Test 2: Fill in the Blanks Flashcards by Vivian Caloobanan

If primary non-disjunction occurs, all of the resulting gametes will be abnormal; half of them will _________ and the other half __________.

diasomic, nullisomic

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Individuals with Klinefelter’s will have a diploid number of ___, and the chromosomal genotype ___.

47, XXY

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Two purines in RNA are _______and _______

adenine, guanine

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The _______ sub-unit of RNA polymerase is critical for initiation of transcription.

sigma

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The _____ sequence is a basal promoter at position -10.

TATA

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The genetic code is not ________, but it is __________

ambiguous, degenerate

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The _______ level of protein structure is the most important because it is determined by the ______ ______

primary, genetic code.

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Nirenberg ultimately confirmed codon meanings with the ___________ assay.

triplet-binding

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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

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Proof of _____________ replication was provided by _________ and ______

semi-conservative, Messelson and Stahl

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Proof of high-fidelity synthesis by DNA polymerase was provided by __________.

Kornberg

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Termination of transcription can be __________ or _________.

simple (factor independent), complex (factor dependent)

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The two strands of DNA are __________ in their orientation and are held together by ________ _______ between ________ bases

anti-parallel, hydrogen bonds, complimentary

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Beadle and Tatum proposed the _________________ hypothesis, which was the first solid link between gene expression and _______.

One Gene One Enzyme, proteins

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The only known viable monosomy in humans is __________________.

Turner Syndrome

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If the amount of guanine in a DNA sample is 42%, then the amount of adenine would ____.

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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

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The two pyrimidines in RNA are _______ and ________.

uracil, cytosine

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The initial products of ____________ synthesis on the lagging strand are _______ fragments.

discontinuous, Okazaki

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Work done with Neurospora and ________ mutants ultimately lead to the proposition of the _____________ hypothesis

auxotrophic, One Gene One Enzyme

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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

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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

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The core enzyme in bacterial replication lacks the ______ subunit.

sigma

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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

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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.

In nucleotides, the sugar is ___________ for DNA and _________ is a base unique to RNA

deoxyribose, Uracil

Test 2: Fill in the Blanks Flashcards

(98 cards)