Mod 2 Chap 2: Cell Structure and Microscopy Flashcards
How do you convert from mm to micrometers?
X 1000
How do you convert from micrometers to mm?
divide by 1000
How do you convert from micrometers to nm?
X 1000
How do you convert from nm to micrometers?
Divide by 1000
What does epu stand for?
Eye piece units across
What is the equation needed for magnification calculations?
I
AM
I = image size A = actual size M = magnification
So I = A x M
A = I / M
M = I / A
Answer these questions for a light/ optical microscope: Source of image: How the beam is focused: Max effective magnification: Max resolution: Can a live specimen be used: Section / external view: Cost: Staining of specimen required:
Source of image: BEAM OF LIGHT How the beam is focused: LENSES Max effective magnification: X 1500 Max resolution: 200 nm Can a live specimen be used: YES Section / external view: SECTION Cost: CHEAP Staining of specimen required: NO
Answer these questions for transmission electron microscope (TEM): Source of image: How the beam is focused: Max effective magnification: Max resolution: Can a live specimen be used: Section / external view: Cost: Staining of specimen required:
Source of image: ELECTRON BEAM How the beam is focused: ELECTROMAGNETS Max effective magnification: X 500,000 Max resolution: 0.2nm Can a live specimen be used: NO Section / external view: SECTION Cost: EXPENSIVE Staining of specimen required: YES WITH METAL SALTS
Answer these questions for a scanning electron microscope (SEM): Source of image: How the beam is focused: Max effective magnification: Max resolution: Can a live specimen be used: Section / external view: Cost: Staining of specimen required:
Source of image: ELECTRON BEAM How the beam is focused: ELECTROMAGNETS Max effective magnification: X 100,000 Max resolution: 10 nm Can a live specimen be used: NO Section / external view: EXTERNAL Cost: EXPENSIVE Staining of specimen required: COATED WITH GOLD
List the four types of microscope
Scanning Electron Microscope
Light / Optical
Transmission Electron Microscope
Laser
Define Magnification:
How many times larger the image is than the actual size of the object being viewed.
Define Resolution:
The ability to see individual objects as separate entities.
Which types of microscope can produce 3D images?
Scanning (SEM)
Which microscope uses fluorescent dyes to stain specimens?
Laser scanning
What are the organelles present in animal cells?
Plasma membrane Nucleus Nucleolus Nuclear envelope Nuclear pore Peroxisome Ribosome Golgi complex Lysosomes Secretory vesicle Mitochondrion Cytoplasm Centrioles Cytoskeleton - filaments Microtubules Smooth endoplasmic reticulum Rough endoplasmic reticulum
What are the organelles present in plant cells?
Plasma membrane Cytoplasm Mitochondria Cytoskeleton: micro tubules, filaments Nucleus Nucleolus Nuclear envelope Nuclear pore Rough endoplasmic reticulum Smooth endoplasmic reticulum Golgi complex Peroxisome Cell wall Chloroplast Permanent vacuole: tonoplast Plasmo desmata Ribosomes
What is the function of the centrioles?
Component of the cytoskeleton involved in assembly and organization of spindle fibers during cell division
Describe the preparation and examination of slides used in light microscopy.
- sample placed on a slide + allowed to air dry
- then heat fixed by passing through a flame
- specimen then adheres to microscope slide + takes up stains
Describe the various methods in which samples and specimens can be prepared for examination by light microscopy.
- dry mount: specimen place onto slide dry + covered with a slip
- wet mount: specimens suspended in liquid such as water + covered with a slip
- squash slides: wet mount is prepared, cover slip is pressed down with a lens tissue, damage to cover slip can be avoided using two microscope / squash slides
- smear slides: edge of a slide used to smear sample on another slide, cover slip then placed on top.
Describe the importance of the cytoskeleton in terms of its structure.
- it’s a network of protein structures within cytoplasm
CONSISTS OF:
- rod like MICROFILAMENTS made of subunits of protein actin, they are polymers of actin.
- INTERMEDIATE FILAMENTS about 10nm in diameter
- MICROTUBULES that are straight and cylindrical, made of subunits of protein tubulin
- CYTOSKELTAL MOTOR PROTEINS: myosins, kinesins, and dyenins are molecular motors, they are enzymes that allow hydrolysis of ATP as the energy source.
- cytoskeleton is present in all eukaryotic cells
- network of fibers necessary for shape and stability of cell
- holds organelles in place
- controls cell movement and movement of organelles within cells
Describe the importance of the cytoskeleton in terms of cell movement.
- movement of cells like phagocytes depends on activity of actin filaments in cytoskeleton
- filament lengths change w/ addition + removal of monomer subunits. (Rate these subunits added is diff at each end of filament)
- so at certain concentrations, subunits added at one end + removed at other, called ‘treadmilling’, causing cells to move in a particular direction.
Describe the differences in structure and ultra structure of prokaryotic and eukaryotic cells.
Eukaryotic Prokaryotic
-Has membrane bound organelles. -Does not
-Has a nucleus. -Does not
-Large ribosomes. -Small ribosomes
-DNA on linear chromosomes. -DNA on circular
chromosomes
-DNA within cytoplasm. -DNA within nucleus
-ATP production in folded regions of. -ATP production in
cell membrane called mesosomes. mitochondria
-cellulose based cell wall. -peptidoglycan based
cell wall
- may have undulipodia. - may have flagella
(Cilia and flagella)
What is differential staining?
It can distinguish between two types of organisms that would otherwise be difficult to differentiate between different organelles of a single organism within a tissue sample.
What techniques can be used when staining samples in microscopy?
Gram Stain Technique - separates bacteria into two groups
Acid-fast technique - differentiates species of Mycobacterium from other bacteria.
