Chapter 3: Cells and methods to observe them

_______ ______ makes up the surface layers of prokaryotic cells

cell envelope

cell envelope (if present) consists of cytoplasmic membrane, ____ _____, and capsule

cell wall

_________ is enclosed within the envelope, it is a thick material filled with nutrient, ribosomes and enzymes

cytoplasm

________ a gel like region in the cytoplasm where the generic material of the cell is found

nucleoid

T or F: a nucleoid IS membrane-bound.

False

________ ________- structure that surrounds the cytoplasm and creates the boundary of the cell

cytoplasmic membrane

cytoplasmic membrane is made up of a ________ ________ embedded with _________.

phospholipid bilayer; proteins

Phospholipids consist of ___________ polar (phosphate) head that faces outward, interacting with fluid inside and outside the cell

hydrophillic

Phospholipids also consist of ___________ nonpolar (fatty acids) tails that face inward, away from water

hydrophobic

Proteins embedded in the membrane have a variety of functions, including:

________ _______, ______ __ _____ ____, _____ ____ _____.

selective gates, sensors of environmental conditions, and they act as enzymes.

_____ ____ _____- membrane proteins move through the fluid like lipid bilayer

fluid mosaic model

the membrane is ______ _______, meaning only cerain substances can cross it

selectively permeable

___ , ___, ____, are small hydrophobic molecules that can pass freely through the membrane. H2O can also pass freely

O2, CO2, N2

some cells facilitate water passage through the membrane using _______.

aqua porins

other molecules trying to be moved across the membrane must use other _____ ________.

transport systems

_______ ________- movement of molecules from high to low concentration until equal on both sides of the membrane

simple diffusion

______ of diffusion depends on cencentration

speed

the ______ the difference in concentration on either side of a membrane, the higher the rate of diffusion

greater

_________- diffsuion of water across a selectively permeable membrane due to unequal solute concentrations

osmosis

______ ______- there are less solutes (more water) outside of the cell

hypotonic solution

hypotonic solutions cause cells to ______.

swell

_____ _______- there are more solutes (less water) outside of the cells

hypertonic solution

hypertonic solutions cause cell cytoplasmic membrane to ________.

shrink

equal solute/water ______, means no net movement

isotonic

Environments of prokaryotes are typically _______

dilute (hypotonic)

______ ______ prevents the cell from bursting

cell wall

________- when the cell wall bursts

plasmoptysis

______- when the cytoplasmic membrane shrivels/shrinks

plasmolysis

most molecules pass through _____, functioning as selective gates

proteins

_______ ________- permeases or carriers. Span the membrane; highly specific. Carriers move certain molecule type.

transport system

_______ ______- is a form of passive transport, movement down the gradient (high to low) so no energy is required. NOT useful in low-nutrient enviornments

facilitated diffusion

______ ______- requires energy for molecules moving against their concentration gradient (low to high). Sometimes driven by proton-motive force, sometimes driven by ATP.

active transport

_______ ________- is common is bacteria, a molecule is chemically modified as it passes through the cytoplasmic membrane. Phosphorylation is common, adding a phosphate group.

group translocation

what mode of transport is often used by bacteria as glucose is transferred into the cell?

group translocation

_______ _______- cells actively move proteins they have made out of cell and into the enviornment.

protein secretion

what mode of transport is this an example of? Extracellular enzymes and external structures

protein secretion

what mode of transport is this an example of? Polypeptides are tagged for secretion with a signal sequence of amino acids

protein secretion

the two main distingishing types that bacteria can be are ______ _____ and _____ ______.

gram positive; gram negative

what color is gram positive?

purple

what color is gram negative?

red

___________- is only found in bacteria and gives gram + and gram - bacteria their strength.

peptidoglycan

peptidoglycan is made up of alternating series of subunits that form ____ ______.

glycan chains

_-_______ _____ and _-_________ are the subunits that make the glycan chains in peptidoglycan.

n-acetylmuramic (NAM); n-acetylglucosamine (NAG)

____________ chain links glycan chains.

tetrapeptide

peptide _______ in ghram positive cells.

interbridges

_______ _______- have a thick peptidoglycan layer

gram-positive

____ _____- are negatively charged chains with attached sugars that extend above the peptidoglycan layer.

teichoic acids

_____-_____ material below the peptidoglycan layer has a similar function to the periplasmic space in gram-negative cells.

gel-like

______ _______- have a thin layer of peptidoglycan

gram negative

outside of the thin peptidoglycan layer, is an outer membrane ______ layer embedded with _____.

lipid; proteins

the layers in the outer membrane of gram negative cell walls are joined by ________.

lipoproteins

the outer membrane outside layer of a gram negative cell is ____________.

lipopolysaccharide (LPS)

______________ signals our immune system of invasion by gram negative bacteria.

lipopolysaccharide (LPS)

LPS is also called _________- large amounts accumulating in bloodstream can be deadly.

endotoxin

includes ____ __, recognized by immune system

lipid a

icludes __ ______ can be used to identify species or strain

O angtigen

________ _______ blocks theb passage of many molecules, including certain antimicrobial medications.

outer membrane

small molecules and ions can cross the outer membrane via ________.

porins

________ ______ move proteins across the cytoplasmic and outer membranes. this is important in pathogenesis.

secretion systems

_______- between the cytoplasmic membrane and outer membrane is the periplasmic space

periplasm

the periplasm is filled with ____-____ periplasm

gel-like

exported proteins ________ in the periplasm unless specifically moved across outer membrane

accumulate

binding proteins of ABC transport systems are _________ in the periplasm

located

________- gelatinous structure that is distinct

capsule

_____ _____- diffuse and irregular

slime layer

what is the purpose of some bacteria having a gel-like layer outside of the cell wall?

it protects the cell or allows it to adhere to surfaces

most capsules/slime layers are composed of ______ (sugar cell), but some are polypeptides.

glycocaylx

some _____ allow bacteria to evade host immune system

capsules

once bacteria is attached to a surface, cells can grow as ______.

biofilm

________- long protein that allow for prokaryotic motility, spin like propellers to move cell.

flagella

what is an example of where flagella could be important in?

disease

what bacteria is an example of flagella being important?

Helicobacter pylori

________ & ______ of flagella help with characterization of bacteria

numbers and arrangements

__________- bacteria sense a chemical and move toward it (nutrient) or away (toxin)

chemotaxis

what does the movement in chemotaxis look like if you had to describe it?

series of runs (straight lines) and tumbles (changes in direction)

why do bacteria move the way they do during chemotaxis?

due to coordinated rotation of flagella

Aero taxis refers to...

oxygen

megneto taxis refers to...

magnetic (north and south pole)

thermotaxis refers to..

temerpature dependent

photo taxis refers to...

light

_____ shoerter and thinner than flagella

pili

______- are types that allow cells to attach to specific surfaces

fimbrae

___ ___- used to join bacteria together for DNA transfer

sex pili

_____ _______- is a singular circular double stranded (ds) DNA molecule

prokaryotic chromosome

prokaryotic chromosomes are packed tightly via binding proetins and _______.

supercoiling

prokaryotic chromosomes form gel-like region called the ______.

nucleoid

_________- do NOT encode essential genetic information

plasmids

plasmids are similar structure to chromosomes, but much ______.

smaller

_______ may be shared with other bacteria (sex pili)

plasmids

plasmids are antibiotic ________, which allows them to spread

resistant

_______- involved in protein synthesis and facilitate the joining of amino acids

ribosomes

prokaryotic ribosomes are __s, composed of __s and __s.

70; 30 and 50

______ interior protein framework.

cytoskeleton

bacterial proteins _____ to eukaryotic cytoskeleton have been characterized.

similar

cytoskeleton is likely involved in ___ _____ and controlling cell shape.

cell division

____ _____ are produced by some aquatic bacteria (photosynthetic), which allows them to be aquatic.

gas vesicles

gas vesicles regulate the number of vesicles to rise or fall from the surface to reach ideal ____ ______.

sunlight levels

___________- a type of dormant cell

endospores

what are endospores produced by?

members of Bacillus and Clostridium

Dormant cells may remain dormant for ____ years or longer.

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