Chapter 9

When in a complex with ________, the CAP protein binds to the CAP site and ________ the expression of the lac operon.

cAMP; switches on

The specific sequence of 3 bases in mRNA that encodes a particular amino acid is the ______ whereas the complementary sequence of 3 bases in tRNA that bind to the mRNA is known as the _______.

codon; anticodon

In addition to transformation, the other two forms of horizontal gene transfer (or recombination) are ________.

conjugation and transduction

T or F: Both DNA and RNA are usually double-stranded molecules.

false

T or F: The pilus is found on both the donor and recipient cells.

false

Which is true regarding DNA replication?

Each new DNA helix contains one parent strand and one newly synthesized strand

In the central dogma, DNA encodes ______ which encodes protein.

RNA

Which enzyme transcribes DNA into RNA?

RNA polymerase

_______ ______ is the enzyme that transcribes DNA into RNA.

RNA polymerase

During transcription, RNA polymerase synthesizes ______ from a(n) ______ template.

RNA; DNA

Select the term that best describes any organism that contains and expresses genes that originated in another organism.

Recombinant

Which term refers to the transfer of genes from donor to recipient microorganisms?

Recombination

Which of the following is the genetic pattern of viral genomes?

Single or double stranded DNA or RNA

______ is the process of decoding DNA into messenger RNA.

Transcription

Which recombination method involves transfer of DNA via bacteriophages?

Transduction

All of the following are complementary nucleotide base pairs EXCEPT

U-C

Which is the main event of translation termination?

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

In the absence of lactose, the lac repressor is _______.

active and can bind to the operator

The arginine operon is "on" when the cell is

actively growing

Nucleotide is to nucleic acid as _______ _______ is to protein.

amino; acid

The basic parts of a bacteriophage are _______.

an icosohedral head, central tube, tail pins, and fibers

In DNA, the two strands of the helix are arranged in _______ orientation.

antiparallel

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

frameshift

The classic transformation experiment done by Griffith used _______.

harmless and virulent strains of Streptococcus pneumoniae

The lac operon in E. coli regulates the metabolism of

lactose

The bond connecting amino acids is a _______ bond.

peptide

When E. coli is grown in a medium containing both glucose and lactose, the lac operon will be

repressed until the glucose is consumed

Protein synthesis occurs on ______.

ribosomes

Mutations that occur because of errors in DNA replication are termed

spontaneous

The ______ DNA contains the order of nucleotides that are transcribed into RNA.

template

The parent strands in a DNA molecule are used as a _______ to synthesize a complementary strand of DNA.

template

DNA is semiconservative because the ______ strand will become half of the ______ molecule.

template; finished

_____ are "jumping genes".

transposons

An induced mutation arises in DNA from

treatment with ultraviolet light

Building blocks of DNA, called _________ , contain the same sugar and phosphate, but different nitrogenous bases.

nucleotides

RNA is a chain of ______.

nucleotides

Which two of the following operons in E. coli would be repressible?

-an operon encoding amino acid biosynthetic enzymes -an operon encoding vitamin biosynthetic enzymes

True or false: Bacterial conjugation is a sexual process.

False

Which enzyme synthesizes primer sequences during replication initiation?

Primase

The processes of transcription and translation differ between prokaryotes and eukaryotes in the following way

Prokaryotes transcribe and translate simultaneously.

True or false: During protein synthesis, many copies of a specific protein can be synthesized from a single mRNA transcript.

True

During bacterial conjugation, plasmid replication occurs in _______.

both the donor and recipient

DNA polymerase _______.

can only add nucleotides in a certain direction Correct

The genes of the lac operon in E. coli encode enzymes that

catabolize lactose

The advantageous genes that can be transferred by transduction are genes for ______.

drug resistance, sugar fermentation, toxin production

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

DNA _______ is the enzyme that synthesizes DNA strands in the 5' to 3' direction.

polymerase

During protein synthesis, many copies of a specific ________ can be synthesized from a single mRNA transcript.

protein

Transformation is facilitated by _______.

proteins on the cell wall that bind DNA from the environment.

DNA replication is described as ______.

semi-conservative

T or F: If you know the sequence of nucleotides in mRNA, you can deduce the DNA sequence it was transcribed from.

true

T or F: When RNA polymerase is bound to the lac promoter sequence, transcription of the lac operon is on.

true

True or false: A bacterial cell described as competent can accept soluble DNA from the surrounding environment.

true

True or false: The parent strands in a DNA molecule are used as a template to synthesize a complementary strand of DNA.

true

Which of the following does NOT occur during bacterial conjugation?

unidirectional transfer of both DNA strands

Unlike DNA, RNA contains the nitrogenous base ______.

uracil

Select the enzymes that function in DNA replication.

-DNA polymerase -Helicase -Ligase

Which is true regarding adenine and guanine?

Both are purines

What is the central dogma hypothesis of genetics?

DNA encodes RNA which encodes protein

A(n) ______ is a sequence of DNA nucleotides that codes for one functional protein or RNA.

Gene

______ is the study of the inheritance of living things.

Genetics

_____ contains the codes for the sequence of amino acids in protein

Messenger RNA

Which best describes the antiparallel orientation of strands in DNA?

One strand is 5' to 3' and the other is 3' to 5'.

Which operational unit in bacteria consists of a regulatory gene, a control region, and structural genes?

Operon

What three components make up RNA structure?

Phosphate, nitrogenous base, ribose sugar

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

______ genes are DNA segments that code for proteins.

Structural

Which nitrogenous base is NOT present in RNA?

Thymine

T or F: The inducer of the lac operon is an isomer of lactose.

True

The tRNA bound to the growing polypeptide chain during translation can be found in what area of the ribosome complex?

Within the A or P site, but not the E site

Most bacterial plasmids carry an origin of replication and at most _____ genes.

a few dozen

_____ in bacteria refers to horizontal gene exchange via pili.

conjugation

The science of heredity is ______.

genetics

The complete set of chromosomes and genes in an organism is referred to as the

genome

During the process of transformation in the lab setting, cells are plated on selective media to ________.

make sure that only transformants grow

Which term refers to an organism that has a mutation?

mutant

A permanent inheritable alteration in the DNA sequence of a cell is a(n)

mutation

The three basic parts of a nucleotide are ______.

phosphate, deoxyribose sugar, nitrogenous base

Donor and recipient bacterial cells are connected by the sex ______ during conjugation.

pilus

The following sequence is found at the beginning of a gene in the wild type: 5'-ATGCCAGGTCGTACA-3'. In a related strain of bacteria, the sequence is 5'-ATGCCCGGTCGTACA-3'. Since the codons CCA and CCC both encode proline, this mutation is best described as a _____ mutation.

silent

The lactose operon itself has three important features. Which of the following is NOT one of these features?

the inducer

True or false: A mutation is an alteration in the DNA sequence or content of a cell that is passed on when the cell divides.

true

True or false: DNA replication must occur prior to cell division to ensure that each new cell has a complete set of DNA chromosome(s).

true

True or false: The native or wild type strain describes cells that exhibit a nonmutated property.

true

Which two of the following statements regarding eukaryotic transcription and RNA processing are correct?

-A series of adenosines is added to the mRNA. -Splicing to remove introns occurs in the nucleus.

Which two of the following statements regarding DNA packaging are correct?

-DNA is thousands of times longer than the cell. -The intricate coiling of DNA is required to package it inside the cell.

Which two statements are correct?

-Eukaryotes initiate replication from multiple origins of replication. -Telomere DNA gets progressively shorter with each copy.

Which two of the following statements are correct?

-Eukaryotic DNA is linear whereas bacterial DNA is circular; -Topoisomerases relieve the superhelical tension as DNA is replicated.

DNA transfer between bacterial cells typically involves DNA in the form of ______ and ______.

-plasmids -chromosomal fragments

Which of the following operons in E. coli would be repressible?

-the thr operon, encoding threonine biosynthetic enzymes -the rib operon, encoding riboflavin biosynthetic enzymes -the pyr operon, encoding pyrimidine biosynthetic enzymes

Consider the following wild-type DNA sequence on the template strand: TACGACACCTTA Four different mutations of this sequence are indicated. Match the mutated sequence with the type of mutation it represents. Use the genetic code to help you. 1. TACGATACCTTA 2. TACGTCACCTTA 3. TACTGACACCTTA 4. TACGACACTTTA

1. Silent mutation 2. Missense mutation 3. Frameshift mutation 4. Nonsense mutation

If one donor cell is mixed with 20 recipient cells, eventually ______ cells will become donors.

20

Which sequence of DNA nucleotides is complementary to the DNA triplet 5'-ATG-3'?

3'-TAC-5'

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

5'-TATGATTTTAAA-3'

The genes of which microorganism(s) are arranged as operons?

Bacteria

Which of the following are methods of gene transfer in bacteria?

Conjugation, Transduction, Transformation

Which enzyme adds nucleoside triphosphates to a growing DNA strand?

DNA Polymerase

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

DNA polymerase

What determines the order of amino acids in the primary structure of a protein?

DNA sequence of a gene

Which of the following depicts the direction genetic information flows?

DNA → RNA → protein

True or false: Mutations are always harmful to cells.

False

True or false: Operons are found in fungi and helminths.

False

True or false: Plasmids are insertion sequences that can lead to changes in genotype within a cell or between cells.

False

True or false: Viral genomes are always composed of either single or double stranded DNA.

False

Which term represents all of the genetic information within a cell?

Genome

Identify the purine from the list below:

Guanine

Which is a purine?

Guanine

Which strand is replicated discontinuously in segments during DNA replication?

Lagging

Which strand is replicated continuously without segments during DNA replication?

Leading

On one of the strands of bacterial DNA, the new complementary strand is synthesized discontinuously into small pieces of DNA called ______.

Okazaki fragments

What component of RNA is different from one individual (or one bacterium) to the next?

Order of nitrogenous bases

_______ refers to the transfer of genes from donor to recipient microorganisms, where the recipient strain shows a change in genetic makeup at the end.

Recombination

Which of the following is not a mechanism of horizontal gene transfer?

Spontaneous mutations

After mRNA is made, what generally occurs?

The mRNA is translated to protein.

True or false: During DNA replication, both the leading and lagging strands are synthesized in the 5' to 3' direction.

True

The two strands of the DNA molecule are ______.

antiparallel

A ______ is a discrete cellular structure composed of a discretely packaged DNA molecule

chromosome

A bacterial cell described as _______ can accept soluble DNA from the surrounding environment.

competent

Cells that are capable of bringing DNA from their environment in through their cell wall are called ______.

competent

Donor and recipient bacterial cells are connected by the sex pilus during

conjugation

DNA repair enzymes have as their substrate

damaged DNA

One bacterial chromosome replicates to become two chromosomes with _______.

each made of one strand of DNA from the original chromosome and one newly synthesized strand

Most DNA damage is resolved by

enzymes

A spontaneous mutation arises in DNA from

errors in DNA replication

T or F: The purpose of RNA synthesis is to provide a new copy of DNA as the original strand deteriorates over time.

false

Which type of mutation is generally most harmful to cells?

frameshift

A segment of DNA encoding a protein or an RNA molecule is a ________.

gene

A segment of DNA that contains the necessary code to make a protein or an RNA is called a(n)

gene

Generalized transduction differs from specialized transduction in that ________.

generalized transduction transfers random DNA fragments while specialized does not

In _____ transduction, random fragments of host DNA are taken up by the bacteriophage during assembly.

generalized.

When E. coli is grown in a medium containing both glucose and lactose, it will first consume the

glucose

The lac operon is expressed when _______.

glucose is low and lactose is present.

In DNA replication, _______ unwinds the double helix, primase synthesizes the short RNA primer, and DNA _______ adds nucleotides to the new chain.

helicase; polymerase

The two strands of DNA are joined to each other or held together by ______.

hydrogen bonding

Mutations that occur because of exposure to known mutagens are termed

induced

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

mutations

The ______ DNA strand is the strand that is not directly used for transcription into mRNA during protein synthesis.

nontemplate

When a cell is actively growing, the arg operon is _____, and arginine is _____.

on; actively synthesized

Transformation is a form of recombination. Recombination is _______.

one bacterium donating DNA to another

Bacteriophage adsorb or attach _______.

only to members of the same species

In bacteria, a regulatory gene, a control region, and structural genes collectively are referred to as a(n)

operon

After host cell DNA is broken down by a viral enzyme _______.

phage DNA is replicated and phage coat proteins are produced

A _______ is the physical expression of the genes present and can change depending upon what genes are turned "on".

phenotype

A difference between transferring plasmids and fragments of DNA between cells is _______.

plasmids can replicate independently

During replication initiation, the enzyme _______ synthesizes primer sequences.

primase

In _____ transduction, a particular part of the host genome is included in the virus.

specialized

An organism that has a mutation is called a mutant

strain

An organism that has a mutation is called a mutant ________

strain

Which kind of gene encodes a protein?

structural

All DNA nucleotides contain ______.

the same sugar and phosphate, but different nitrogenous bases

The process of transcription is similar to _______.

the synthesis of the leading strand during DNA replication

______ involves the transfer of DNA via bacteriophages.

transduction

Small chromosomal DNA fragments or plasmids are the forms of DNA most often ______.

transferred between bacteria

Conjugation, _______ , and transduction are methods of gene transfer in bacteria.

transformation

When a competent cell takes in DNA from outside the cell, it is termed

transformation

Which gene transfer method involves the uptake of free DNA by competent bacterial cells?

transformation

________ involves the uptake of free DNA by competent bacterial cells.

transformation

During which process is mRNA converted into a protein?

translation

Synthesizing amino acid sequences from messenger RNA is called

translation

_____ is the process of decoding the messenger RNA into a polypeptide.

translation

"Jumping genes" or __________ , are insertion sequences that can lead to changes in genotype within a cell or between cells.

transposons

T or F: Plasmids are small pieces of DNA that may carry genetic information for antibiotic resistance.

true

T or F: Replication, transcription and translation take place in the bacterial cytoplasm.

true

T or F: Unlike DNA, RNA is usually single-stranded.

true

Which two of the following statements regarding plasmids are true?

-Plasmids may contain genes that specify resistance to antibiotics. -Many bacteria carry plasmids in addition to their chromosome.

How does RNA differ from DNA in bacteria and eukaryotes?

-RNA is single-stranded -In RNA, uracil replaces thymine

Which two statements regarding eukaryotic transcription and RNA processing are correct?

-The exon-intron junction is recognized by a spliceosome. -Transcription occurs before splicing.

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

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

The E. coli chromosome is about _____ an E. coli cell.

1000 times longer than

Which of these are base-paired correctly?

T - A

"Finishing touches" on proteins are termed _____ modification.

posttranslation

During translation elongation, peptide bonds form between:

Amino acids

The native or _____ type strain exhibits nonmutated characteristics.

wild type