Lecture 4 Flashcards
Enzyme action
-_________ binds to enzyme’s active site
-molecules form-enzyme substrate complex
-enzyme–substrate ________ (lock and key)
-enzyme releases reaction products
-enzyme ________ and can repeat process
enzymes _________ activation energy–> allows reaction to occur at a faster rate
substrate
-specificity
-unchanged
-lower
cofactors:
coenzymes:
-inorganic elements (metal) (copper, magnesium, zinc) that help enzymes move along
-organic molecules (derived from vitamins) that help enhance enzyme activity
Nucleotides
-organic compounds with three principal components:
1: ___________ (single or double ______- nitrogen ring
2: ___________ (monosaccharide)
3: one or more __________ groups
examples of nucleotides:
-________ -energy transfer
nucleotides are building blocks for ______ and ______
1: nitrogenous base; carbon
2: Sugar
3: phosphate
-ATP (Adenosine triphosphate)
-DNA; RNA
Glucose + oxygen –> carbon dioxide + _______ + ______
H2O (water); ATP (energy)
If there is NO oxygen….
a total of ___ ATP made per glucose molecule
since NADH is recycled
2
if there is oxygen…
a net total of up to ____ ATP made per glucose molecule
32
Cell Shapes and Sizes Human cell size
-most cells about ___-___ um (micrometers) in diameter
-Egg cells are 100 um diameter (YOU CAN SEE WITH NAKED EYE)
-the RBC is Mother Nature’s internal micrometer for histology labs (___-____ micrometers in diameter and about ___ micrometers thick)
10-15
7-8; 2
Limits on cell size:
-an overly large cell CANNOT support itself
-______ increases faster than SA which could lead to a cell to _________
volume; rupture
The Plasma membrane
-it is a compartment boundary!
-_____% of membrane molecules are lipids
-phospholipids _____%
-cholesterol _____%
-glycolipids ____ %
-___% of molecule protein (____% of weight)
98
75
20
5
2;50
the plasma membrane is a lipid ________
phospholipids have…
-a _____, hydrophilic head group
-a ________, hydrophobic tail
bilayer
polar
non-polar
Membrane proteins
1.
2.
peripheral protein (hydrophilic)
transmembrane protein (outside parts are hydrophilic; while inside is hydrophobic)
proteins are sometimes clustered on _________- rich lipid “rafts” that are hard
keeps proteins anchored
cholesterol
transmembrane proteins are often:
a.
b.
c.
d.
e.
f.
receptor
enzyme
channel
gated channel
cell-identity marker
cell-adhesion molecule (CAM)
receptor transmembrane protein
a receptor that binds to chemical messengers such as hormones sent by other cells
enzyme transmembrane protein
an enzyme that breaks down a chemical messenger and terminates its effect
channel transmembrane protein
a channel protein that is constantly open and allows solutes to pass into and out of the cell
gated channel transmembrane protein
a gate that opens and closes to allow solutes through only at certain times
cell-identity marker transmembrane protein
a glycoprotein acting as a cell-identity marker distinguishing the body’s own cells from foreign cells
Cell-adhesion molecule (CAM) transmembrane protein
a cell-adhesion molecule (CAM) that binds one cell to another
many peripheral proteins act as _________ __________
second messengers
kinase
adds phosphate to a protein–> activates protein–> triggers cellular response
the glycocalyx: fuzzy coat external to plasma membrane
-involved in cell _______
identity
Membrane transport:
Requires energy-
1.
2.
Does NOT require energy-
1.
2.
3.
4.
- active transport
- bulk transport (ex. endocytosis)
- Osmosis
- Diffusion
- Facilitated diffusion
- Filtration
Filtration:
particles are driven through membrane by physical ________
-type of passive transport that relies on pressure of your _____
-blood pressure in capillary forces ____ and small _____ such as salts through narrow clefts between capillary cells
pressure
blood
water; solutes
osmosis: diffusion of _____ from ____ concentration to _____ concentration
water; high; low
hypotonic solution: high water concentration; low solutes–> water moves _____ the cell
hypertonic solution: low water concentration; high solutes–> water moves ______ the cell
isotonic: equal water and solute concentrations
into; out of
Carrier-mediated transport
Three kinds of carriers
1.
2.
3.
uniport
symport
antiport
uniport carrier
moves only one type of molecule in one direction
symport
moves 2 different molecules in one direction
antiport
moves 2 different molecules in two directions
Three mechanisms of carrier-mediated transport:
1.
2.
3.
- facilitated diffusion
- primary active transport
- secondary active transport
