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What is magnification
how much bigger an image is compared to real size
what unit is image size measured in
mm
what is the equation for magnification
image size / actual size
how do you calculate magnification with a scale bar
magnification = measure scale line length / given length
how do you find magnification with given scale sixe
(image size / scale size) x given scale size
What is the resolution of a light microscope
200nM
what is resolution
measure of the ability to distinguish between two points in detail
what are some negatives if light microscopes
sample must be thin, materials distorted when cut thin, most biological material is colourless
How can you prevent cell distortion
wax blocks
what is the resolution of electron microscopes
0.2 nM
what can you see with electron microscopes and not light ones
cell ultrastructure
what is cell ultrastructure
organelles
What image does a TEM produce
2D
what image does a SEM produce
3D
why are electron microscopes high resolution
due to short wavelength of electrons
what are disadvantages of electron microscopes
dead specimens only, no colour, can cause artefacts, long preparation process
why can electron microscopes only use dead specimens
its in a vacuum
what does cell fractionation do
breaks open cells and the organelles are seperated
what does cell fractionation allow
study of cellular / ultra cellular function and structure
what must you put the tissue in before cell fractionation
a cold isotonic buffer solution
why must the tissue be cold in CF
to prevent enzymes reactions which could break down organelles
why must the tissue be isotonic in CF
osmosis net movement is equal to prevent bursting / shrinking
why must the tissue be in a buffer in CF
so the pH doesn’t change to prevent organelle damage
what is homogenisation
breaks open cell membrane / cell wall
what does homogenisation allow
access to organelles
what occurs before centrifugation
filtering to remove debris (i.e. cell wall)
what does centrifugation seperate first
the heaviest organelles
what do the organelles form in a test tube
sediment pellet
what is the liquid in the test tube with the remaining organelles
supernatent
How do you find the next organelle in centrifugation
increase the spin speed
What does the second supernatant spin produce
Chloroplasts
Describe how to make a temporary cell mount
Add a drop of water, stain tissue, place coverslip using a mounted needle to avoid air bubbles
Why would a TEM be used
To produce a high resolution image to allow visibility of internal structures of organelles
Eukaryotic cells
Cells that contain a nucleus and membrane-bound organelles.
describe the nucleus’s structure
A double membrane structure that contains nuclear pores, chromatin, and a nucleolus.
Describe the Nucleoplasm structure
A granular jelly-like material that makes up the bulk of the nucleus.
Describe the Rough endoplasmic reticulum (RER) structure
Flattened membrane sacs with ribosomes on their surface
what is the purpose of the RER
that fold and process proteins.
Describe the Smooth endoplasmic reticulum (SER) structure
A system of membrane-bound sacs
What is the function of the SER
produces and processes lipids
Describe the Golgi apparatus structure
A series of fluid-filled flattened sacs
What is the function of the golgi apparatus
processes, packages and transports proteins and lipids, adding carbohydrate groups to proteins
Describe the Mitochondria structure
Oval-shaped organelles with a double membrane and loop of DNA
What is the function of mitochondria
respiration and energy production
What are cristae
Folded inner membrane of mitochondria
What do cristae do
increases surface area for respiration.
what are Centrioles
Hollow cylinders
what are Ribosomes structures
made of two subunits
what do ribosomes do
protein production
What do centrioles do?
producing spindle fibers for cell division
what are Lysosomes
Vesicles containing digestive enzymes
what do lysosomes do
involved in breaking down waste
what is a Cell wall
Rigid outer covering
what is a cell wall made of
cellulose
What is the structure of a vacuole
a tonoplast
what is the function of a vacuole
helps maintain cell pressure, stops wilting
What structures are in chloroplasts
Lamella, stroma, thylakoids, loops of DNA, starch grains and lipid stores
What is the function of chloroplasts
Isolates photosynthesis
What are specialised cells?
Cells that have specific structures and functions adapted to their roles.
What is the function of red blood cells?
They transport oxygen and carbon dioxide in the bloodstream.
Describe the structure of sperm cells.
They have a streamlined shape and a flagellum for mobility.
What is the function of root hair cells in plants?
They absorb water and minerals from the soil.
What specialized function do xylem cells serve?
They transport water and nutrients from roots to other parts of the plant.
What is the role of white blood cells?
They are involved in the immune response, protecting the body against pathogens.
why is differentiation needed
to perform more functions as SA: Vol ratio decreases
How can you tell specialised cells apart from normal cells
change in shape, gain/loss of organelles
What to cells start as
STEM cells, embryonic undifferentiated cells
Name four structures present in plant cells not animal cells
Cell wall, chloroplast, vacuole, starch grain
What surrounds the vacuole
Tonoplast
What is the function of the smooth endoplasmic reticulum
Allows for lipid synthesis
What is the function of the nucleus
To allow protein synthesis
What system would contain a lot of lysosomes
Digestive system
Why are no organelles visible in the cytoplasm of a red blood cell
The cytoplasm is filled with haemoglobin
what is a prokaryote
a cell with no nucleus or membrane bound organelles
what organelles do prokaryotes always have
cell wall, plasma membrane, cytoplasm, ribosome, circular DNA
what is a slime capsule
a sticky coat to prevent drying out
what is flagellum
fibres which propel the cell
what are nucleoids
contains circular DNA
What is peptidoglycan
found in cell walls for rigidity
what are plasmids
small rings found in cytoplasms
what are mesosomes
inner extensions of the cell surface membrane and site of respiration
what are ribosomes
where protiens are made
whats the difference between and eukaryotic and prokaryotic ribosome
prokaryotic ribosomes are smaller
where is found murein
cell walls
what does acellular mean
not a cell
are viruses acellular
yes
what doesnt have organelles in it
virus
what do all viruses have
attatchment protiens, capsid, generic material
what do capsids do
protein coats to protect DNA/RNA
what is the genetic material of a virus
DNA or RNA
what are pili
hair like structures which attach to things
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