BIO 225 Lecture - Chapter 8

The purpose of RNA synthesis is to provide a new copy of DNA as the original strand deteriorates over time. (True or False)

False

Translation occurs on ribosomes only in prokaryotes. (True or False)

False

Translation of eukaryotic mRNA can occur in the nucleus after exons are spliced together. (True or False)

False

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

Okazaki fragments

The initial transfer RNA occupies the _____ site on the ribosome.

P site

Please label the images to demonstrate your understanding of the various technologies that may be involved in genetic engineering.

Polymerase Chain Reaction (top left) Denaturation of DNA by heating (top right) Cloning Vector (plasmid) (bottom left) Restriction Enzymes (bottom middle) Gel Electrophoresis (bottom right)

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

Prokaryotes transcribe and translate simultaneously.

Move the correct terms into their corresponding empty boxes within the figure to complete the concept map.

Recombinant Cells contain FOREIGN DNA which an produce PROTEIN, ORGANISM WITH DESIRED TRAIT, DNA

After mRNA is made, what generally occurs?

The mRNA is translated to protein.

Plasmid DNA is transferred:

in single-stranded form

Synthesis of mRNA is:

in the 5' to 3' direction with new nucleotides being added to the 3' end of the mRNA molecule.

Eukaryotic mRNA contains non-coding regions called ___.

introns

A mechanism that blocks transcription:

will block the production of mRNA

Eukaryotic mRNA usually specifies multiple proteins. (True or False)

False

The F pilus binds to:

specific receptors on the cell wall of the recipient.

Move each term to the correct example to review the categories of point mutations.

(labels only....not the genetic codes) - normal gene - missense mutation - silent mutation - frameshift mutation

Label the image to review the major elements needed to synthesize a protein during translation.

(start at top left and go clockwise around) exit site amino acids large subunit small subunit mRNA transcript tRNAs

Label the images to assess your knowledge of nucleic acid structure.

(start at top left and work way down, around, back up to top right) phosphate guanine thymine adenine deoxyribose H bonds DNA RNA cytosine ribose uracil backbone

Match the term with the molecule on which it is found.

- A and P sites - rRNA - Promoter - DNA - Start codon - mRNA

Label the image to test your understanding of the flow of genetic information in cells.

- DNA (circle at the top, then move counterclockwise to next label) - Transcription of DNA - tRNA, mRNA, rRNA (group of 3 on the left side) - Translation of RNA - Ribosome (rRNA + protein) - Protein - Micro RNA, interfering RNA, antisense RNA, riboswitches - Regulatory RNAs (last label before reaching DNA at the top)

Select all of the materials and procedures necessary to clone a gene into a bacterium. Assume the gene to be cloned has been isolated and purified.

- DNA (gene) to be cloned - Transformation - Cloning vector - Restriction endonucleases - Screening for recombinants - Bacterium serving as host (cloning host)

Place the steps in the correct order to review the steps of mRNA processing in eukaryotes.

- DNA Template - Primary Transcript - Transcript Processing - Exons are Spliced - mRNA Ready for Translation

Select all of the differences between DNA and RNA to test your understanding of these nucleic acids.

- DNA is double stranded, RNA is single stranded. - DNA nucleotides contain deoxyribose whereas RNA nucleotides contain ribose.

Select those statements that describe features of transcription and translation that are found in eukaryotes but not in bacteria.

- Genes are interrupted by intervening sequences. - A tail of multiple adenine ribonucleotides is added to the mRNA transcript. - mRNA transcript must pass through pores to get out of the nucleus. - RNA transcript is processed to remove introns and splice together exons.

Select the products developed by recombinant DNA technology that have contributed to human health.

- Hormones, such as human growth hormone - Enzymes, such as tPA - Vaccines, such as Hepatitis B vaccine

Label the image to review the process of horizontal gene transfer. Please use the pop-up hints to help you with correct label placement.

- Mutations (top) - Drug Inactivation (left), Altered Ribosome Binding Sites (right) - Vertically (left), Horizontally (right) - Transformation, Transduction, Conjugation, Transposition

Select the components and equipment that would be necessary for doing PCR.

- Sample containing the DNA to be amplified - dNTPs (deoxyribonucleotide triphosphates) - Taq polymerase (thermostable polymerase) - Primers specific to the DNA sequence to be amplified - Thermocycler

One common analogy used to illustrate the nature of genetic material involves comparing the different components of genetic material to a textbook. Match the genetic terms to the best textbook component to show that you understand these terms as they relate to one another.

- The whole textbook - GENOME - A chapter in the textbook - CHROMOSOME - A sentence in a chapter of the textbook - GENE

Select all of the features that you would include if you drew a short segment of DNA.

- double stranded - helical shape - chains of nucleotides - the backbone of the chains are created by bonds between sugars and phosphates of nucleotides - nucleotides are base-paired with T bonded to A and C bonded to G through hydrogen bonds

Select characteristics exhibited by the ideal cloning host.

- grows easily - readily accepts recombinant DNA - will synthesize large quantities of desired gene products

Please label this figure to demonstrate your understanding of the lac operon as a model of inducible gene regulation in bacteria.

- regulator, lactose, no transcription and translation (top row) - promoter, operator, repressor protein (2nd row) - RNA polymerase, transcription and translation (3rd row) - inactive repressor (bottom row)

Select those statements that describe the main points of lac operon operation.

- the regulator gene encoding the repressor lies upstream of the operator region and is transcribed constitutively - the lac operon only functions in the absence of glucose - the structural genes are transcribed in a single unbroken transcript coding for all three enzymes needed for lactose metabolism

Order the following choices to reflect the order of the three basic steps in each PCR cycle. Assume that all the reagents and the DNA sample to be amplified are mixed and ready to go.

1. Denaturation at 94 C 2. Annealing primers at 60 C 3. Extension at 72 C

Order the following choices to reflect the process of DNA replication.

1. Helicase starts at the origin of replication separating the two strands of DNA, forming two replication forks. 2. Primase synthesizes RNA primers. 3. Two molecules of DNA polymerase III (one at each replication fork) build DNA by adding nucleotides onto the primers, extending them. 4. The leading strand is synthesized continuously while the lagging strand is synthesized in fragments (Okazaki fragments). 5. DNA polymerase I removes the RNA primers and replaces them with DNA. 6. DNA ligase joins the Okazaki fragments.

Order the following choices to examine the process of transcription.

1. RNA polymerase binds at the promoter region just upstream from the gene. 2. RNA polymerase unwinds the DNA at the promoter site and begins to transcribe the template strand of DNA. 3. RNA polymerase moves along the template strand of DNA adding complementary RNA nucleotides, extending the mRNA. 4. Transcription continues until a termination site in the DNA is reached.Transcription continues until a termination site in the DNA is reached. 5. The mRNA transcript is released.

Consider the following original DNA sequence: TACGACACCTTA Four different mutations of this sequence are indicated. Match the mutated sequence with the type of mutation it represents. NOTE: You will need to refer to the genetic code table in section 8.2 of the textbook to answer this question.

1. TACTGACACCTTA = frameshift 2. TACGACACTTTA = nonsense 3. TACGATACCTTA = silent 4. TACGTCACCTTA = missense

If the codon GGU is positioned in the A site of the ribosome, which of the following will occur?

A tRNA with the anticodon CCA will deliver its amino acid to the site.

Which of the following occur(s) in both prokaryotes as well as eukaryotes?

All of these

Move the descriptions to the correct type of bacterial genetic recombination.

CONJUGATION - direct transfer between two living cells - requires a pilus - commonly transfers drug and metal resistance/toxin production genes TRANSFORMATION - live competent cell picks up DNA fragment from environment - transfer of capsule genes - can be used in the lab to introduce a plasmid to a host bacterial cell TRANSDUCTION - requires a bacteriophage - bacterial donor and recipient must be from the same species - may be specialized or generalized

Which of the following depicts the most common direction genetic information flows?

DNA --> RNA --> protein

Move the terms to their correct description to review a variety of enzymes involved in DNA replication.

DNA POLYMERASE III - Responsible for adding bases to the new DNA chain and proofreading the newly laid down bases TOPOISOMERASES I & II - Responsible for supercoiling and untangling of DNA DNA POLYMERASE I - Responsible for removing the primer, closing gaps in the DNA and repairing mismatched bases LIGASE - Responsible for the final binding of nicks in DNA during replication PRIMASE - Responsible for synthesizing an RNA primer HELICASE - Responsible for unzipping the DNA helix

Both DNA and RNA are usually double-stranded molecules. (True or False)

False

When an amino acid such as arginine binds to a repressor:

the repressor binds to the operator site on the DNA.

Label the image to review the types of genomes found in various cells and viruses.

LARGE ROUND CELL (UPPER LEFT) - Eukaryotes (yellow label tag, then go counterclockwise) - Chromosomes - Mitochondrion - Chloroplasts SMALL ROUND CELL (BOTTOM LEFT) - Viruses (blue label tag) - dsDNA - ssRNA OVAL CELL - Bacteria (yellow label tag) - Chromosome (bottom left), Plasmids (bottom right)

Which of these are base-paired correctly?

T - A

Please complete this Venn diagram to demonstrate your understanding of transcription and translation. Place labels that represent transcription into the left circle, labels that represent translation into the right circle, and labels that represent both processes into the intersected area of the two circles. NOTE: You must use the roll-over hints provided to correctly place your labels.

TRANSCRIPTION - Utilizes a polymerase to build a growing nucleic acid chain - Involves DNA as a template - In eukaryotes, this takes place in the nucleus BOTH - Involves mRNA - Involves and initiation step, elongation of product, and termination step - Part of protein synthesis TRANSLATION - tRNAs carry amino acids to a growing chain - This process takes place at the ribosomes - The genetic code is used to determine the correct order of amino acids

Match the processes to their proper description to test your understanding of horizontal genetic transfer mechanisms used in bacteria.

TRANSDUCTION - DNA transfer from one bacterial cell to another cell via bacteriophage CONJUGATION - DNA transfer from a donor bacterium to a recipient via sex pili TRANSFORMATION - The transfer of naked DNA from one cell to another

What happens when a hairpin loop forms in mRNA?

The RNA polymerase and the mRNA dissociate from the DNA.

Which nitrogenous base is NOT present in RNA?

Thymine

If you know the sequence of nucleotides in mRNA, you can deduce the DNA sequence it was transcribed from. (True or False)

True

In prokaryotes, the mRNA transcript encounters ribosomal parts immediately as it leaves the DNA. (True or False)

True

Mutations are the primary source of genetic variation that makes evolution possible. (True or False)

True

Only eukaryotic mRNA is processed prior to translation. (True or False)

True

Prokaryotes lack membrane-enclosed organelles. (True or False)

True

Replication, transcription, and translation take place in the bacterial cytoplasm. (True or False)

True

The sequence of DNA bases ultimately determines the sequence of amino acids in a polypeptide. (True or False)

True

Unlike DNA, RNA is usually single stranded. (True or False)

True

If one strand of DNA contains the bases ACAGT, what would be the complementary bases on the mRNA strand?

UGUCA

The F pilus is:

a protein appendage that attaches the two cells.

The plasmid is mobilized for transfer when:

an endonuclease cleaves it at the origin of replication.

The two strands of the DNA molecule are:

antiparallel

Mismatch repair is activated by:

any difference between the nucleotide sequence in the donor and recipient DNAs.

Repressible operons (such as the arg operon):

are usually in the "on" mode

Introns are removed and exons are spliced together:

before translation

DNA polymerase:

can only add nucleotides in a certain direction

As a result of mismatch repair during transformation:

cells may have either original DNA or donor DNA in them.

_____ are groups of three bases in mRNA that specify one amino acid in the amino acid chain.

codons

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

competent

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

conjugation and transduction

The first step in conjugation is:

contact between the donor and recipient

In the beginning of transformation, ______ binds to the target cell.

double-stranded 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

One advantage of having genetic control mechanisms is:

enzymes are only produced when they are needed.

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

gene

The classic transformation experiment done by Griffith used:

harmless and virulent strains of streptococcus pneumonia

Early in the process of DNA replication, the enzyme ______ separates the two strands.

helicase

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

hydrogen bonding

When a repressor binds to the operator site on DNA:

it blocks RNA polymerase and mRNA synthesis.

When a bacterium is grown on glucose only:

it must synthesize all the amino acids it needs.

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

make sure that only transformants grow

RNA is a chain of:

nucleotides

Transformation is a form of recombination. Recombination is:

one bacterium donating DNA to another

During the entry of the donor DNA into the recipient cell:

one strand is broken down by nucleases.

A recombinant organism is:

one that contains genes from another organism.

A(n) ______ is a cluster of genes that perform related functions found in _____.

operon, prokaryotes

Coordinated sets of genes that are regulated as a single unit are referred to as ______.

operons

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

order of nitrogenous bases

The specific point on the DNA molecule where replication begins is the:

origin of replication

The donor DNA:

pairs with a homologous region of the recipient DNA.

he bond connecting amino acids is a ____ bond.

peptide

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

phenotype

The three basic parts of a nucleotide are:

phosphate, deoxyribose sugar, nitrogenous bases

What three components make up RNA structure?

phosphate, nitrogenous base, ribose sugar

What usually terminates the process of translation?

presence of a stop codon on mRNA

Translation of mRNA into protein begins before transcription is complete in ______.

prokaryotes only

Transcription begins when RNA polymerase binds to the ____.

promoter on DNA

Transformation is facilitated by:

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

If you find that a particular plasmid has an R factor, the bacteria that has it will be:

resistant to antibiotics

Protein synthesis occurs on the ____.

ribosomes

After the transfer of the F plasmid is complete:

the F- cell becomes F+.

Two different mechanisms for copying the DNA strands are used because:

the strands are oriented in opposite directions

The process of transcription is similar to:

the synthesis of the leading strand during DNA replication.

The main value of bacteria being able to carry out conjugation and other forms of recombination is:

they create genetic diversity

The process of synthesizing RNA from a DNA template is ________.

transcription

Select the mechanisms below which enable the horizontal transfer of antibiotic resistance genes.

transformation, transduction, conjugation