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Bios1500
exam 3
240
Biology
Undergraduate 2
02/13/2013

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Term
Metbaolism
Definition
sum total of all chemical reactions that occur w/in an organism
Term
What else can metabolism refer to?
Definition
specific chemical reactions at the cellular level
Term
What are two factors that govern the fate of a chemical reaction?
Definition
1) Direction (favorable or unfavorable)
2) Rate - reaction may be favorable but too slow (paper turing yellow)
Term
First law of Thermodynamics
Definition
1) Law of conservation of energy
2) Energy cannot be created or destroyed
Term
Second law of Thermodynamics
Definition
1) Transfer or transformation of energy from one form to another increases entropy or degree of disorder of a system
Term
Favorable reaction
Definition
monomer to polymer
Term
Unfavorable reaction
Definition
polymer to monomer
Term
H=G+S
Definition
H= total energy
G=free energy or amount of energy for work
S=entropy or unusable energy
Term
Delta G=change in free energy

Spontaneous
Definition
(exergonic) favorable; (-) Delta G : free energy change
Term
Delta G=change in free energy

Not spontaneous
Definition
(endergonic); (+) Delta G - positive free energy change; requires addition of free energy
Term
The energy in a reaction available to do work is
Definition
Free energy/G
Term
How many kcal/g are in fat?
Definition
9kcal/g
Term
(c) calorie
Definition
energy to raise 1 gram of water 1 degree centigrade
Term
how many kcal/g in alcohol?
Definition
7kcal/g
Term
how many kcal/g in protein and carbohydrates?
Definition
4kcal/g
Term
how many kcal/g in organic acids?
Definition
3kcal/g
Term
Catalyst
Definition
agent that speeds up the rate of a chemical reaction w/out being consumed during the reaction
Term
What are enzymes?
Definition
biological catalyst made of protein (also some ribosomes made of RNA)
Term
What do biological catalysts do?
Definition
Speeds up a reaction, but doesn't get destroyed in the reaction (reused)
Term
How do proteins w/3D spaces Act as catalyst?
Definition
By binding to a substrate
Term
Active site
Definition
primary space that binds substrate
Term
An enzyme is what kind of protein?
Definition
Globular protein
Term
Enzyme active sites are...
Definition
substrate specific
Term
What does an enzyme actually do?
Definition
Reduce activation energy
Term
What are two common ways to over come activation energy?
Definition
1) Large amounts of heat
2) Using enzymes to lower activation energy
Term
Can delta G be changed by an enzyme?
Definition
No. Enzyme only speeds up the reaction.
Term
Lock and Key model
Definition
Substrate fits into Active site; active site is complementary to the substrate; able to break bond easily
Term
Induced fit
Definition
interaction involves conformational changes; changes shape so substate can fit an active site
Term
Co-enzyme site
Definition
organic molecule that helps the enzyme carry out its function, but left unchanged afterwards
Ex) ATP, ADP, Vitamins, B complex
Term
Cofactor site
Definition
mineral; calcium, K+, Mg; temporarily binds to enzyme
Term
inhibitor site
Definition
control shape of the active site
Term
Coupled reaction
Definition
two reactions occurring very close together, one is favorable (-) delta g and one is (+) delta g, and the net is negative then it's favorable
Term
How can a biological system convert a monomer to polymer?
Definition
Coupled reaction
Term
What effects allow an enzyme to function maximally?
Definition
Narrow range of temperature and pH
Term
What happens to an enzymes function as it leaves its narrow range of function?
Definition
Function decreases
Term
How do enzymes control cell metabolism?
Definition
1) Increase rate of reaction so much that reaction w/in the cell that have an enzyme will go in that direction
2) Enzymes using active site and coenzyme site can couple reaction - use this to store energy and use energy to make complex molecules
Term
Two basic ways of storing energy
Definition
1) Bond energy - ADP + PO_4 = ATP (-7kcal)
2) Storing electrons - oxidation/reduction (NAD + 2e- becomes NADH (-21kcal))
Term
LEO
Definition
loss of electrons is oxidation
Term
GER
Definition
gain of electrons is reduction
Term
Pathway
Definition
multiple(enzyme) steps leading to a final product
Term
How is each step in a pathway coordinated?
Definition
by a specific enzyme
Term
In a pathway the of a first enzyme becomes what for a second enzyme?
Definition
substrate
Term
Why are pathways important to the cell?
Definition
multiple steps means each has a small number of kcal (either needed or released) so that they can be coupled
Term
How are intermediate steps useful in pathway?
Definition
they make other molecules the cell needs
Term
Pathway is a ...
Definition
feedback control
Term
What is a pathway?
Definition
A series of enzyme mediated reaction with a final product
Term
Glucose metabolism Pathways (4 of them)
Definition
1) Glycolysis
2) Breakdown of pyruvate to an acetyl group
3) Citric acid cycle (KREBS cycle)
4) Oxidative phosphorylation
Term
Glycolysis
Definition
1) Can occur w/or w/out O_2
2) 10 enzymes in pathway nearly identical in all living species
3) Occurs in the CYTOSOL
4) Net 2ATP (and 2NADH if O_2 is present)
5) Final product - 2 pyruvates (2 Carbons each)
Term
Where does Glycolysis take place?
Definition
In the cytosol
Term
What is the net production of Glycolysis?
Definition
2 ATP and 2NADH (if O_2 is present)
Term
What is the final product of Glycolysis?
Definition
2 pyruvates (3 carbons each)
Term
True or false. Glucose gets broken down into ATP?
Definition
False
Term
Mitochondria
Definition
1) Double Membrane - outer membrane and inner membrane (folds called Cristae)
2) Matrix - area w/in the inner membrane
3) contains own DNA, ribosome but still requires genes/proteins from nucleus - semi autonomous
4) Comes from mother
Term
Matrix
Definition
area w/in the inner membrane
Term
Pyruvate Decarboxylation
Definition
1) Transported to the mitochondrial matrix
2) Molecule of CO_2 removed from each pyruvate
3) Remaining acetyl group (acetic acid) attached to coenzyme A to make acetyl CoA
4)1 NADH is made for each pyruvate
Term
What product is made in pyruvate decarboxylation?
Definition
1 NADH for each pyruvate
Term
when no O_2 available
Definition
1) Anaerobic animal cells (net 2 ATP) muscle cells on exercise; pyruvate (3c) + NADH <-> Lactate (3c) + NAD
2) Fermentation (net 2 ATP) + CO_2
3) Pyruvate (3c) + NADH -> ethanol (2c) + NAD
Term
metabolic cycle
Definition
particular molecules enter while others leave, involving a series of organic molecules regenerated w/each cycle
Term
How is citrate or citric acid formed?
Definition
Acetyl is removed from Acetyl CoA and attached to oxaloacetate (4C)
Term
What is released during the citric acid cycle?
Definition
1) 2 CO_2
2) 1 ATP
3) 3 NADH
4) 1 FADH_2
Term
What in the citric acid cycle is regenerated to start the cycle again?
Definition
Oxaloacetate (4C)
Term
What is the location of the Citric acid cycle?
Definition
Matrix of mitochondria
Term
Aerobic energy respiration
Definition
1) Requires O_2
2) C_6H_12O_2 + 6O_2 goes to 6CO_2 + 6H_2O
3) coupled to e-stored in 10 NADH and 2 FADH_2
4) coupled to the phosphylation of 2 ATP and 2 GTP
Term
Is O_2 required in the Kreb cycle?
Definition
No O_2 is required
Term
2 ways to make ATP
Definition
1) Substrate-level phosphorylation
2) Oxidative phosphorylation
Term
Substrate-level phosphorylation
Definition
enzyme directly transfers phosphate from one molecule to another molecule
Term
oxidative phosphorylation
Definition
1) energy stored in an electrochemical gradient (chemiosmosis) is used to make ATP from ADP and P_i
2) of the app. 34 ATP couple in aerobic respiration of glucose 30 ATP oxphos
Term
Total energy from glucose
Definition
1) Glycolysis 2ATP, 2NADH
2) Pyruv to Acetyl 2NADH one for each pyruvate
3) Krebs 6NADH, 3 for each cycle
4) Krebs 2FADH_2, 1 for each cycle
5) Krebs 2GTP, one for each cycle
6) total equivalent energy - 34 ATP
Term
What is the location of oxidative phosphorylation?
Definition
inner membrane/criastae in the mitochondria
Term
Oxidative phosphorylation
Definition
1) requires O_2, O_2 is the final electron acceptor
2) Electrons from NADH (or FADH_2) used for ATP production ; NADH -> NAD + 2e- + H+
Term
What are the two steps involved in oxidative phosphorylation?
Definition
1) Electron transport making proton gradient
2) ATP synthase driven by proton gradient
Term
Electron transport chain
Definition
1) group of protein complexes and small organic molecules associated w/the inner mitochondrial membrane
2) can accept and donate electrons in a linear manner in a series of redox reactions
3) movement of electrons generates H+ electrochemical gradient (chemiosmotic)/proton-motive force
Term
Where are protons pumped to and from in the electron transport chain?
Definition
Matrix to space inner and outer membrane
Term
Cytochromes
Definition
proteins w/a HEME like ring molecule attached that has a metal ion like iron. It can store and release electrons. Does not require a proton like NADH
(pick up electrons, change it's valence, and transport it)
Term
ATP synthase
Definition
1) multiple subunit (quanternary structure) both transmembrane and peripheral membrane protein complex
2) energy conversion - H+ electrochemical gradient converted to chemical bond energy in ATP
Term
How do the electrons that started out in NADH end up in water?
Definition
Term
ATP's generated from ADP + PO4 in glycolysis are made by
Definition
substrate level phosphorylation
Term
How is oxygen used in aerobic metabolism?
Definition
as electrons are passed to different proteins in the electron transport chain the final step splits oxygen and accepts the electrons to make water
Term
photosynthesis
Definition
energy from light is captured and used to synthesize carbohydrates
Term
photosynthesis reaction
Definition
6CO_2 + 12H_2O + light energy -> C_6H_12O_6 + 6O_2
Term
Chloroplast anatomy
Definition
1) outer and inner membrane
2) thylakoid is 3rd membrane system
3) stroma
Term
stroma
Definition
fluid filled region between thylakoid membrane and inner membrane
Term
Thylakoid
Definition
1) contains pigment molecules
2) membrane forms thylakoids
3) each thylakoid is a disk w/an inner lumen, granum-stack of thylakoids
Term
2 stages of photosynthesis
Definition
1) light reactions
2) calvin cycle
Term
Light reactions
Definition
1) take place in thylakoid membranes
2) produce ATP, NADPH and O_2
Term
Calvin cycle
Definition
1) occurs in stroma
2) uses ATP and NADPH to incorporate CO_2 into organic molecules
3) CO_2 fixation
Term
photosystems
Definition
pigment molecules are arranged w/proteins into complexes (integral membrane proteins)
Term
Where are PSI and PSII located?
Definition
Thylakoid membrane
Term
Which photosystem is used first?
Definition
PSII
Term
Which PS makes O_2?
Definition
PSII
Term
light energy in molecules excites what molecules?
Definition
pigment molecules
Term
What does PSI do?
Definition
provides energy to make NADPH
Term
Where is the energy in pigment molecules captured?
Definition
chlorophyll molecules in what is called the reaction center
Term
What is the major pigment in photosynthesis?
Definition
chlorophyll
Term
Where does the light reaction of photosynthesis take place?
Definition
Thalakoid membrane
Term
Electrons transport (in photosynthesis)
Definition
1) electrons accepted by primary electron acceptor in PSII transported PSI
2) Establishes H+ electrochemical gradient where protons high in lumen of thalykoid and lower in stroma
Term
oxidation
Definition
loss of electrons
Term
In enzymes what is available for work?
Definition
Delta G and free energy
Term
What is responsible for an enzyme proteins 3D shape?
Definition
active, coenzyme, feedback, cofactor
Term
What is the function of enzymes?
Definition
reduce activation energy and thereby increase rate of run
Term
oxidative phosphorylation
Definition
in electron transport 2 electrons from NADH used to generate a proton gradient, which then is used to make ATP in ATP synthase complex. Oxygen finally accepts the 2 electrons and forms water. This is the only place oxygen is used. Most of ATP made by oxphos compared to substrate level.
Term
if no oxygen is present what kind of metabolism is it?
Definition
anerobic
Term
What happens in anaerobic metabolism?
Definition
NADH builds up in mitochondria which backs up the system to pyruvate. Pyruvate converted either to lactic acid (animals) or ethanol (fermentation), energy yields only 2 ATPs
Term
What is substrate level phosphorylation?
Definition
When coupled rxn w/in enzyme (coenzyme site) takes energy from breakdown of one molecule and uses it to add a phosphate to ADP to make ATP (7kcal) free energy
Term
In substate level phosphorylation what other ways can energy be stored?
Definition
oxidation reduction reaction in the form of electrons:
NAD + 2e- + H^+ goes to NADH and 20kcal
Term
How does ATP synthase complex use protons?
Definition
Protons turn complex and force ADP and PO4 together
Term
Location of electron transport in oxidative phosphorylation
Definition
inner membrane/cristae of mitochondria
Term
PSII (photo system 2)
Definition
oxygen from water then electron transport and H^+ gradient used to make ATP
Term
PSI (photo system 1)
Definition
electrons for NADPH
Term
in photosynthesis what are the major photo pigments
Definition
chlorophyll
Term
communication btw. cells requires
Definition
ligand and receptor protein
Term
ligand
Definition
the signaling molecule (like a substrate but not changed during binding)
Term
receptor protein
Definition
the molecule to which the receptor binds NON-covatlently
(maybe on the plasma membrane or w/in the cell)
Term
4 basic mechanisms for cellular communication
Definition
1) direct contact - junctions
2) paracrine signaling - neighboring cells
3) synaptic signaling - neurons
4) endocrine signaling - long distances, blood stream
Term
paracrine signaling
Definition
neighboring cells
Term
endocrine signaling
Definition
long distances
Term
Membrane receptor
Definition
1) ligand bind non-covalently to site on transmembrane protein
2) protein changes shape - activates receptor (inside cell)
3) signal transduction
4) ligand is released unchanged and receptor returns to inactive shape
Term
Signal transduction
Definition
w/in cell, amplifies signal of the receptor binding and final product of pathway activates gene or enzyme in metabolism
(events w/in the cell that occur in response to an activated receptor)
Term
A membrane receptor
Definition
binds a ligand which changes the receptor protein shape
Term
3 subclasses of membrane receptors in response to receptor activation
Definition
1) channel linked receptors (gated channel)
2) enzyme linked receptors
3) G protein-coupled receptor (GPCR)
Term
Channel linked receptors ( Gated channel)
Definition
ion channel that opens in response to a ligand
Term
Enzyme linked receptors
Definition
receptor has built in enzyme (protein kinase) that is activated inside cell by the ligand binding
Term
G protein-coupled receptor (GPCR)
Definition
a protein called G-protein (binds GTP) assists in transmitting the signal
Term
protein kinase
Definition
an enzyme that adds a phosphate to a protein 1 in 50 proteins in humans are protein kinases
Term
What is a common way to change the activity of a protein?
Definition
Phosphorylation
Term
What does a cell's response to a signal often involve?
Definition
activating or inactivating proteins
Term
Signal transduction pathways amplify signal
Definition
1) receptro activates protein kinase pathway. One PK can activate multiple proteins, which themselves are PK
2) second messenger - many copies of a small molecule are made. G protein or master protein kinase activates enzyme that makes cAMP or releases Ca that activates other protein kinase
3) Combine 1 and 2
Term
phosphate
Definition
an enzyme that removes a phosphate from a protein
Term
What do protein kinases do?
Definition
add a phosphate group to another protein to activate it
Term
G-protein
Definition
has 3 parts. All 3 are together inactive form when GDP is bound, but when activated GTP binds and splits in two
Term
G-protein-coupled receptor (GPCRs)
Definition
receptors bound to G proteins
Term
One reaction -Delta G other +Delta G
Definition
Coupled reaction
Term
NAD + 2e- to NADH
Definition
reduction (oxidative)
Term
Multiple step
Definition
pathway
Term
Metal ion
Definition
cofactor binds
Term
active site
Definition
substrate binds
Term
Steps in Glucose metabolism
Definition
1) Glycolysis
2) Decarboxylation - pyruvate to acetyl coa
3) Kreb cycle
4) oxidative phosphorylation
Term
Glucose to 2 pyruvate
Definition
Glycolysis
Term
Pyruvate to lactate
Definition
Animal anaerobic metabolism
Term
CO2 to 3 carbon
Definition
Calvin cycle
Term
Pyruvate to Acetyl CoA
Definition
decarboxylation
Term
pyruvate to ethanol
Definition
fermentation
Term
How does the electron transport chain work and how does it produce ATP
Definition
Called oxidative phosphorylation (movement of electrons) - results in making ATP from ADP and phosphates.
1) NADH -> 2e- + NAD
2) same two electrons from first step moved through electron chain and end up in water at end of reaction
3) Protons get pumped to one side of the membrane
4) ATP synthase - ADP + Pi -> ATP
Term
Matrix
Definition
Citric Acid Cycle
Term
Thalykoid
Definition
oxidative phos. or light reaction
Term
In the citric acid cycle an enzyme helps rearrange bonds w/in a 4 carbon molecule and couples that to formation of GTP, how is the GTP made?
Definition
substrate level phosphorylation
Term
oxygen produced
Definition
PSII
Term
NADPH produced
Definition
PSI
Term
2,3 carbon molecule formed
Definition
Calvin cycle
Term
occurs first
Definition
PSII
Term
RUBESCO
Definition
calvin cycle
major enzyme that links CO2 to organic molecule
Term
Second messenger
Definition
Signal transduction, calcium and cyclic AMP
Term
G coupled protein
Definition
receptor, indirect signal transduction
Term
Ligand gated
Definition
receptor, channels
Term
signal transduction phosphorylation
Definition
protein kinase
Term
ligand
Definition
receptor activated
Term
Place the following in order
Definition
1) Ligand binds to receptor
2) receptor changes shape
3) signal transduction started
4) protein kinase pathways
5) cell metabolism change
Term
Anabolism
Definition
synthesize larger substances from smaller ones; build things
Term
catabolism
Definition
break down of large substances into smaller ones
Term
Chemical reactions are dependent on 2 main processes
Definition
1) direction
2) rate
Term
Direction
Definition
which way the reaction proceeds -> forward or reverse; can be favorable or unfavorable
Term
rate
Definition
how fast a reaction takes place
Term
Thermodynamics
Definition
the study of energy interconversions; how energy is converted from one form to another
Term
entropy (S)
Definition
the measure of randomness of molecules in a system
Term
enthalpy (H)
Definition
defined as the total energy
Term
free energy (G)
Definition
the usable energy or the amount of energy available to do work/promote change
Term
exergonic reaction
Definition
favorable; spontaneous; occur when delta G is negative
Term
endergonic reaction
Definition
unfavorable; nonspontaneous; requires the addition of free energy and occurs when delta G is positive
Term
calories
Definition
units of energy; also called kilocalories
Term
coupling
Definition
when an unfavorable reaction is paired w/a favorable reaction, which enables the unfavorable reaction to still occur as long as there is a net negative delta G
Term
enzyme
Definition
biological catalyst composed of amino acids (protein); reduces activation energy
Term
catalyst
Definition
speeds up a chemical reaction and is not consumed during the reaction
Term
substrate
Definition
the reactant molecule that binds to the active site on an enzyme; specific
Term
Active site
Definition
location on an enzyme where the chemical reaction takes place
Term
activation energy
Definition
the energy level needed to be overcome for a reaction to occur; is decreased by enzymes; overcoming does not change delta G
Term
transition site
Definition
the top part of an energy diagram
Term
lock and key model
Definition
specific to the enzyme and substrate
Term
induced fit model
Definition
involves conformational (shape) changes
Term
Allosteric site
Definition
changes shape
Term
Cofactor
Definition
inorganic ions that temporarily bind to the enzyme; minerals like, Ca2+ and K+
Term
Coenzyme
Definition
organic molecule that helps the enzyme carry out its function but are not changed during the reaction; vitamins, ATP, ADP
Term
denaturation
Definition
enzymes can become inactivated if they're outside their narrow working pH or temp. range
Term
Two main ways of storing energy
Definition
1) bond energy
2) redox reactions
Term
bond energy
Definition
like the creation of ATP from ADP + PO4
Term
redox reactions
Definition
storing/transferring electrons; NAD + 2e- -> NADH
Term
loss of electrons is
Definition
oxidation
Term
gain of electrons is
Definition
reduction
Term
Pathway
Definition
a series of enzymes-linked steps to get a product
Term
feedback inhibition
Definition
when the products of a reaction 'turn off' the reaction and prevent it from producing more products because the cell has enough
Term
glycolysis
Definition
a type of glucose metabolism; can work w/or w/out O2 present; occurs in the cytosol of the cell; uses 10 enzymes
Term
products of glycolysis
Definition
1) 2 3-carbon pyruvate molecules
2) 2 ATP
3) 2 NADH molecules
Term
Fermentation
Definition
when no O2 is present, glucose ferments into lactic acid or ethanol
Term
lactic acid
Definition
fermentation product that builds up in muscles and causes soreness; can be reversed back into glucose
Term
Pyruvate
Definition
the 3-carbon molecules produced during glycolysis; is transported to the mitochondrial matrix in the presence of O2
Term
pyruvate decarboxylation
Definition
removal of a CO2 molecule in order to make Acetyl CoA
Term
anaerobic
Definition
w/out O2; does not need oxygen to occur
Term
aerobic
Definition
w/O2; must have O2 to occur
Term
mitochondrial matrix
Definition
inner-most part of the mitochondria that is equivalent to the cytosol of a cell
Term
Mitochondria
Definition
double-membrane eukaryotic organelle that makes ATP
Term
inner/outer mitochondrial membrane
Definition
the mitochondria is a double membrane organelle; the inner membrane has folds called cristae
Term
semi-autonomous
Definition
mitochondria have their own ribosomes and DNA/genetic material that they replicate
Term
metabolic cycle
Definition
certain molecules enter as others leave, involving a series of organic molecules regenerated w/each cycle
Term
Citric Acid Cycle
Definition
in the mitochondrial matrix; acetyl group is removed from Acetyl CoA and attached to a 4-carbon oxaloacetate to make 6-carbon citrate/citric acid
Term
What is released in the citric acid cycle?
Definition
1) 2 CO2
2) 1 ATP
3) 2 NADH
4) 1 FADH2
Term
What is regenerated in the citric acid cycle to start it back up again?
Definition
oxaloacetate
Term
how many turns of the Krebs cycle must occur before the radioactive/original C comes off as CO2?
Definition
3
Term
two main methods to make ATP
Definition
1) substrate-level phosphorylation
2) oxidative phosphorylation (chemiosmosis)
Term
substrate-level phosphorylation
Definition
an enzyme directly transfers PO4 from one molecule to another; makes about 4 ATP; examples are ATP in glycolysis, GTP in Krebs cycle
Term
oxidative phosphorylation (chemiosmosis)
Definition
energy stored in electrochemical gradient is used to make ATP from ADP + PO4; makes 30 ATP; O2 is the final electron acceptor to make water; inner men./cristae
Term
in oxidative phosphorylation, electrons come from NADH or FADH2 and are used to make ATP in 2 steps
Definition
1) Electron Transport Chain
2) ATP synthase
Term
ETC
Definition
making H+ or proton gradient; group of protein complexes; can accept and donate electrons in a linear manner in a series of redox reactions; movement of e- generates H+ gradient that deposits protons in space btw. inner and outer membrane
Term
CoQ/Ubiquinone
Definition
lipid soluble molecule
Term
Cytochrome C
Definition
peripheral protein that store/release electrons
Term
ATP synthase
Definition
driven by proton gradient; multiple subunit (quaternary structure); energy conversion of gradient to chemical bond energy in ATP; rotary machine makes ATP as it spins and knocks ADP and Pi together; requires O2; inner membrane/cristae
Term
Photosynthesis
Definition
process of using light energy to synthesize carbs
Term
photons
Definition
massless particles that contain energy
Term
2 types of reactions
Definition
1) light reactions
2) dark reactions
Term
light reactions
Definition
light energy captured by chlorophyll and converted to ATP and NADPH; starts w/light and converts it to chem. energy stored in covalent bonds; 3 products-ATP, NADPH and O2; NADPH is an electron carrie of 2 e- to drive the dark reactions and is produced in the stroma; ATP is produced in the stroma via ATP synthase w/H+ gradient; O2 produced in thylakoid membrane from PSII
Term
dark reactions
Definition
calvin cycle; ATP, NADPH used to drive synthesis of carbs; doesn't directly make glucose-makes G3P which is the starting product for glucose synthesis
Term
carbon fixation
Definition
CO2 becomes part of RuBP which generates 2 molecules of 3PG (this step is catalyzed by rubisco)
Term
reduction and carb production
Definition
3PG made into G3P by ATP and NADPH
Term
regeneration of RuBP
Definition
10 G3P to make glucose/carbs
Term
Thylakoid membrane
Definition
is a third membrane that contains pigment molecules like chlorophyll; forms flattened fluid-filled tubules called thylakoids which have a lumen inside; stacks are called grans
Term
2 types of chlorophyll
Definition
a (alpha) and B (beta) are bound to integral proteins in the thylakoid membrane
Term
PSI
Definition
make NADPH; is how pigment molecules receive electrons; high energy electron removed from pigment molecule P700; formation of NADPH creates H+ electrochemical gradient across thylakoid membrane from fewer H+ in the stroma; doesn't generate water
Term
PSII
Definition
initial step in photosynthesis; pigment molecule P680 transfers excited e-; P680 receives e- from water; captures light energy and produces O2 from oxidizing water;
Term
ligand
Definition
the signaling molecule that binds to a receptor to activate it; not changed during binding; can be an ion, carb., protein, nucleic acid or chemical; binding changes the shape of the receptor to activate it; falls off-receptor is deactivated
Term
receptor protein
Definition
the molecule that ligand noncovalently binds to; the receptor can be on the plasma membrane or w/in the membrane; always transmembrane/integral proteins
Term
signal transduction
Definition
the events w/in a cell that occur in response to an activated receptor; receptor changes shape to open a channel of activate enzyme function w/in the cell; direct or indirect
Term
3 subclasses of membrane receptor types
Definition
1) channel linked/ligand gated
2) enzyme-linked
3) G protein coupled receptor
Term
channel linked/ligand gated
Definition
simplest type; an ion channel opens in response to binding of a ligand
Term
enzyme linked
Definition
receptor has built in enzyme that is activated w/in the receptor when a ligand binds
Term
G protein coupled receptor (GPCR)
Definition
G protein binds GTP when a ligand binds, and assists in transmitting the signal; indirect signal transduction; found in yeast and also are target by many medicines
Term
4 main mechanisms for cell communication
Definition
1) junctions
2) paracrine signaling
3) endocrine signaling
4) synaptic signaling
Term
junctions
Definition
direct contact btw. adjacent cells
Term
paracrine signaling
Definition
communication btw. neighboring cells
Term
endocrine signaling
Definition
communication of long distances through the blood stream
Term
synaptic signaling
Definition
neurons in the brain
Term
second messengers
Definition
small molecules that aid in signal transduction by activating various cell reactions, like cyclic AMP (cAMP) and the release of Ca2+ in the cell
Term
G protein
Definition
has 3 parts, all of which are bound together in the inactive GDP form -> when activated GTP binds and splits in 2
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