Cells Flashcards
(19 cards)
What is the equation for the magnification
Size of image/ actual size of object
What is cell fractionation and what are the conditions
Cells are broken up and the different organelles they contain are separated. Cold- reduce enzyme action that may break down organelles
Isotonic- same water potential to prevent organelles shrinking or bursting
Buffered- so pH doesn’t change the organelles structure or affect enzyme function
What are the two stages of cell fractionation
Homogenation
Cells are broken up using a homogeniser (blender) releasing the organelles into the fluid known as the homogenate. It is then filtered.
Unltracentrifugation
Homogenate span in a centrifuge- spun at low speed
Heaviest organelle nuclei forced into pellet at bottom of tube
Fluid left at the top (supernatant)
Supernatant is transferred and spun to make mitochondria pellet
Next heaviest organelle is mitochondria
What are the main features of the chloroplasts
Chloroplast envelope- double plasma membrane that surrounds the organelle highly selective in what can enter and leave
Grana- stacks of up to 100 disc like structures called thylakoids. Within the thylakoids is the chlorophyll
Stroma- fluid filled matrix where second stage of photosynthesis the synthesis of sugars take place
How have the chloroplasts adapted for their function
Granas membranes provide a large surface area for the chlorophyll
Fluid of the stroma posses all the enzymes needed to make sugars in the second stage of photosynthesis
Chloroplasts contain both DNA and ribosomes so they can quickly make proteins needed for process
What are the advantages of an electron microscope
Very short wavelength so can resolve objects well
Focused using electromagnets
What’s in eukaryotic cells
Membran Nucleus Mitochondrial Chloroplasts RER SER Ribosome Golgi body Vesicles Lysosomes Cytoplasm Cell wall Vacuole Starch grains
What’s in prokaryotic cells
Cell wall capsule cell membrane Flagellum Circular dna Plasmid Ribosome Cytoplasm circular dna
Nucleus
Nuclear envelope, nuclear pores nucleoplasm
chromatin nucleolus
Store genetic info
DNA replication
Transcription to rna
Plasmid
Small circles of dna used to exchange dna between bacterial cells
Circular dna
Contains genetic information to let cells replicate not associated with proteins
Mitochondria
Release energy produce atp From aerobic respiration Double membrane controls entry and exit from cell Cristae us extension of membrane Matrix contains enzymes for respiratory
Cell wall
Cytoplasm
Capsule
Cell wall- made of peptidoglycan (murein in bacteria) protect cell against damage.
Cytoplasm- contains enzymes for metabolic reaction
Capsule thick polysaccharide layer outside of the cell for protection/helps group of bacteria stick together for more protection
Flagellum
Ribosomes
RER
SER
Flagellum - rail for movement rotated and spins cell through fluid
Ribosomes- 80s in eukaryotes 70s make proteins
RER- surface ribosomes for proteins synthesis provide pathway for transport of materials
Ser- makes stores and transports lipids and carbohydrates
Golgi body
Modified polypeptide chains into mature proteins. Sorts and ships lipids for secretion or use within cell
Forms glycoproteins
Modified proteins and lipids transported in Golgi vesicles
Lysosomes
Break down and recycle materials in the cell
Adaptations of epithelial cells for absorption
Microbilli large s a
Many mitochondria release energy for active transport
Carrier proteins for active transport
why is atp useful
releases energy in small suitable amounts
broken down in one step
makes energy rapidly available
makes phosphorylated substances more reactive. lowers activation energy
can be reformed
why do we need atp
to provide energy for reactions e.g active transport metabolic processes movement etc
add phosphate to other substances make them more reactive
