Lecture slides 9-11 Flashcards
(65 cards)
Antibiotics
- There are many ________.
-some are specific to certain types of_______:
-based on their ability to _______________.
-naturally occurring antibiotics
-bacteria
-target prokaryote-specific structures
Antibiotics
Two common targets are:
1) prokaryotic ribosomes (responsible for protein synthesis)
2) prokaryotic cell walls
Antibiotics
-prokaryotic cell walls
a)_________ ___________ present in our ________.
-Enzyme that _____________ of ___________ between __________.
-(__________ falls apart ,__________.)
b)______________.
- Lysozyme
-antimicrobial - bodily fluids (tears, milk, saliva, mucous)
-catalyzes hydrolysis
-b 1-4 linkages
-NAG and NAM
-peptidoglycan
-cells lyse
-Penicillin
Antibiotics: How does Penicillin work?
As bacterial cell grows, it __________.
-synthesizes more peptidoglycan
-the _______ is __________.
- inhibition leads to a ____________.
-works best on ________.
- As the cell grows ___________.
-eventually the cell_______.
-enzyme
- inhibited by penicillin (and derivatives)
-weakened peptidoglycan
-Gram positive cells
-new peptidoglycan is not formed
- bursts (lysis)
Is there anything else outside the bacterial cell wall?
Many bacteria also have a “capsule” surrounding the cell wall
Capsule
-mostly _________.
-further protects________.
- can be used to ____________.
- capsule is very rare in _______.
- polysaccharides
- cell from environment
- stick bacteria to surface
-Archaea
Pili (two types)
-fimbriae (attach to surfaces or host cells)
-sex pilus (for transfer of DNA between bacteria cells
Pili
-fimbriae (attach to surfaces or host cells)
e.g., Neisseria gonorrhoeae the
causative agent of gonorrhea
uses __________.
fimbriae to attach itself to
mucus membranes.
sex pilus (for transfer of DNA between bacteria cells)
-_______ is transferred to another _______
- DNA
- bacteria (termed bacterial
conjugation)
In a __________, many bacteria exhibit _______, the ability to _______________.
- Chemotaxis is the movement toward or away from ___________.
-Motile bacteria move in a series ______________.
- Duration of the run is longer if the ________ increases during the run.
-heterogeneous environment
- taxis
- a stimulus
- a chemical stimulus
- of “runs” and “tumbles”.
- concentration of the “attractant”
Another external structure:
Flagella (for movement)
- Flagella of bacteria, archaea, and
eukaryotes are composed of __________.
- Rotation can be ____________.
-CCW_____.
-CW______.
- different proteins and likely
evolved independently - clockwise
or counterclockwise (to
allow changes in direction) - “run”
- “tumble”
Bacterial flagella motors are
composed of many individual
components!
- E. coli uses a ________ to power the motor.
(some other bacteria use a ________)
- This is a type of ______ that
couples H+ ___________. - The overall rate of proton flow through the
motor is around ________.
- ~600 H+____________.
- Thus the motor can spin at about ______
- proton-based (H+) electrochemical gradient
- Na+ gradient
1.
-ion channel
- nflux to physical rotation of
the rotor/flagellum (like a turbine).
- -200 000 H+ per second
(when motor is not under load)
- go through the motor per revolution
- 300 Hz
Archaea Cell Walls
- no __________.
- various _______ surrounding the plasma membrane (__________)
-outer membrane
- coverings
- depends on species
Archaea Cell Walls
- no ______ but related molecules have been found in some species
- some Archaea are covered by _______________________.
- In general, they have ____________ due to a number of unique
differences______________.
- true peptidoglycan
- Archaea-specific lipopolysaccharides
- stronger membranes
- e.g., an ether linkage, rather than ester in their triacylglycerols.
Eukaryotic Cell Walls
- Animal cells do not have _______ but, _______________.
Cell Wall function:
-_______________
-_______________
- Cell wall = ________ chains embedded
in a matrix of other _____________.
-cell walls
- plants and fungi do!
-provides shape and function
- strong cell walls of plants help hold them upright
-cellulose
- polysaccharides
and proteins
Plant Cell walls
- young plant cell secretes a _____________.
-the ____________.
- as cell matures,___________.
- some secrete ______________.
- others add a _____________.
- A cell may have many layers per _________
- made of a matrix of ________.
- e.g., cells in ________ have many layers of ____________.
- thin cell wall outside the
plasma membrane
-primary cell wall
-cell wall is strengthened - hardening substances into the primary cell wall
- secondary cell wall
- secondary cell wall
- strong materials
- wood
-cellulose, lignin, proteins
Plant Cell walls
-Between primary cell walls of adjacent plant cells is the____________.
-The middle lamella is composed of:
- ________________ (this effectively glues
the adjacent cells together)
-middle lamella
-sticky
polysaccharides called
pectins
Note: Pectin is not the same thing as __________ Pectin is a
more general term referring to a mixture of _________ , e.g., pectin typically has __________ .
- amylopectin
- polysaccharides that are more complex
in structure - a 1-4 linked D-galacturonic acid (an oxidized
form of galactose) as its monosaccharide.
Plant Cell walls
-Because of the thick cell wall and middle lamella, plant cells are __________.
- To allow “communication” between cells, plant cell walls contain_________.
- allows passage of___________.
- Thus, the interior of all cells can be_________.
- These pores can ___________ depending on the
environmental conditions or age of the plant.
- isolated from
each other. - pores (tunnels)
between cells. - H2O and small solutes between cells
- connected
- open and close
Animal cells
- No cell wall but they secrete ______________.
- ______________.
- Some cells attach to the _____ using additional _______.
- most common is _________.
- _______ also binds to a specific class of integral
membrane proteins called _______.
- proteins and polysaccharides
- = extra cellular matrix (ECM)
- ECM
- specialized proteins
- fibronectin (interacts with collagen)
-Fibronectin
-integrins
Animal cells
- ECM consists mostly of _______.
- ________ is embedded in a network of other ____________
- glycoproteins and protein fibres (e.g.,
collagen, which is the most abundant protein in our body) - Collagen
- glycoproteins,
called proteoglycans
Proteoglycan
