Microbiology Final

Systemic lupus erythematosus is caused by a(n) ______

(SLE), also known simply as lupus, is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body.

Select cellular characteristics exhibited by all bacteria.

1. Cell (cytoplasmic) membrane 2. Bacterial chromosome or nucleoid 3. Ribosomes 4. Cytoplasm

Properly order the stages of clinical infection.

1. Incubation period 2. Prodromal stage 3. Period of invasion 4. Convalescent period

One question about stages of mitosis.

1. Interphase- Before mitosis 2. Prophase- Spindle fibers, Centromere, Chromosome. 3. Early Metaphase 4. Metaphase- Chromosomes line up in the middle. 5. Early Anaphase- Chromosomes pull apart 6. Late Anaphase 7. Early Telophase- Cleavage 8. Telophase- Two cells

Phases of growth curve

1. Lag Phase - Little to no growth. 2. Log Phase - Cells doubling at exponential rate. 3. Stationary Phase - Cell death equals rate of division. 4. Death Phase - Steady decline in population numbers.

Exceptions to Koch's Postulates

1. Some infectious agents are not readily isolated or grown in the lab. 2. If there is no suitable animal model, it is very difficult to prove the etiology. 3. It's difficult to satisfy Koch's postulates for viral diseases because viruses usually have a very narrow host range. 4. Or, perhaps the majority of human infections are polymicrobial. If that's the case, Koch's postulates cannot be satisfied.

Transfer (tRNA), contains codes for:

A clover leaf tRNA to carry amino acids.

Clostridium botulinum

A neurotoxin leading to flaccid paralysis but also used in cosmetics.

Clostridium tetani

A neurotoxin leading to uncontrolled muscle contractions.

Photoheterotroph

A type of microbe that uses sunlight as an energy source and an organic carbon source is called______

Select the statements that are true of inducible operons. (Mark all) A. Inducible operons often contain genes for enzymes that function in catabolic processes. B. Inducible operons are usually in the "turned on" state and are 'turned off' when not needed. C. The inducer is often the product of the enzymes encoded. D. Inducible operons will be "turned on" in the presence of the substrate and turned off in its absence. E. The lac operon is an example of an inducible operon.

A. Inducible operons often contain genes for enzymes that function in catabolic processes. D. Inducible operons will be "turned on" in the presence of the substrate and turned off in its absence. E. The lac operon is an example of an inducible operon.

Select characteristics of biofilms that differentiate them from planktonic (= unattached) bacteria. (Mark all that apply.) A. Microorganisms live singly, independently. B. Microorganisms participate in quorum sensing. C. Microorganisms secrete extracellular material, usually polysaccharides that forms a matrix. D. Microorganisms are readily eradicated using antibiotics. E. Microorganisms exist as part of a diverse interdependent community.

A. Microorganisms live singly, independently. B. Microorganisms participate in quorum sensing. C. Microorganisms secrete extracellular material, usually polysaccharides that forms a matrix. E. Microorganisms exist as part of a diverse interdependent community.

What is active, what is passive immunity?

Active immunity involves your bodies direct response to an unknown pathogen. This response is the production of antibodies specific to the antigen of a particular pathogen. ... Conversely, passive immunity is an immune response which involves antibodies obtained from outside the body.

Vibrio cholerae

An enterotoxin causing loss of electrolytes in intestinal epithelial cells.

Horizontal Gene Transfer

Any transfer of DNA that results in organisms acquiring new genes that did not come directly from parent organisms

Your patient has blood type 0 and needs a transfusion. What choice(s) of donor blood do you have to avoid a transfusion reaction?

Avoid type A & B.

Know sites where normal microbiota is NOT found in humans. Thought to be sterile.

Body fluids (CSF), organs and blood.

tRNA's function in the cell

Brings amino acids to ribosome during translation.

Helical and icosahedral are terms used to describe the shape of a viral ______

Capsid. The capsid encloses the genetic material of the virus.

Which of the following is NOT part of a progressing replication fork (in bacteria)? A. DNA polymerase III B. Leading strand C. Lagging strand D. Catalase E. RNA primase

Catalase

Enzymes act as catalysts to lower which aspect of a chemical reaction?

Catalysts lower the activation energy for reactions.

How T Cells Respond to Antigen

Cell-mediated immunity, do not produce antibodies

Types of Horizontal Gene Transfer in Bacteria

Conjugation, Transformation, Transduction

Reverse transcriptase synthesizes _____

DNA

Slime layer

Diffuse and irregular layer outside of the cell wall, loosely attached to cell surface, water soluble

Capsule

Distinct and gelantinous layer outside of the cell wall, strong/stable, firmly attached to cell surface, may prevent bacteria from being recognized and destroyed by host

After a bone marrow transplant, dendritic cells of the recipient appear to be attacked. The most likely explanation is that ______

Donor and recipient MHC proteins are too different

Conjugation

Donor cell with pilus. Fertility plasmid in donor Both donor and recipient alive Bridge forms between cells in transfer DNA

Transduction

Donor is lysed bacterial cell. Defective bacteriophage is carrier of donor DNA. Live recipient cell of same species as donor.

Which step of PCR synthesizes the complementary DNA strands?

Extension - add DNA polymerase and nucleotides at 72C

Koch's Postulates # 1

Find evidence of a particular microbe in every case of a disease.

In general, how do bacterial flagella work?

Flagellum: propeller for self-propulsion Counterclockwise movement (Run) Cell swims in a smooth, linear direction, toward a stimulus. (Tumble) Flagellum reverses direction, causing the cell to stop and change course.

Golgi apparatus

Flattened membranous sacs that modify, store and route endoplasmic reticulum products.

Cytotoxic T cells. Killer T cell.

For a CD8 killer T cell to become activated, it must recognize a foreign peptide complexed with self MHC- I and mount a direct attack upon the target cell. After activation, the Tc cell severely injures the target cell. This process involves the secretion of perforins and granzymes.

rRNA's function in the cell

Forms the major part of a ribosome and participates in protein synthesis.

What is neuraminidase?

Found on the surface of influenza viruses that enables the virus to be released from the host cell. An enzyme required for influenza virus replication.

Transformation

Free donor DNA (fragment) Live, competent recipient cell.

Hyphae are associated with which organisms?....

Fungi or molds

A fungus is called dimorphic if ....

Fungi that can take on yeast-like cell form or hyphae.

Which antibody isotype is a pentamere (= 5 molecules) and produced early during the adaptive immune response? Which one is typically secreted?

IgM, IgA

Mitochondria

In what organelle would you find Kreb's cycle and the electron transport chain?

Chronic carrier

Individuals who shelter the infectious agent for a long period after recovery because of the latency of the infectious agent.

Asymptomatic carrier

Infected but show no symptoms of disease.

Incubating carrier

Infected but show no symptoms of disease.

Period of invasion:

Infectious agent multiplies at high levels, exhibits greatest virulence, fever, specific signs & symptoms

Which is the initial event that starts the complement cascade (according to the classical pathway)?

Initiation - The classical pathway begins when C1 components bind to antibodies bound to a foreign cell.

Koch's Postulates #3

Inoculate a susceptible healthy subject with the laboratory isolate and observe the same disease.

Koch's Postulates #2

Isolate the microbe from an infected subject and cultivate it in pure culture in the lab.

A major component of gram-negative outer membranes, lipopolysaccharide can stimulate shock and fever and is referred to as...

Lipid portion = Endotoxin

A bacteriophage infection in which the host bacteria are lysed and killed by the infection is called ______.

Lytic

Nucleus

Main site of the genetic material in a eukaryotic cell.

Passive carrier

Medical and dental personnel who must constantly handle patient materials that are heavily contaminated with patient secretions and blood risk picking up pathogens mechanically and accidentally transferring them to other patients.

Translation by ribosomes

Methionine, Arginine, Tyrosine, Leucine

Diapedesis is _____

Migration of intact white blood cells from between endothelial cells of a blood vessel such as a venule out to the tissues

What do cytotoxic T cells do?

Must recognize a foreign peptide complexed with self MHC-I presented to it Mount a direct attack on a target cell exhibiting the same antigen Severely injures target cells. This process involves the secretion of perforins and granzymes. Perforins punch holes in membranes. Granzymes - Death by programmed suicide = apoptosis.

Rough Endoplasmic Reticulum

Network of intracellular membranes with attached ribosomes.

Cytoskeleton

Network of microtubules and microfilaments that serve as structural components within cells.

Ribosome

Organell of protein synthesis in a eukaryotic cell.

Cilia and flagella

Organelles used for motion of pro- and eukaryotic cells.

Convalescent period:

Patient responds to infection, symptoms decline

Bacteria that have flagella dispersed randomly over the surface of the cell are called...

Peritrichous

____ is the clear fluid found in whole blood in which the cells are suspended; however, when the clotting factors are removed it is now called ____.

Plasma, serum

Glycocalyx

Polysaccharide/polypeptide substance external to the cell wall.

During a recent survey, 0.2% of the population showed evidence of a particular respiratory infection. Select the term that is illustrated by this statistic....

Prevalence

Gene regulation can involve a protein repressor that blocks _____ from initiating transcription.

RNA polymerase

Translation

RNA used to produce proteins.

Koch's Postulates #4

Re-isolate the laboratory isolate from this subject.

Convalescent carrier

Recuperating patients without symptoms; they continue to shed viable microbes and convey the infection to others.

What is the most common portal of entry for microorganisms?

Respiratory tract

RFLP (restriction fragment length polymorphism) means _____?

Restriction fragment length polymorphism (RFLP) is a change in the length of restriction fragments due to a single nucleotide polymorphism that alters a restriction site.

What are you going to find inside a mature HIV virus?

Reverse transcriptase Integrase Protease tRNA

Ribosomal (rRNA) contains codes for:

Several large structural rRNA molecules.

A red blood cell placed in a hypertonic medium will do what?_____...

Shrink

Which statements for interferons are true? ....

Small proteins produced naturally by certain WBCs and tissue cells. a, b: many cells including lymphocytes, macrophages, fibroblasts g: T lymphocytes Used in therapy against certain viral infections and cancer Bind to cell surface and change gene expression Involved in defenses against other microbes and in immune regulation.

Carbon dioxide is a by-product of which of the following?...

The Krebs cycle

Prophase

The first and longest stage of mitosis. In this stage the chromosomes become visible and the centrioles separate and move to opposite poles of the cell.

Telophase

The fourth and last stage of mitosis. During this stage the chromosomes gather at opposite ends of the cell and lose their distinct rod-like shapes. Two new nuclear membranes then form around each of the two regions of DNA and the spindle fibers disappear.

Entamoeba

The one-celled organism seen in your microscope moves very slowly, by protruding its cytoplasm. The specimen was taken from a patient having diarrhea. You would predict that the patient has an infection caused by this pathogen:

Metaphase

The second stage of mitosis. In this stage the chromosomes line up across the center of the cell and become connected to the spindle fiber at their centromere.

Anaphase

The third stage of mitosis. In this stage the sister chromatids separate into individual chromosomes and are pulled apart.

Incubation period:

The time from initial contact with the infectious agent to the appearance of first symptoms

You observe that a certain substance can enter E.coli cells. Which additional observations will tell you if this is an active transport and not diffusion or facilitated diffusion?

Transports nutrients against a concentration gradient (or with a concentration gradient at a faster rate) Presence of specific membrane proteins: permeases and pumps (ion pumps) Expenditure of energy

The presence of active motile multiflagellated trophozoites in vaginal or urethral secretion is indicative of infection with_______

Trichomonas vaginalis

Destruction of fetal blood cells following a Rh factor incompatibility is an example of _____hypersensitivity

Type II

The process of dissolving the envelope and capsid to release the viral nucleic acid is called_______

Uncoating

In positive-sense ssRNA viruses, what is the role of the incoming viral RNA strand?

Viral multiplication. + RNA strand in virion is directly translated.

Which are characteristics of B lymphocytes?

When activated by antigen, a B cell divides, giving rise to plasma cells. Mature in bone marrow. Specific surface markers - Immunoglobulin. Circulate in blood in low numbers. Receptors for antigen, immunoglobulin. Distribution in Lymphatic organs - Cortex (in follicles) Require Antigen presented with MHC - No Product of antigenic stimulation - Plasma cells and memory cells. Function - Production of antibodies to inactivate, neutralize, target antigens.

Prodromal stage:

When the earliest notable symptoms of infection appear, vague discomfort, e.g. malaise, fatigue

Glycolysis

Which of the part of the cellular respiration process takes place in the cytoplasm?

The membrane attack stage of the complement cascade involves ______

a ring-shaped protein digests holes in bacterial cell membranes and virus envelopes

What is the end product of beta-oxidation of fatty acids?...

acetyl-CoA - which enters the citric acid cycle. NADH and FADH2, which are co-enzymes used in the electron transport ...

Helper T cells

activate cytotoxic T cells, macrophages, assist B-cell processes

Fomite

any nonliving object or substance capable of carrying infectious organisms, such as viruses or bacteria, and transferring them from one individual to another. Skin cells, hair, clothing, and bedding are common hospital sources of contamination.

Vector

any organism that carries and transmits an infectious agent into another organism. A really famous example is a mosquito.

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

_______ inhibition of an enzyme occurs when the inhibitor mimics the substrate and occupies the active site of the enzyme.

competitive

Regulatory T cells

control the T-cell response

A frameshift is caused by ______ mutations.

deletion and insertion

Among the virulence factors produced by Staphylococcus aureus are hemolysin, coagulase, hyaluronidase, and enterotoxin. Which of these factors contributes to the ability of S. aureus to invade tissues?

hyaluronidase

A sequence of bases within a eukaryotic gene that does not code for protein is called a(n) ___________

intron

Cytotoxic T cells

lead to the destruction of infected host cells and foreign cells

What are examples of exogenous pyrogens?

lipopolysaccharide, which is a component of the cell wall of certain gram-negative bacteria. Of microbial origin.

The most numerous white blood cells that are very phagocytic are _______

neutrophils

In general, most DNA viruses multiply in the host cell's _____, while most RNA viruses multiply in the host cell's _____.

nucleus, cytoplasm

Sequences of DNA that are identical when read from the 5' to 3' direction on one strand and the 3' to 5' direction on the other strand are called______

palindromes

In gel electrophoresis, DNA molecules move toward the ________ electrode because they have an overall ________ charge.

positive, negative

Describe the phases of mitosis.

prophase: chromatin coils making chromosomes metaphase: spindel fibers attach; chromosomes align in middle anaphase: centromeres separate causing chromosomes to pull apart telophase: cleavage furrow is created and chromosomes uncoil again; nucleus forms in each half of cell

Which technique of the measurements of culture density detects turbidity?

spectrophotometry

Pathogenicity

the ability of an organism to cause disease

Virulence

the severity or harmfulness of a disease or poison.