Microbial Cell Structure Flashcards
What is resolution?
The ability to ditinguish two adjacent objects or points from one another.
What is refraction?
Passage through lens material bends light.
Do short or long wavelengths provide better resolution?
Short
What color gives the best resolution?
Violet
What are ball shape bacteria called?
Coccus
What are stick shape bacteria called?
Bacillus
What is a chain of cocci called?
Streptococci
What is a chain of bacilli called?
Streptobacilli
What is a cluster of cocci called?
Staphylococci
Why can bacilli never form staphylo (cluster)?
They divide (|) not (–) so they cannot attatch in that way.
What is the advantage of being small?
More surface area relative to cell volume. This allows faster growth and better exchange
The structure that defines the existence of a cell is the _____.
Cell membrane
Cemm membranes have approximately equal parts of _____ and ____.
phospholipids, proteins
What makes up a phospholipid?
Glycerol with ester links to two fatty acids and a phosphoryl head group.
Membrane protein functions:
- structural support
- secretion of virulence factors
- transmission of communication signals
- ion transport and energy storage
The cell mambrane acts as a _______ barrier.
semi-permeable
_______ transport is essential for survival.
selective
Small uncharged molecules such as O2 and CO2 easily permeate the membrane by _____.
diffusion
How does water diffuse across the membrane?
osmosis (moves to where more stuff is dissolves in water)
Most bacteria are _____, drawing water ____, making them _____.
hypertonic, in, swell.
What heppens with weak acids change the pH of a cell?
It allows some compounds to cross the membrane that could not before.
Molecules move along their concentration gradient.
Passive transport
Molecules move against their concentration gradient.
Active transport
Does passive or active transport require energy?
Active transport
Saturated fats are _____ at room temp.
solid
Unsaturated fats usually have ___ bonds and are ____ at room temp.
cis, oil
Bacteria adapt to the temp of their environemnt by becoming less saturated when temp _____.
decreases
In eukaryotic membranes, the reinforcing agents
are _____ , such as cholesterol and ergosterol.
sterols
Bacteria do not use sterols, but use ____ or _____ for the same function.
Hopanoids or hopanes
T/F: The nucleoid has a nuclear membrane.
False
Nucleoids are
haploid
What is the total size of prokaryote ribosomes?
70S (two subunits, 30S and 50S)
Extensively folded intracellular
membranes
Thylakoids
Polyhedral bodies packed with
the enzyme Rubisco for CO2 fixation
Carboxysomes
What is used to increase buoyancy?
gas vesicles
What are the kind of storage granules?
- glycogen, PHB (for energy)
- sulfur (for oxidation)
- volutin (phosphate)
FtsZ
Forms a Z ring for septum placement (pinch off point for cytokinisis
MreB
Forms a coil inside rid shaped cells, keeps the rod shape
CreS
Forms a polymer along the inner side of crescent-shaped bacteria, creates the bent chape
The cell wall conifers ____ and _____ to the cell, and helps it ____________.
shape, rigidity, withstand turgot pressure
Most bacterial cell walls are made up of _____.
peptidoglycan (or murein)
What does peptidoglycan consist of?
NAG- NAM - peptide (4-6 aa)
The peptides of peptidoglycan form ________ connecting the parallel glycan strands.
cross-bridges
Gram prositive cells have
lipoteichoic acid linked to lipids, act to anchor the wall to membrane
Thick cell wall are gram ______ and think cell walls are gram ______.
thick = +
thin = -
Mycobacterial cell envolopes include unisual membrane lipids (______) and ususual sugars (______).
mycolic acids, arabinogalactans
Gram positive have ___ membrane(s) while gram negative have ____ membrane(s)
one, two
The ___ _________ _____ consists of one or two sheets in gram negative bacteria.
thin peptidoglycan layer
