Module 2-Basic components in living organisms Flashcards
Light microscope and Confocal microscopy
LIGHT MICROSCOPE: Magnification x1500 Resolution: 200nm Adv: Can study whole organisms Portable and cheap Living and dead organisms can both be viewed Dis: Specimens often need to be stained Low resolution and magnification
LASER SCANNING CONFOCAL MICROSCOPE: Magnification x1500 Resolution 160nm Adv: Laser can scan at different depths in living tissue Dis: Expensive Requires stain and dye
SEM and TEM
SEM:
Magnification x100,000
Resolution 0.1nm
Electron bream ‘bounces off’ sample
TEM:
Magnification x500,000
Resolution: 0.1nm
Electron beam penetrates through thin sample
ADV AND DIS OF ELECTRON MICROSCOPY: Adv: Produces detailed images SEM produces 3D images showing contour Dis: Sample must be in a vacuum Expensive Sample must be dead High degree of skill needed to use
Specimen preparation for slides
1) FIXING:
Used to preserve specimen in a near natural state
2) SECTIONING:
Specimen embedded in wax top preserve structure of sample’s cell walls while cutting into thin slices
3) STAINING:
Binds to structure, increases visibility
4) MOUNTING:
Specimen secured to slide and cover slip placed on top
Define Magnification and Resolution
Magnification formula
MAGNIFICATION:
Number of times larger an image appears compared to its real size
RESOLUTION:
Ability to distinguish between two adjacent but separate points
FORMULA:
Magnification=Image size/Actual size
m x100 cm x10 mm x1000 um x1000 nm
Advantages of staining and examples
Define Artifacts
ADVANTAGES:
See more detail
Increased contrast
Recognize organelles more easily
EXAMPLES: \+ Crystal violet and Methyine blue Stains cell components - Nigrosin and Congo red Stains backgrounds
ARTIFACTS:
Visible structural details caused by processing
Can change ultra-structure in TEM
Functions of Nucleus, Nucleolus and Nuclear envelope
NUCLEUS:
House’s cells genetic material
Contains DNA
Instructions for making proteins
NUCLEOLUS:
Makes RNA and ribosomes
Site of protein assembly
NUCLAR ENVELOPE:
Allows passage of relatively large molecules
Functions of Smooth ER and Rough ER
SMOOTH ER:
Production of lipids
ROUGH ER:
Transports proteins made on attached ribosomes
Functions of Mitochondria and Lysosomes and Centrioles
MITOCHONDRIA:
Aerobic respiration
Production of ATP
LYSOSOMES:
Contains digestive enzymes that breaks down material
CENTRIOLES:
Involves in cell division
Functions of Golgi apparatus and Ribosomes and Plasma membrane
GOLGI APPARATUS:
Receives proteins from Rough ER
Modifies proteins and repackages them into vesicles
Makes lysosomes
RIBOSOMES:
Site for protein synthesis
Assembly line for mRNA
PLASMA MEMBRANE:
Isolation for metabolic pathways
Compartmentalization
Partially permeable
Role of Cytoskeleton
- Helps cell maintain shape
- Microfilament in involved in cytokenisis
- Movement of cilia
- Movement of chromosomes and mRNA
- (named) organelle held in place
Vesicle transport relies on the cytoskeleton to move substances across organelles. Moves along microtubles. ATP is required
What is Cilia and Flagella
CILIA:
‘Hair-like’ extensions
Allows for movement of substances
Sticks out on cell surface
FLAGELLA
Extension that sticks out of cell
Tail for cell movement
Stages of Protein Production
1) Proteins synthesized by ribosome bound Rough ER
2) In cisternae it is packaged into transport vesicles
3) Proteins moved to Golgi apparatus, packaged and modified into secondary vesicles
4) Vesicles fuse with plasma membrane. Exoscytosis
5) Correct target organelle identified for each organelle
Key features of a Prokaryotic cell
- Smaller ribosomes ‘20nm’
- One cell membrane
- Free DNA (linear)
- Capable of anaerobic respiration
- Unicellular
- Energy from chemiosmosis
- Reproduced in binary fusion
- No nucleus
Function of Chloroplast and Vacuole in a Plant cell
CHLOROPLAST: Site of photosynthesis Double membrane Flattened sacs= Thylakoid Stacked up= Granum Fluid filled space= Stroma
VACUOLE:
Maintenance of turgor
Tonoplast membrane
Selectively permeable
