MICR Unit 7 Study Guide

Events that take place during the elongation phase of translation

- A peptide bond is formed between amino acids on adjacent tRNAs - Empty tRNAs leave the ribosome via the E-site - tRNAs carrying amino acids occupying the A-site and the P-site of the ribosome

Streps of how CRISPR systems

1. Cas protein complex cuts initial invading DNA into short fragments 2. Short DNA fragments are inserted into chromosomal region called CRISPR array 3. The cell transcribes the CRISPR array to produce small RNAs and called crRNAs 4. Each crRNA binds to a Cas nuclease 5. If crRNA base-pairs to invading DNA, Cas nuclease cuts the DNA

Conversion of mRNA to a protein

Translation

Insertion of DNA segments into DNA

Transposase

Deoxynucleotides

Building blocks of DNA

Transposons

Can lead to changes in genotype with a cell or between cells

Broad host range

Can replicate in many different species

Narrow host range

Can replicate in only one species

The dideoxy chain termination method is a widely used method for the sequencing of

DNA

Translation

Decoding RNA to synthesize protein

A transducing particles carries

Donor cell DNA

DNA

Essential macromolecules that contains all of the information needed by a cell to synthesize its components

True or False: An RNA transcript is a strand of RNA copied from an RNA template

False

True or false: Bacterial conjugation does not require contact between the two cells

False

True or false: In bacterial conjugation, all F+ donor cells are high frequency recombinant (Hfr) cells

False

A mutagen that causes insertions

Frameshift mutatgen

Complementary DNA produced form mature mRNA is used in cloning most eukaryotic genes, since it lacks _________

Introns

What are components of the simplest transposon, an insertion sequence?

Inverted repeats Transposase gene

A mutagen that causes the formation of highly reactive ions

Ionizing radiation

What is the importance of the polymerase chain reaction (PCR)

It can be used to detect target DNA in a sample It can be used to increase the amount of a select region of DNA in a sample

What is the fourth basic step of genetic engineering?

Ligation

Bacteria can acquire antibiotic resistance by:

Mutation Insertion of transposons Acquiring plasmids

A mutagen that causes the formation of thymine dimers

Nonionizing radiation

A mutagen that is incorporated into DNA in place of a normal base

Nucleoside analog

High copy number

Occur in many copies in a cell

Low copy number

Occur in one or a few copies per cell

What is the second step to make cDNA?

RNA processing to remove introns

What are systems bacteria can use to protect against invading DNA?

Restriction-modification CRISPR

What initiates translation?

Ribosomes assemble on the mRNA

DNA _________ involves determining the order of nucleotides in a fragment of DNA

Sequencing

Inducible

Synthesized only when needed

Plasmids

Typically do not encode genes essential to the life of the cell

Helicases

Unwind the double helix at the replication fork

When bacteriophages replicate, phage components are synthesized in the host cell and assemble into new viruses

Within that cell before being released

Replication Fork

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

DNA in the environment that is not contained within a cell or virus is called _____ DNA

naked

All DNA nucleotides contain the same deoxyribose and phosphate group, but different

nucelobases

A set of regulated genes transcribed as a single mRNA molecule, along with the sequences that control its expression, is called an

operon

Genomic islands that encode disease-causing factors such as exotoxins, capsules, and adherence factors are called ________ islands

pathogenicity

A virus that infects bacteria is called a

phage

After a new virus particles have assembled in the bacterial host cell, they are usually

released as a result of host cell lysis

Enzymes that are usually synthesized but are not made when they are not needed are _________ enzymes

repressible

Carries the specific amino acid to the ribosome

tRNA

In generalized transduction, donor DNA is mistakenly packaged into a phage coat, forming a __________ particle

tranducing

Most transposons contain _______________ terminators

transcriptional

Most transposons contain ______________ terminators

trasncriptional

Restriction-modification system were discovered

while studying why certain bacterial strains are relatively resistant to phage infection

Spontaneous mutations are important because

They allow populations of bacteria to adapt to a changing environment

Metagenomics is the analysis of

Total microbial genomes in an environment

Conversion of a DNA message to a RNA strand

Transcription

If you put a gene in a virus, the next step in genetic engineering would be

Transduction

Transfer of naked DNA from the environment to a recipient cell

Transformation

Roles of ribosomes in translation

- Aligning amino acids and catalyzing formation of peptide bonds between them - Ribosomes detect sequences that indicate where translation should start and finish

Steps of F plasmid transfer

1. F pilus makes contact with recipient cell 2. One strand of F plasmid is cut in origin of transfer 3. Single strand of F plasmid is transferred to the recipient cell 4. Complement of transferred strand is synthesized

The subunits of the 70S ribosomes are

50S 30S

A collection of clones that together contain the entire genome of an organism being studied is

A DNA library

Missense Mutation

A base substitution that changes the codon to one that specifies a different amino acid

Mutation

A change in DNA that is passed on to daughter cells

What is needed for the polymerase chain reaction (PCR)?

Deoxynucleotides DNA polymerase Primers Template DNA

What is needed for the dideoxy chain termination method of sequencing?

Deoxynuclotides Dideoxynucleotides Template DNA Primer DNA Polymerase

The use of an antibiotic resistance gene on a plasmid used in genetic engineering makes

Direct selection possible

Each PCR cycle _____ the number of copies of DNA

Doubles

Replication

Duplication of the genome

Taq polymerase

Enzyme that copies target DNA sequence

Reverse Transcriptase

Enzyme used to convert mature, eukaryotic mRNA into a strand of complementary DNA

True or false: An RNA transcript in the 3' to 5' direction

False

Different versions of Cas9 can be used

For gene editing To deliver molecules to certain chromosomal locations To block transcription of individual genes

A ________ mutation results from an insertion or deletion of nucleotides, leading to a shift of the reading frame from the point of mutation downstream

Frameshift

Functional unit of a genome that codes for a product

Gene

A ______ ___________ is a large segment of a cell's genome that has clearly originated in a different species

Genomic island

Sequence of nucleotides of an organism or a cell

Genotype

Enzymes that function in DNA replication

Helicase Ligase DNA Polymerase Primase

During transduction, donor DNA is injected into a recipient cell by a phage. This DNA integreates into the recipient's chromosome by

Homologous recombination

The necessary ingredients for DNA synthesis can be mixed together in a test tube. The DNA polymerase is from Thermus aquaticus and the template is from a human cell. The DNA synthesized would be most similar to:

Human DNA

Sources of "naked" DNA

Lysed (burst) bacterial cells Secreted into the environment by bacteria

Which method is not used by a cell to prevent mistakes from occurring in DNA?

Recombination

A binding protein that blocks transcription is called

Repressor

Composed of rRNA and proteins, performs translation

Ribosome

In prokaryotes, translation begins when the ribosome binds to the _________ of the mRNA

Ribosome-binding site

DNA replication is said to be __________________, because the newly made double helices are composed of one strand from the original molecule and one newly synthesized strand

Semiconservative

Primers

Short DNA molecules that determine site of amplification in target DNA

What property of a DNA fragment determines the distance it moves during gel electrophoresis?

Size

Two types of transduction

Specialized Generalized

Removal of introns

Spliceosome

Repressible

Synthesis is turned off when not needed

Primase

Synthesizes the short RNA primer

Why is Tag polymerase used in the PCR reaction?

Taq polymerase is heat-stable and can withstand the high temperature used in the denaturation step of the reaction Using heat-stable polymerase prevents the need to add more enzyme at each PCR cycle

Double-stranded DNA

Template containing target sequence

What region of DNA signals the end of an RNA transcript?

Terminator

In addition to using naturally-occurring mutants with desirable characteristics in biotechnology, researchers can now also use __________ ___ technique to genetically alter organisms

recombinant DNA

Random genetic changes that occur as a result of natural cellular processes are celled ___________ mutations

spontaneous

Staggered cuts in a double-stranded DNA molecule by a restriction enzyme leave single-stranded overhands known as _____ ends

sticky

The native or ____ _________ strain describes cells that carry non-mutated DNA

wild type

Transcription

Copying DNA into RNA

____ is transcriped from a DNA template and translated during protein synthesis

mRNA

The _________ gene pool consists of genes that can move from one DNA molecule to another

mobile

Steps involved in the dideoxy chain termination DNA termination DNA sequencing method from the beginning to the end of the process

1. DNA template, DNA polymerase, primer, deoxynucleotides and labeled dideoxynucleotides are mixed together and heated to denature the DNA 2. The reaction tubes are incubated at an appropriate temperature, facilitating primer annealing and DNA synthesis 3. DNA fragments are separated by gel electrophoresis 4. A laser is used to detect the fluorescent dyes of the dideoxucleotides 5. The DNA sequence is obtained by determining the order of the colored peaks obtained after laster analysis of the gel

Streps of DNA-mediated transformation

1. Double-stranded DNA molecule transformation into the correct order 2. Nucleases degrade one strand of double-stranded DNA at the cell surface 3.. Single-stranded DNA enters cell after one strand has been degraded 4. Single-stranded DNA integrates into genome after entering the cell 5. Stand being replaced by donor DNA is degraded

Order of events in trasnscription

1. Initiation 2. Elongation 3. Termination

Steps of polymerase chain reaction (PCR)

1. Template DNA is denatured 2. Primers anneal to denatured DNA 3. DNA synthesis occurs

Restriction enzymes are naturally produced by

bacteria

A bacterial cell describes as __________ can take up DNA from the surrounding environment

competent

Cells that have the ability to take up DNA from the environment are called _________________ cells

competent

In E.coli, about 75% of the genes are found in all strains. These conserved genes are called the _____ genome

core

In recent years, a new field of bioinformatics has emerged, which

creates the computer technology to store, retrieve, and analyze nucleotide sequence data

In bacterial conjugation, F+ donor cells are high frequency recombinant (Hfr) cells when the F plasmid

is integreated into the chromosome

What proteins are involved in the initiation of DNA replication?

DNA gyrase Helicase

Joins segments of DNA

DNA ligase

Makes a molecule of DNA from a DNA template

DNA polymerase

The molecule that contains all the instructions all the instructions needed to produce a cell's components is

DNA

Plasmids and chromosomes

Contains an origin of replication Made of double stranded DNA

Gene

A sequence of nucleotides that usually codes for one functional protein

Bacteriophage

A virus that infects bacteria, and can transfer bacterial genes from a donor cell to a recipient cell

Protein that facilitates transcription is called

Activator

DNA Polymerase

Adds nucleotides to the new chain

Restriction enzyme recognition site

Allow vector to be cut so that gene of interest can be inserted

Selective marker

Allows for elimination of bacterial cells that do not contain recombinant molecule or vector

Origin of replication

Allows plasmid to replicate independent of host chromosomes

Subunits of proteins and nucleic acid

Amino acids Nucleotides

The polymerase chain reaction (PCR) is used in

Amplifying target DNA Differential disease diagnosis

Found on the tRNA and matches the codon

Anticodon

Plasmids differ from transposons because plasmidds

Are self-replicated outside the chromosome

A mutant that requires a growth factor is an

Auxotroph

A mutagen that alters adenine so that is base-pairs with cytosine

Base-pair mutagen

Mutation rates of genes

Between one in 10,000 and one in a trillion

Chromosomes

Cells cannot survive their loss Found in all eukaryotes and prokaryotes

Proteins involved in folding newly synthesized proteins into functional structures are called

Chaperones

Found on the mRNA and codes for an amino acid

Codon

Transfer of a plasmid from a donor cell to a recipient cell

Conjugation

Constitutive

Constantly synthesized

Proteins are synthesized by translating ________ RNA

Messenger

The _____ DNA strand is used as the template for RNA synthesis

Minus (-)

Restriction enzymes were first discovered with the observation that

Phage DNA is destroyed in a host cell

The ___ strand of DNA contains the same order of nucleotides as the corresponding RNA transcript

Plus (+)

Genetic engineering has been used for what?

Produce vaccine Pharmaceutical proteins Transgenic plants, animal DNA

RNA polymerase binds to a _________ to begin transcription

Promoter

Cloning a segment of DNA into bacteria provides a readily available source of

Protein DNA

Genetically engineered bacteria have many uses, including

Protein production DNA production Research

What method is "hit and miss" - that is, does not added a specific gene to a cell?

Protoplast fusion

_ plasmids encode resistance to a variety of antimicrobial agents and heavy metals

R

Bacteriophages can consist of

RNA genome Protein coat DNA genome

In addition to separating DNA, gel electrophoresis can also separate ______________ and ___________ according to size

RNA molecules Proteins

Makes molecule of RNA from a DNA template

RNA polymerase

What enzyme binds to a DNA promoter region to initiate transcription?

RNA polymerase

While standard sigma factors recognize promoters for genes that need to be expressed during routine growth conditions, alternative sigma factors

Recognize different sets of promoters, thereby controlling expression of specific groups of genes

Transfer of genetic material from one cell to another by a bacteriophage

Transduction

Because E. coli are not naturally competent, when used for cloning, they must be treated to induce them to take up DNA by the process of

Transformation

The transfer of DNA from a donor to a recipient as naked DNA in solution is termed

Transformation

The process of decoding the information carried by mRNA to synthesize a protein

Translation

Variation in the color of corn kernels, as described by Dr. Barbara McClintock, is an example of the process called

Transposition

True or false: A point mutation involves any substitution of a single nucleotide

True

True or false: Deoxyribose is the pentose sugar in DNA

True

qPCR

Used to amplify target sequences and monitor PCR product accumulation

RT-PCR

Used to detect certain mRNA sequences in a sample

A genetic element such as a plasmid or a bacteriophage that is used to introduce genetic material into a cloning host during recombinant DNA experiments is called a

Vector

Some types of bacteria become competent

When there is a high concentration of bacterial cells When nitrogen or carbon sources are scarce

Carries the message for a polypeptide, translated by the ribosome

mRNA

When two or more DNA molecules are linked together using in vitro methods, the resuling molecule is called ________ DNA

recombinant