UF MCB2000 Exam 1 - Study Guide material

What is the purpose of a concept based approach to topics in Microbiology?

Emphasizing skills and concepts that remain important long after students exit the course

Features of microbes

-most consist of a single cell

-contains in its genome the capacity to reproduce its own kind

-too small to be seen by the naked eye

-lack differentiated tissues

-just a few are pathogenic

-the traditional concept of species is not applicable

Roles of microbes

-decompose organic waste

-generate O₂ via photosynthesis

-produce chemical products

-produce fermented foods

-produce products used in manufacturing and disease treatment

-helps to train the immune system to resist disease

Types of microbes

-bacteria

-fungi

-protozoa

-microscopic algae

-viruses

Prokaryotes

-Bacteria

-Archaea

Eukaryotes

-fungi

-protozoa

-algae

Viruses

-do not fit into any of the 3 domains

-obligate intracellular parasites

-need host to survive

-acellular

Human Microbiome Project

To determine the makeup of typical microbiota of various areas of the body, and to understand the relationship between changes in the microbiome and human diseases

National Microbiome Initiative

explores the role microbes play in different ecosystems

3 domains of microorganisms

-Bacteria

-Archaea

-Eukarya

Cyanobacteria

Bacteria that can carry out photosynthesis and fix CO₂

protozoa

-single-celled eukaryotes

-lack a cell wall

-animal like

-water-borne

fungi

-chemoheterotrophs (decompose complex matter)

-air-borne

-eukaryotes

dimorphic fungi

may grow as mycelia or yeast AND are often associated with disease in humans

opportunistic mycosis

fungi harmless in normal habitat but pathogenic in a compromised host

archaea

-unicellular prokaryotes

-extremophiles (halophiles and thermophiles)

-methanotrophs

-methanogens

halophiles

extremophile archaea that require salt concentration of greater than 25%

thermophiles

extremophile archaea that require a temp of greater than 80° C

methanotrophs

archaea that use methane as carbon source

methanogens

anaerobic archaea that produce methane

Louis Pasteur

-disproved spontaneous generation with swan neck flask

-invented pasteurization

Edward Jenner

Developed a vaccine for smallpox by inoculating someone with cowpox

Robert Koch

-Koch's postulates

-microbe --> specific disease

Alexander Fleming

discovered penicillin

spontaneous generation (disproved)

Hypothesis stating that life could arise from nonliving matter.

biogenesis

development of life from preexisting life

microbial ecology

the study of the relationship between microorganisms and their environment

biofilms

-microbes that attach to solid surfaces and grow into masses

-grows on rocks, pipes, teeth, and medical implants

-can cause infections and are often resistant to antibiotics

which parts of bacteria contribute to biofilm formation?

-fimbriae

-pilli

-flagella

-proteins

-polysaccharides

emerging infectious diseases (EIDs)

-zika virus

-MERS

-H1N1 (swine and avian flu)

-MRSA

-ebola (EHF)

ALL cells must have

-a cell membrane with selective permeability

-double stranded DNA

-ability to self replicate

unit of life

the cell

why do viruses not fit into any of the three domains?

-no cell structure/cytoplasm

-no independent reproduction (needs host cell)

-inactive until they infect a host

-cannot generate energy

3 acellular infectious agents

-viruses

-prions

-viroids

List the structures present on a typical bacteria cell

-peptinoglycan in cell wall

-slime layer or capsule (glycocalyx)

-cytoplasm

-ribosomes

-inclusions

-nuceloids/chromosomes

-cytoskeleton

-endospore

-plasmid

micro compartments

-fimbriae, flagella, pili

List the structures every bacterium MUST have.

-cytoplasmic membrane

-ribosomes

-nucleoid/chromosomes

plasmid

small, circular piece of DNA located in the cytoplasm of many bacteria

endospore

dormant form of bacteria

prokaryotic cells

-binary fission

-DNA: one circular, some two circular, some linear, NOT in a membrane

-no organelles

-small ribosomes (70s)

-glycocalyx as slime layer/capsule

-peptinoglycan cell walls

eukaryotic cells

-mitosis

-paired linear DNA

-has organelles

-polysaccharide cell walls, when present

-glycocalyx

-large ribosomes (80s)

endosymbiosis

-A theorized process in which early eukaryotic cells were formed from the infoldings of simpler prokaryotes

-includes chloroplasts and mitochondria

light microscopy

-any kind of microscope that uses visible light to observe specimens

-compound light

-darkfield

-phase contrast

-flourescence

-confocal

differences between light and electron microscopy

-the magnification is larger on the electron

-the resolution is better on the electron (in the range of nanometers instead of micrometers)

-the illumination is from a beam of electrons vs. a visible light source

TEM microscopy

-reveals interior of cell

-beam of electrons passed through the specimen sections

SEM microscopy

-scans surface of entire specimen

-electron gun produces a beam of electrons

fluorescence microscopy

-short wavelength of light

-cells are stained

-used as a diagnostic tool to ID infectious diseases

magnification vs. resolution

-magnification makes the object larger

-resolution makes the object clearer

smear

-a thin film of material containing microorganisms is spread over a slide

-the sample is then fixed via a bunson burner to kill the microorganisms

wet mount

a glass slide holding a specimen suspended in a drop of liquid (as water) for microscopic examination

positive stains

dye binds to the specimen's negatively charged surface

negative stains

stain the background

basic dye

positive stain

acidic dye

negative stain

differential staining

-Gram staining

-acid-fast staining

-not useful for bacteria without cell walls

structural staining

-stains a particular structural component of a bacterial cell one color while the bacterial cell is stained a contrasting color

-acid fast

-capsule

-flagella

-endospore

gram staining

A method of differentiating bacteria into Gram-positive and Gram-negative.

gram staining steps

1. crystal violet

2. iodine

3. alcohol

4. safranin

bacilli

Rod shaped bacteria

cocci

spherical bacteria

spiral

vibrio, spirillum, spirochete

vibrio

spirillum

spirochete

important features of the plasma membrane

-lipid bilayer

-integral/peripheral proteins

-glycolipids/glycoproteins

-cholesterol

which molecules can easily pass through the plasma membrane?

-nonpolar (O2, CO2, N)

-uncharged polar (H2O)

-lipid soluble molecules

gram positive cell wall

-thick layers of peptinoglycan

-teichoic acids

-NAG and NAM polysaccharides

gram negative cell wall

-thin layers of peptinoglycan

-unique outer membrane

-lipid A, LPS, endotoxin

-periplasmic space

-porins

-more resistant to chemicals, so infections like sepsis are more dangerous

True or false: not all bacteria have cell walls

true

acid fast cell walls

thick waxy cell wall-like

mycobacterium

TB, acid fast cell

mycoplasmas

no cell wall

importance of protein molecules

They act as enzymes, provide structural support, regulate cellular processes, surface receptors, and are carriers

polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

primary structure

peptide covalent bonds

secondary structure

Either an alpha helix or beta pleated sheet held together by peptide and hydrogen bonds

tertiary structure

both helix and pleat, ionic, peptide, and hydrogen bonds (globular and fibrous)

quaternary structure

Results from two or more polypeptide subunits (alpha and beta chains)

importance of hydrogen bonds in DNA and RNA

maintains bonds between the complementary base pairs

pili vs. flagella

-pili adhere

-flagella move

-both are found on surface

phospholipid bilayer

composed of phospholipids with polar heads and non polar tails

true of false: ribosomes are involved in protein synthesis

true! Ribosomes facilitate translation, where mRNA is used as a template to synthesize proteins

true or false: all bacteria must have a cell membrane

true!

true or false: all bacteria must have a cell wall

false!

true or false: cell morphology is determined by its cell wall structure

true! think about the differences between gram neg. and gram pos. bacteria

endergonic reaction

-Reaction that absorbs energy

-forms bonds

exergonic reaction

-reaction that releases energy

-breaks bonds

-spontaneous

synthesis reactions

-small molecules --> large molecules

-anabolism

-dehydration

decomposing reactions

-large molecules --> small molecules

-catabolism

-hydrolysis

6 major bio elements

-hydrogen (all organic)

-carbon (all organic)

-nitrogen (proteins, DNA/RNA)

-oxygen (everywhere)

-sulfur (proteins)

-phosphorus (DNA/RNA)

polysaccharide components

-carbon

-hydrogen

-oxygen

lipid components

-carbon

-hydrogen

-oxygen

protein components

-carbon

-hydrogen

-oxygen

-nitrogen

-sometimes sulfur

nucleic acid components

-phosphate group

-sugar

-nitrogenous base

what are most hormones composed of

proteins, peptides, or steroids

chromosome

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

gene

A segment of DNA on a chromosome that codes for a specific trait

genome

all of an organism's genetic material

2 types of nucleic acids

DNA and RNA

organisms with a cell wall

plants, fungi, and some bacteria

polysaccharide examples & functions

-starch

-glycogen

-cellulose

-cell structure and energy source