Test 2: Fill in the Blanks Flashcards
If primary non-disjunction occurs, all of the resulting gametes will be abnormal; half of them will _________ and the other half __________.
diasomic, nullisomic
Individuals with Klinefelter’s will have a diploid number of ___, and the chromosomal genotype ___.
47, XXY
Two purines in RNA are _______and _______
adenine, guanine
The _______ sub-unit of RNA polymerase is critical for initiation of transcription.
sigma
The _____ sequence is a basal promoter at position -10.
TATA
The genetic code is not ________, but it is __________
ambiguous, degenerate
The _______ level of protein structure is the most important because it is determined by the ______ ______
primary, genetic code.
Nirenberg ultimately confirmed codon meanings with the ___________ assay.
triplet-binding
Within the cell the tRNAs can be subdivided into 20 _______ ______, each acted on by a specific ________ __________ and each carrying a different _____ ____.
iso-accepting groups, amino-acyl synthetase, amino acid
Proof of _____________ replication was provided by _________ and ______
semi-conservative, Messelson and Stahl
Proof of high-fidelity synthesis by DNA polymerase was provided by __________.
Kornberg
Termination of transcription can be __________ or _________.
simple (factor independent), complex (factor dependent)
The two strands of DNA are __________ in their orientation and are held together by ________ _______ between ________ bases
anti-parallel, hydrogen bonds, complimentary
Beadle and Tatum proposed the _________________ hypothesis, which was the first solid link between gene expression and _______.
One Gene One Enzyme, proteins
The only known viable monosomy in humans is __________________.
Turner Syndrome
If the amount of guanine in a DNA sample is 42%, then the amount of adenine would ____.
8%
DNA and RNA polymerases are alike in that they both require _________ nucleotides and synthesize in the _______ direction , but DNA polymerase is different because it requires _______.
tri-phosphate, 5’ to 3’ direction, primer
The two pyrimidines in RNA are _______ and ________.
uracil, cytosine
The initial products of ____________ synthesis on the lagging strand are _______ fragments.
discontinuous, Okazaki
Work done with Neurospora and ________ mutants ultimately lead to the proposition of the _____________ hypothesis
auxotrophic, One Gene One Enzyme
Two critical players during replication that relieve supercoiling are _________ and ____________.
Individuals with Turner Syndrome have a diploid number of ___ and represent the only known viable _______ __________ in humans.
gyrases and topoisomerases, 45, monosomic condition
The only difference between the 5-carbon sugar of DNA and RNA is the presence of a ________ ______ at the 2’ position in RNA but not DNA.
hydroxyl group
The core enzyme in bacterial replication lacks the ______ subunit.
sigma
Among the main differences between DNA and RNA are the presence of the base _______ that is unique to DNA, the sugar ______ that is unique to RNA and the fact that RNA is a ____________ molecule.
thymine, ribose, single-stranded
All known DNA polymerases synthesize in the _______ direction, but may display bi-directional ___________ activity.
5’ to 3’, exonuclease
Synthesis of the lagging strand requires repeated _________ events and leads to the initial formation of ________ fragments.
discontinuous, Okazaki
A deoxyribonucleotide consists of ___________, __________ and __________.
deoxyribose, nitrogenous base, and phosphate group
For RNA polymerases, the direction of synthesis is ________ and ___________ nucleotides are required, but _______ are not required.
5’ to 3’, tri-phosphate, primers
The minimum length of DNA required to code for a polypeptide with X number of amino acids is _______.
3(X)
For DNA polymerase to work, ____________ deoxynucleotides must be present along with a primer that provides a _____ ________ ________.
5’ tri-phosphate, free 3’ hydroxyl group
In all matters involving high fidelity, _____________ is critically involved.
complementarity
The most common cause of aneuploidy is ___________, and the two types that can occur are .__________ and __________.
non-disjunction, primary and secondary
One source of evidence that DNA is the genetic material in eukaryotes is the close correspondence between _________ of uv (260 nm) and the frequency of observed _________.
absorption, mutations
Two purines in nucleic acids are _________ and __________.
adenine and guanine.
Complementarity between the bases on two strands of DNA is the product of ______ _____ that will occur only if the two strands are __________ to each other.
hydrogen bonds, anti-parallel
Plants with seedless fruits are often ___________ and are therefore _______.
auto-polyploids, sterile
For in vitro synthesis by DNA polymerase I, a single-stranded ____ ______ must be present along with a primer that provides a free ______.
DNA template, 3’ OH
The core RNA polymerase of transcription lacks the ______ subunit, which is required for _________.
sigma, initiation
Stem and loop configurations in DNA and even in tRNA are produced by _______ _____________.
intra-strand complementarity
The genetic code was broken largely by the work of _________, and he demonstrated that there were ___ codons that specify amino acids.
Nirenberg, 61
In the genetic machinery, each individual amino acid is represented by a group of __________ tRNAs and has its own ________ system.
iso-accepting, charging
The final signpost basal promoter is the __________ sequence in prokaryotes.
Pribnow (TATA)
Garrod’s work of 1909 suggested that genes work by way of _________ _________, but the work of Beadle, Tatum, Srb, Horowitz, and others refined the view to specific enzymes.
metabolic pathways
Of the two types of euploidy, ___________ is the most biologically important.
allopolyploidy
During replication, primers made of _____ are added prior to DNA synthesis and provide the __________ required by DNA polymerase.
RNA, free 3’ OH
In the latter stages of his work, Nirenberg used ____________ to establish the ____________.
triplet binding, genetic code
Of the aneuploidy conditions known for humans, those affecting _______ chromosomes are the most common.
X sex
Two forms of more densely packaged DNA that can occur in eukaryotes during Interphase are ________ and _________.
A-DNA and Z-DNA.
Of the four chemical groupings of amino acids, only one is ____________.
hydrophobic
Synthesis by DNA polymerase is 5’ to 3’ and is always ______________.
unidirectional
Tighter coiling of the DNA helix, as found in __ DNA, can play a role in ___________ gene expression.
A, inactivating
Beadle and Tatum induced ___________mutations in Neurospora, and the screening of mutants was made easier because these molds are _________.
auxotrophic, haploid
In nature, hybridization between members of two species usually leads to inviable or _______ offspring, but if chromosomal __________ occurs, fertile _________ may be produced that are instantly new species.
sterile, doubling, offspring
The ____________ form of the DNA-dependent RNA polymerase involved in transcription has five subunits, but the core enzyme is formed when the _______ subunit dissociates.
holoenzyme, sigma
Nucleotides are linked together by _________________ in a polynucleotide chain.
phosphodiester bonds
There is a very intimate correlation between polynucleotides and polypeptides because each nucleotide _______ can be matched to a specific polypeptide __________.
triplet, amino acid
Genes affect phenotypes by specifying the _________________ of a protein.
linear sequence
The charging of a tRNA requires the action of an ______________________ that specifically adds an _____________ to the free __________________.
amino-acyl tRNA synthetase, amino acid, 3’ OH of the acceptor on the tRNA.
Re-association of single-stranded DNA is prevented during replication by ________________________.
single stranded binding protein
Z-DNA is characterized by having ___________ per period and assumes a ______________________
12 base pairs, left-handed helical structure.
Factor dependent termination in bacteria involves the ____ protein and the depletion of __________________.
Rho, tri-phosphonucleotides
On average DNA is a double-stranded molecule, but __________ leads to the equilibrium occurrence of single-stranded regions.
breathing
During translocation of translation, the energy of GTP is utilized as the ribosome moves _________ down the message.
3 codons
The genetic code as described by Nirenberg consists of ___ triplet codons but only ___ specify amino acids.
64, 61
D- and E-DNAs are generally ______ rich and have _____ stability than B-DNA.
A-T, less
The two critical differences between DNA and RNA are the presence of the sugar _______ in RNA and the occurrence of the nitrogenous base _________ in DNA.
ribose, thymine
DNA polymerase must have a ___________ to initiate synthesis during replication, and this is provided by a short _________ composed of _____.
free 3’ OH, primer, RNA
Structural configurations in RNA molecules are produced by ____________________________.
intra-strand complementarity
In the basic structure of DNA, two ___________ strands are associated in ___________ configuration to form an ____________.
complementary, anti-parallel, alpha helix
There is a one to one correlation between ________ of nucleic acids and the amino acids in a polypeptide.
triplets
The proof that DNA was the genetic material came from experiments done by ___________. and _________________.
Avery et. al, Hershey and Chase
Discontinuous synthesis leads to the initial production of __________ fragments that are about ______ bases in length.
Okazaki, 1000
The probability of autosomal monosomies occurring is equal to that of autosomal trisomies, and yet the observed occurrence is ______, suggesting that autosomal monosomies are _______.
zero, lethal
Patau’s syndrome is due to a __________ condition of chromosome ___.
trisomic, 13
The presence of _________ ________ sequences in DNA can lead to cruciform configurations by way of _____________________.
inverted repeat, intra-strand complementarity
A ribosomal sub-unit is composed of ________ and a set of _________.
rRNA, proteins
After transcription gets underway, the _______ sub-unit dissociates and the ______ ________ carries out the rest of synthesis.
sigma, core enzyme
High fidelity copying of DNA was demonstrated by __________, when he was able to produce _________ ________ DNA in vitro.
Kornberg, infective strand
Rolling circle replication is unusual because one complete strand is built ___________ and the other strand is built ______________.
continuously, dis-continuously
Re-association of a DNA strand with an inverted repeat can lead to the formation of ________ DNA due to the possibility of _________ __________.
cruciform, intra-strand complementarity
All the DNA polymerases found by Kornberg display __________ synthesis in the _______ direction.
continuous, 5’ to 3’
The chromosomal make-up of an individual with Klinefelter’s syndrome is ______.
XXY
In the experiments of Hershey and Chase, ____________ was found in cells, indicating that _____ was the viral genetic material.
radio-labeled phosphorus, DNA
In bacterial translation, the start codon ____ specifies the amino acid ____________.
AUG,methionine
Avery et al determined that DNA was critical for the conversion of avirulent ___________ to virulent___________.
IIR bacteria, IIIS bacteria
Allopolyploids are produced when __________ followed by doubling occurs, and they differ from autopolyploids in that they usually are ___________.
hybridization, not sterile
The _______ hypothesis was proposed as a result of the observation that the third base of a codon was relatively free.
wobbling
Primer removal is accomplished by the enzyme _________________
DNA polymerase I
One very important aspect of the genetic code is that it is ____________, and that provides a buffer against ___________.
degenerate, mutation
The amino acids are grouped as ________, ________, _______, and _______ on the basis of chemical properties.
polar, non-polar, acidic, and basic
Multiple copies of viral genomes included in a single molecule are known as _______________.
concatamers
The sequence common to all 3’ ends of tRNA molecules is ____ and serves as the ______________.
CCA, acceptor stem
The basic _________ structure of DNA is maintained in aqueous environments due to the _________ nature of the nitrogenous bases and the _________ nature of the sugar-phosphate backbone.
alpha helical, hydrophobic, hydrophilic
Two types of chromosomal variation caused by segregational mistakes are ____________ and ___________.
autopolyploidy and allopolyploidy
The primary cause of aneuploidy is _________ and it can be of two types, ________ and _________.
non-disjunction, primary and secondary
According to Watson and Crick model for DNA, ____________ between base pairs can only occur if the two strands are ____________.
complementarity, antiparallel
The only difference between the 5C sugar of DNA and RNA is the presence of an ___ at the 2’ position in RNA but not in DNA.
OH
In nucleotides, the sugar is ___________ for DNA and _________ is a base unique to RNA
deoxyribose, Uracil
