Biology Exam 3

What is energy?

The capacity to do work; exists as potential or kinetic energy

First law

energy cannot be created or destroyed

second law

energy transformations increase entropy

what is exergonic reaction

releases energy - example cellular respiration

what is endergonic reaction

requires energy - example glucose synthesis

what do enzymes do?

act as catalysts that lower activation energy.

what is the active site?

region where the substrate binds.

how does temperature effect enzymes?

rate increases until optimum; high heat denatures the enzyme

enzyme pH effect

each enzyme has an optimum, beyond that it will denature

what is a competitive inhibitor

binds active site; blocks function

noncompetitive inhibitor

binds elsewhere leading to a change in enzyme shape

substrate concentration effect

increases rate until active sites are saturated.

enzyme concentration effect?

Increases rate until active sites are saturated

enzyme concentration effect

more enzymes lead to faster reactions (if substrate available)

what is ATP synthase role?

to produce ATP through chemiososmosis

chemiosmosis

is the movement of ions down their electrochemical gradient across a selectively permeable membrane to generate energy. it powers ATP synthase occurring in the mitochondria, chloroplasts, and bacteria during cellular respiration and photosynthesis

what is rubisco role

fixes CO2 to RuBP in the Calvin Cycle

what is PEP carboxylase role?

Initial CO2 fixation in C4 and CAM plants.

overall equation for photosynthesis

6CO2+6H2O+light yields C6H12O6+6O2

where do light reactions occur?

thylakoid membranes

main products of light reactions?

O2, ATP, NADPH

where does the calvin cycle occur?

stroma

main product of the Calvin Cycle

G3P (used to make Glucose)

How many CO2 molecules are needed per G3P?

3CO2

what pigment is the main reaction center?

chlorophyll a

what colors do chlorophyll a and b absorb best?

A- absorbs blue-violet & red

B- absorbs blue & orange

Function of carotenoids?

light capture+ photoprotection

overall equation for cellular respiration?

C6H12O6+6O2 yields 6CO2+6H2O+ATP

where does glycolysis occur?

cytoplasm

Net ATP from glycolysis?

2 ATP

where does the Krebs cycle occur?

mitochondrial matrix

Krebs Cycle produces?

CO2,NADH,FADH2, ATP

where is the electron transport chain?

inner mitochondrial membrane

approx ATP from oxidative phosphorylation

28-34 ATP

Lactic Acid Fermentation produces

Lactate+ 2ATP

Alcoholic fermentation produces

Ethanol+CO2+2ATP

Proton-motive force

energy stored as a proton gradient

oxidative phosphorylation

ATP Production using ETC+ chemiosmosis