Micro Final Exam

Describe Biofilm

Describe Biofilm

A microbial community that usually forms as a slimy layer on a surface.

Describe Protozoans

eukaryotic; unicellular; live as free entities or parasites

Describe viruses

acellular; replicate only inside a living host cell

Describe algae

eukaryotic; cell walls made of cellulose; includes diatoms, seaweed, and kelp; energy from photosynthesis

Describe Archaea

prokaryotic; cell walls made of pseudomurein (some do not have a cell wall); none known to be pathogenic; found in extreme environments

Describe Fungi

eukaryotic; cell walls composed of chitin; get energy by absorption (do not perform photosynthesis)

Describe Bacteria

prokaryotic; cell walls made of peptidoglycan

Describe Helminths

eukaryotic; worms

What are the three categories of archaea

Extreme halophiles, extreme thermophiles, and methanogens

What are the three domains of life?

Eukarya, Archaea, and Bacteria

Describe the scientific accomplishments of Anton Van Leeuwenhoek

Sketched living microbes which he observed with a simple microscope

Describe the scientific accomplishments of Pasteur

Used S-shaped flasks to support biogenesis and disprove spontaneous generation

Describe the accomplishments of Carrolus Linnaeus

Developed systems to name organisms

Describe the scientific accomplishments of Joseph Lister

Developed aseptic techniques to prevent surgical wound infections

Describe the scientific accomplishments of Edward Jenner

Developed the first vaccine (developed for smallpox)

Describe the scientific accomplishments of Ignaz Semmelewis

Proposed that physicians should wash their hands before interacting with women in labor

Describe the scientific accomplishments of Robert Hooke

reported that living things were made of cells after viewing slices of cork

Describe the scientific accomplishments of Rudolf Virchow

Cells arise from preexisting cells

Protons

positive charge; in the nucleus

Neutrons

neutral charge; in the nucleus

Electrons

negative charge; moving around the nucleus in the electron cloud

atomic number

number of protons

atomic mass

number of protons and neutrons

dehydration synthesis

Smaller molecules are combined into a larger molecule

Biosynthesis

Smaller molecules are combined into a larger molecule

Exchange reactions

Two molecules are broken down and then the pieces are rearranged and combined into new molecules

Reversible Reaction

A reaction which occurs in both directions at the same time

Hydrolysis

A larger molecule is broken into smaller pieces

Carbohydrates

Monosaccharides and disaccharides provide an energy source to fuel cell activities. Eukaryotic cell walls are composed of polysaccharides

Protein

Enzymatic activity, metabolic regulation, structural support, cell movement, cell transport, pH buffering, antibodies.

Lipids

Hydrophobic molecules, important in cell membranes

Nucleic acids

DNA is double-stranded helix, carries genetic information, determines inherited characteristics.

RNA is single stranded and carries information from DNA to ribosomes to create proteins

Protein Denaturation

Change in structure of a protein due to temperature or pH changes. The unfolded protein will be nonfunctional.

Compound light microscopy

Has a series of lenses. Can examine some fine details on small specimens.

Darkfield Illumination

Produces light objects against a dark backround. Because cells don’t have to be stained, it is useful to examine live microbes.

Phase contrast microscopy

Brings together two sets of light rays. Useful to examine living organisms and internal cell structures.

Fluorescence microscopy

Uses fluorescently-tagged antibodies; useful to diagnose the presence of a particular microbe

Scanning microscopy

Uses sound waves

Electron microscopy

Uses electrons which has a shorter wavelength than light, which yields better resolution

How do you determine total magnification of a microscope?

Multiply magnification of objective lens x magnification of ocular lens

Why is immersion oil used in microscopy?

It prevents light from bending, which increases the resolution of the image

What are two ways to fix a slide?

heat or alcohol

Gram- Positive bacteria

Thick peptidoglycan layer; tend to be killed by penicillin and detergents; appear blue/purple in Gram strain

Gram negative bacteria

thin peptidoglycan layer; outer membrane which contains the endotoxin Lipid A; more resistant to penicillin and detergents; appear pink/red in Gram stain

acid fast stain

Binds to bacteria that have a waxy material in their cell walls

Acid-fast microbes appear red in an acid fast stain

Identifies bacteria in the genus Mycobacteria or Nocardia

strepto

chain

staphylo

cluster

diplo

groups of 2

tetra

groups of 4

coccus

spherical

bacillus

rods

vibrio

curved rods

flagella

long, exterior appendages that propel bacteria

axial filaments

Inner flagella that cause twisting movement of spirochetes

glycocalyx

A sugar coat which surrounds a cell

cell wall

Glycoprotein network which gives bacterial cells their shape and prevents osmotic lysis

pili

Allows bacteria to horizontally transfer DNA

capsule

A glycocalyx which is firmly attached to the cell wall; prevents phagocytosis

fimbriae

Hair-like appendages that allow bacteria to adhere to each other and to other surfaces

What causes a cell to sporulate (form an endospore)?

Harsh conditions, such as the depletion of essential nutrients

mitochondria

produces ATP from food

chloroplasts

used in photosynthesis

lysosomes

Provide an isolated environment for dangerous chemical reactions

endoplasmic reticulum

Synthesis of proteins, carbohydrates, and lipids; detoxification of drugs or toxins

Golgi Apparatus

modifies secretions from endoplasmic reticulum; transports vesicles to be released out of cell, become part of plasma membrane, or develop into a lysosome

nucleus

Where DNA is stored and where RNA is transcribed

hypertonic solution

Water will flow out of the cell, leading to plasmolysis

hypotonic Solution

Water will flow into the cell, leading to osmotic lysis/bursting

Isotonic solution

Water will flow both into and out of the cell at equilibrium

Describe endosymbiotic theory

Larger bacteria engulfed smaller bacterial cells, developing the first eukaryotes. Ingested aerobic bacteria became mitochondria. Photosynthetic bacteria were ingested and became chloroplasts.

What is activation energy?

The energy required to break bonds in the reactants and form new bonds in the products

glycolysis

Occurs in cytoplasm of prokaryotic and eukaryotic cells

One molecule of glucose is oxidized to 2 molecules of pyruvic acid

kreb cycle

Occurs in the cytoplasm of prokaryotic cells and the mitochondrial matrix of eukaryotic cells.

Acetyl is completely oxidized to Carbon dioxide.

NADH and FADH2 produced in the Krebs Cycle carry energized electrons to the electron transport chain.

Describe chemiosmosis in the electron transport chain.

Electrons pass down the electron transport chain as H+ are pumped across the membrane. The H+ diffuse back across the membrane through an enzyme, producing ATP.

What is the role of ATP synthase

Used in the electron transport chain to generate ATP through oxidative phosphorylation

amphibolic pathway

A metabolic pathway that bridges both the breakdown and synthesis of macromolecules. Whether it runs as catabolic or anabolic will depend on what molecules are present in the cell and the environment surrounding the cell.

Psychrophile

Live in polar temperatures

Psychrotroph

Live in refrigeration temperatures. May spoil the food in your refrigerator.

Mesophile

Live at body temperatures. Includes most human pathogens

thermophile

heat loving microbes

hyperthermophiles

Extreme thermophiles (almost boiling water)

Obligate aerobes

Require oxygen to live. Produce more energy and nutrients than anaerobic bacteria

Facultative anaerobes

Use oxygen when available, but can continue growing in the absence of oxygen

Obligate anaerobes

Bacteria that cannot use oxygen and are killed by oxygen

Aerotolerant anaerobes

Cannot use oxygen but can survive its presence

Microaerophiles

Require oxygen but at concentrations lower than those in the air

What is quorum sensing?

Cell-to-cell chemical communication. Bacteria secrete a chemical signal which is received by other bacteria. Allowing them to coordinate their activity.

reducing media

Remove oxygen, allowing anaerobic organisms to be cultures

complex media

Exact composition is not known, but it contains all the necessary components to support diverse microbial life.

selective media

Suppresses the growth of unwanted bacteria/encourages the growth of desired microbes

Differential media

Medium that makes it easier to distinguish colonies of the desired organism; media or colony will change color

refrigeration

bacteriostatic

lyophilization

bacteriostatic

autoclaving

bactericidal

boiling

bactericidal

Serial dilution

Diluting the original sample so that bacteria can be counted on plates

filtration

Passing liquid through a screen (filter) which traps bacteria, and then counting how many colonies are grown

turbidity

Measures the cloudiness of a suspension. More bacteria will make a suspension cloudier, allowing less light to pass through.

pour plate count

Bacteria are mixed into a melted medium, then poured onto a plate to solidify; individual counties growing on or in the medium can be counted.

lag phase

Period of little/no cell division while cells are preparing for growth