Chapter 3: Cells Flashcards
What is cytology?
What are the three main components of a cell?
What is the plasma membrane made of? (I.e. how much is phospholipids, cholesterol and glycolipids)
The plasma membrane has some anchored proteins and some floating ones. What is the model for this called?
cytology: cell biology
plasma membrane, cytoplasm and nucleus are main components
plasma membrane: 75% phospholipids, 20% cholesterol (weakly amphipathic), 5% glycolipids (only in outer layer, facing ECF)
fluid mosaic model
What are integral proteins? Peripheral proteins?
Which one has oligosaccharide carb group attached that goes into the ECF?
integral proteins: embedded, usually transmembrane, amphipathic, mostly glycoproteins (have oligosaccharide carb group attached which goes into the ECF)
peripheral proteins: at inner or outer surface
integral protein
What is the glyocalyx? What detects the glyocalyx?
glyocalyx: hydrophilic, sugary coat of glycolipids/glycoproteins that sticks cells together in tissue and protects from enzyme (it is a signature)
white blood cells detect the glyocalyx as part of the immune response
Match functions:
a. integral protein
b. peripheral protein
i. ion channels (usually selective), carriers/transporters (selective), specific receptors, enzymes, links between cells/filaments, cell identity markers
ii. support membrane, anchor integrals, move materials/organelles, attach to cells, change cell shape
a & i, b & ii
How does cholesterol concentration affect membrane fluidity?
How do large macromolecules like protein cross the membrane?
- at body temp: more cholesterol = more rigid membrane
- at low temp: more cholesterol = more flexible membrane
proteins cross the membrane by endo/exocytosis
What is the lipid bilayer highly permeable to, moderately permeable to and impermeable to?
a. small alcohols, water, urea (small, non-charged polar as they sneak through gaps)
b. ions, large uncharged polar (ex. glucose)
c. O2, CO2, steroids (non polar), N2, fatty acids, vitamins A, D, E and K
highly permeable: c
moderately permeable: a
impermeable: b
Is there more Na+ in the ECF or cytosol?
Which two ions have the most ion channels?
Which is more positive: the ECF or cytosol?
more Na+ in the ECF, more CO2 and K+ in the cytosol
more K+ and Cl- ions than Na+ or Ca2+
the ECF is more positive, the cytosol is more negative
Which molecule is not moved by facilitated diffusion carriers:
glucose, oxygen, fructose, galactose, some vitamins
What is GluT?
What effect does insulin have on GluT?
oxygen
GluT: glucose transporter
insulin increases the number of GluT so more glucose is moved into cells
Is osmosis active transport?
Where does osmosis occur?
What is hydrostatic pressure?
no, osmosis is passive
osmosis occurs through membrane gaps or aquaporins
hydrostatic pressure: pressure liquid exerts on membrane
What is osmotic pressure?
What effect does a hypotonic solution have on a cell?Hypertonic? What is isotonic in the human body?
What are the two types of active transport?
pressure that would prevent water movement
hypotonic: cell swells and bursts (lysis), hypertonic: cell shrinks (crenation), isotonic: 0.9% saline or 5% dextose in water
active transport: primary (consumes ATP directly, ex. 3 Na+/2 K+ pumps) and secondary (Na+ or H+ gradient drives other ion against their gradient, ex. Na+/Ca2+ antiporters)
What are symporters? Anti porters? Examples?
What does digitalis do?
Is endocytosis passive?
symporters: move substances in same direction, anti porter: move substances in opposite directions
digitalis: slows Na+/K+ so there is more Ca2+ in the heart so the heart is stronger
no, endocytosis is active
Which is not one of the three types of endocytosis? receptor mediated (highly selective) phagocytosis lysocytosis bulk phase
lysocytosis
Put the steps of receptor mediated endocytosis in order?
a. recycle receptors to membrane (endosome brings it)
b. uncoated
c. bind membrane in clathrin coated pit
d. clathrin fold around it
e. fuse with endosome which releases it
f. degradation in lysosomes (particle taken by transport vesicles, lysosome has enzymes)
What is not transported by this?
LDLs, transferin, some vitamins, alcohol, antibodies and some hormones
c, d, b, e, a, f
alcohol
What are the two types phagocytes that do phagocytosis?
What does phagocytosis protect against?
How does phagocytosis work?
macrophages (common) and neutrophils (white blood cells)
phagocytosis protects against disease
phagocytosis involves: binding to receptor on phagocyte, pseudopods extending, vesicle “phagosome” forms, lysosome breaks it down, leftovers (residual body) are either secreted or stored as lipofuscin granules
What is another name for bulk phase endocytosis?
What does it transport?
What organs is it especially common in?
bulk phase endocytosis: aka pinocytosis (“cell drinking”)
it transports the ECF (no receptors needed, membrane forms the vesicle)
very common in kidneys and intestines
What does exocytosis transport? (hint: big)
What is pus?
What is transcytosis?
Where does glycolysis happen?
exocytosis transports enzymes and neurotransmitters
pus is a mix of dead neutrophils, macrophages, tissue and fluid
transcytosis: moving across cell from wall to wall
glycolysis occurs in the cytosol (glucose -> 2 ATP)
What does the cytoskeleton do?
Match the three types of filament with their function:
a. microfilament
b. microtubule
c. intermediate filament
i. strong, stabilize organelles and attach cells together
ii. long, hollow, mostly tubular protein, made in centrosome, determine cell shape, movement of vesicles, chromosomes, cilia and flagella
iii. actin and myosin, edge of cell, movement/mechanical support, anchors to membrane and supports microvilli
cytoskeleton: movement and scaffold
a & iii, b & i, c & ii
- microfilament: thinnest
- microtubule: thickest
Which types of transport are passive? Which are active?
passive: diffusion (simple and facilitated), osmosis
active: primary, secondary, vesicle transport, endocytosis (receptor mediated, phagocytosis, bulk-phase), exocytosis, transcytosis
What do centrosomes do and what are they made of?
do cell division
made of centrioles (9 clusters of 3 microtubules) and pericentriolar material (ring shaped tubular, organizing centres)
What are cilia? What are they made of?
What is a flagella?
cilia: many, short projections, move fluids along cell surface, made of 20 microtubules (1 pair in the middle with 9 pairs surrounding), adheres to basal body, just below membrane surface
flagella: like long cilia, move whole cells, wavelike wiggle (ex. on sperm)
What do ribosomes do? How many parts do they have? Where are they made? Where are they assembled?
Ribosomes make proteins, have 2 subunits, made in nucleolus, assembled in the cytoplasm
What do ribosomes do in the ER? What do they do if they are free? What do they do in the mitochondria?
in ER: make organelle, membrane or exporting proteins
free ribosomes: make cytosol proteins
in mitochondria: make mitochondrial proteins
Match:
a. rough ER
b. smooth ER
i. have many enzymes, make fatty acids, steroids, deactivate drugs/toxins, remove P from G6P (so it can enter blood), stores/releases Ca2+ for muscle contraction
ii. attach proteins to carbs/lipids/phospholipids, have ribosomes on surface
a & ii, b & i
What role does the smooth ER play in drug resistance and dependence?
get more smooth ER and enzymes to protect cells from toxins so more drug is needed to get the same effect
