Cell Energy (Photosynthesis and Respiration) Notesstaff.katyisd.org/sites/khspapbio/PreAP Biology...

Cell Energy (Photosynthesis and Respiration) Notes

I. Energy – ability to do work; forms of energy: heat, light, chemical, electrical, mechanical, kinetic, potential

A. Energy for living things comes from - foodOriginally the energy in food comes from - sun

B. Uses light energy from the sun to produce food –autotrophs

Examples: plants + some microorganisms (bacteria and protists)

C. Cannot use the sun’s energy to make food –heterotrophs; obtain energy from food they consume

Examples: animals, fungi, most microorganisms

II. Cell Energy – needed for active transport, making proteins and nucleic acids, chemical signals (fireflies’ light)

A. Cells usable source of energy – ATP

1. ATP stands for adenosine triphosphate

adenine3 Phosphate groups

ribose

ATP

2. ADP stands for – adenosine diphosphate

2 phosphate groups adenine

ribose

ADP

B. All energy is stored in the bonds of the compoundBreaking the bond releases energy

C. When cell has energy available it can store this energy by adding a phosphate group to ADP, producing ATP

D. Example:

ATP ADP + P + E from breaking bond

ADP + Energy + P ATP

http://www.youtube.com/watch?v=bbtqF9q_pFw&NR=1

III. Photosynthesis – energy of sunlight is converted to energy of glucose

A. General Formula:

H2O + CO2 + light C6H12O6 + O2

water + carbon dioxide + light glucose + oxygen

B. 2 parts of photosynthesis:

1. light reaction – forms ATP and NADPH – contain chemical E, but are unstable

2. Calvin cycle (dark reaction) – uses E from ATP and NADPH to produce glucose

C. Photosynthesis occurs in the organelle –chloroplast

D. Light absorbing (and reflecting) compounds – pigments

Most common photosynthetic compound –chlorophyll (a + b)

Absorbs light energy needed for photosynthesis to work

Absorption of Light by Chlorophyll a and Chlorophyll b

F. Sun’s energy is stored in – glucoselight energy chemical energy

CO2 + H2O + light C6H12O6 + O2

H2O CO2

O2

released

C6H12O6

produced

Light

Light Dependent Reactions

Calvin Cycle

ATP

NADPH

NADP+

ADP+P+

Light Dep. Reactions:

•Trap E of sun in chemical form•Produces O2,

ATP, NADPH

high E cmpds.

Chloroplast

Light Dep. Reactions occur in thylakoid

stroma—Calvin Cycle occurs here

Calvin Cycle:

•Uses E from Light Dep. Reactions and CO2 to make glucose

IV. Cellular Respiration – process by which E of glucose is released in the cell to be used for life processes (movement, breathing, blood circulation, etc…)

A. General Formula:

C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP

B. Cellular respiration occurs in all cells of all organisms –plants, animals, bacteria

C. Energy stored by photosynthesis in glucose is converted into the energy of – ATP

E. Respiration requiring oxygen – aerobic respiration

C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP

1. organelle occurring in – mitochondria

Human cells contain a specialized structure – the

mitochondrion – that generates energy.

E. Respiration NOT requiring oxygen – anaerobic respiration (an = without)

Also called – fermentation

1. Alcoholic Fermentation: glucose ethyl alcohol + CO2 + 2 ATP

a. organisms -- yeast, bacteria

b. industries – baking, brewing, wine-making

2. Lactic acid fermentation: glucose lactic acid + 2 ATP

a. lactic acid is produced in the muscles during rapid exercise when the body cannot supply enough oxygen to tissues (burning painful sensation)

3. occurs in – cytoplasmSore Muscles and

C6H12O6 + O2 CO2 + H2O + 36 ATP

**E transferred from glucose to ATP

3 stages of aerobic respiration:1. Glycolysis – cytoplasm, 2 ATP2. Krebs cycle – mitochondria, 2 ATP3. Electron Transport Chain – mitochondria, 32 ATP

36 ATPtotal

Glucose1 6-C molec.

Glycolysis

Pyruvic Acid2 3-C molec.

Cytoplasm

2 322

MitochondriaCO2

released

Krebscycle

E. T. C.

High E e- carried in NADH

High E e-

carried in NADH and FADH2

H2O released

O2

AEROBIC

Glucose1 6-C molec.

Glycolysis

Pyruvic Acid2 3-C molec.

Fermentation

Alcoholic Lactic Acid

YeastBacteria

muscles

2

Cytoplasm

ANAEROBIC

Mitochondria

ANAEROBICalcoholic fermentation = 2 ATP

glucose 2 pyruvic acid lactic acid fermentation = 2 ATP

cytoplasm

mitochondriaAEROBIC

Krebs cycle ETC = 36 ATP