chapter 9 microbiology

which is the main event of transcription termination?

RNA polymerase reaches a terminator region

neculotide is to nucleic acid as __ __ is to protein

amino acid

in replication of DNA, the lagging strand is replicated in a discontinuous manner forming __ fragments

okazaki

t or f: ultraviolet rays are chemical mutagens

false

t of: a point mutation results from an insertion or deletion of nucleotides, and always leads to a shift of the triplet sequence from the point of mutation downstream

false; frameshift mutation

the replication __ is the Y-shaped point on a replicating DNA molecule where the DNA polymerase is synthesizing new strands of DNA

fork

__ mutations are generally most harmful to cells because they cause the change in the amino acid sequence of a protein

frameshift

mutations that occur because of exposure to known mutagens are termed

induced

an agent that induces changes in DNA is a __

mutagen

an agent that induces in DNA is an

mutagen

a __ mutation results in early termination of the protein

nonsense

an organism that has a mutation is called a mutant

strain

__ genes are DNA segments that code for proteins

structural

__ RNA is transcribed and then plays a role in translation by carrying amino acids to the ribosome

t

t or f: the expression of the genotype creates traits referred to as the phenotype

t

the coding strand, or __ DNA contains the order of nucleotides that are transcribed into RNA

template

the pentose sugar RNA is __ while in DNA the pentose sugar is __

ribose deoxyribose

rRNA composes __ subunits together with protein

ribosomal

what is the central dogma hypothesis of genetics?

DNA encodes RNA which encodes protein

how many stop codons are contained within the genetic code?

3

during transcription, RNA polymerase synthesizes __ from a __ template.

RNA; DNA

__, __ and __ are the stop codons within the genetic code

UAA, UAG, UGA

during translation elongation, peptide bonds form between:

amino acids

an __ is the specific sequence of 3 mRNA nucleotides that encodes a particular amino acid

codon

each mRNA ______ codes for a particular amino acid which is then bonded with other amino acids during translation to form a protein

codon

In the bacterium Escherichia coli, where is the chromosome located?

cytoplasm

DNA repair enzymes have as their substrate

damaged DNA

ensuring that the DNA code will be maintained during cell growth and cell __ is one of the two essential effects of the structure of DNA

division

Watson and Crick discovered the structure of DNA in 1953, and termed it a

double helix

t or f: DNA polymerase converts DNA into the various types of RNA during transcription

false

which strand is replicated discontinuously in segments during DNA replication?

lagging

during translation initation, the ribosome binds to the __ RNA transcript

messenger

a mutation that changes a base but does not change the amino acid sequence of the encoded protein is termed a __ mutation

silent

mutations that occur because of errors in DNA replication are termed

spontaneous

the mRNA sequence AUG, specifying the first amino acid in protein sequences, is called the __ codon

start

__ brings the amino acids to the ribosome

tRNA

mRNA binds to this strand in transcription

template strand

all DNA nucleotides contain

the same sugar and phosphate, but different nitrogenous bases

T or F: a mutation is an alternation in the DNA sequence or content of a cell that is passed on when the cell divides

true

t or f: DNA polymerase is involved in the synthesis of new DNA strands during DNA replication

true

a small number of __ are considered beneficial in that they provide the cell with a useful change in structure or physiology

mutations

RNA polymerase binds to which region of DNA to begin transcription?

promoter

__ and proteins compose ribosome subunits

rRNA

which two of the following statements regarding tRNA charging with amino acid are correct

"charging" refers to the process of adding an amino acid to a tRNA the anticodon is tRNA specifies which amino acid it carriers

the term __ is a sequence of 3 consecutive nucleotide bases in DNA that encodes an amino acid

triplet

How does RNA differ from DNA in bacteria and eukaryotes?

RNA is single-stranded, DNA is double-stranded RNA, uracil replaces thymine

_________ _______ is the enzyme that transcribes DNA into RNA.

RNA polymerase

what is the main event of translation termination?

a nonsense codon is reached and the peptide is released from the ribosome

biosynthesis of DNA RNA and protein __ energy

consumes

according to the rules of complementary base pairing, the nitrogenous base __ forms hydrogen bonds with guanine

cytosine

the complete set of chromosomes and genes in an organism

genome

the purine nitrogenous bases found in DNA are adenine and __

guanine

the __ is a particle composed of two subunits of rRNA that is the site of protein synthesis

ribosome

a mutation that produced neither adverse nor helpful changes is termed a __ mutation

neutral

a nitrogen-containing molecule found in DNA and RNA that provides the basis for the genetic code is an

nitrogenous base

genes are amde of DNA building blocks called __ __

nucleic acids

the DNA genome of DNA animal viruses is replicated in the __; the genome of RNA viruses is replicated in the __

nucleus; cytoplasm

"finishing touches" on proteins are termed __ modification

posttranslation

during replication initiation, enzyme __ synthesizes primer sequences

primase

RNA polymerase binds to the __ region of the DNA to initiate transcription

promoter

which RNA carries amino acids to the ribosome during protein synthesis?

tRNA

the process of shifting the ribosome down the mRNA to read new codons is termed

translocation

t or f: several codons code for the same amino acid, which is called the redundancy of the code.

true

t or f: the parent strands in a DNA molecule are used as a template to synthesize a complementary strand of DNA

true

t or f: within a nucleotide, the phosphate group is linked to the 5' carbon of the pentose suguar

true

unlike DNA, RNA contains the nitrogenous base __

uracil

what determines the order of amino acids in the primary structure of a protein

DNA sequence of a gene

which is the main event or transcription elongation?

RNA polymerase joins nucleotides

whta is the genetic pattern of viral genomes?

SS or DD, DNA or RNA

which two are responsible for induced mutations

UV, 2-amino purine

what is the function of tRNA?

brings amino acids to the ribosome

the sequence of this strand is the same as the mRNA

coding strand

the pyrimidine nitrogenous bases found in DNA are thymine and __

cytosine

proteins that remove incorrect bases and replace them with correct ones termed __ repair enzymes

excision

in eukaryotes, which DNA sequences encode functional protein?

exons

t or f: a RNA template is a strand of RNA made from DNA

false

t or f: deoxyribose is the pentose sugar in RNA

false

__ is the study of the inheritance of living things

genetics

which is largest in terms of molecular size?

nucleic acid

chromosomes are located in the __ of protozoal and fungal cells

nucleus

a mutation that affects only a single base pair in DNA is termed a __ mutation

point

a fragment of DNA with the wild type sequence 5'-AGCTGACGACCAGGTGACCAG-3' is found in a mutant to be 5'-AGCTGAGGACCAGGTGACCAG-3'. The term that best describes this mutation is

point mutation

During semiconservative _________ the DNA is duplicated prior to binary fission.

replication

during __ DNA replication, the newly made double helices are composed of one parent template and one newly synthesized strand

semiconservative

the 3' end of a eukaryotic chromosome that cannot be copied is called the __

telomere

number of genes humans carries in their genome

ten of thousands of genes

t or f: the anticodon for the codon AUG is UAC

true

t or f: the phenotype is the sum of all the genes constituting an organisms distinctive genetic makeup

false; genotype

which two of the following have damaging effects on DNA?

gamma rays, X rays

the process of replication of the DNA molecule is describes as being __ because the parent strands serve as templates for the production of two new daughter strands of DNA

semiconservative replication

t or f: during protein synthesis many copies of a specific protein can be synthesized from a single mRNA transcript

true

if a DNA molecule contains 15% adenine nucleotides, what percent of cytosine does it contain?

35% A-T and C-G are complementary, the cell would contain 30% A-T and 70% C-G, half of which is 35% cytosine

The E. coli chromosome is about __ and E. coli cell

1,000 time longer than

A DNA triplet encodes _____ mRNA codon(s) and _____ amino acid(s).

1;1

correct regarding DNA replication elogation

DNA ligase joins the lagging strand fragements DNA ploymerase I removes RNA primers used to initiation synthesisreplication proceeds at a rate of 750 bases per second

which is the main enzyme in elongation of a DNA strand during replication?

DNA polymerase

in which organisms is a polyribosome more likely to be found

E. coli

in the central dogma, DNA encodes __ which encodes protein

RNA

number of genes virus carries in their genome

a few dozen genes

__ is the process of decoding the messenger RNA into polypeptide

translation

what is the complementary DNA sequence to the DNA template 3'-ATACTAAAATTT -5'?

5'-TATGATTTTAAA-3'

what is the length of a typical tRNA molecule?

75-95 bases

which test is a method of detecting mutagenic and potentially carcinogenic agents based upon the genetic alteration of nutritionally defective

Ames Test

what enzymes that function in DNA replication

DNA polymerase, ligase, helicase

number of genes bacterium carries in their genome

a few thousand genes

which three of the following events in protein synthesis occur post-translationally?

addition of cofactor; protein folding; removal of the formyl methionine

the purine nitrogenous bases found in RNA are guanine and __

adenine

In DNA, the 2 strands of the helix are arranged in ___ orientation

antiparallel

__ are DNA sequences which encode for functional proteins

exons

__ are DNA sequences that do not encode protein, but may have a regulatory function

introns

the newly forming DNA strand that is replicated without segments is called the __ strand

leading

the final sealing of nicks in a newly synthesized DNA strand is catalyzed by the enzyme __

ligase

which enzyme completes the final sealing of nicks in a newly synthesized DNA strand?

ligase

__ contains the codons for the polypeptide

mRNA

which type of RNA is a copy of the DNA template corresponding to a protein-encoding gene?

mRNA

a mutation that leads to the insertion of a different amino acid in the encoded protein is termed a __ mutation

missense

the pyrimidine nitrogenous bases found in DNA are cyrosine and __

thymine

which nitrogenous base is found in DNA but not found in RNA?

thymine

RNA polymerase binds the DNA promoter to initiate __

transcription

one reason protein synthesis is more efficient in bacteria than in eukaryotes because bacterial __ and __ are simultaneous

transcription; translation

the native or __ strain describes cells that exhibit non mutated properties

wild type