Respiration and

Photosynthesis

Cellular Respiration

Glycolysis

The Krebs Cycle

Electron Transport Chains

Anabolic Pathway

Photosynthesis

Calvin Cycle

Flow of Energy

Energy is needed to support

all forms of life

We have talked about that

energy is transferred from

producer to consumer but

how?

How does light energy from

the sun get transferred into

usable forms of energy?

The Short Answer

Plants use sunlight to go through

photosynthesis

Photosynthesis generates

Oxygen and organic molecules

used by the mitochondria as fuel

for respiration

Respiration breaks down that

fuel to generate ATP which is

the molecule that drives cellular

work

Catabolic Pathways

Catabolic (break down complex molecules) pathways create

energy by oxidizing organic fuel

Cellular Respiration-The chemical process that generates most

of the energy in the cell

Aerobic Respiration- oxygen is consumed as a reactant along

with organic fuel (aerobic=air)

Fermentation- partial degradation of sugar or other organic

fuels that occurs without the use of oxygen

Anaerobic- without air

Glucose

Glucose is a sugar

C6H12O6

The typical formula for the break down in Glucose

usually has the products of CO2 H2O and Energy in

the form of ATP and Heat

C6H12O6 + 6O2 —> 6CO2 + 6H2O + Energy

Misnomer about Catabolic Pathways

They do not do they work of the cell

Move the cell

Pump molecules across a membrane

Ect.

They just provide the Fuel in order to preform

these functions

Cellular Respiration

Think of this as 3 stages

Glycolysis, The Krebs (aka Citric Acid) Cycle, & Electron

Transport

Glycolysis and Its Reactants

Glycolysis- literally means glucoses splitting so this is the stage of

cellular respiration where glucose molecules are split up

Enzymes split the glucose molecules into 2 Pyruvate molecules (or

Pyretic acid)

In order to split the Glucose there is energy needed so 2ATP molecules

are used to start off the reaction

The ATP break a Phosphate off to release the energy needed to start

the reaction off and form 2 ADP (adenosine diphosphate)

Glycolysis Products

In order for glycolysis to be effective it has to

produce more energy then it takes in

The key products formed from glycolysis is 4 ATP,

2 NADH, 2H+, 2 Pyruvate & 2 H2O

Glycolysis Net Payout

Net pay is how much did you profit

If I pay someone $500 and they made me $750 then I only

profited $250 over my investment of $500

Same concept with Glycolysis we used resources to start the

process so they will be counted against the product to form

the net profit

Krebs Cycle

The Pyruvate travels to the mitochondria where the Krebs

cycle takes place

3 Carbon Pyruvate

Before the Krebs

cycle the 2 Pyruvate

combine coenzyme

A

This reaction

produces acetyl-CoA

The other product

are CO2 & 2NADH

Krebs Cycle

Acetyl-CoA is a 2 carbon molecule it combines

with a 4 carbon molecule called oxaloacetate

(OAA) this produces citric acid a 6 carbon atom

Citric acid goes through a series of reactions that

release energy in the forms of NADH, ATP, and

FADH2

OOA is then regenerated and reused and the

cycle is repeated for the other pyruvate made in

glycolysis

http://www.youtube.com/watch?v=FgXnH087JIk

The Results Up To This Point

After the 2nd time through the Krebs cycle the

original glucose molecule has been completely

broken down

16 energy carrier molecules

4 ATP

10 NADH

2 FADH2

Electron Transport Chain

Electron Transport Chain - a collection of molecules

embedded in the inner membrane of the mitochondrion

All the folds in the mitochondrion allows more surface

area which allows more proteins to be added to the

surface

As an electron is transported along the chain, the carries

(NADH & FADH2) alternate between oxidizing and

reducing as the donate and take on electrons

Through out the movement of the electron H+ ions are

pumped out of the organelle creating a concentration

gradient

NADH looses its H+ ion

FADH2 loses both of its H+

ions

1 H+ is released out of

the mitochondrion

1 H+ is used up the

chain to combine

oxygen (why this is

aerobic respiration) to

form H2O

Electron Transport Chain Continued

ATP Synthesis- the creation of ATP molecules

ATP Synthase- and enzyme that makes ATP from

ADP and Inorganic phosphate

It takes the H+ gradient that is produced and

uses the energy of the ions to allow free ADP

and Phosphorous ions to form together to form

ATP

What is our overall product?

Anaerobic Respiration

No oxygen

Is the sole source of ATP in anaerobic bacteria

Starts off like cellular respiration using glycolysis to

produce 2 ATP molecules and 2 Pyruvate

Then it uses Fermentation to produce ethanol and

NAD+

Which then fuels glycolysis this process does not net

the huge amount of ATP that cellular respiration

does

Fermentation

2 pathways

Alcoholic Fermentation

Products: 2 Ethanol & 2 CO2

Lactic Acid Fermentation

Products: 2 Lactates

Both replenish NAD+ for glycolysis

Both net yield 2 ATP molecules per glucose

Ways Plants Get Energy

Photosynthesis- the process plants uses to

convert light energy and convert it to chemical

energy that is stored in sugar

Autotrophs- self feeders, they make their own

energy

Heterotrophs- obtain energy from consuming

organic materials (with plants think of

decomposers)

Photosynthesis Sites

The Mesophyll of the leaves contain Chloroplast

Chloroplast-a plastid that contains chlorophyll and in

which photosynthesis take place

Mesophyll- the tide in the interior of the leaf

CO2 enters and exits the leaves through pores called

stomata

Water is absorbed through the roots and other non

photosynthetic parts of the plant

Mesophyll Cells

30-40 chloroplasts

Chloroplast

Stroma- the envelope of 2 membranes surround a

dense fluid

Thylakoids- suspended sacked which segregate the

stoma from the thylakoid space

Chlorophyll- free pigment that gives leaves it color,

resides in the thylakoid membranes

Photosynthesis Reaction

6 CO2 + 12H2O + Light Energy —> C6H12O6 + 6 O2 + 6 H2O

The process in which plants make glucose is called the Calvin Cycle

Calvin Cycle takes CO2 and uses it to make a 3-C sugar this by sunlight

(provides ATP and NADPH)

Consist of 3 parts

Carbon Fixation

Reduction

Regeneration

Calvin Cycle Carbon Fixation

A CO2 molecule combines with a 5-Carbon

acceptor molecules and makes a 6-Carbon

molecule (RuBP or ribulose-1,5-bisphophate)

RuBP is split into 2 molecules of a 3-Carbon

molecule (3-PGA)

Calvin Cycle Reduction

ATP & NADPH are used to convert 3-PGA into a 3

carbon sugar (glyceralheyde-3-phosphate or G3P)

Calvin Cycle Regeneration

Some G3P molecules go make glucose whole

others are recycled to regenerate RuBP acceptors

Regeneration requires ATP