known as a. dehydration b. oxidation c. reduction d. phosphorylation e. allosteric regulation

b. oxidation

amino acids are joined together in proteins by a. hydrogen bonds b peptide bonds c. anticodons d. base pairing bonds e. codon bonds

b. peptide bonds

enzymes used to cut dna molecules in recombinant DNA research are a. ligases b. restriction enzymes c. transcriptase d. DNA polymerase e. replicases

b. restriction enzymes

reverse transcriptase produces a ____ molecule a. double stranded dna b. single stranded dna c. double stranded rna d. single stranded rna e. protein

b. single stranded dna

restriction enzyme cut a. specific RNA nucleotide sequences b. specific dna nucleotide sequences c. nonspecific sites in mrna d. nonspecific sites in protein molecules e. nonspecific sites in chromosomes

b. specific dna nucleotide sequences

during translation, free amino acids are carried to the ribosomes by____ a. mRNA b.tRNA c. microRNAs d. rRNA e. any form of RNA

b. tRNA

a purine base contains a. one less phosphate group than a pyrimidine base b. two rings c. sulfur instead of nitrogen d. phosphate instead of nitrogen e. one ring

b. two rings

the rate of diffusion through a semipermeable membrane is slowest when a. molecules are small b. there is a concentration gradient c. there is a difference in charge d. there is high pressure e.temperatures are low

e. temperatures are low

translation begins with the initiation tRNA binds to the a. large ribosomal unit b. small ribosomal unit c. second trna d. terminator codon e. first codon of the mrna

e. the first codon of the mrna

which nitrogenous base is present in dna but not rna a. adenine b. cytosine c. guanine d. uracil e. thymine

e. thymine

which nucleotides are used in dna sequencing reactions a. deoxynucleotides only b. dideoxynucleotides only c. ribonucleotides only d. deoxynucleotides and ribonucleotides e. deoxynucleotides and dideoxynucleotides

E

a codon consist of ____ nucleotide bases a. 3 b. 4 c. 6 d. 20 e. 64

a. 3

the normal start codon for protein synthesis is a. AUG b. UAA c. UAG d. UGA e. GGU

a. AUG

*figure shows point a to point assisted by enzyme 1, then point b to point c assisted by enzyme 2* if the metabolic pathway in the accompanying figure is regulated by feedback inhibition, ______ inhibits the activity of ______ a. C, enzyme 1 b. enzyme 1, B c. enzyme 2, enzyme 1 d. ensyme 1, enzyme 2 e. B, A

a. c, enzyme 1

because if does not contain introns, researchers prefer to use ____ when working with human genes a. cDNA b. cloned DNA c. hybridized DNA d. recombinant DNA e. viral DNA

a. cDNA

probes for cloned genes of interest are ___ a. complementary nucleotide sequences labeled with a tracer b. certain media with specific antibodies c. specific enzymes d. certain bacteria sensitive to the genes e. a labeled tracer gene from bacteria

a. complementary nucleotide sequences labeled with a tracer

which bases are pyrimidines a. cytosine and thymine b. guanine and thymine c. guanine and cytosine d. adenine and guanine e. adenine and thymine

a. cytosine and thymine

a glucose transporter changed shape when it binds to a molecule of glucose. the shape change moves glucose down its concentration gradient to the opposite side of the membrane, where it detaches from the transport protein. what does this illustrate? a. facilitated diffusion b. endocytosis c. active transport d. exocytosis e. osmosis

a. facilitated diffusion

dna ligase a. joins dna fragments together b. replaces mispaired bases c. initiates dna replication d. forms new dna polymers e. breaks hydrogen bonds

a. joins dna fragments together

which type of rna carries the protein-building message a. messenger rna b. nuclear rna c. ribosomal rna d. transfer rna e. structural rna

a. messenger rna

transcription is catalyzed by the enzyme a. RNA polymerase b. dna polymerase c. ligase d. gyrase e. ribosomes

a. rna polymerase

many restriction enzymes leave single-stranded tails called _____ ends on dna fragments a. sticky b. blunt c. cut d. jagged e. sharp

a. sticky

what provides the energy for DNA replication a. the loss of two phosphate groups from the newly added nucleotide b. the loss of two phosphate groups from the end of the DNA strand to which a new nucleotide is added c. the formation of the bond between complementary bases d. the kinetic energy of DNA polymerase e. the breaking of hydrogen bonds during the separation of double-stranded dna

a. the loss of two phosphate groups from the newly added nucleotide

what happens directly after DNA polymerase adds a modified, colored nucleotide to the DNA strand during DNA sequencing a. the synthesis of the strand ends b. a normal nucleotide must be added next c. the dna repair enzymes remove the nucleotide d. restriction enzymes cut the dna fragment e. the next nucleotide will be added at random

a. the synthesis of the strand ends

when dna replication begins, a. the two dna strands unwind from each other b. the two dna strands condense c. two dna molecules bond d. old dna strands move to pair with new strands e. the sugar phosphate backbone is degraded

a. the two dna strands unwind from each other

pepsin and trypsin are digestive enzymes. in the stomach, normal pH is 2, while in the small intestine, normal pH is about 7.5. based on this information and the accompanying figure, a. trypsin functions optimally in the small intestine b. trypsin functions optimally in the stomach c. both trypsin and pepsin function optimally in the stomach d. both trypsin and pepsin function optimally in the small intestine e. both pepsin and trypsin function equally well in the stomach and the small intestine

a. trypsin functions optimally in the small intestine

researchers clone a fragment of dna by interring it into a _____ a. vector b. CRISPR c. restriction enzyme d. chromosome e. sister chromatid

a. vector

if a DNA sequence contains 30 percent adenine bases, then it also contains a. 40 percent guanine b. 35 percent cytosine c. 20 percent guanine d. 35 percent thymine e. 60 percent guanine plus cytosine

c. 20 percent guanine

there are a total of ______ codons that specify a total of ____ natural occurring amino acids a. 4, 20 b. 20,20 c. 64, 20 d. 64, 64, e. 4, 64

c. 64, 20

dna synthesis on the discontinuous strand produces a. dimers b. primers c. Okazaki fragments d. clones e. mutations

c. Okazaki fragments

if the DNA triplets were ATG and CGT, the mRNA codons would be a. AUG and CGU b. ATG and CGT c. UAC and GCA d. UAG and CGU e. UAU and GCA

c. UAC and GCA

in transcription, _____ is used as a template for the construction of a single new rna molecule a. the entire dna molecule b. both strands of a double-stranded segment of DNA c. a segment of one strand of double stranded dna d, an entire rna molecule e. a single stranded segment of rna

c. a segment of one strand of double stranded dna

the second law of thermodynamics states that a. matter can neither be created nor destroyed b. energy can be neither created nor destroyed c. as energy disperses, entropy increases d. entropy decreases with time energy is the capacity to do work

c. as energy disperses, entropy increases

during dna replication, ______ serve(s) as a template for the newly synthesized dna a. primers b. one parent strand c. both parent strands d. dna polymerase e. dna ligase

c. both parent strands

in eukaryotes, translation occurs in the ______ ; in prokaryotes translation occurs in the _____ a. nucleus; cytoplasm b. cytoplasm, nucleus c. cytoplasm, cytoplasm d. nucleus, nucleus e. endoplasmic reticulum, cytoplasm

c. cytoplasm, cytoplasm

The enzyme used in the polymerase chain reaction is a. a restriction enzyme b. reverse transcriptase c. dna polymerase d. rna replicase e. ligase

c. dna polymerase

the template for transcription is ____ and the template for translation is _____ a. mRNA, protein b. RNA, DNA c. dna, mrna d. amino acids, protein e. protein, dna

c. dna, mrna

a(n) ______ is an organized series of reaction steps in which membrane-bound arrays of enzymes and other molecules give up and accept electrons in turn a. cyclical metabolic pathway b. endergonic reaction c. electron transfer chain d. concentration gradient e. passive transport

c. electron transfer chain

the protein coding regions of DNA molecules are the a. introns only b. anticodons c. exons only d. transcriptons e. eons and introns

c. exons only

how can only four nucleotides account for the extreme diversity of traits observed in living organisms a. the biochemical structure of nucleotides differs between cell types b. the nucleotides can base pair with any other nucleotide c. nucleotides are arranged in many different sequences d. different proteins can be encoded from the same dna sequence e. complex organisms have more than 4 types of nucleotides

c. nucleotides are arranged in many different sequences

tan can serve as a template for the production of complementary dna via the action of a. dna polymrease b. rna polymerase c. reverse transcriptase d. ligase e. restriction endonuclease

c. reverse transcriptase

which step occurs first during transcription a, free rna nucleotides are added to an rna chain b. rna polymerase unwinds dna c. tna polymerase attaches to the promoter site d. the new rna strand is released from era polymerase e. the introns are removed from the rna strand

c. rna polymerase attaches to the promoter site

which type of rna shows enzymatic activity by catalyzing peptide bond formation between amino acids a. mrna b. trna c. rrna d. all types of rna e. no rna shows enzymatic activity

c. rrna

dna is heated at the beginning of each par cycle to a. inactivate the dna polymerase b. allow primers to bind to template dna c. separate double stranded dna d. allow a new nucleotide chain to be produced e. denature contaminating proteins

c. separate double stranded dna

a DNA molecule has a ____ backbone held together by ____ bonds a. sugar-phosphate, hydrogen b. nitrogenous base, covalent c. sugar-phosphate, covalent d. nitrogenous base; hydrogen e. phosphorous Base; covalent

c. sugar phosphate, covalent

dna synthesis proceeds from a. the beginning of the parent strand b. where dna ligase is first present c. the 5' to the 3' end of the strand d. the 3' to the 5' end of the strand e. both the 5' and the 3' ends of the dna strand

c. the 5' to the 3' end of the strand

a single-celled freshwater organism, such as protistan, is transferred to salt water. what is likely to happen a. the cell will burst b. salt will be pumped out of the cell c the cell will shrink d. enzymes will flow out of the cell e. water will move into the cell

c. the cell will shrink

the synthesis of an RNA molecule from a DNA template strand is called a. replication b. translation c. transcription d. dna synthesis e. metabolism

c. transcription

dna replication produces a. one single stranded rna molecule b. one double stranded dna molecule c. two double stranded dna molecules d. one single stranded dna molecule e. new proteins

c. two double stranded dna molecules

a collection of cells containing different fragments of foreign DNA, often representing an organisms entire genome, is called a. copied DNA b. transcribed dna c. dna amplification d. a dna library e. plasmid dna

d. a dna library

which statement best describes a dna mutation a. dna polymerase adds an incorrect base during replication b. dna is damaged by uv radiation c. a mistake in the DNA sequence is repaired during replication d. a permanent change occurs in the nucleotide sequence of DNA e. a proofreading during replication replaces a mismatched nucleotide

d. a permanent change occurs in the nucleotide sequence of dna

in DNA molecules, complementary base pairing occurs between a. cytosine and urasil b. adenine and guanine c. adenine and uracil d. adenine and thymine e. sugar and phosphate

d. adenine and thymine

a molecule that gives up an electron becomes a. ionized only b. oxidized only c. reduced only d. both ionized and oxidized e. both ionized and reduced

d. both ionized and oxidized

the process by which an enzyme allows a reaction to run much faster than it would on its own is known as a. a redox reaction b. allosteric regulation c, induced fit d. catalyst e. phosphorylation

d. catalyst

some enzymes require inorganic or organic molecules for proper function, these molecules are known as a. coenzymes only b. cofactors only c. anitoxidants d. coenzymes and cofactors e, coenzymes, cofactors and antioxidants

d. coenzymes and cofactors

which enzyme assembles new strands of DNA during replication a. dna ligase b. dna synthase c. primers d. dna polymerase e. hybridization

d. dna polymerase

a teacher the front of the classroom sprays a mist of the perfume into the air. after a few mins, the student in the back of the room are able to smell the perfume. this is an example of a. increasing entropy only b. diffusion only c. decreasing entropy only d. increasing entropy and diffusion e. decreasing entropy and diffusion

d. increasing entropy and diffusion

in a cyclic metabolic pathway, the a. product inhibits the activity of the first enzyme in the pathway b. last step regenerates the enzyme that catalyzes the first step in the pathway c. product inhibits the activity of the enzyme that catalyzes the last step in the pathway d. last step regenerates the reactant for the first step in the pathway e. regulatory molecules bind to regions of enzymes other than the active site

d. last step regenerates the reactant for the first step in the pathway

electrophoresis is used in dna sequencing to separate dna fragments based on their a. percentage of c-g base pairs b. biochemical properties c. colored pigment d. length e. number of copies

d. length

the building blocks of nucleic acids are a. amino acids b. fatty acids c. monosaccharides d. nucleotides e. lipids

d. nucleotides

removal of introns, addition of a poly-A tail, and addition of a 5' cap are all events that occur during a. protein folding b. transcription c. replication d. post-transcriptional modification e. translation

d. post-transcriptional

during enzymatic catalyzed reactions, the substrate is also known as the a. end product b. byproduct c. enzyme d. reactant e. cofactor

d. reactant

which molecule has an anticodon and binds to the protein synthesizing machinery a. dna b. mrna c. rrna d. trna e. ribosomes

d. tRNA

dna fragments from different organisms can be combined becayse a. dna repair enzymes can change the dna composition of one organism to match the other b. dna ligase can insert new base pairs to combine the fragments c. DNA polymerase can insert new base pairs to combine the fragments d. the chemical structure of dna is the same in all organisms e. dna nucleotides from different organisms can pair even if they are not complementary

d. the chemical structure of DNA is the same in all organisms

what is occurring when a transport protein uses energy to pump a solute across a cell membrane against its concentration gradient a. osmosis b. passive diffusion c. facilitated diffusion d. phagocytosis e. active transport

e. active transport

the genetic code is comprised of the a. four nucleotide bases b. set of the tRNA molecules that carry amino acids c. set of 20 amino acids d. proteins encoded by the DNA e. complete set of 64 mRNA codons

e. complete set of the 64 mRNA codons

proofreading by DNA polymerase must occur before the end of ____ to prevent mistakes from becoming mutations a. cell division b. chromatid duplication c. transcription d. translation e. dna replication

e. dna replication

within chromosomes, DNA is wrapped around proteins called a. karyotypes b. chromatids c. nucleosomes d. centromeres e. histones

e. histones

which example of complementary base pairing is correct a. C ro G b. A to C c. pyrimidine to pyrimidine d. purine to purine e. purine to pyrimidine

e. purine to pyrimidine