Chapter 8.1 – The Need for Energy

I. The Need for Energy – all organisms must get energy from their environment to do work

A. Autotrophs – organisms that harvest energy from sunlight or

chemicals green plants, green algae, green

bacteriaB. Heterotrophs – organisms that

consume energy from other organisms humans, snakes, cockroaches,

tapeworms, bacteria, yeast/fungi, venus fly trap

C. ATP – an energy molecule1. Energy is stored in its bonds2. Energy gets released when ATP

is broken apart, forming ADP

Adenosine triphosphate (ATP)

Adenosine diphosphate (ADP)

D. Examples of Cells Using Energy:1. any exercise2. thinking3. digesting4. breathing

II. Photosynthesis – trapping the sun’s energy

A. Chloroplast – part of an autotroph’s cells that trap light energy

B. Chlorophyll – green pigment in the chloroplast that converts the

sun’s energy into ATP it absorbs all colors, except green green is reflected back to our eyes

C. Photosynthesis – the process that uses the sun’s energy to make glucose

6CO2 + 6H2O + sun → C6H12O6 + 6O2

2 steps:

1. Light-Dependent Reactions Sunlight is converted into

ATP2. Light-Independent Reactions

(Dark Reactions / Calvin Cycle) ATP (from step 1) and CO2 are

used to make glucose (C6H12O6)

III. Cellular Respiration – the process where cells in ALL living things use cell parts called mitochondria to get ATP energy from glucose

C6H12O6 + 6O2 → 6CO2 + 6H2O

3 Steps to make 36 ATP:

1. Glycolysis – chemical reactions that break apart glucose (2 ATP made)

2. Citric Acid Cycle / Krebs Cycle (2 ATP made)

3. Electron Transport Chain (32 ATP made)

A. Aerobic Respiration – happens with oxygen when your body

operates normallyB. Anaerobic Respiration –

fermentation happens when your body lacks O2

1. In Animals: lactic acid fermentation causes muscle stiffness (side aches)

2. In Plants or Fungi: alcoholic fermentation produces

ethanol & CO2

Brewing Industry – ethanol is the “alcohol” in beer and wine, CO2 adds fizz

Bread Industry – yeast produces CO2, but ethanol evaporates during baking

CellularRespiration

O2 Who? Products Made

Causes…

AerobicCellular

Respiration

present All living things

(plants, animals,

bacteria, fungi, protists)

CO2

H2O

Energy

Anaerobic Respiration:Lactic AcidFermentati

on

absent Animals CO2

H2O

Lactic Acid

Muscle Stiffness(side aches)

AnaerobicRespiration:

AlcoholicFermentati

on

absent Plants, bacteria, fungi,

protists

CO2

H2O

Ethanol

Bread to rise

beer to have fizz

Evaporates in oven w/ bread

Stays in beer to make it “alcoholic”

Photosynthesis

Cellular Respiration

Food- Made or Broken down?

Made Broken down

Energy- Stored or Released?

Stored Released

CO2- Taken in or Given off?

Taken in Given off

O2- Taken in or Given off?

Given off Taken in

Produces- What 2 things?

Glucose & O2 CO2 & H2O

Light - Required or Not?

Light required Light NOT required

Where does it happen?

Chloroplasts of Plants Mitochondria of ALL living things