Microbiology Ch 4

prokaryotes = prenucleus (bacteria, archaea)

• 1. no nucleus - single circular chromosome
• 2. no histones - structural proteins of a chromosome
• 3. cell wall - peptidoglycan
• 4. reproduciton - binary fission

Eukaryotes = true nucleus

• 1. Nucleus - DNA/ histones -separted by plasma membrane
• 2. organelles - mitochondria, ER, etc
• 3. no cell wall - simple if present
• 4. reproduction - mitosis/ meiosis

bacteria cells are 1-8 micrometers (um) in length

• 1. Cocci = balls
• 2. Bacillus = rod
• 3. Spirals
• 4. Others - starts, rectangles

Balls - attached - starts as 1 cell that divides and remains attached to one another

• 1. diplo-cocci - two
• 2. strepto-cocci - chain (strip)
• 3. tetrads - groups of 4
• 4. sarcinae - 8 in a cube
• 5. staphylo-cocci - clusters

Rod

• 1. Simple - one
• 2. diplo-bacilli - two end to end
• 3. strepto-bacillit - chains (end to end)
• 4. cocco-bacilli - oval so that they look like cocci

• 1. vibrios - curved rods
• 2. spirilla - helical shape - inflexible
• 3. spirochetes - helical with flexible flagella

monomorphic - bacteria in 1 shape

peomorphic - bacteria in many shapes

glycocalyx means sugar coat

external to cell wall - surrounds the cell

capsule - called a capsule if organized and firmy attached

slime layer - called slime layer if unorganized and loosely attached

long filamentous appendages that propel bacteria

atrichous - bacteria that lack flagella

peritrichous - flagella distributed over the entire cell

monotrichous - single flagella at one pole

lophotrichous - tuft of flagella at one pole

amphitrichous - flgella at both poles

endoflagella - axial filaments - structure is within the cell - enclosed by outer sheath - rotates to make entire cell move like a corkscrew(ONLY on SPRIOCHETES)

• 1. filament - flagellin = protein helix
• 2. hook - another protein
• 3. basal body - anchor = rotates like rotary motor - can go in reverse

motility = movement

1. chemotaxis - move toward or away from chemical (glucose, oxygen)

2. phototaxis - move toward or away from light

fimbriae = fingers that allow attachement

pili - tube - used to transfer DNA from one cell to another during conjugation (sex pili)

both found on gram (-) bacteria more commonly

• the prokaryotic cell wall is rigid
• protective, gives the cell shape, prevents rupture anchors falgella, surrounds the plasma membrane

• made primarily of peptidoglycan =
• disaccharide (NAG/NAM) + protein (tetrapeptide)

• gram (+) many layers of peptidoglycan
• teichoic acids (negatively charged) ion channels that regulate movement of cations in and out of cell
• has peptide crossbridges - penicillin breaks these and causes cell lysis
• cell wall has negative charge
• gram (-) - 1 layer of peptidoglycan with outer layer of phospholipids - weaker
• cell wall had negative charge

the purpose of gram stain is to identify different types of bacteria and know how to treat them from medical purposes

• Gram stain procedure
• 1. crystal violet
• 2. iodine (mordant)
• 3. alcohol wash (makes gram (-) colorless
• 4. safranin

• gram (+) = purple
• gram (-) = pink

causes osmotic lysis - too much water enters cell and cell bursts - can not happen with intact cell wall but if cell wall is damaged -ie penicillin attacks protein crossbridges and allow osmotic lysis

• 1. phopsholipids (bilayer)
• 2. proteins
• -peripheral proteins - can be removed w/o damage to membrane
• -integral proteins - can not be removed w/o damage to membrane - most are transmembrane
• -transmembrane proteins - penetrates membrane completely - pores & channels

primary function is selective permeability - certain molecule and ions can pass through but others are prevented from passing through

#2 function - enzymatic - ATP formation & catalyze decompression

note: no carbohydrates or steroids (cholesterol) in prokaryotic plasma membrane

• NO
• ATP is made on the plasma membrane (enzymes)

Photosynthesis takes place in folds called thylakoids or chromatophores

note - prokaryotic cells have ribosomes for protein synthesis

• Passive transport - no ATP used - materials move down the concentration gradient
• 1. simple diffusion
• 2. facilitated diffusion -via membrane protein - down the concentration gradient
• 3. Osmosis - movement of water across selectively permeable membrane

• Active transport- requires ATP - movement against the concentration gradient
• 1. uses transport proteins
• 2. group translocation - ONLY IN BACTERIA - substance changed as it is transported so that it cannot leak back out of the membrane

ONLY IN EUKARYOTIC CELLS

• endocytosis - taking nutrients in
• phagocytosis - eating
• pinocytosis - drinking
• exocytosis - moving waste out

describe the concentration of solution outside the cell relative to the concentration inside the cell

• isotonic - equilibrium
• hypotonic - solution outside has less solute (more inside) so water moves in and blows cell up

hypertonic - solution outside has more solute so water moves out of cell (plasmolyzed cell)

• cytoplasm - gel inside cell - mostly water (80%)
• contains: nuclear area, ribosomes, and inclusions

• nuclear area:
• 1. nucleoid - one single chromosome of circular DNA (NO HISTONES)
• 2. plasmids - small circles of genes (5-100) that are not essential for everyday life

• ribosomes - site of protein synthesis
• protein + rRNA
• 30S + 50S = 70S

• metachromatic granules - phosphate reserves for ATP
• polysaccharide granules - energy reserves
• lipid granules - energy reserves
• sulfur granules - energy reserves
• carboxysomes - enzymes for CO₂ fixation
• gas vacuoles - buoyancy
• magnetosomes - iron oxide - for attachement

• Endospore - resting or dormant state that is formed when nutrients are depleted in the environment
• only in bacteria - mostly gram (+)
• dehydrated
• durable - survives extreme heat, no water, toxins, time

Sporulation (sporogenesis) formation of the endospore

germination - sport returns to normal state

• made of tubulin (a microtubule)
• contain cytoplasm
• covered by plasma membrane
• whip motion - don't rotate

numerous short projections for cellular locomotion

long, hollow tubes made of a protein called tubulin (make up eukaryotic flagella)

• 1. phospholipids
• 2. proteins (peripheral & integral)
• 3. glycoproteins & glycolipids
• 5. carbohydrates - cell recognition
• 6. steroids (cholesterol) - suport - prevents osmotic lysis

• 1. cytoskeleton - for shape, to move cell, to move substances within the cell
• a. microfilaments - rods
• b. microtubuels - tubes

• 2. nucleus/ nucleolus - contains DNA (w/histones) - cromatin (loose) or chromosome (helix during mitosis)
• has nuclear envelope
• nucleolus - makes rRNA

• 3. golgi complex - protein processing plant
• stacked cisterns (pita bread)
• transport vessicle from ER to GC:
• a. secretory vessicle - to outside cell
• b. transfer vessicle - to another cystern
• c. storage vessicles - for lysosome

• 4. ER - endoplasmic reticulum
• 1. Smooth ER - contains enzymes to synthesize lipids & steroids -
• -detox drugs
• -breakdown glycogen into glucose
• 2. Rough ER - covered with ribosomes - makes proteins - connected to nuclear envelope

5. lysosomes - digestive enzymes

6. vacuoles - in plants (for storage)

• 7. mitochondria - ATP synthesis
• -double membrane - inner cristae
• -matrix= fluid inside
• - contains ribosomes & DNA - can replicate

8. chloroplast - in algea & green plants - photosynthesis - chlorophyll contains in thylakoids

9. Peroxisome - makes & degrades peroxide

10. centrosome - organizes microtubules for mitosis

11. ribosome - protein synthesis

• Replication = DNA → DNA
• Transcription = DNA → mRNA
• Translation = mRNA → protein