Cells Flashcards
gWhat does nucleus have
Nuclear envelope
Nucleurnpores
Nuecluoplasm
Chromosomes
Nucleolus
Nuclear ENVELOPE
Nuclear pores
Nucleoplasm
Chromosomes
Nucleolus
Functions of nucleus
Mitochondria structures
Inner membrane folds to form Cristae
Holds the protein in place required for aerobic respiration
Double membrane
Cristae
Matrix
What chloroplasts contain
Grana
Stroma
How chloroplast adapted
Rough endoplasmid reticulum
To hold ribosomes in place
Form vesicles to seperste proteins products from the cytoplasm
Smooth endoplasmid reticulum
Function of Golgi apparatus
Function of lysosomes esicles
Vesicles contsintjng hydrolysis enzymes
Seperste hydroylytic enzymes from the cytoplasm
Ribosomes
Cell wall
Vacuoles
Why is tissue placed in buffer
Keeps the ph constant
Enzymes are protein which would be affected by the ph so if ph changes they would denature
Why would specimens be held in vacuum chamber
To hold it still
Largest to smallest chloroplast nucleus ribosome mitochondria
Nucleus
Chloroplast
Mitochondria
Ribosomes
Why is tissue placed in cold
Stop harmful bacteria down
Slow enzymes down
Stops breaking down the organelles for digestion
Why do some parts of a specimen see, bright
Allows electrons to pass through
Electron beam characteristics
Short wavelength
Resolve objects well
High revolving power
Negatively charged
Beam focused using electromagnets
Cell fractionation
Separates organelles according to their density
Centrifuge process
1)filtrate placed In centrifuge and spun at low speed
2)heaviest organelle forced to bottom of tube forming thin sediment or pellet
3)fluid at top is supernatant is removed leaving nucleui sediment
4)supernatant transferred to another tube and spun even faster
What are the two stages of cell fractionation
1)homogenation
2)ultracentrifugation
What does transmission microscope consider
Electron gun that produces a beam of electrons that is focused onto the specimen by a condenser electromagnet
How electron microscopes works
1)Use an electron beam of light which is focused using electromagnets as electrons are neg charged
2)Specimen has to be spec prepared and held inside vacuum chamber
3)Beam passes through this section of specimen .heavy metal stain absorbs electrons but electron passes through other parts of specimen
4)These areas appear brighter
5)the image formed as photograph (electron micrograph)or as image on tv
Homogenised
Cells are broken up
Resolution definition
The minimum distance apart that two objects can be in order for them to appear as separate items
Why tissue in same water potential
Isotonic
It would burst
Prevents osmosis so no lysis shrinkage of organelles
Light microscope characteristics
Light
Longer wavelengths
Cannot see objects more than 200nm
Glass lens focuses
What actually is ultracentrifugation
Process when the drag,ente are filtered and homogenate are separated from in centrifuge sounnng the tubes at high speed
What does resolving power depend on
The wavelength or form of radiation used
Greater resolution greater Clarity clearer image and more precise
How has fractionation and ultrafugation has helped
Allow detailed study of structure and function of organelles by showing what isolated components do
Tem characteristics
Electrons
Very short wavelength
0.1 nm resolving power
Prices by electromagnets
Vacuum needed
Complex staining process
2d image
Extremely thin specimen
Electrons from below
What actually happens in homogenation
Cells broken in blender releasing organelles fro, cell. Resultant Fukui (homogenate) filtered to remove complete cells or large pieces of debris
How to obtain large numbers of isolated organelle
Cells are broken up and then different organelles separated out
Tissue is placed in cold buffered solution of same water potential
Scanning electron microscope
Also beam of electron onto surface pf specimen from above rather than below
Beam passed backcknand forfth
3d
Lower resolving power