Lecture 2 Flashcards
The passage through lens meterial bending light is called
Refraction
Visible light range
400 - 750 nm
What is the resolution of our eyes?
150 MICRO meters (mew)
The ability to distinguish two adjacent objects or points from one another
Resolution, aka resolving power
Do short or long wavelength provide better resolution?
short
Resolving power equation
RP = wavelength of light in nm / 2 x NA
What is the numerical aperture?
describes the relative effeciency of a lens in bending light rays
What is a chain of bacteria cells called? What about a cluster?
Strepto-, Staphylo-
What are some advantages of microbes for being small?
- more surface area relative to cell volume
- grow faster
- more mutations = faster evolution
What structure defines the existence of a cell?
The cell membrane
Membranes have approx. equal parts of ______ and _____.
Phospholipids, proteins
A phospholipid consists of ______ with ____ links to _____ ______ ____ and a ______ _____ ____.
glycerol, ester links, two fatty acids, phosphoryl head group
Membrane protein fucitons.
- structural support
- secretion of virulence factors
- transmission of communication signals
- ion transport and energy storage
The cell membrane acts as a ___-______ barrier.
semi-permiable
_____ transport is essential for survival.
selective
How to small molecules, like O2 and CO2, permeate the membrane?
Diffusion
How does water diffuse across the membrane?
Osmosis
How to acids/bases get thrugh the membrane?
They exist in uncharged states to diffuse across and then change the pH of the cell.
Molecules move along their concentration gradient.
Passive transport
Molecules move against their concentration gradient
requires energy
Active transport
In eukaryotic membranes, the reinforcing agents are _____, such as cholesterol and ergosterol.
sterols
In bacteria, the reinforcing agents are _______, or ________.
hopanoids, or hopanes.
Describe the nucleoid.
- no nuclesar membrane
- haploid
- contains genetic material
Size of prokaryote ribosome
70S (two subunits 30S and 50S)
Extensively folded intracellular membranes in phototrophs.
Thylakoids
Polyherdral bodies packed with the enzyme Rubisco for CO2 fixation in phototrophs.
Carboxysomes
Increases buoyancy in phototrophs.
gas vesicles
List inclusion bodies in phototrophs.
- storage granules
- glycogen, PHB
- sulfur
- volutin
- magnetosomes
What shape determining protein do cocci have?
FtsZ - forms a Z ring for septum placement
What shape determining protein do baccili have?
MreB - forms a coil inside rod shaped cells
What shape determining protein do vibrio have?
CreS - crescentin, forms a polymer along inner side of crescent-chapes bacteria, leading to the kink
The cell wall confers _____ and _____to the
cell, and helps it _______ ______ ______.
shape, rigidity, withstand turgor pressure
Most becterial cell walls are made up of _________.
peptidoglycan
What does peptidogylcan consist of?
NAG, NAM, bound to a peptide. These peptides can form cross-bridges connecting the parallel glycan strands.
Gram positive bacteria have a ____ cell wall and stain _____.
thick, purple
Gram negative bacteria have a ____ cell wall and stain _____.
thin, pink
_______ acid is linked to lipids. This acts to anchor the wall to membrane.
Lipoteichoic
Mycrobial cell envelopes include unusual membrane lipids (_____ _____) and unusual sugars (_______).
mycolic acids, arabinogalactans
Only gram ____ contain lipoteichoic acid
positive
Long chains of mycolic acids are only found in _____ _____ bacteria.
acid fast
When the mycolic acid side chains are not too hydrophobic, they are ___ - ___ carbons.
30 - 40
When the mycolic acid side chains are somewhat hydrophobic, they are ___ - ___ carbons.
40 - 60
When the mycolic acid side chains are very hydrophobic, they are ___ - ___ carbons.
60 - 90
In the gram - negative outer membrane, the ___ _______ ____ consists of one ot two sheets.
thin peptidogylcan layer
In gram-negative cells, the peptidogycan leyer is covered by an ______ ____ which confers defenseive abilities and _____ properties on many pathogens.
outer membrane, toxigenic
Lipopolysaccharide (LPS) structure
- Lipid A (6 fatty acids)
- Core (adaptor structure)
- O-Antigen (repeats) (barrior function)
LPS is only found in gram _____ bacteria because ________.
negative, it is in the outer membrane
Gram-negative cells primarily use _____, which are ___to transport substances across their outer membrane.
porins
The peptidoglygan layer is in the _____.
periplasm
Mycoplasma have a cell membrane, but do not have _____, ____ ____, or a ___ ___.
peptodiglycan, mycolic acid, cell wall
What are the flagellar arrangements?
- monotrichous
- amphitrichous
- lophotrichous
- petritrichous
Spirochete flagella are known as ____ ____ because they are located in the ______.
axial filaments, periplasm (they are gram negative)
The movement of a bacterium in reponse to chemical gradients.
Chemotaxis
Short, numerous structures used to attach to cells and other stuctures, like rocks.
Fimbriae
A single, long structure used to attach to only cells ot transfer genetic code.
Sex pilus
Types of stuctures cells use to adhere to things.
- fimbriae
- stalks
- sex pilus
The outermost layer of a bacteria cell is the ____.
capsule
The capsule is made of _____.
carbohydrates
What is the most abundant macromolecule in a cell?
protein
______ does not contain murein.
Mycoplasma
_______ contains teichoic acid
Gram positive
