Prokaryote Bio Exam 1

Methanogens, a anaerobic archaea were responsible for producing ______, which helped warm early Earth?

CH4 (methane)

Cyanobacteria, a photosynthetic bacteria produced ______ as an end product.

O2 (oxygen)

What are some limitations to Koch’s postulates?

Asymptomatic carriers, immunity, and some microbe may not be able to grow in a lab.

The first molecular phylogenetic tree that showed that there are 3 domains of life that was based on sequencing of the gene encoding _____ from different organisms.

rRNA

Why did scientist use rRNA sequencing?

found in every cellular organism, changes slowly over an evolutionary time, fundamental process

What was the most recent domain branching between?

Archaea and Eukarya

What bacteria were once free living?

proteobacteria (mitochondria) and cyanobacteria (chloroplast)

What is a microbe?

an organism or infectious agent that you cannot see with a naked eye *A bacterium can be both a microbe AND a prokaryote.

A prokaryote _____ have membrane bound organelles.

does not

Microorganisms are major _______

decomposers

Microorganisms are essential for….

Carbon cycle, Nitrogen cycle, Sulfur cycle, Phosphorus cycle

T/F: If all archaea were permanently removed from Earth, human life would eventually cease to exist.

True

Cyanobacteria first evolved _______ ________, making complex life possible.

oxygenic photosynthesis

Proteobacteria perform _________ using their plasma membrane to house the electron transport chain and generate ATP

aerobic respiration

What is the substrate that cyanobacteria uses to produce oxygen?

water

What happens to the water that cyanobacteria uses to produce oxygen?

Its being oxidized, loosing electrons.

The genomes of mitochondria and chloroplast both show extreme reduction, why does this make sense?

more efficient, it takes a lot of energy to transcribe DNA.

Prokaryotes are said to be a open system, what does that mean?

They are extremely dependent on the environment

What region do gram negative bacteria fall into?

Proteobacteria

How are gram pos and neg bacteria identifed?

By how their cell envelope/wall react to the stain.

rRNA based taxonomy typically coincides with structural properties like…

type of cell envelope, metabolism, size & shape

T/F: Cryo-electron microscopy can be used to determine the 3-dimensional structure of proteins.

True

In general, metabolic/growth rates are _______ proportional to cell size

inversely, if you are smaller you can metabolize faster

• a larger S/V ratio

4 macromolecules and which one is most abundant

Proteins, carbohydrates, lipids, nucleic acids; PROTEINS

Why does protein take up most of the dry weight of a cell?

structure, sensing, its the enzymes

Nucleic acids are the 2nd most abundant in a cell, why?

DNA, need a lot of RNA to make the proteins

Polysaccharides are found primarily in ______ and _____

cell wall; outer surface layers

What makes up the cell envelope?

outer layers, cell wall, membranes

What decides what goes in and out of the membrane?

membrane proteins

What is the proton motive force used for?

generate ATP by ATP synthase, short term energy storage, energy for active transport

What makes up the cytoplasmic membrane?

Lipids and membrane proteins

What are the two types of lipids found in the cytoplasmic membrane?

Glycerophospholipids and hopanoids (bacteria)

What are some functions of membrane proteins?

transport, respiration (PMF), ATP synthesis, cell wall synthesis, signaling

Structure of bacterial glycerophospholipids?

fatty acid side chains, glycerol, phosphoryl head group, and R-group. form into bilayers

Saturated fats contain _____ bonds, and are ____ rigid, and _____ fluid.

single; more; less

Unsaturated fats contain ____ bonds, are _____ rigid, and ____ fluid.

at least one double bond; less; more

Ester-linked lipids are found in?

bacteria and eukaryotes

Ether-linked lipids are found in?

archaea only

What are hopanoids and where are they found?

pentacyclic, act like cholesterol in the membrane. more rigid, decreases fluidity. found in bacteria only.

What makes up the prokaryote cell wall? What is the function?

polysaccharides and protein; protection (withstand turgor/osmotic pressure) and transport

What is hypotonic?

higher solutes, water moves into cell, builds up pressureWh

What is hypertonic?

solutes outside cell, water moves out, cell shrinks

Do human cells have cell walls?

NO

What is the polymer made of amino acids and sugars that makes up the bacterial cell wall?

Peptidoglycan

Peptidoglycan can form cross-brides with adjacent glycan stands, why do they do this?

Increase rigidity, preventing the cell from osmotic bursting

What is the common bond that N-acetylglucosamine and N-acetylmuramic acid create?

B 1,4-glycosdic bond

What is the purpose of Lysozyme in the peptidoglycan?

cleaves the 1,4-glycosdic bond, weaking the cell wall

In peptidoglycan what are the amino acids attached to N-acetylmuramic acid, held together by?

amide/peptide bonds

What is a common transpeptidation in peptidoglycan?

m-Diaminopimelic acid (DAP) and alanine, VITIAL to the cell wall rigidity

Penicillin is effective because it inhibits?

the transpeptidation reaction preventing the cross-bridge formation, mimics D-ala-D-ala portion

What enzyme is found in penicillin resistance?

B-lactamase which cleaves the B-lactam ring

Most archaea cell walls are composed of?

the s-layer

What is the s-layer?

crystalline outer layer composed of protein or glycoprotein

The s-layer is common in what type of bacteria?

gram-positive

What is the polysaccharide-containing matrix outside of the bacterial cell wall? *Rare in archaea

glycocalyx/capsule

What is the function of the glycocalyx/capsule?

• attachment- helps bacteria hide from immune system and stick

  • keeps cell hydrated by water storage

What commonly happens to the glycocalyx and s-layer when pure cultures of bacteria are continuously grown in “laboratory conditions”?

• lose their glycocalyx and s-layer

• bacteria are shielded from any threat, they don’t need any protection.

Gram-positive bacteria _____ the crystal violet stain because of the ____ cell wall

retain; thicker

Gram-pos bacteria have ___ membrane and gram-neg bacteria have ___ membrane?

1; 2

In gram-neg bacteria lipoproteins link the ____ and the _____

peptidoglycan; outer membrane

In gram positive bacteria, what anchors the peptidoglycan layer to the cytoplasm and is negatively charged?

Teichoic acid

In gram-neg bacteria which membrane has PMF and stores energy?

Inner, cytoplasmic

Where are porins found and in which type of bacteria?

Outer membrane; gram-neg bacteria

What is lipopolysaccharide and what bacteria is it unique to?

in outer membrane, shields bacteria from toxins, unique to gram neg!

A bacterium that grows optimally at 37C but is put at 45C would most likely add more ____ to its cytoplasmic membrane

lipids with saturated fatty acids

T/F: Vancomycin breaks down peptidoglycan by breaking the glycosidic bonds in the glycan chains

False; it just inhibits the synthesis

What type of flagella does E.Coli have?

Peritrichous

Is E.Coli gram pos or gram neg

gram neg

What is FtsZ and why is it essential?

protein that forms a “Z-ring” in spherical cells, analog of tubulin, site of cell division

What is MreB in bacteria?

forms a coil inside rod-shaped cells, analog of actin, non essential

Do bacteria and archea have nuclei?

NO

In photosynthetic bacteria, what are thylakoids in cyanobacteria and chloroplasts?

captures energy from sun

What is the purpose of bacterial microcompartments?

Help to concentrate enzymes and metabolites, and sequester toxic metabolites

How does the microcompartment, Carboxysome work?

packed with RuBsiCO for CO2 fixation, improves the efficiency

What does Salmonella use as a carbon and nitrogen source?

Ethanolamine which breaks down to acetaldehyde (volatile and mutagenic)

What are magnetosomes

Membrane enclosed structures that contain iron and oxygen that magnetically directly the motility

What is the storage granule, poly-B-hydroxybutyrate (PHB)? When you find most of this, carbon rich or poor?

forms polymers for carbon energy storage; carbon RICH

Why are trace elements still essential?

active sites of many enzymes, many proteins NEED cofactors

What happens during cell elongation?

cell mass increases and DNA replication occursWhat

What happens during septum formation?

Divisome: cell division apparatus contains FtsZ

Faster growing cells have more…..

RNA, protein, mass, and DNA

To have a lot of protein, you need alot of…

RNA

What is the function of MinCDE?

inhibits FtsZ ring formation, ensures that cell division happens in the center of the cell

Cells need time to sense new environment, express the right enzymes, time is variable

Lag phase

Rapid growth phase, cells grow/divide at the max rate possible based on their conditions

Log phase

Cell division stops as nutrients are depleted, waste products accumulate

Stationary phase

T/F: Both bacteria and archaea may contain carboxysomes

False, only bacteria

What is a auxotroph?

an organism that cannot make a specific organic compound needed for its growthA

T/F: A phenylalanine auxotroph of E.Coli would NOT be able to grow in M9 medium if glucose was provided as the only carbon and energy source?

True, M9 has no phenylalanine

Growth above 80C

Hyperthermophile

Growth between 50C and 80C

Thermophile

Growth between 15C and 45C

Mesophile *Humans

Growth below 15C

Psychrophile

Growth above pH of 9

Alkaliphile

Growth between pH 5 and pH 8

Neutralophile

Growth below pH of 3

Acidophile

Change in pH can alter the charge of ____

amino acids

What does a aerobe use oxygen for?

terminal electron acceptor for growth

What does a anaerobe use oxygen for?

DOES not use O2 as a terminal electron acceptor for growth

What does facultative mean?

can grow with or without O2