Seminar 5: Exploring Cell types Flashcards
(31 cards)
what is the cytoplasm composed of ?
cytosol + cytoskeleton
what is the cytoplasm?
- entire space inside cell (excl. nucleus)
- gel-like, contains organelles & supports cellular activities
- moves by cytoplasmic streaming
what is the cytosol
- liquid part of cytoplasm (excl. organelles)
- made of ions, H2O, small molecules & soluble proteins
- LESS DYNAMIC than cytoplasm (not much VISIBLE movement)
what is the cytoskeleton & what is it composed of?
anchor organelles, scaffolding/structural part of cytoplasm
composed of:
- microfilaments
- intermediate filaments
- microtubules
desc the microfilament & its functions
2 actin polymers into fine, small wires
- Contraction of cell (animal, contractile ring)
- Cell motility (cytoplasmic streaming)
- Maintain shape & cell structure
desc the intermediate filaments & its functions
thick cables of fibrous proteins (keratin)
- Anchors organelles
- Formation of nuclear lamina (membrane)
- Helps cell deal w/ mechanical stress (take some tension)
desc the microtubule & its func
Alpha & Beta tubulin wrapped into tube.
- Framework for motor proteins
- Allow cell movement
- Aids in chromosomal movement in cell division
what is the order of size of the components of the cytoskeleton?
microfilament > intermediate filament > microtubule
what is the order of the secretory pathway?
Nucleus > RER > Golgi > Vesicle > Cell membrane
desc func of RER in secretion
- Ribosomes on surface synthesise proteins from mRNA
- Transport to golgi in vesicle
desc func of golgi in vesicle
- Vesicle enters @ Cis face, leave @ Trans
- Package & process proteins
(Modify by adding/removing) - Products are pinched off in vesicle
desc func of vesicle in secretion
- Export: go to cell membrane, exits via exocytosis
- Use w/in cell: lysosome
desc func of plant vacuole
- Store nutrients & pigments
- Breakdown material
- Maintains cell turgor/pressure
desc func of lysosome
- Break down ingested materials (v. acidic interior w/ enzymes)
- Phagocytosis or Autophagy (break old organelles)
- Prod of digestion used to make NEW PROD
- Digest pathogens
desc func of microbodies (not part of endomembrane system)
Peroxisomes: break down a.a
Glyoxysomes: breakdown F.A
desc the phospholipid bilayer
- NP & P parts
- P = phosphate head, NP = F.A tails
- cholesterol embedded w/in
- NP &/or small molecules can pass thru (via diffusion or dissolve in bilayer)
- P &/or large molecules can’t pass easily
what does cholesterol do w/in the bilayer
- decreases membrane fluidity by decreasing phospholipid movement
- OH grp in cholesterol binds to phosphate head (both P), rest of molecule forms DF w/ F.A tails (NP)
- this anchors the tails in the bilayer to PREVENT MOVEMENT
define hypotonic sol
- sol outside cell has LOW solute conc
- H2O will flow into the cell to increase the conc of the sol
- becomes LESS diluted & MORE CONCENTRATED
- the cell will lyse
define isotonic sol
conc same inside & outside a cell
define hypertonic sol
sol outside cell has HIGH solute conc
- H2O from inside cell flows OUT to decrease conc
- causes cell to shrivel
what is facilitated diffusion
Passive movement through a membrane involving a specific carrier protein; does not proceed against a concentration gradient.
what is active transport
energy-dependent transport of a substance across a biological membrane against a concentration gradient—that is, from a region of low concentration (of that substance) to one of high concentration
what is the diff b/w active transport & facilitated diffusion
active req energy, transport from low to high conc
facilitated is opposite
what is pinocytosis
Endocytosis by a cell of liquid containing dissolved substances w/in vesicles.
