microbio (fixed)

How is Lipid A related to endotoxin? a) Lipid A is metabolized by the liver then activates an adverse immune secretion called endotoxin b) Lipid A is the G- cell wall component that is toxic to the body and was named endotoxin c) Lipid A releases endotoxin when it reacts with Gram negative bacteria d) No relation - 23 and Me DNA tests show different genetics

b

Why does the bacterial cell need such a strong cell wall? a) To prevent valuable nutrients from escaping out of the cell b) To prevent osmotic water pressure from bursting the cell like an overfilled water balloon c) The cell needs the cell wall to hold the flagella and pili d) Motile cells bump into things that might crack or damage the outer cell shell

b

What is the periplasm and what's in it? a) A structure outside the outer membrane that collects nutrients b) The volume between the inner and outer membrane with enzymes and receptors c) The space around the cell's DNA that prevents bad mutations d) The material around the capsule that keeps it intact

b

What is the nature of the outer membrane of G- cells? a) Another membrane-like structure plus LPS and porins b) A layer of protein protecting the cell c) Just a slime layer d) Left over makeup still on after a date with a protozoan

a

What makes the G- cell wall so much more complex than the G+ cell wall? a) G- randomly adds things to its cell wall b) G- has a peptidoglycan layer plus an outer membrane layer c) G- incorporates ribosomes and DNA into the cell wall d) G+ species are very poor and lead simple lives, they can't afford a fancy cell wall

b

What is Lipid A? a) A component of the LPS layer that can be toxic to humans b) The lipid that is connected to Lipid B, C, and D c) The component of ribosomes important in proper protein function d) The lipid that scored the highest on the cell wall quiz

a

Name one species of bacteria that does not contain a cell wall. a) Mycoplasma b) E. coli c) Staphylococcus aureus d) Bacillus subtilis e) Streptococcus pyogenes

a

What best describes the chemical make-up of the peptidoglycan component of bacterial cell walls? a) A sheet of protein embedded with lipids b) Fibers composed of repeating sugar units crosslinked with short peptide chains c) Gel-like polysaccharide layer just underneath the cell membrane d) Solid layer of large peptide chains crosslinked with sugar molecules e) Waterproof polyester fleece with short zippers

b

How does the human body respond to endotoxin? a) Edema (swelling), low blood pressure, rapid pulse and respiration, sometimes death b) Feelings of euphoria and well being c) Heighten sense of power and superiority d) Fear of another microbiology quiz

a

What contributes to the G+ cell wall being so much thicker than G- cell walls? a) It has more capsule material in it. b) The periplasm is thicker c) It swells a lot in water d) The peptidoglycan in G+ consists of multiple layers, many more that the few in G- cell walls e) The G- cells are too stingy with peptidoglycan, hence the thinness.

d

Cell membrane

site of transport components to move substances into and out of the cell

Ribosome

site of protein synthesis

Pilus (pili)

attachment to surfaces and other cells

LPS layer

protection from large antibiotic molecules

Nucleoid

area of DNA (free floating)

Inclusion

storage of extra nutrients

Capsule

protection from dehydration and phagocytosis, role in adhesion to surfaces

Cell wall

protection from osmotic bursting

Flagellum

motility of the cell in the environment

Periplasm

site for receptors and digestive enzymes, space between inner membrane and outer membrane in G- bacteria

The end (last) product of the glycolysis pathway is a) Glucose b) Pyruvate c) Ethanol d) CO2 e) Protons

b

What organic compound is the most common electron acceptor in fermentation? a) Protons b) Pyruvate c) Oxygen d) Glucose e) Peptidoglycan

b

At the end of the Electron Transport Cycle what is the final acceptor of the traveling electrons? a) Protons b) Pyruvate c) Oxygen d) Glucose

c

After it "leaves" glycolysis and does 1 round of the Krebs cycle what becomes of the 3 carbons of the pyruvate molecule? a) They turn into glucose b) They are fermented into ethanol c) They are completely oxidized to CO2 d) They become ATP molecules e) They completely lose control and do wild things to attract attention

c

What is the fate of fermentation end products? a) They are stored in granules as long term nutrients b) They are incorporated into cell structures c) They are excreted into the cell's environment d) They are metabolized into ATP e) They are auctioned on eBay

c

Biological oxidation of a molecule is the _____________ (removal, addition) of (protons, electrons, enzymes, sugars) ______________ a) Removal, enzymes b) Removal, protons c) Removal, electrons d) Addition, protons and sugars e) Borrowing, protein and lipids

c

In chemiosmosis what is "pushed" out of the cell and what is made in the cell when that substance comes back in through the membrane? a) Electrons, carbohydrates b) Protons, ATP c) Protons, enzymes d) Protons, cytochromes e) Electrons, glucose

b

How many net ATP per glucose does glycolysis pathway produce? a) 2 b) 3 c) 8 d) 9 e) between 5 and 1294

a

What is the carrier of the electrons generated from glycolysis and the Krebs cycle? a) Ethanol b) Pyruvate c) NAD+ d) CO2

c

The function of the Krebs cycle is to a) Make carbon compounds for cell growth b) Oxidize the carbons from the glycolysis pathway c) Make some ATP for the cell d) All of the above e) None of these - it only spins so we can call it a cycle

d

What method of horizontal gene transfer in bacteria involves the direct cell to cell contact between the live donor and the live recipient? a) Transformation b) Conjugation c.) Transduction d) Transcription

b

Plasmids are best described as: a) Small, extrachromosomal circles of DNA that can be transferred to another cell b) A metabolic pathway that makes energy for DNA replication c) Copies of some cell genes transferred by virus infections d) Large pieces of duplicate cell genomes that can be transferred to another cell e) Plasma content in the cell that can lead to ID - plasmID.

a

What method of horizontal gene transfer in bacteria involves the direct uptake of DNA from dead donors? a) Translation b) Transduction c) Transformation d) Transcription

c

By what mechanism does the process of transduction transfer donor cell genes to a recipient cell? a) DNA pieces are released into the environment b) The genes are shoved through a small pilus. c) Bacterial viruses do the transfer d) The DNA slips in through a weak spot in the cell membrane

c

Compared to the size of the host cell's DNA, a plasmid would be: a) nearly twice the size. b) much smaller. c) many times larger. d) about the same size. e) purple.

b

Plasmids can be transferred to other cells with what cell structure? a) flagella b) capsule c) 70S ribosomes d) pili e) aorta

d

How do most mutagenic agents exert their activity on cells to cause mutations? a) They interfere with protein synthesis b) They make the cell membrane leaky c) They alter or interfere with some activity of the cell DNA . d) They interfere with tRNA translating the DNA genes e) They make the double helix DNA twist the other way.

c

To assure that the off-spring cells all receive a copy of the same DNA genes as the parent bacterial cells, the process of ____________________ must happen in the parent cell. a) Transformation b) Transduction c) Replication d) Translation e) Creationism

c

The making of protein by the ribosomes reading the genetic code on the messenger RNA is called a) Replication b) Translation c) Transformation d) Transcription

b

Which of the following can be mutagenic agents. (Choose all the apply) a) DNA disrupting chemicals b) gamma radiation c) UV light d) 6 carbon sugars such as glucose

a,b,c

Star-shaped bacteria

Stella

square-shaped bacteria

Haloarcula

examples of final e- acceptors in anaerobic respiration

nitrate, sulphate, carbonate

glucose end products of fermentation (species dependant)

-alcohol: 2 ethanol and CO2 -lactic acid: 2 lactic acids -mixed acid: ethanol, lactic, succinic, formic, H2, CO2 -acetone/butanol: variety of solvents

Streptococci

bacteria that form a chain

sarcinae

cubic configuration of 8 cocci

Staphylococci

a group of about 30 species of bacteria that form irregular groups or clusters resembling grapes

internal pressure in bacteria

10-25 atm

What is the cell wall made of?

peptidoglycan

What is peptidoglycan made of?

NAM, NAG, & polypeptides

Gram + cell wall

• thick multilayer peptidoglycan

• teichoic acid (ONLY IN GRAM +)

• polysaccharides provide antigenic variation

Gram - cell wall

• thin peptidoglycan layer in periplasm

• LPS layer

• dual layer system

What is the LPS layer composed of?

lipopolysaccharides, lipoproteins, phospholipids

• O polysaccharide

• Lipid A

• Porins

O polysaccharide

antigen, stimulates immune system to form antibodies

Lipid A

endotoxin, causes death to humans

Porins

proteins that form channels through membrane (entry for molecules)

• limit size of molecules entering

substance in acid fast that makes it waxy

mycolic acids

pleomorphic bacteria

can morph into many shapes

what is another name for the cell envelope

glycocalyx

endospores have a high concentration of...

dipicolinic acid

what are gas vacuoles

found in aquatic, photosynthetic bacteria and archaea provide buoyancy in gas vesicles

what proteins are the flaegella made of

flagellin

protoplast

cell wall completely removed

spheroplast

weakened or partially removed cell wall

lysozyme

hydrolyzes bond connecting sugars in peptidoglycan (may cause lysis)

Gram Stain Mechanism: Gram-positive

1. Alcohol dehydrates peptidoglycan

2. CV-I crystals do not leave Turns purple

when subunits of flagella regenerate where do they go

they reach tip and spontaneously regenerate

Gram Stain Mechanism: Gram-negative

1. Alcohol dissolves outer membrane and leaves holes in peptidoglycan

2. CV-I washes out Turns pink

Mycoplasmas

lack cell wall

3 parts of flagella

1. filament: chain of protein subunits, 10-20x length of cell

2. hook: flexible attachment to anchor

3. basal body: anchors in membrane and cell wall, motor

peritrichous flagella

flagella that cover the surface of a cell

monotrichous flagella

one flagella

lophotrichous flagella

multiple flagella at one end

amphitrichous flagella

flagella at both poles of the cell

CCW rotation of flagella

caused by attractants, flagella bundle together, pushes cell forward, called a run

CW rotation of flagella

caused by repellants, flagellar bundle falls apart; called a tumble because bacteria briefly stop and then change direction

capsule layer

slimy/gummy, made of polysaccharides (mostly)

cytoplasmic membrane

• phospholipid bilayer (outside is polar, inside is non-polar)

• proteins: transmembrane (integral), cytoplasmic (peripheral)

• fluid mosaic model

ribosomes in prokaryotes

70s, protein synthesis, smaller than eukaryotes

metachromatic granules

phosphate reserves

polysaccharide granules

energy reserves

lipid inclusions

polyhydroxybutyrate (PHB) stores

magnetosomes

iron oxide (destroys H2O2)

endospores

• produced through sporulation as a survival mechanism

• resistant to heat, drying, UV

• metabolically inactive

• can survive for millions of years

vegetative cell from spore =

germination

metabolism

the sum of all chemical processes that occur in an organism

catabolism

metabolic pathways that break down molecules, releasing energy

anabolism

metabolic pathways that construct molecules, requiring energy.

Reduction

gain of electrons

Oxidation

loss of electrons

aerobic respiration

glycolysis -> krebs cycle -> oxidative phosphorylation -> 36 ATP per glucose molecule

How is anaerobic respiration different from aerobic respiration?

final electron acceptor is an organic molecule

fermentation

alternate energy pathway, no O2, no Krebs or Chemiosmosis, end products secreted

glycolysis

oxidation of glucose to pyruvic acid -6C sugar in (takes 2 ATP to import)

• products: 2 net ATP, 2 3C pyruvates, 2 NADH

• no O2 needed

• substrate level phosphorylation

How is the flagella powered?

proton motive force (H+)

ATP from aerobic total for bacteria

34-38 per glucose

krebs cycle

cell's grocery store for biosynthesis converts pyruvate to

• CO2 (all carbons oxidized)

• more substrate level ATP

• reducing power for ATP making and chemiosmosis

• NADH and FADH2

What is the central dogma of molecular biology?

DNA -> RNA -> Protein

facultative anaerobes have ability for aerobic and fermentation, what determines this choice?

O2 availability regulates the genes

chemiosmosis (oxidative phosphorylation)

• ETC - final e- acceptor is O2

• generates proton gradient

• high concentration of H+ outside of cell which re-enter to make ATP