MBI 201 exam 1 **found quizlet**

microbe

biological entity that requires a microscope to be seen

unique to microbes

-single or multicellular

-can reproduce its own kind

what are prokaryotes

bacteria and archaea

what are eukaryotes

algae, fungi, protists

3 domains of life

bacteria, archaea, eukaryotes

Robert Hooke

-Built the first compound microscope

-observed mold and coined the term cell

Antonie Leeuwenhoek

-built single lens magnifiers

-observed single celled microbes ("small animals")

Louis Pasteur

-fermentation

-refuted spontaneous generation

Lady Montagu

-introduced smallpox inoculation (vaccine) in europe

Edward Jenner

-infected people with cowpox lesions

-this practice was called a vaccination

Ignaz Semmelweis

-chlorine as an antiseptic agent

Joseph Lister

-carbolic acid to treat and clean surgical instruments

-led to aseptic surgery

Alexander Fleming

Penicillium mold that kills bacteria

Who purified penicillin

Howard Florey and Ernst Chain

What did the passage or tobacco mosaic disease through a porcelain filter discover?

viruses

what was the winogradsky column?

model of a wetland ecosystem containing regions of enrichment for microbes utilizing diverse metabolisms

what are endosymbionts

microbes that live inside a larger host organism

what endosymbiotic bacteria facilitated bacterial nitrogen fixation

rhizobia

What are cells made of? What makes up the majority of cells?

mostly water. ions, small organic molecules, and macromolecules are the remaining materials in cells

what did Sergei Winogradsky discover?

-lithotrophs

-built the winogradsky column

-geochemical cycling

what is the periplasm?

space between the cell membrane and outer membrane

cell membranes have equal volumes of...

phospholipids and proteins. The mass of phospholipids and proteins is approximately equal but there are more phospholipids than proteins

the two layers of phospholipids in the bilayer are called

leaflets

unsaturated is how many bonds?

a double bond.

what are the flat molecules that fill gaps in the hydocarbon chains in both eukaryotic and prokaryotic membranes?

eukaryotic: cholesterol

prokaryotic: hopanes or hopanoids

what organism has the most extreme variety in membrane lipid structure?

archaea. It's hydrocarbon chains are branched terpenoids

what makes archaea able to survive in extreme environments?

ether bonds. They're energetically costly to make and hard to break (more stable).

what can easily pass through the cell membrane by passive diffusion?

small uncharged molecules like O2 and CO2. no charged molecules

passive transport

molecules move from high to low concentration. no energy

active transport

requires energy. molecules move from low to high concentration

mycoplasmas

prokaryotes with a cell membrane and no further outer layers

the cell wall helps the cell withstand

turgor pressure

what is a bacterial cell wall called and describe how it is made

Sacculus. single interlinked molecule (flexible mesh bag)

describe what a bacterial cell wall is made of

peptidoglycan. the molecule consists of NAG and NAM. the peptides form cross-bridges connecting parallel glycan strands

cell wall extension is organized by a protein called...

elongasome

what does penicillin inhibit?

enzymes that cross link peptides to each other (stops elongasomes from cell wall extension)

describe gram positive bacteria

thick cell wall, multiple layers of peptidoglycan, threaded by teichoic acids. The capsule is made of polysacharide and glycoprotein, protects cell from phagocytosis

describe gram neg bacteria

thin cell wall, covered by outer membrane for defense, inward facing leaflet including lipoproteins, outward facing leaflet containing lipopolysaccharide molecules, transmembrane proteins called porins

mycobacteria

complex, multilayered cell wall

mollicutes/mycoplasmas

no cell wall

what is more selective: the outer or inner membrane

the inner membrane is more selective. cell wall is not selective

what is the S layer?

additional protective layer in gram pos and gram neg bacteria and archaea. consists of protein of glycoprotein. protects the cell from osmotic stress and attack from the immune system

how are bacterial phospholipids linked

ester-linked

what do FTsZ proteins form in bacteria?

FTsZ forms a Z-ring in spherical cells (cocci). Related to tubulin

what do MreB proteins form?

MreB forms short filamets inside rod-shaped cells (bacilli). Related to actin

how do bacilli divide?

They're cut in half. They get longer then split. In order for bacterial cells to grow they need to take up more water and nutrients, make more membrane and cell wall

How does elongation of the cell wall work

MreB is attracted to places where the membrane is deformed. MreB assembles a complex of membrane proteins (an elongasome) that allows the cell wall to grow. More peptidoglycan can be inserted

what is septation?

formation of the septum. The septum is part of the cell wall that bounds off daughter cells from each other

what is used to direct the construction of the septum

FtsZ

what does FtsZ direct the synthesis of?

FtsZ filaments assemble at the midcell and direct the synthesis of divisomes. This forms a structure called the Z ring. FtsZ also enables pinching of the cell membrane inward.

Elongasomes are based on the protein:

Divisomes are baed on the protein:

elongasome: MreB (inserts new peptidoglycan)

Divisomes: FtsZ (creates septum ad pulls membrane inward)

where is DNA organized in prokaryotes?

nucleoid region (not enclosed by membrane)

what are loops of DNA called in the nucleoid and what are these loops bound to?

loops of DNA: domains

and bound to DNA binding proteins

what is unique about translation and transcription in prokaryotes?

translation and transcription are coupled. Translation begins even before transcription of mRNA strand is complete

what is the protein complex engaged in DNA synthesis:

replisome

what has more diversity: prokaryotes or eukaryotes

prokaryotes (can make use of many different nutrients in many different ways)

Thylakoids

extensive folded intracellular membranes in photosynthetic bacteria that accommodate large amounts of photosynthetic machinery

carboxysomes

polyhedral bodies packed with enyzyme Rubisco for CO2 fixation to increase metabolic pathway efficiency

gas vesicles

protein bound gas filled structures that increase buoyancy allowing cells to adjust location in the water column

what is the importance of sulfur globules in prokaryotes

oxidation

what are pili used for?

attachment. Pili are straight filaments of pilin proteins. Gram neg bacteria use sex pili for conjugation

what are extensions of the cytoplasm

stalks

what is flagellin powered by?

proton motive force

what generates torque and makes the flagellum spin?

FliG

what forms the proton channel through which protons enter the cell?

MotB

what is chemotaxis

movement of bacterium in response to chemical gradient

what type of rotation do attractants cause

CCW rotation

flagella bundle together

push cell forward

what type of rotation do repellants cause

CW rotation

flagellar bundle falls apart "tumble"

what cause chemoreceptors to detect attractant

sugars and amino acids

what are the macronutrients

C, O, H, N, P, S

cations necessary for protein function like Mg2+, Ca2+, Fe2+, K+

what are the micronutrients?

trace elements necessary for enzyme function. Co, Cu, Mn, Zn

what is fixation?

conversion of an element from a form that's not useful to most organisms to a form that's useful for most organisms. usually the reduction of N2 and CO2

what do nitrogen fixers do?

possess nitrogenase which convert N2 to ammonium ions (NH4+)

what do nitrifiers do?

oxidize ammonia to nitrate (NO3-). an example includes bacteria and archaea

what do denitrifiers do?

convert nitrate to N2.

Bacteria and archaea

what are the two ways carbon can be obtained

1. heterotrophs use organic carbon to make biomass

2. autotrophs fix inorganic carbon in the form of CO2 converting it to organic carbon

how can organisms require energy from electrons?

compounds must be oxidized (lose their electrons)

what are chemotrophs

organisms who get electrons from compounds whose elections already have a lot of energy

what are phototrophs

organisms that direct the energy from light to be absorbed by low energy elections in some compound and then extract the energy from those electrons

organotrophs vs. lithotrophs

organotrophs: use electrons from organic compounds

Lithotrophs: use electrons from inorganic compounds

describe chemoorganoheterotrophs

electrons already energized (chemo-), electron source is organic molecules (organo-), carbon source is organic molecules (hetero-)

describe photolithoautotrophs

electrons must be energized by light (photo-), electron source is inorganic molecules (litho-), carbon source is CO2 (auto-)

chemolithoautotrophs

electrons already energized (chemo-), electron source is inorganic molecules (litho-), carbon source is CO2 (auto-)

describe mixotrophs

can switch between the utilization of organic and inorganic sources of electrons and carbon

when protons re-enter the cell the potential energy stored in them can be used for

transport nutrients, drive flagellar rotation, make ATP using ATP synthase

how is selective permeability achieved?

permeases, nutrient binding proteins, membrane spanning protein channels

what does an aquaporin do?

type of facilitated diffusion. transports water and small polar molecules. more efficient than osmosis

symport vs antiport

both types of active transport. symport is two molecules in the same direction and antiport is two molecules in the opposite direction

describe an example of symport

LacY

-transports lactose into the cell

-lactose accumulates in the cell, H+ at higher conc outside the cytoplasm

-proton and lactose pass through the cytoplasm where they're released

-lacY using proton force to drive import of lactose

describe an example of antiport

Na+/H+ antiporter

-sodium is at too high of conc in the cytoplasm (the cell needs to pump it out)

-H+ is too high outside the cytoplasm

-NhaA uses the energy of proton gradient to drive export of sodium

what's the largest family of energy driven transport systems?

ABC transporters (uptake and efflux ABC transporters)

what are siderophores

specialized molecules secreted to bind ferric iron and transport it into the cell. Then the iron is reduced inside the cell

liquid/broth culture media is useful for studying growth of

the growth characteristics of a pure culture of bacteria

solid culture media is useful for

trying to sperate mixed cultures from clinical specimens or the natural environment

How do the majority of bacteria divide?

binary fission. a small minority divide asymmetrically

what is the equation to describe a cell dividing by binary fission?

# of cells = 2^n

whats the simplest way to model the effects of a changing environment is to culture bacteria in a

batch culture (liquid medium within a closed system)

what are the order of phases in a bacterial growth curve?

lag phase, log phase, stationary phase, death phase

what does a continuous culture allow the study of?

detailed study of bacterial physiology. The chemostat ensures logarithmic growth by constantly adding and removing equal amounts of culture medium

biofilms

specialized, surface-attached communities of bacteria