Studing Cells Flashcards
Eukaryotic
true nucleus and the cells have membrane bound
organelles= plants Augie animal protozoan and fungi are all eukaryotic
Nucleus
nuclear envelope, nuclear pores, double membrane, nucleolus, chromatin which is DNA associated with histones
Store genetic information for polypeptide production
Site of DNA replication
Site of production of mRNA and tRNA
Site of production of rRNA or ribosomes
Mitochondrian
double membrane= outer membrane and inner membrane which is highly folded to form cistea, matrix= 70 S ribosomes, circular DNA
Site of ATP production by aerobic respiration
Rough endoplasmic reticulum
highly folding membrane with 80s ribosomes . Membrane is folded into flattened sacks called cisternea
Synthesis and transport of proteins throughout the cell
Smooth endoplasmic reticulum
highly folded membrane flattened into sacks called cisternea with no 80s ribosomes
Recombines glycerol and fatty acid to make a triglyceride
Packages triglycerides into vehicles and transport them to the Gogi body.
Cytoplasmic ribosome
made of two sub units that are made of long strands of rRNA and ribosomal proteins.
Site of protein synthesis from amino acids
Golgi Body
flattened sacks made up of membrane filled with fluid. Golgi vesicles pinch off from the main membrane.
Sort modifies and packages proteins into vehicles.
Lysosomes
stores and releases many hydrolytic enzymes
Cell surface membrane
made up of phospholipids specific transport proteins and carbohydrates into a fluid mosaic model
Controls the passage of molecules in and out the cell
Centrioles
microtubles
form a network of spindle fibres onto which chromosomes attach and pull apart chromosomes during mitosi
Chroplasts
Granum = stacks of thyokoid membrane, thylakoid membrane contain chlorophyll fo photosynthesis and ATP synthase enzymes to produce ATP, stroma = fluid filled part where photosynthetic reactions occur eg LIR, starch grains = energy store in plants, DNA and ribosomes = contain thier own DNA and 7Os ribosomes abd double membrane
Fungi cell wall
made of chitin not cellulose
Plants cell
Cellulose cell wall
Chloroplasts
Large vacuole
Carbohydrates stored as starch
No centrioles
Animal cells
No cell wall
No chloroplast
No large central vacuole
Carbohydrates stored as glycogen
Has centrioles
Prokaryotic cells
no nucleus and no membrane bound organelles. DNA is circular and non associated with histones. = bacteria cell only
Bacteria cell
capsule, 70s ribosomes, flagella, plasmid, cell wall, cell membrane, mesosome, circular DNA free
Prokaryotic cells
DNA is circular and not associated with histones
No membrane bound organelles
No true nucleus as DNA is free in cytoplasm
Cell wall made of murien or peptiglcogen
Have a capsule/flagella
Contains 70s ribosome which are smaller
Mesosome for ATP synthesis
Eukaryotic cells
DNA is linear and associated with histones
Contains membrane bound organelles
Has a nucleus and DNA contained within nuclear membrane
Cell wall made from cellulose
No capsule /flagella
Mitochondria for ATP synthesis
Contains larger 80s ribosome
Viruses
acellular and not alive as they are small and require a living cell to replicate inside
RNA, capsid , attachment proteins, capsid, enzymes
TEM
electrons passed through the specimen which allows you to view internal structures. Less dense areas absorb less electrons and appear lighter whereas dense areas absorb more electrons appear darker.
SEM
electrons bounce of the surface of the specimen. Images are always in black-and-white and produce a 3-D image.
Electron microscope
Uses a beam of electrons
Focused by electromagnet
Higher resolution as shorter wavelength of light
Must be in a vacuum, so are dead
Complex staining process
Artefacts present
Specimen must be very thin
Light microscope
Uses light
Focused by lens
Lower resolution as long wavelength of light
Can be living or dead
Can be easily dyed
Describe how you could make a temporary amount of a piece of a plant tissue to observe the position of starch grains in the cell when using a light microscope?
Add a drop of water to the microscope slide
Get a section of a plant tissue and float on top of the drop of water
Stain with potassium iodide solution
Lower the cover slip using a mounted needle to avoid air bubbles
Describe how a student could have used an eye gratitude to determine the main diameter of the stomata?
When using a light microscope, it requires two pieces of equipment called eyepiece lens and stage micrometer.
Stage micrometre is a microscope slide which has an accurate scale.
Measure each stomata using an eye piece graticule
Calibrate the eyepiece gratitule using a stage micrometre
Take at least five measurements on calculating mean.
I = A/M
Everything needs to be in same units
Cm=10mm(I)
1mm =1000 um (A)
1um= 1000nm(A)
Cell fractionation and differential centrifuge
Tissue is homogenised in a blender to break open cells into solution which must be ice cold = reduces action of enzymes that would digest organelles, buffered= stop PH changes that would denature proteins, isotonicv prevents osmosis of water in and out of organelles so organelles don’t burst or shrivel
Filter the mixture to remove any cellular debris producing supernatant which is a solution of suspended organelles
Differential centrifuge of the supernatant by centrifuge at higher speed to remove dentist organelles into pallet which is removed and then central future at a high speed for a longer time so next densest organelle forced to the bottom into pallet which can be removed
Process can’t be repeated many times are high speeds with each step
Nucleus= mitochondria/chloroplast= ribosomes
