Chap 21 Flashcards
1) What are the building blocks of nucleic acids?
nucleotides.
2) In the bonding of nitrogenous bases guanine pairs with which base?
guanine is paired with cytosine.
3) True or False: The DNA molecule could be compared to a ladder.
True.
4) In DNA, complementary base pairing occurs between adenine and what base?
adenine and thymine.
5) True or False: In DNA molecules the nucleotides are arranged in a linear, unbranched pattern.
TRUE
6) True or False: The hydrogen bonding of cytosine to guanine is an example of complementary base pairing.
TRUE
7) Each DNA strand has a ?backbone? that consists of alternating what?
sugar and phosphate units.
8) The DNA molecule usually is made up of how many strands?
2
9) The steps of a spiral staircase would compare to what part of a DNA molecule?
base pairs
10) True or False: Biochemically, a gene is BEST defined as a region of DNA that codes for protein assembly.
TRUE
11) A linear stretch of DNA that specifies the sequence of amino acids in a polypeptide is called a(n) what?
gene.
12) Each DNA strand serves as which of the following during DNA synthesis?
Template
13) The appropriate adjective to describe DNA replication is what?
semiconservative.
14) True or False: Replication of DNA produces two molecules, each of which is half-new and half-old DNA joined lengthwise to each other.
TRUE
15) What is DNA polymerase and what does it do?
is an enzyme, adds new nucleotides to a strand, proofreads DNA strands to see that they are correct, derives energy from ATP for synthesis of DNA strands.
16) True or False: The difference between normal hemoglobin and sickle-cell hemoglobin is in the substitution of a specific amino acid for another specific amino acid.
True
17) What is a gene mutation and what causes it.
is a change in the nucleotide sequence of DNA, may be caused by environmental agents, may arise spontaneously, can occur in all organisms.
18) Mutations can be ??.?
random, beneficial, harmfu, heritable.
19) What is a DNA region that can “jump” from one location to another called?
transposable element.
20) The RNA molecule is made up of how many strands?
1
21) What is the form of RNA that carries the code from the DNA to the site where the protein is assembled called ?
messenger RNA.
22) All the different kinds of RNA are transcribed in what part of the cell?
nucleus.
23) What is the nitrogenous base found in DNA but not in RNA?
thymine.
24) What is the nitrogenous base found in RNA but not in DNA
uracil.
25) Uracil can pair with what base?
adenine.
26) The synthesis of an RNA molecule from a DNA template strand is called what?
transcription.
27) The portion of the DNA molecule that is ultimately translated is composed of
exons
28) The portion of the DNA molecule that is not translated and is a noncoding portion of DNA is composed of
introns
29) True or False: In transcription, a special sequence, called a promoter, is necessary for transcription to begin.
True
30) True or False: Only red blood cells have hemoglobin genes.
FALSE
32) The genetic code is made up of units, each of which consists of how many nucleotides?
3
33) There are how many different kinds of amino acids in proteins?
20
34) The concept that a set of three nucleotides specifies a particular amino acid provides the basis for
the genetic code
35) Each ?word? in the mRNA code consists of how many letters?
3
36) If the DNA triplets were ATG-CGT, what would the mRNA codons be?
UAC-GCA.
37) How does recombinant DNA occur and what can be the results of it?
has occurred in sexually reproducing forms, can be produced with new biological techniques, occurs with viral infections of various forms of life, has produced changes that resulted in evolution.
38) New genetic combinations result from what?
crossing over, sexual reproduction, mutations, exchange of genes between different species.
39) True or False: Recombinant DNA technology uses bacteria to make copies of the desired product and splices DNAs together.
TRUE
40) What are small circular molecules of DNA in bacteria called?
plasmids.
41) What are plasmids and how are they used?
are self-reproducing, circular molecules of DNA, are sites for inserting genes for amplification, may be transferred between different species of bacteria, may confer the ability to donate genetic material when bacteria conjugate.
42) What are the enzymes used to cut DNA molecules in recombinant DNA research called?
restriction enzymes.
43) True or False: The fragments of chromosomes split by restriction enzymes have specific sequences of nucleotides and sticky ends.
TRUE
44) What is the ?natural? use of restriction enzymes by bacteria?
destroy viral DNA.
45) True or False: Restriction enzymes are used along with ligase and plasmids to produce a DNA library.
TRUE
46) Where do restriction enzymes work?
at recognition sites.
47) What enzymes joins the paired sticky ends of DNA fragments?
DNA ligase
48) Because it has no introns, researchers prefer to use __________ when working with human genes.
cDNA
49) True or False: For polymerase chain reaction to occur, isolated DNA molecules must be primed and the DNA must be separated into single strands.
TRUE
50) How can multiple copies of DNA be produced?
cloning a DNA library, genetic amplification, the use of reverse transcriptase, the action of DNA polymerase.
51) What is a collection of DNA fragments produced by restriction enzymes and incorporated into plasmids called?
a DNA library.
52) True or False: Probes for cloned genes use complementary nucleotide sequences labeled with radioactive isotopes.
TRUE
53) What does the human genome project seeks to do?
identify the nucleotide sequence of all human genes.
54) True or False: Gene therapy has never been used successfully with mammals.
False
55) Recombinant DNA research uses plasmids and what as cloning vectors?
viruses
56) True or False: The use of RFLPs for ?genetic fingerprinting? is based upon differences of locations where enzymes make their cuts.
TRUE
57) True or False: RFLPs can be used to distinguish between identical twins.
FALSE
58) What are genetically-engineered organisms that carry some foreign genes called?
transgenic.
59) What is genetically engineering bacteria that may be used to break down pollutants in the environment in a process called ?
bioremediation.
