Unit 3 terms

Metabolism

the chemical reactions in an organsim

metabolic pathways

series of chemical reactions that either build complex molecules or breakdown complex molecules

Catabolic pathways

pathways that release energy by breaking down complex molecules into simpler compounds

anabolic pathways

pathways that consume energy to build complicated molecules from simpler compounds

energy

the ability to do work

survive and function

why do organism need energy?

kinetic energy

energy associated with motion

thermal energy

energy associated with the movement of atoms or molecules

potentiali energy

stored energy

chemical energy

potential energy avaliable for release in a chemical reaction

exergonic reactions

reaction that releases energy

endergonic reactions

reactions that absorb energy

phosphorylation

the released phosphate moves to another molecule to give energy

enzymes

macromolecules that speed up reactions by lowering the activation energy

induced fit

enzymes will change the shape of their active site to allow the substrate to bind better

enzyme catabolism

enzyme helps breakdown complex molecules

enzyme anabolism

enzymes help build complex molecules

cofactors

non-protein molecules that assist in enzyme function

competitive inhibitors

reduce enzymes activity by blocking substrates from binding to the active site

noncompetitive inhibitors

bind to an area on the enzyme other than the active site which changes the shape of the active site preventing substrates from binding

allosteric regulation

molecules bind (noncovalent interactions) to an allosteric site which changes the shape and function of the active site

allosteric activator

substrate binds to allosteric site and stabilizes the shape of an enzyme so that the active site remains open

allosteric inhibitor

substrate binds to allosteric site and stabilizes the enzymes shape so that the active sites are closed

cooperativity

substrate binds to one active site which stabilizes the active form

feedback inhibition

sometimes the end product of a metabolic pathway can act as an inhibitor to an early enzyme in the same pathway

cyanobacteria

early prokaryotes capable of photosynthesis

reactants of photosynthesis

6CO2 + 6H2O + light energy

products of photosynthesis

C6H12O6 + 6H2O + 6O2

oxidation

loss of electrons

reduction

gain of electrons

chlorophyll a

-primary pigment
-involved in light reactions
-blue/green pigment

chlorophyll b

-accessory pigment
-yellow/green pigment

carotenoids

Broaden the spectrum of colors that drive photosynthesis pho

photoreception

carotenoids absorb and dissipate excessive light energy that could damage chlorophyll or interact with oxygen

photosystems

reaction center and light capturing complexes

reaction center

a complex of proteins associated with chlorophyll a and an electron acceptor

photosystem 2

reaction center p680

photosystems 2

reaction center P700

carbon fixation

- CO2 is incorporated into the Calvin cycle one at a time
- each CO2 attaches to a molecule of RuBP
-forms 3-phosphoglycerate

Reduction

-each molecule of 3-phosphoglycerate is phosphorylated by ATP is 6 total
- becomes 1,3-biphosphoglycerate
- 6 NADPH donate electrons to 1,3- biphosphoglycerate
-reduces to G3P
- 6 molecules of G3P are formed but only one is counted as a net gain
- the other 5 G3P molecules are used to regenerate RuBP

Regeneration of RuBP

-5 G3P molecules are used to regenerate 3 molecules of RuBP
-uses 3 ATP for regeneration
- cycle is now ready to take in CO2 again

inputs of calvin cycle

3CO2, 9 ATP, 6 NADPH

outputs of calvin cycle

1G3P, 6 ADP, 6 NADP+

CAM plants

open stomata at night and close during the day
CO2 is incorporated into organic acids and stored in vacuoles

C4 plants

spatial separation of steps; stomata partially close to conserve water

cellular respiration

cells harvest chemical energy stored in organic molecules and use it to generate ATP

Glycolysis

-starting point of cellular respiration
- splits glucose into 2 pyruvates
two stages

Energy investment stage

the cell uses ATP to phosphorylate compounds of glucose

energy payoff stage

energy is produced by substrate level phosphorylation

Citric Acid cycle

-known as Krebs cycle
-occurs in the mitochondrial matrix
-turns acetyl CoA into citrate

outputs of citric acid cycle

2 ATP
6 NADH
4 CO2
2 FADH2

Electron Transport chain

-located in the inner membrane
-collection of proteins

ATP synthase

the enzyme that makes ATP from ADP +P
-uses energy from the H+ gradient across the membrane

anaerobic respiration

-generates ATP using the electron transport chain in the absence of oxygen
-takes place in prokaryotic organisms that live in environments with no oxygen
- final acceptors: sulfate and nitrates

Fermentation

generates ATP with out the ETC

Alcohol fermentation

pyruvate is converted into ethanol

Lactic acid fermentations

pyruvate is reduced directly by NADPH to form lactate

breakdown of lactate:

muscles produce lactate which goes into the blood and is broken down back into glucose in the liver