Cell Structure Flashcards
Chloroplasts + Mitochondria similarities
- both have double membrane
- large internal SA
- contains circular DNA
- contains 70s ribosomes
Features present in animal cells but not plant cells
1) microvilli
2) centrioles
3) cilia
resolution of light microscope and resolution of electron microscope
200 nm
0.5nm
advantages of using a light microscope over electron microscope
1) portable
2) easier to use;
3) able to see natural colours
4) able to see living tissue
5) particular tissues/organelles can be stained for better visibility
6) no heavy metal staining
State the piece of equipment that can be used in the light microscope to work out the correct proportions of tissues
eyepiece graticule
outline the function and structure of plasmodesmata
1) allows transport of water, sucrose, amino acids, ions, etc between cells
2) without crossing membranes
3) this is movement through symplastic pathway
4) allows communication/cell signalling
outline the function and structure of cell wall
1) rigid = made of cellulose
2) freely permeable
- protects + encloses cell
3) prevents cells from bursting/maintains turgidity
- contains plasmodesmata connecting cytoplasm a+ adjacent cells
outline the function and structure of chloroplasts
1) 5 to 10 μm
2) carries out photosynthesis
3) contains starch grains = temp store of carb produced during photosythensis
4) double-membrane
- inner folded –> lamella = control entry + exit of subst
- stroma = circular loop of DNA + 70s ribosomes//LIR
- grana= flattend sacs of thlakoids memb + carry out LDR
outline the function and structure of microtubules + centrioles
- 2 centrioles are present adjacent to centrosome/MTOC = 9 paired microtubules
- 2 centrioles = centrosome
TUBULIN –> DIMER–> 13 PROTOFILAMENTS rings–>MICROTUBULE - involved in nucleur division –> spindle fibres where they move chromosmes
outline the function and structure of mitochondria
1) aerobic respiration+ ATP synthesis
2) contain 70s ribosomes
3) double-membrane
- inner memb folded inwards = CRISTAE = LARGE SA for attachment of particles containing ATP synthase enzyme
- outer memb more permeable than inner due to transport protein porins = controls entry + exit of subst
7) Matrix contains have small circular DNA + NAKED
outline the function and structure of lysosomes
2) single membrane
3) contain conc hydrolytic enzymes e.g protease
- made by golgi body + RER
4) macrophage to kill bacteria - lysosome fuses w vacuole + released by Exo
- autolysis - cell dies + lysosomes release digestive enzymes for self-digestion
outline the function and structure of ribosomes
2) composed of 2 subunits ( S + L)
- made of protein + rRNA
3) Translation- protein synthesises = makes collagen etc
4) 80s - eukaryotes
5) 70s - smaller, present in prokaryotes, mitochondria and chloroplasts
outline the function and structure of the golgi body
1) stack of flattened sacs/cistanre formed from vesicles + bud off from the RER
2) SINGLE MEMBRANE
3) packaging proteins into vesicles for exocytosis
- production of secretory golgi vesicles
6) modifying proteins folding proteins into tertiary ss
- removal of 1st AA methionine activates proteins
outline the function and structure of the SER
synthesises lipids, steroids, hormones
- no ribosomes
outline the function and structure of the rough endoplasmic reticulum (RER)
1) flattend sacs of cisternae (large SA)
2) attached to nuclear envelope
3) ribosomes are attached to RER + synthesize proteins (translation) transported by exocytosis in vesicle to golgi body
- EXPLAIN EXOCYTOSIS
substances leaving the nucleolus
1) mRNA
2) ribosomes for protein synthesis
substances entering the nucleolus
1) protein to make ribosomes
2) ATP
3) nucleotides
outline the function and structure of a nucleolus
2) contains DNA
3) synthesises ribosomes
outline the function and structure of a nucleus
- Contains chromatin (DNA + histone proteins)
- transcription - makes mRNA
- contains nucleolus - makes ribosomes
- nuclear envelope continous w RER + nuclear pores = allows entry + exit of ribosomes and mRNA
- allows compartmentalisation = activities in nucles seperated from surronding cytoplasm
Structure of prokaryotic cells
-unicellular
No membrane around organelles = golgi, ER, nucleus, mitochondrion and chloroplast
- 70s (smaller) ribosomes
- 1-5um
- circular + naked DNA NO NUCLEUR MEMB
- no nucleulos
- saprotrophic nutrition OR photosynthesis
- carries out aerobic respiration
- murein cell wall- peptidoglycan
- slime capsule- protection
- piilli - adhesion
- plasmid-= produce enzymes to break down antibiotics
Virus structure
- non cellular/acellular
- protein coat (CAPSID)
- nucleic acid core; DNA or RNA strand
- replicates in host cells
- no characteristics of living organisms
- virus DNA/RNA injectes cell + takes over protein synthesis of host cell = new virus particles (lytic + lysogenic cycle)
-some have protective envelope - lipid envelope (soluable)
What restricts the resolution of light microscope
- wavelengths of visible light
single membrane structures
- Golgi apparatus
- lysosome
- vacuole
- ER (only in eukarotic)
explain how H+ bonds between water mol affect properties of water +help make water ideal enviornmet for organisms
- Cohesion between water mol
- mol held together/strong attraction
- water mol are polar = high boiling point/100ºC
- high latent heat of vaporisation so water is liquid over wide range of temps
- liquid so provides support/buoyancy
- high specific heat capacity
- stable temp + high latent heat of fusion
eyepiece graticule
- measuring device placed in the eyepiece of a microscope
The eyepiece lens of a microscope is fitted with an eyepiece graticule. Which statements about the graticule are correct?
It allows you to draw cells with correct proportions.
Which organelle does not contain a partially permeable membrane?
ribosomes,
At approximately which magnification is light microscopy not suitable because the resolution
becomes too low?
x1500
Where would cisternae be found in a cell?
ER + Golgi apparatus
Which statements about a stage micrometer are correct?
- allows you to calibrate the eyepiece graticule
- it changes in size as the objective lens changes from x10 to x40
organelles in prokaryotes
There are no membrane bound organelles in prokaryotes, so even photosynthetic prokaryotes don’t have chloroplasts
Golgi identification vs RER
- flattend sacs w NO membrane connection
- continous w nucleur evelope
- vesciles at end of sacs
- no ribsomes
describe nucleosome +how regulates transcription
- loosely coiled DNA/CHROMATIN supercoiled around 8 histone proteins
- lots of nucleosomes = chromatid
- formed in G2 of interphase (B4 mitosis) @ promotor region
- PR NOT accessible to RNA polymerase = doesn’t bind w TF
- DNA helicase cannot unzip DNA + RNA polymerase cannot unwind DNA = RNA nucleotides cannot CBP
- Template strand not made + no PDB = no mRNA made
- No transcription gene/switched off
PLANT VS ANIMALS
PLANTS
- plasmodesmata
- tonoplast
- cellulose cell wall
- chloroplasts
- large central vacuole
ANIMALS:
- Microvilli
- Centriole
- Cillia
- Flagella
EM BENEFITS
- higher resolution
- can see internal ss only visible in LM e.g cristae in mitochondria
- can see ss not seen in LM e.g ribsomes
- shorter wavelength
- resolution is = 1/2 wavelength
- 0.5nm in EM vs 200nm in LM
can see in LM + RULES
- Nucleus, nucelolus
- Vacuole
- Cell wall
- Chloroplasts
- Chromosome
NO RIBOSOMES + TONOPLASTS
- ALWAYS eye piece lens = x5
- ALWAYS objective lens = x10
- 200nm
ATP
- universal energy currency
- energy released when hydrolyzed
- easily hydrolyzed
- energy used in BAMTA/process
- links catabolic + metabolic reactions
- found in most cells
- soluable so easily moved in cells
state precsily 2 place ATP synthseised
- mitochondrial matrix
-cytoplasm - grana
- crista
cillia ss + function
- 2 central microtubules
- ring of 9 MTDS - 9+2 arrangements
- wall of A microtubule complete ring of 13 protofilaments + B microtuble attached to INCOMPLETE ring of 10 protofilaments
- A MICROTUULE = inner + outer arms made of protein DYNEIN –> connect w B microtubules of neignouting MTDS during beating
- cylindrical ss inside CSM = axoneme
- base of cillium = basal body identical to centriole (centrioles replicate = basal bodies)
- beating motion of cillia + flagella = dyenin making contact w neighboring microtubues = force for cilli to beat
- used for locomotion + maintains flow of mucus removal containing debris
Cholera = ORT (TB, Cholera,Malaria, HIV)
- contains glucose, salt
- reduced water potential in blood
- water from intestine enters blood
- down water potential gradient by osmosis
- reduced diharrea
Malaria drugs
Chloroquine - inhbits protein synthesis, prevents mRNA binding to small subunit of ribosome, no translation
Proguanil - inhibits sexual reproduction by preventing gametes from fusing in gut of female anopheels mosquito
HIV treatment
Zidovudine
- reassembles nucleotide thymine + similar ss in ss to thymine
- CI to reverse transcriptase + DNA polymerase
- so reduces repro of virus
