Biology 205 Miramar College



Exam 1 Study Guide

Note: These learning objectives are intended as a study guide. This is not intended to be the sole source of your studies. This is not necessarily a complete guide and you should be familiar with all topics covered in lecture as well as Independent Study. Focus topics will form the basis of the short answer and essay questions on exams.

CHAPTER 1

- Know introductory material on the ways microbiology has contributed to the understanding of infectious disease, biotechnology, environmental science, and human health

- Describe to contribution of the following to science and microbiology:

Anton van Leeuwenhoek

Robert Hooke Edward Jenner

Louis Pasteur Paul Ehrlich

Robert Koch Alexander Flemming

Joseph Lister

Francesco Redi

- Describe the difference between spontaneous generation and biogenesis

- Explain the significance of the criteria called Koch's Postulates

- Define and give an example of the binomial nomenclature system in proper scientific format

- List the three domains of life and know which kingdoms belong to each domain

-The Center for Disease Control (CDC) and other world health organizations are intensely focused on EIDs and re-EIDs. Describe three different factors that are responsible for the recent increase in EIDs (or re-EIDs) and give microbial examples of each. Which factor do you think will be the biggest contributor to EIDs in the future?

CHAPTER 3

Define the following and be able to convert from one unit to another:

meter (m)

centimeter (cm)

millimeter (mm)

micrometer (µm)

nanometer (nm)

Be able to identify and give the function of the following components of a light microscope:

ocular lens

objective lens

stage

light source

condenser

iris-diaphragm

coarse adjustment

fine adjustment

arm

Define resolving power

Determine the total magnification of a light microscope for different objective lenses

Describe basic characteristics, including most beneficial use, of the following types of microscopy:

brightfield

darkfield

phase-contrast

fluorescence

transmission electron

scanning electron

Define the following:

staining

heat fixation

basic dye

acidic dye

simple stains

differential stains

special stains

mordant

decolorization

Be able to differentiate between Gram (+) and Gram (-) bacteria, both in their stain color and why they stain differently:

To observe specimens under the scope, often times one must rely on staining. One of the most influential and crucial stains might well be the Gram stain. Know the following about the Gram stain:

- Steps used to prepare a slide for staining (smear, air dry, heat fix)

- Steps used in the Gram stain itself, along with reagents used, including the appearance of cells at each step

- Why the Gram stain is a differential stain and not a simple stain

- How cell wall composition results in the differential staining results (see Focus Topic #1 in Chapter 4)

CHAPTER 4

List 4 differences between prokaryotic and eukaryotic cells, and define the terms prokaryotic and eukaryotic.

Define the following:

coccus

bacillus

spirillum

vibrio

diplo- strepto- staphylo-

pleomorphic

Describe the structure and function of the following prokaryotic structures:

capsule (glycocalyx)

flagella

sex pili

attachment pili

axial filaments

ribosomes

Compare the chemical components of the cell walls of Gram + versus Gram -

Describe why the cell wall composition contributes to the results of Gram staining

Describe what aspects of the Gram – and Gram + cell walls contribute to pathogenicity

Define the following:

osmotic lysis

diffusion

osmosis

osmotic pressure

semipermeable membrane

concentration gradient

Describe the purpose and circumstances for endospore formation, including the processes of sporulation and germination.

FOCUS TOPICS:

1. Within the prokaryotes, the cell wall plays a crucial role in both determining the properties of the microbe, as well as the way in which humans attempt to control them. You should know the components of the prokaryotic cell wall and the differences between a Gram positive and Gram negative wall.

2. Based on the properties of prokaryotic cells, provide evidence supporting the endosymbiotic theory.

CHAPTER 6

Be able to define what "growth" refers to in microbiology.

Be able to explain how the following factors affect growth:

temperature

pH

osmotic pressure

Explain the difference in temperature requirements of the following groups of bacteria:

psychrophiles

psychrotrophs

mesophiles

thermophiles

Know the difference between osmotic pressure requirements for:

non-halophiles

extreme halophiles

moderate halophiles

Know the chemical requirements for growth (macro- and micro- elements) and how different organisms acquire these chemicals

Describe the significance/ function of the following forms of oxygen and important enzymes:

superoxide free radicals

superoxide dismutase

peroxide anion

catalase

peroxidase

Differentiate, on the basis of oxygen tolerance and metabolism, of the following groups of bacteria:

obligate aerobes

facultative anaerobes

obligate anaerobes

aerotolerant anaerobes

microaerophiles

Describe the following types of culture media and know the examples given in class:

chemically defined

complex

selective

differential

Describe how a streak plate is used to isolate pure cultures from a mixed culture

Recognize and describe the phases of a typical bacterial growth curve: Lag phase, Log phase, Stationary phase, and Death phase.

Explain general process and advantages of the following methods of measurement of microbial growth:

direct microscopic count

serial dilution and standard plate count

filtration

most probable number

turbidity

Oxygen is a key chemical involved in both metabolic pathways and the growth and survival of microbial cells. Understand and be able to describe the enzymes and metabolic pathways used by obligate aerobes, facultative anaerobes, obligate anaerobes, and aerotolerant anaerobes.

Proper media is essential for working in a microbiology lab, or for culturing pathogenic microbes in a medical environment. You should understand the different types of media used in the laboratory setting (i.e. selective, differential, complex, etc.), know examples of each, and be able to use this information to answer questions such as:

a. What media you would use to isolate Gram negative from a Gram positive bacteria and why?

b. What media would you use to identify E. coli from a stool sample and why?

c. What media would show if Staphylococcus aureus is present in a nasal swab from a patient and why?

CHAPTER 7

Define the following terms of bacterial destruction and suppression:

sterilization

disinfection

antisepsis

degermation

sanitization

bacteriostatic

bacteriocidial

Be familiar with mechanism of action for:

PHYSICAL METHODS:

boiling

autoclaving

dry heat

pasteurization

osmotic pressure

nonionizing radiation

CHEMICAL METHODS:

biguanides

alcohols

halogens

surfactants

organic acids

aldehydes

Given the options of chemical growth control methods shown above, identify which one/s would be optimal for use against a:

a. Spore forming organism

b. Gram-negative bacteria

c. Mycobacterium

d. Virus

Be able to support your answer using mechanisms of action (note: there might be more than one chemical that would work. It is sufficient to identify ONE and provide mechanism of action)

CHAPTER 8/9

Define the term biofilm and give examples of where you would find them in nature, medicine, and industry.

Describe 5 advantages of biofilm formation for a microbe.

Define the following terms:

genetics

genomics

chromosome

gene

genetic code

genetic recombination

phenotype

genotype

intron

exon

Describe the structure and base pairing of DNA.

Know the process of DNA replication in bacteria, including key enzymes (See Figure 8.6).

Know the process of transcription, including key enzymes (see Figure 8.7)

Transcribe and translate from a strand of DNA

Recognize the following mutations and examples given in class:

missense mutation

nonsense mutation

silent mutation

frameshift mutation

Describe the following mutagens and know examples of each:

nucleoside analogs

alkylating agents

deaminating agents

radiation

Explain how a gene may be repressed or induced. Use terminology that includes the following:

promoter

structural genes

operator

operon

regulatory gene

repressor protein

inducer

co-repressor

Describe the lac operon model of E. coli for the lactose operon.

Describe Griffith's experiment demonstrating genetic transformation.

Describe conjugation in bacteria using the following key terms:

F+ cell

F- cell

plasmid

Hfr cell

Describe the different between a temperate (lysogenic) and virulent (lytic) phage and how it results in generalized or specialized transduction

Describe the following:

F plasmids

Resistance plasmids

Virulence plasmids

Operons are gene arrangements unique to prokaryotic organisms. Be able to define an operon, including the roles of promoters, repressors, operators, structural genes and regulatory genes. Explain how these genes and proteins work together to induce expression of a particular gene. Give an example.

There are several gene transfer methods unique to bacteria that have been harnessed for our own use for genetic recombination in the biotechnology and laboratory environment. Describe these gene transfer methods: transformation, transduction, and conjugation. Be sure to include the type/ source of DNA transferred, the mediator of DNA transfer (if any) and any additional requirements. In what situations are these methods useful in the lab?

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