Microscopes and Cell Structures

Flashcards for vocabulary related to microscopes, cell structures, and staining techniques

Compound light microscope

Uses visible light to observe objects, finding microorganisms in typical micro Lab

Ocular Lens

Magnifies

Collector

Collects light

Ocular Lens

Magnifies

Stage

Holds clips, holds in place

Resolution

How sharp image is

Magnification

Apparent increase in size

Total magnification (TM)

Power of ocular lens X Power of objective lens

Resolution

Minimum distance between any two objects closer than 0.2 microns, blend together

Immersion oil

Needed to enhance resolution

Contrast

Determines how easily cells can be seen against background

Staining

Increases contrast but kill microbes

Light microscope

Uses visible light

Brightfield

To view colored or stained specimen. If they're clear we Won't see with bright background

Darkfield

Increases contrast of live specimen

Darkfield

Cells appear as bright objects against dark background

Phase-Contrast Microscope

To view internal structures of live organisms

Fluorescence Microscopes

Use on cells/materials naturally flourescent or tagged with fourescent dyes

Fluorescence Microscopes

Diagnosis of disease with Flourescent-tagged antibodies that marks their location

Scanning Laser Microscopes (SLM)

Allow detailed views of interior of intact cells

Electron Microscopes

Uses electron beams for high resolution

SEM

Used to observe surface details

TEM

Used to view internal detail

Scanning Probe Microscopes

Detailed images of surface bumps

Wet mount

Live bacteria - hard to see due to lack of contrast

Smear

A thin layer of cells dried and fixed onto a slide before staining

Basic dyes

Carry (+) charge, stains bacteria

Acidic dyes

Carry (-) charge, stains the background

Simple stain

Uses one stain to stain cell, increases contrast

Differential Stains

To distinguish different types of bacteria

Gram Stain

Based on Gram-positive and Gram-negative

Gram-positive

Stained purple (retains primary dye)

Gram-negative

Stained red or pink (loses primary dye)

Mycobacterium

Includes causative agents of TB and leprosy

Primary dye (Carbol fuchsin)

Colors acid-Fast bacteria red

Counter stain (Methylene blue)

Colors Non-acid-fast bacteria blue

Endospore

Resistant formant structure formed by species of Bacillus, Clostridium

Endospore stain

Uses heat to facilitate uptake of the primary dye malachite green by endospore

Flagella

Used for prokaryotic motility

Coccus

Spherical

Bacillus

Rod or Cylinder shaped

Vibrio

Curved Rod

Spirochete

Helical shape

Fission

Division on plane usually without tell wall

Diplococci

Pairs

Streptococci

Chains

Tetrad

Cubical pockets

Staphylococci

Grape-like Structures

Capsule

Organized, attached to cell wall

Slime Layer

Unorganized, loose

Glycocalyx

Protection from host defenses (phogocytosis)

Dental Plaques

Oral streptococci use capsular slime to adhere to surfaces of teeth and gums

Fimbriae

Hair-like, facilitates attachment

Sex pilus

Attachment to another cell

Flagella

Long protein structure for motility

Filament

Made of proteins called flagellin

Basal body

Anchors filament into cell wall

Flagellar Arrangement

Vary and help with characterization

Motility

Movement is series of runs and tumbles

Chemotaxis

Bacteria sense chemicals and move accordingly

Cell Wall

Maintain cell shape

Peptidoglycan (PTG)

Found only in Bacteria

PTG

Crosslinked by tetrapeptide chains

Penicillin

Prevents crosslinking of adjacent glycan chains

Lysozyme

Breaks bonds linking glycan chain

Gram positive cell wall

Has thick peptidoglycan layer

Gram-negative cell wall

Has thin peptidoglycan layer, outer membrane, and lipopolysaccharide (LPS) layer

Gram-positive bacterium

Retains crystal violet-iodine complex

Gram-negative bacterium

Loses crystal violet-iodine complex

Mycoplasma species

Have sterols in membrane give strength to membrane

Domain Archaea

Does not contain peptidoglycan but rather pseudopeptidoglycan (lack NAM)

The Cytoplasmic Membrane

Phospholipid bilayer embedded with proteins

The Cytoplasmic Membrane

Energy production

Simple diffusion

Molecules move freely across cytoplasmic membrane

Simple diffusion

Moves from area of high concentration to low concentration until equilibrium is reached

Facilitated diffusion

Moves molecules across membrane with aid of a carrier protein

Active transport

Moves molecules against concentration gradient using a transporter protein

Cytoplasm

Chromosome

Plasmids

Extrachromosomal, circular, dsDNA

Ribosomes

Involved in protein synthesis

Cytoskeleton

Controls cell shape

Gas vesicles

Provides buoyancy

Endospores

Unique dormant structure

Endospores

Resistant to adverse conditions

Sporulation

Endospore formation

Germination

Return to vegetative state

Endosymbiosis

mitochondria and chloroplasts were derived from bacteria