Cumulative Final Exam Review Questions

What is a Microorganism?

Very small organism

What does it mean that microorganisms are ubiquitous and diverse?

Microorganisms vary in all sorts of ways (like size, appearance, and rates of reproduction)

What invention came about in the 1600’s that was essential to the discipline of microbiology?

Microscope

What are Koch’s postulates and the Germ Theory of Disease?

Guidelines for establishing that microbes cause specific diseases

Germ Theory — theory that many diseases are the result of microbial infection; microbes are causative agents

What microorganisms did Robert Koch originally work with to formulate Koch’s postulates?

The causative agents of Anthrax, Cholera, and Tuberculosis

What is Taxonomy?

Identification, classification, description, and naming of a group of organisms

What is Phylogeny?

Establishing the evolutionary relationship between groups of organisms

What are the three domains of life?

Which of the domains contain microorganisms?

Archaea, Bacteria, and Eukarya

All three contain microorganisms

What is Binomial Nomenclature?

How do you correctly write Genus and Species names?

Universal convention for the scientific naming of organisms using Latinized names for genus and species

Genus species or G. species

How does the definition of species change when describing Prokaryotes vs. Eukaryotes?

Prokaryote — determined by degree of genetic relatedness

Eukaryote — defined by two organisms that can breed and produce fertile offspring

What are the relative sizes of different groups of microorganisms?

(Check Binder on Sticky Note)

What are the characteristics of a Prokaryotic cell?

An organism whose cell structure does not include a membrane-bound nucleus

What are the characteristics of Archaea?

Domain of life separate from the domains Bacteria and Eukarya

What are the characteristics of a Eukaryotic Cell?

Organism made up of one or more cells that contain a membrane-bound nucleus and organelles

Do all domains contain pathogens?

No? Maybe not Archaea

What was the importance of Miller and Urey’s work?

Demonstrated that organic molecules could be created from inorganic molecules believed to be present in the early Earth environment

Why do cells need access to macronutrients?

Macronutrients are the components needed to build cellular macromolecules

What is the difference between Ionic, Covalent, and Hydrogen bonds?

Ionic — results from transfer of one or more electrons between atoms

Covalent — occurs when two atoms share electrons

H-Bonding — weak electrostatic attraction between one electronegative atom and a hydrogen atom covalently linked to a second electronegative atom

What is the relative strength of Ionic, Covalent, and Hydrogen bonds?

Ionic — relatively weak

Covalent — strong

Hydrogen Bonds — relatively weak

Strong > Ionic > Covalent > H-Bond > Weak

How does bonding work within a molecule of water?

How does this bonding compare between molecules of water?

Covalent bonds between O—H

Stronger than between water

How are Polymers constructed?

What types of bonds are used to construct these polymers?

What Monomers are used to construct each Polymer?

Made of multiple monomers linked by covalent bonds

Covalent bonds

Nucleic Acids —> nucleotides

Carbohydrates —> Monosaccharides

Proteins —> Amino Acids

What is the structure of a Lipid?

What is a Phospholipid?

Glycerol backbone and fatty acid tails

Complex lipid that contains a phosphate group

What does it mean if something is Hydrophobic?

Hydrophilic?

Hydrophobic — does not like water

Hydrophilic — loves water

What changes would need to be made for a Phospholipid to be more or less fluid?

Change in temperature

Higher Temp. = More Fluid

Lower Temp. = More Rigid

What are Phospholipids used to construct?

Biological membranes (ex. Phospholipid Bilayer)

How are Amino Acids grouped?

What is the significance of the R Group in driving protein folding?

According to the chemical properties of their R groups

Polar R Groups = H-Bonds to stabilize the secondary structure

Nonpolar R Groups = drive folding process through hydrophobic interactions

What are the different levels of protein structures?

Primary — bonding sequence of amino acids in a polypeptide chain

Secondary — structure stabilized by hydrogen bonds; can be an alpha-helix or a beta-pleated sheet

Tertiary — large-scale, three-dimensional structure of a polypeptide

Quaternary — formed by the combination of several separate polypeptides or subunits

What does it mean if a protein becomes denatured?

Protein has lost its secondary and tertiary structures (and quaternary structure, if applicable) without the loss of its primary structure

What are the different types of Nucleic Acids?

DNA and RNA

What is Spontaneous Generation?

What did Louis Pasteur do to disprove that microorganisms spontaneously generate?

Says that living organisms could generate from non-living matter

Used a swan-neck flask to prevent outside air from entering the flask (no air-borne contaminants)

What is the Cell Theory?

Says that:

1. All cells come from other cells (Biogenesis)

2. Cells are the fundamental units of organisms

What is the Endosymbiotic Theory?

What are the lines of evidence that support that theory?

Theorizes that Mitochondria and Chloroplasts come Prokaryotic origin

Lines of evidence include:

• Ribosomes (similar to bacterial ribosomes)

• Size (similar to bacterial cell)

• Division (autonomous, binary fission)

• DNA (contains its own DNA)

How are Prokaryotes and Eukaryotes similar?

Both contain:

• Ribosomes

• Genetic Material

• Cytoplasm

• Plasma Membranes

• Carbohydrates and Proteins

What is a Capsule?

Why might it be considered a virulence factor?

An outer layer of polysaccharides that covers the cells of many different bacterial species

Enhances the ability of bacteria to cause disease by preventing phagocytosis

What are the different types of flagella arrangements?

Monotrichous — single flagellum, usually at one pole

Amphitrichous — single flagellum at both ends

Lophotrichous — two or more flagella at one or both poles

Peritrichous — flagella over the entire surface

What is Chemotaxis?

Directional movement of a cell in response to a chemical attractant

What is Peptidoglycan?

Where can it be found?

What is it constructed from?

Main component of bacterial cell walls

Found on the outside of the Cytoplasmic Membrane

Made of long chains of alternating NAG and NAM

Which components do you find in both Gram-Positive and Gram-Negative bacterial cell walls?

Which components would you find in one but not the other?

Gram-Positive:

• Many layers of Peptidoglycan

• No outer membrane

• Teichoic Acids (- Charge)

  • Lipoteichoic Acid

  • Wall Teichoic Acid

Gram-Negative:

• Little layers of Peptidoglycan

• Has outer membrane

• Lipoproteins

• Periplasm

• Lipopolysaccharide

• Phospholipids

• Porins

How do Mycobacteria differ from other bacteria?

What special type of staining procedure is used to identify them?

Unique cell wall structure

• Thin layer of Peptidoglycan

• Waxy lipids

• Polysaccharide links

Acid-Fast Staining

What is a Lysozyme?

Enzyme that breaks down and digests Peptidoglycan in cell walls

What antibiotics work on cell wall synthesis?

Beta-Lactams

• Penicillin

• Cephalosporins

• Carbapenems

• Monobactams

Vancomycin

Bacitracin

What is the Plasma Membrane constructed from?

How are plasma membranes related to many disinfectants?

Lipids, proteins, and carbohydrates

Many disinfectants work by disrupting the plasma membrane

What does it mean that the plasma membrane is selectively permeable?

Some substances are able to pass through the membrane, while other substances are not able to pass through

How do molecules move along a concentration gradient?

Move down the concentration gradient

What is Osmotic Pressure?

How does the concentration of solutes outside the cell affect the movement of water from the cell?

Why is it important that cells be able to control the movement of water / molecules across the cell membrane?

Force or pressure generated by water diffusing across a semipermeable membrane, driven by differences in solute concentration across the membrane

Yeah

Cause if they don’t, they die

What is the difference between active and passive transport?

Active Transport — movement from LOW concentration to HIGH concentration

Passive Transport — movement from HIGH concentration to LOW concentration; does not require something to facilitate the diffusion

What is the Nucleoid?

Condensed area of DNA found in Prokaryotic Cells

How does the inside of a Eukaryotic cell differ from the inside of a Prokaryotic cell?

it just does

What is a Plasmid?

How does it differ from the chromosome?

Small, circular, double-stranded DNA molecules

They are EXTRACHROMOSOMAL DNA (not part / outside of the chromosome)

What is a Ribosome?

What is the general structure of a Ribosome?

Macromolecular machine made up of Proteins and rRNA

(Check photos)

Compare and Contrast Prokaryotic and Eukaryotic ribosomes.

Prokaryotic — in the Cytoplasm, 70S

Eukaryotic — 80S

What is the function of an Endospore?

Do all bacteria form Endospores?

What are some key terms related to Endospore Formation?

Protects the genome when conditions become unfavorable

Not all bacteria can form endospores

Vegetative Cell — cell that is actively growing and dividing, and does not contain an endospore

Sporulation — process by which a vegetative cell produces a dormant endospore

Germination — process of an endospore returning to the vegetative state

What is the difference between Transient and Normal microbiota?

Transient — microorganisms, sometimes pathogenic, that are only temporarily found in the human body

Normal / Resident — microorganisms that constantly live in the human body

Explain the Endosymbiotic Theory.

mitochondria and chloroplasts go brbrbrbbrbrrrrr

What is significant about Cyanobacteria?

What is their contribution to the early Earth environment?

Heterocysts

Thought to be one of the first to generate oxygen

What is a Heterocyst?

Differentiated cyanobacterial cell that carries out nitrogen fixation

What are Lactic Acid bacteria?

Where are these bacteria usually found / used?

Bacteria that can ferment carbohydrates into Lactic Acid

Usually used in food production and can be found in the human microflora

What are the different shapes and arrangements of bacteria?

(Check Binder at Sticky Note)

What is a Virus?

Acellular microorganism, consisting of proteins and genetic material (DNA or RNA), that can replicate itself by infecting a host cell

How does the size of a virus compare to that of other organisms, such as Prokaryotes and Eukaryotes?

Very, very small compared to them

Define the following:

• Acellular

• Host Range

• Bacteriophage

• Virion

Acellular — Not made up of cells (contains no Phospholipid Bilayer / cell membrane)

Host Range — range of specific host cells needed to replicate

Bacteriophage — virus that specifically infects bacteria

Virion — individual viral particles

What is the basic structure of a virus?

1. Genetic Material

2. Protein Coat

What is the difference between an enveloped virus and a nonenveloped virus?

Enveloped — virus formed with a nucleic-acid packed capsid surrounded by a lipid layer

Nonenveloped — naked virus

What different types of genetic material are found in viruses?

DNA or RNA (BUT NEVER BOTH)

Which domains of life can be infected by a virus?

All domains

How are viruses transmitted?

yes

What is the difference between a Lytic vs. Lysogenic phase of viral infection?

Lytic Phase — reproduction of viruses using a host cell to manufacture more viruses; the viruses then burst out of the cell

Lysogenic Phase — incorporation of the viral genome into the host cell genome, infecting it from within

What are the steps of viral infection and replication?

1. Infection

2. Incorporation of Phage DNA into Host Genome

3. Cell Division

4. Prophage DNA cast out, enters Lytic Cycle

5. Phage DNA Replication

6. Assembly

7. Cell Lysis, releases Phages

What is a Plaque?

Clear area on bacterial lawn caused by viral lysis of host cells

What is a Prophage?

Phage genome that has incorporated into the host genome

What is Transduction?

Mechanism of horizontal gene transfer in bacteria in which genes are transferred through viral infection

What is Reverse Transcriptase?

What does it do?

Enzyme that is specific to retroviruses, such as HIV

Converts RNA template genome into DNA

What is a Viroid?

What does it infect?

Infectious nucleic acid particles (RNA)

Infects plants

What is a Prion?

Infectious proteins

Are viruses exclusively “bad”?

Some can be harmless

Define:

• Chemotrophs

• Phototrophs

• Autotrophs

• Heterotrophs

Chemotrophs — gets its energy from the transfer of electrons originating from chemical compounds

Phototrophs — gets its energy from light

Autotrophs — converts inorganic carbon dioxide into organic carbon

Heterotrophs — uses fixed organic carbon compounds as its carbon source

What is Metabolism?

All of the chemical reactions inside of a cell

What is Anabolism?

Catabolism?

Anabolism — chemical reactions that convert SIMPLE molecules into more COMPLEX ones

Catabolism — chemical reactions that break down COMPLEX molecules into more SIMPLE ones

How do enzymes facilitate chemical reactions?

What happens to the energy of activation?

Increases the rate of a reaction by DECREASING the energy of activation

What is the difference between competitive and noncompetitive inhibition?

Competitive — binds to the active site to prevent substrate binding

Noncompetitive — binds to allosteric sites to induce conformational change and prevent enzyme function

What is the active site of an enzyme?

Location within an enzyme where substrate(s) bind

What does it mean that enzyme interactions are specific?

One enzyme binds to a very limited / specific number of substrates

Why do temperature and pH have an effect on enzyme activity?

Extreme temperatures and pH can cause enzymes to denature and affect their performance

Would Sulfanilamide be an example of a competitive or noncompetitive inhibitor?

Competitive Inhibitor

What is feedback inhibition?

Product of a metabolic pathway binds to an enzyme early on in the pathway, preventing the synthesis of the product

What is Oxidation?

Reduction?

How are they coupled together?

Oxidation is Loss, Reduction is Gain (of a proton / H+)

Coupled together into a Redox reaction

What reactions drive Metabolism?

Redox Reactions

What is the difference between Oxidative Phosphorylation and Substrate-Level Phosphorylation?

What is the end result of both processes?

Oxidative — mechanism for making ATP that uses the potential energy stored within an electrochemical gradient to add Pi to ADP

Substrate-Level — direct method of ATP production in which a high-energy phosphate group is removed from an organic molecule and added to an ADP molecule

End result of both is ATP

What is Glycolysis?

What is the starting molecule and what are the end products?

Glycolysis — breaking down of sugar

Starting molecule is Glucose

End products:

• 2 Pyruvate

• 2 NADH

• 2 ATP per Glucose

Do all organisms have the same pathway for the breakdown of Glucose?

What other pathway is often used by Enteric bacteria?

Why is this other pathway used?

No

Entner-Doudoroff Pathway

Used due to the abundance of Gluconate in the gut

What happens to Pyruvate before it can enter the Citric Acid Cycle?

What are the products of the Citric Acid Cycle?

Converted into Acetyl-CoA

End products:

• 3 NADH

• 1 FADH2

• 1 ATP

• CO2

How are the products of Glycolysis and the Citric Acid Cycle used to drive the ETC?

Electrons for the ETC come from the electron carriers NADH / FADH2, which passed electrons along through Glycolysis and the Citric Acid Cycle

Where is the ETC located in Eukaryotes and Prokaryotes?

Prokaryotes — Plasma Membrane

Eukaryotes — Inner Mitochondrial Membrane

How does the ETC work to drive ATP production?

Generates a proton motive force that is used to drive the ATP production

What is the terminal electron acceptor in Aerobic Respiration?

Oxygen

What is the difference between Aerobic Respiration, Anaerobic Respiration, and Fermentation?

Which of these uses an ETC?

Aerobic — use of an oxygen molecule as the final electron acceptor of the electron transport system

Anaerobic — use of a non-oxygen inorganic molecule as the final electron acceptor at the end of the electron transport system

Fermentation — uses an organic molecule as a final electron acceptor to regenerate NAD+ from NADH such that glycolysis can continue

Aerobic and Anaerobic use an ETC

What would be the electron acceptor in Fermentation?

Pyruvate

How are the end products of Fermentation important?

Cause economic importance or something idk

How much ATP is produced through Fermentation?

Why does the organism ferment / not stop with the production of Pyruvate?

Why does it convert the Pyruvate to something like Lactic Acid?

2 ATP per Glucose

So that it can regenerate NAD+ from NADH

When oxygen is missing, it allows SUBSTRATE-LEVEL PHOSPHORYLATION TO CONTINUE

What molecules transport electrons to the ETC in Aerobic Respiration?

NADH and FADH2