Medical Microbiology Final Exam

The basic functional unit of life is a:

cell

The process of maintaining a stable internal environment is called:

homeostasis

Protist, fungi, and helminths are all part of which domain of life?

Eukarya

which domain of life does Vibrio cholera belong to:

bacteria

This type of bacteria is shaped like a rod:

bacillus

These are unicellular prokaryotes that have no known human pathogens and no peptidoglycan in their cell walls:

archaea

This type of bacteria is stained purple by the gram stain procedure because of a very thick layer of peptidoglycan in their cell walls.

gram +

Almost all viruses must be viewed with ____ because of their extremely small size.

electron microscopy

These are small circular units of DNA the reside in the cytoplasm of cells.

plasmids

This term describes a bacterium that has two flagella on each end of the cell:

amphitrichous

3 multiple choice options

A staphylococcus bacteria will appear under a microscope as:

grape-like clumps of spheres

3 multiple choice options

The main body of DNA in a bacterial cell is contained in one large circular chromosome called a:

nucleoid

3 multiple choice options

Very reduced cores of genetic material that can survive long periods of time and harsh conditions are called:

endospores

3 multiple choice options

An acellular agent composed of protein and genetic material that requires a host to replicate is called a:

virus

3 multiple choice options

This organelle is the sight of cellular respiration and energy production:

mitochondria

3 multiple choice options

This type of bacteria contains only a small layer of peptidoglycan in its cell wall, an outer membrane, and is typically more difficult to treat.

gram -

3 multiple choice options

This part of a bacteria looks like a long tail and is typically used for movement:

flagellum

3 multiple choice options

What is another term for a disease-causing agent?

pathogen

3 multiple choice options

_____ are the site of protein synthesis in the cytoplasm.

ribosomes

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______ is the site of protein processing and modification after proteins leave the ER.

golgi apparatus

3 multiple choice options

What is the difference between a prokaryotic and eukaryotic cell?

Eukaryotes: have nucleus, multicellular or unicellular

Prokaryotes: unicellular

Classically, viruses are not considered to be living organism. Explain why not with reference to the six characteristics of living things we talked about in class.

1. respond to environment

2. grow and develop

3.produce offspring

4. maintain homeostasis

5. complex chemistry

6. consists of cells

Viruses require a host to reproduce and cannot survive on their own

isotonic

when the concentration of two solutions is the same

hypertonic

concentration is higher outside the cell, water moves outside the cell and cell shrinks

hypotonic

when concentration is higher inside so the cell swells because water moves inside the cell

horizontal gene transfer

The transfer of genes from one genome to another through mechanisms such as transposable elements, plasmid exchange, viral activity, and perhaps fusions of different organisms. This is a problem in the medical field because it can create antibiotic resistant bacteria and mutant genes

Four differences between a bacterial cell and human cell

bacterial: prokaryotic, nucleoid, unicellular, isolated

human: eukaryotic, nucleus, multi-celled, in a group

Gram stain steps

1. crystal violet- stain the cell

2. iodine- seals crystal violet into cell wall

3. alcohol- wash away what does not stick to cell wall

4. safranin- stains cell so that it shows up

Prokaryotes are described as ubiquitous this means that they:

are found everywhere

3 multiple choice options

Human pathogens are typically classified as this type of symbiotic relationship:

parasitism

3 multiple choice options

Many betaproteobacteria can be described as eutrophs, meaning that they:

need relatively high amounts of nutrients to survive

3 multiple choice options

These bacteria are the causative agents of a majority of stomach ulcers:

helicobacter pylori

3 multiple choice options

These are corkscrew shaped bacteria that contain an axial filament between their inner and outer membranes:

spirochete species

3 multiple choice options

proteobacteria and nonproteobacteria can both be described as:

gram -

3 multiple choice options

This is a microorganism that is not normally pathogenic but can become so when it encounters an immunocompromised individual:

opportunistic pathogen

3 multiple choice options

This bacterial genus is one of the most studied, particularly because it produces more toxins than any other genus

clostridium

3 multiple choice options

Many helminths are passed to human via another organism called a(n):

intermediate host

3 multiple choice options

Diseases caused by fungus infections (ringworm, athletes foot, etc.) are called:

mycoses

3 multiple choice options

Fungi are especially important in microbiology because they are a common source of?

antibiotics

3 multiple choice options

Bacteria replicate themselves via the process of:

binary fission

3 multiple choice options

The outer protein coat of a virus is called a:

capsid

Viruses DO NOT infect:

none of the above

3 multiple choice options

Diseases that are spread from animals to humans are called:

zoonotic diseases

3 multiple choice options

______ viral trans mission is when a virus spreads from host to host.

direct

3 multiple choice options

The person in the lab session before you sneezes, spreading Influenza A all over the benchtop and does not sanitize it after the class is over. Later, you have lab and catch the virus. This is an example of what type of viral transmission.

indirect

3 multiple choice options

This type of virus integrates into the host's DNA using the enzyme reverse transcriptase:

retrovirus

3 multiple choice options

The specificity of a virus for a specific host is called:

viral tropism

3 multiple choice options

Most viruses mutate at a ___ rate.

high

3 multiple choice options

What does it mean to say that an organism is an obligate intracellular pathogen.

obligate intracellular pathogen means that it can only grow and reproduce inside another organism

What are the four steps in the process of binary fission?

1. DNA division

2. cell elongation

3. division septum formed

4. cells separate

Proteobacteria

gram -, alpha, beta, gamma, delta, epslion

nonproteobacteria

gram -, "weird ones", chalmydia, spirochetes, CFB

Gram + bacteria

high G-C content: actinobacteria

low G-C content: clostridia, lactinobaciale, bacilli

Difference between elementary bodies and reticulate bodies in Chlamydia life cycle:

elementary bodies: infectious extracellular form that initiates infection by attaching to host cells

reticulate bodies: larger metabolic form that occurs inside the cell

What does it mean to say that Gram positive bacteria are divided/ categorized by their G-C content?

By the amount of pairs of G-C in their DNA sequence, some have more G-C pairs and some have less.

What does it mean to say that viral tropism can be at the tissue, cell, and host level?

Tropism means something is specific for a host.

Tissue- influenza infecting a lung (not neuron)

Cell- HIV infecting macrophage ( Not neuron)

Host- myonoma infect rabbit (not human)

Explain why viruses having a high mutation rate can be a problem for the medical field.

Having a high mutation rate can create "super bugs" which can then become resistant

Lytic cycle

1. Attachment- surface protein to host

2. Penetration- insert genetic material

3. Biosynthesis- new viral protein made

4. Maturation- grow into mature virus

5. Lysis- cell burst and virus exit

lysogenic cycle

1. attachment

2. penetration

3.encoding- genetic material encoded in host

4. dormancy- leads to biosynthesis in lytic cycle if stressed

99% of cell weight is made up of six different elements. These include all but which of the following.

Lithium (Li)

3 multiple choice options

This biomolecule is especially important for its role in the structure of cell membranes and vessicles:

phospholipid

3 multiple choice options

Proteins are made up of many different amino acids joined by what type of bond?

peptide bond

3 multiple choice options

This type of protein complexes with reactants to make biochemical reactions more energetically favorable:

enzyme

This is the term for all the chemical reactions in a cell:

metabolism

3 multiple choice options

This is the time between the same points of the life cycle between two successive generations:

generation/ doubling time

3 multiple choice options

Within the typical growth curve, this phase is the point at which exponential growth occurs before plateauing off.

log phase

3 multiple choice options

Highly reactive molecules that contain oxygen, are normal byproducts of metabolism, and cause damage over time are:

reactive oxygen species

3 multiple choice options

The _______ region of a gene is the beginning of the gene where RNA polymerase binds to initiate transcription.

promoter

3 multiple choice options

Prokaryotes typically have ______ origin(s) of replication when duplicating their DNA.

one

3 multiple choice options

This type of operon is usually expressed until a repressing transcription factor binds to shut off the gene:

repressible operon

3 multiple choice options

A _______ is any change in the DNA sequence which may be harmful, beneficial or neutral.

mutation

3 multiple choice options

DNA polymerase

is responsible for adding new nucleotides to a growing DNA strand during replication

DNA ligase

repairs gaps in the new DNA strand, especially on the lagging strand

DNA helicase

unwinds the DNA prior to replication

RNA polymerase

is responsible for building the mRNA strand from the DNA template strand during transcription

Catalase

converts hydrogen peroxide (an ROS) to H2 and O2. Its presence is also used for microbe identification

glycolysis

initial step of metabolism. breaks glucose into two pyruvate molecules, generating ATP and NADH while utilizing ATP as well

transition reaction

the process joins pyruvate to coenzyme A while producing one NADH and CO2

citric acid cycle

This step produces the largest number of energetic molecules during metabolism

electron transport chain

in this process the energetic molecules/ carriers produced in the other reactions are converted to ATP through the movement of ions across a membrane and the enzyme ATP synthase.

fermentation

when there is not enough oxygen, organisms can use this process to recycle NAD+ from NADH so that glycolysis can continue

List the four types of biomolecules we talked about and their function in a cell

carbohydrates- quick energy

nucleic acid- stores information

protein- used for energy

lipid- also used for energy (2nd source)

One difference and similarity between DNA and RNA

DNA- double strand

RNA- single strand

Both- stores information

list and describe the four levels of protein structure:

primary- AA structure

secondary- alpha helices and beta pleated sheets

tertiary- where helices and sheets interact

quaternary- where the subunits interact

Describe the EPS and its relationship to biofilms:

EPS is extracellular polymer substance and it provides elasticity to biofilms

Explain what is meant by saying DNA replication is semi-conservative.

what would be the impact of a point mutation changing the last (rightmost) Adenine to Guanine in the above DNA sequence

A point mutation would cause a change in gene expression or alterations in encoded proteins

This level of microbial control reduces and/or destroys microbial load to safe public health levels

sanitization

3 multiple choice options

The ebola virus, a frequently fatal, dangeroous, and exotic pathogen, is considered a(n):

BSL-4 level organism

3 multiple choice options

_______ discovered the first antibiotic (penicillin) in 1928.

Alexander Fleming

3 multiple choice options

An antibiotic's _______ is the concentration of the drug that is both effective and safe for the patient.

therapeutic window

3 multiple choice options

These antibiotics affect many different species of bacteria:

broad spectrum

3 multiple choice options

The specific way an antibiotic affects the bacteria it tatrgets is known as the antibiotic's:

mode of action

3 multiple choice options

Antibiotics that specifically target the cell membrane and are especially useful for treating:

gram -

3 multiple choice options

These are specialized protein pumps in the cell walls of bacteria that grab antibiotics that have entered the bacteria and pump them back out into the extracellular space.

efflux pumps

3 multiple choice options

This is the term for any condition in which the normal structure or functions of an organism are damaged or impaired:

disease

3 multiple choice options

This is the term for the successful colonization of a host by a microbe:

infection

3 multiple choice options

The signs and symptoms characteristics of a disease are called the:

syndrome

3 multiple choice options

Infectious disease that are commonly acquired in hospitals are called:

nosocomial disease

This is the number of cells or virions that are needed to cause an active infection in 50% of the inoculated individuals.

ID50

3 multiple choice options