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.