BIO-1201 Lecture Notes - Lecture 3: Aureus, Erythromycin, Pilus

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3 Oct 2016

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Transduction: viruses known as bacteriophage that specifically infect bacteria can acquire genes(dna) from one bacterial cell and transfer them to another cell. ) the process where naked dna from an outside source is taken up by a bacterial cell and incorporated into its own dna. (could come from dead cell) Conjugation: (pilus, tube, plasmid) the process where dna from one bacterium is transferred to another via a special structure known as a pilus. Mrsa isolated from pigs and pigs farmers in netherlands. 39% of the pigs carried mrsa in their nares all mrsa isolates were resistant to tetracycline. 25% resistant to erythromycin and cliindasomething netherlands- mrsa patients (. 03-2. 0) 2005 mrsa among pigs was 80%, pig farmers %23 this suggest the resistant bacteria are passed from animals to humans. U. s. study in 2008 found resistant s. aureus in the nasal fluids of 70% of tested farm pigs and in 45% of tested pig farm workers.

Related Questions

In addition to identifying the genetic material, the experiments of Avery, MacLeod, and McCarty with different strains of Streptococcus pneumoniae demonstrated that

	DNA is a double helix.
	DNA may be taken up by bacterial cells and be active.
	DNA is present in bacteriophage T2.
	eukaryotic cells may be genetically transformed.
	DNA binds to the cell wall of the bacterium.

In order to show that DNA in cell extracts is responsible for genetic transformation in Streptococcus pneumoniae, important corroborating evidence should indicate that _______ also destroy transforming activity.

	temperatures high enough to kill cells
	enzymes that hydrolyze proteins
	enzymes that hydrolyze DNA
	enzymes that hydrolyze polysaccharides
	enzymes that hydrolyze RNA

Based on what you have learned about the experiments conducted by Griffith and Avery and colleagues with bacteria, which of the following would result in transformation of living R cells?

	Pure RNA from S cells
	Cell-membrane extracts from S cells
	A mixture of pure RNA and protein from S cells
	Cell-free extracts from S cells
	Pure protein from S cells

A-T base pairs in a DNA double helix

	form three hydrogen bonds with each other.
	are more heat-stable than G-C base pairs.
	are of a substantially different length than G-C base pairs.
	are not accessible to DNA binding proteins.
	are chemically distinct from G-C base pairs.

If 23 percent of the bases in a sample of double-stranded DNA are adenine, what percentage of the bases are uracil?

	27
	50
	0
	73
	23

The uniform diameter of the DNA structure provides evidence for

	antiparallel DNA strands.
	a right-handed helix.
	a double-stranded helix.
	3â² end phosphorylation.
	purineâpyrimidine pairing.

If a sequence of one strand of DNA is 5â²-TGACTATC-3â², what is the complementary strand?

	5â²-ACTGATAG-3â²
	3â²-TGACTATC-5â²
	3â²-ACTGATAG-5â²
	3â²-ACTGATAG-3â²
	5â²-TGACTATC-3â²

What structural aspect of the DNA facilitates dissociation of the two DNA strands for replication?

	3â² end phosphorylation
	Purineâpyrimidine pairing
	Antiparallel DNA strands
	Covalent bonds between sugars and phosphate groups
	Hydrogen bonding between paired bases

If the MeselsonâStahl density gradient experiment had resulted in two bands of DNA molecules after only one round of replication, one containing only ¹⁵N and the second only ¹⁴N, this result would have indicated that replication was

	unidirectional.
	dispersive.
	conservative.
	bidirectional.
	semiconservative.

10.

The nucleoside analogue acyclovir, which is used to treat herpes simplex virus (HSV) infections, lacks a 3â² hydroxyl group (âOH). Predict what will happen if the host cell DNA polymerase incorporates a molecule of acyclovir into an elongating strand of HSV DNA.

	The replication complex will no longer bind to origins of replication.
	The DNA polymerase will only incorporate acyclovir molecules.
	Acyclovir will bind single-strand binding proteins.
	DNA polymerase will not be able to link a successive nucleotide.
	Acyclovir will block the activity of the DNA helicase.

11.

Which of the following does not demonstrate the stability of the DNA double helix?

	Single-strand binding proteins are required to keep the strands apart.
	Paired bases form hydrogen bonds.
	High temperatures are required to denature it.
	DNA synthesis requires energy.
	DNA helicases require ATP.

12.

What effect would a primase inhibitor have on DNA replication?

	DNA polymerase would not be able to add bases to the DNA.
	Primase would be blocked from joining the DNA replication complex.
	Primase would not be able to provide primers for DNA polymerases.
	DNA polymerase would not be able to use DNA as a template.
	There would be no effect on DNA replication.

13.

To replicate their DNA in a timely manner, most eukaryotic chromosomes

	normally have uncoiled DNA.
	have multiple origins of replication.
	contain linear molecules of single-stranded DNA.
	have two replication forks that move in the same direction.
	are composed entirely of DNA.

14.

Which statement about DNA replication is false?

	Okazaki fragments are synthesized as parts of the leading strand.
	Error rates for DNA replication are reduced by proofreading of the DNA polymerase.
	The sliding clamp increases the rate of DNA synthesis.
	Replication forks represent areas of active DNA synthesis on the chromosomes.
	Ligases and polymerases function in the vicinity of replication forks.

15.

In many eukaryotes, there are repetitive sequences called telomeres at the ends of chromosomes. After successive rounds of DNA replication, the _______ strand becomes shorter. In some cells, an enzyme called _______ repairs the shortened strand.

	leading; telomerase
	lagging; telomerase
	lagging; DNA polymerase I
	leading; DNA polymerase I
	leading; replicase

16.

A researcher studies normal human fibroblast cells. They can be maintained in culture but die off after about 30 cell generations. Unexpectedly, a colony of cells continues to survive and divide past 30 generations. Which scenario is most likely true for these cells?

	DNA polymerase is constantly active.
	Primase is able to extend the telomeres.
	The mismatch repair system is extra efficient.
	The telomerase gene is being expressed.
	The cells do not need the ends of their chromosomes.

17.

If DNA polymerase III introduces an incorrect nucleotide, what is the first corrective action made by the DNA repair system?

	The replication complex excises the incorrect nucleotide.
	The excision repair proteins remove the incorrect nucleotide.
	The mismatch repair system scans for base-pairing mismatches.
	There is no correction, because nucleotide errors by DNA polymerases are not repaired.
	DNA ligase connects the correct nucleotide.

18.

Choose the correct order of the following four events in the excision repair of DNA:
(1) Base-paired DNA is made complementary to the template.
(2) Damaged bases are recognized.
(3) DNA ligase seals the new strand to existing DNA.
(4) Part of a single strand is excised.

	1, 2, 3, 4
	2, 1, 3, 4
	3, 4, 2, 1
	2, 4, 1, 3
	4, 2, 3, 1

19.

Six complete cycles of PCR should result in a _______-fold increase in the amount of DNA.

	64
	32
	12
	128
	6

20.

When double-stranded DNA is heated to temperatures above 90Â°C, it denatures. Denaturation is a process that

	breaks covalent bonds.
	hydrolyzes DNA.
	separates double-stranded DNA into two single strands.
	causes new hydrogen bonds to form.
	irreversibly destroys the double helical structure.

DNA Structure and Function LabReport

DNA Structure
Which two scientists are credited with discovering DNA?

Name the nitrogen bases that are purines.

Which nitrogen base pairs with thymine?

List the three components of a nucleotide.

DNA Replication
What is the purpose of DNA replication?

How many times does replication occur in the life of acell?

In the Lab, Exercise 2, the original strand on the left had thebases shown below. Input the new bases that correctly pair with theoriginal strand.

Original	New
C
A
G
T

RNA Structure

Describe the structure and function of RNA.

Refer to Exercise 3 and record the bases of the RNA strandproduced from the replicated DNA strand.

DNA	RNA
C
A
G
T

Record the differences between DNA and RNA in the tablebelow.

	DNA	RNA
Sugars
Bases
Strands

RNA Synthesis

The process of assembling RNA is called _________.

How is replication different from transcription?

Refer to Exercise 4. Write the letters for the base sequence ofmRNA in the spaces below DNA. Note that the order is reversed;start with the 3â end of the DNA strand and the 5â end of the mRNAstrand. Transcription is DNA to mRNA. Note RNA contains Uracilinstead of Thymine; There is no thymine in RNA.

DNA

3â

5â

mRNA

5â

3â

Protein Synthesis

What type of RNA provides amino acids to build polypeptidechains?

If a mRNA strand has the bases 5â CUC 3â, what amino acid willbe translated? Refer to the printable chart in Exercise 5.

Where in the cell does translation occur?

Genes

What could be the problem if there is a change in the basesequence of a gene as it is passed down to the offspring?

Give an example of a disorder that results from changes in theamino acid sequence.

What causes sickle cell anemia?

Gene Cloning

What is the function of a plasmid?

Print the document from Lab, Exercise 6. Complete the activityalong with the video demonstration. Sign, date, and take an imageof your final product and include with this lab report.

raspberrydeer652

HELP WITH BIO MULTI CHOICE QUESTIONS:

QUESTION 2

Which of the following structures discussed in class is NOT found on all bacteria?
Flagella
Capsid
Fimbria
Plasma membrane

QUESTION 3
You are presented with a strain of bacteria that is resistant to the antibiotic penicillin. What steps would you take to confirm that you have a resistant bacterium?
Perform a Gram stain to determine pink stained Gram-positive bacteria.
Perform a Gram stain to determine purple stained Gram-positive bacteria.
Perform a Gram stain to determine pink stained Gram-negative bacteria.
Perform a Gram stain to determine purple stained Gram-negative bacteria.

QUESTION 4
With respect to bacterial growth into a fresh culture tube containing nutrient broth, at which phase do organisms undergo binary fission the most rapidly?
Lag phase
Stationary
Exponential
death

QUESTION 5
How would antibiotic resistance be passed from one bacterium to another bacterium?
Through the flagella via a plasmid.
Through the sex pilus via chromosomal DNA.
Through the sex pilus via a plasmid.
Through the flagella via chromosomal DNA.

QUESTION 6
When an F plasmid integrates into the host chromosome, the strain is referred to as

Hfr.
F'.
F-.
F+.

QUESTION 7
If you remove the peptidoglycan layer from a Gram-positive cell, it would still stain purple with a Gram stain (T/F).
True
False

QUESTION 8
During infection with a bacteriophage, bacterial DNA is packaged into a capsid and will:

be integrated into the genome of a new bacterium upon ligation.
be integrated into the genome of a new virion upon recombination.
be integrated into the genome of a new bacterium upon recombination.
be integrated into the genome of a new virion upon liagation.

QUESTION 9
Which of the following statements best describes most bacteria?
They are generally harmful.
They are limited to living in a few habitats.
They are very common in the environment.
They are responsible for the âcommon cold.â

QUESTION 10
Prokaryotes lack some parts found in eukaryotic cells, including which item?
a nuclear membrane
DNA
one or more chromosomes
a plasma membrane
all of the above

QUESTION 11
With respect to gram negative bacteria, what is the order of the bacterial cell structure from outside to inside?
Thin peptidoglycan layer, plasma membrane

thick peptidoglycan layer, plasma membrane

outer membrane, thick peptidoglycan layer, plasma membrane

outer membrane, thin peptidoglycan layer, plasma membrane

QUESTION 12
In transformation, a piece of DNA from a dead host can be taken up by living host

True
False

BIO-1201 Lecture Notes - Lecture 3: Aureus, Erythromycin, Pilus

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