MICRO Chapter 1 and 3 Microorgansims/Bacteria Cell Structure

Cocci

Circle shape and most common

Diplococci

Cocci that appear in pairs

Streptococci

Cocci that form long chains

Staphylococci

Cocci that form grape like clusters

Tetrads

Cocci that form cube like structures

Bacilli

Rod shaped

Streptobacillus

Long chain of rods

Coccobacilli

Short separated rods

Vibrios

Curved rods

Spirochetes

Internal flagelle and very flexible

Peripheral membrane protein

Attached to other proteins

Integral membrane protein

Embedded on the plasma membrane

Passive transport

High to low concentration

Diffusion transport

High to low concentration, usually of small gases

Facilitated transport

High to low concentration, uses protein channels

Active transport

Low to high concentration (against gradient), uses carrier proteins

Primary active transport

Uses ATP hydrolysis to move molecules

Secondary active transport

Uses an ion gradient to move molecules

Group translocation active transport

Chemically modifies molecules (glucose) to stay within the cell

Symporter protein (secondary active transport)

Transports two different molecules across the membrane in the same direction

Antiport protein (secondary active transport)

Transports two different molecules across the membrane in opposite directions

Cell wall

Prevents the cell from bursting and maintains its shape

What is the cell wall made of?

Peptidoglycan

Peptidoglycan

Polymer of disaccharides (cross linked of 4 peptides)

Gram-positive cell wall

Thick layer of peptidoglycan (cell wall anchored to the membrane)

Gram-negative cell wall

Thin layer of peptidoglycan (cell wall located between the inner/outer membranes)

LPS - lipopolysaccharide (gram negative) 3 parts

Lipid A (endotoxin), core polysaccharide (- charge), and O side chain (O antigen)

Porin proteins (gram negative)

Found in the outer membrane, regulating nutrient uptake

Carl Woese

Discovered the third domain of life, “Archaea” using ribosomal RNA analysis

Miller-Urey experiment

Resulted in the synthesis of amino acids (created early world conditions)

RNA world hypothesis

Believed RNA was the original molecule of life

Endosymbiotic theory

Eukaryotic cells evolved from smaller prokaryotic cells engulfed smaller bacteria

Robert hooke

First to observe cells and created the compound microscope (30X magnification)

Antonie van leeuwenhoek

First to observe single cell microbes and created simple microscope (275X magnification)

Spontaneous generation theory

Living organisms emerge from non-living matter

Louis pasteur

Swan neck equipment experiment and vaccination development

Joseph lister

Developed aseptic agents (phenol)

Robert koch

Established that a specific microbe causes a specific disease

Peptidoglycan proteins consist of

NAM and NAG

Lipoteichoic and teichoic acid (gram positive)

LTA holds wall to membrane and TA gives structure to the wall

Capsule

Composed of polysaccharides

S layer

Structured from proteins and prevents osmotic stress

Nucleoid

Composed of DNA binding proteins

Ribosomes

50s and 30s subunits

Pili and fimbriae

Short/thin protein appendage and can attach to surfaces

Flagellum

Allow movement of the bacteria

Chemotaxis

Allows the microbe to move towards a stimulant or away from repellant (run or tumble)

Monotrichous flagellum

One flagella

Peritrichous flagellum

Flagella all over

Lophotrichous

Flagella on one end

Endospores

Inactive states in bacillus and clostridium

Endospores are triggered by?

Lack of nutrients

Endospores are resistant to

UV light, extreme heat, and boiling temperatures

Bacterial cells divide by

Binary fission (parent cell splits into 2 daughter cells)

Cytokinesis (septation)

Protein FtsZ and the cytoplasm/membrane split resulting in 2 daughter cells

Batch culture

Nothing is added or taken away from the medium

Lag phase

Gets used to the environment and change in gene expression

Exponential phase

Max growth and quick division

Stationary phase

Lack nutrients and waste buildup

Death phase

Decrease cell count

What environmental conditions affect the growth rate of bacterial culture?

Temperature, amount of nutrients, and pH

Acidophiles

Thrive in highly acidic environments (pH 1-5)

Neutrophiles

Thrive in neutral pH environments (pH 5.5-8)

Alkaliphiles

Thrive in highly basic environments (pH above 8)

pH change can effect

Disrupt the hydrogen bond formation and charge residues of active sites

Biofilms

Communities of bacteria formed from planktonic bacteria (free living) that become attached

Quorum sensing

Communication between bacteria and signaling molecule regulates gene expression