Energy

I. Metabolic PathwaysA. Energy = the ability to do work

B. Metabolic processes use chemical E (ATP)

C. E released when chemical bonds break (e- pulled apart)

D. Each step is regulated by

enzymes

II. EnzymesA. = proteins essential for

cells to function

B. Act as catalysts

1. Speed up reactions without being changed

2. Attach to substrate molecule and weaken it

3. Enzyme is not altered

C. Enzymes …. 1. Lower activation energy

(= energy that must be added to a reaction to cause molecules to react)

2. Form enzyme-substrate complexes

3. Allow reactions to proceed at certain temperatures and pH

D. Every enzyme catalyzes only one reaction or one type of reaction

E. Enzymes ….

1. break down toxins (a lot in liver)

2. speed up digestion

Catalase

III. Factors That Affect Enzyme SpeedA. Enzymatic reactions are rapid

1. Most occur 1000 times/secEx: 2H2O2 2H2O + O2

(600,000 times/sec with catalase). B. Temperature

1. Increase temp

Increase molecular collisions

Increase enzyme activity

2. Temp too high (or low?)….. breaks down (denatures) enzyme

3. Human enzymes function best at is 35o-40oC

Catalase

C. pH1. Each enzyme

has optimal pH

2. Large change in pH may denature the

enzyme3. Optimal in humans

pH 6-8D. Other factors: radiation,

electricity, chemicals.

I. Photosynthesis and NatureA. Sunlight provides energy to produce

carbohydrates.B. Equation:

Light

6CO2 + 6H2O C6H12O6 + 6O2

Chlorophyll

C. Autotrophs (make their own food)1. Algae, plants, some bacteria2. Ultimate source of food for life3. Photoautotrophs…..

use light energy4. Chemoautotrophs……

use chemical energyD. Photosynthesis produced the oxygen

in the atmosphere of our planet.

II. Structures of Photosynthesis

A. Chloroplasts

1. = the organelle of Photosynthesis

2. Stroma –

fluid-filled inner space

3. Thylakoids-

internal membranes within

stroma

4. Organized into stacks called grana.

B. Chlorophylls and other pigments are embedded within thylakoid membranes.

C. Pigments absorb solar energy.

III. Photosynthetic PigmentsA. Major pigments are

chlorophyll a and b.1. Both absorb violet, blue, and

red wavelengths best.2. Most green is reflected back.

B. Carotinoids = yellow-orange pigments ; absorb light in violet, blue, and green regions

C. In fall, chlorophyll breaks down and the yellow-orange pigments show through.

D. Accessory pigments capture light when sun changes positions.

IV. Cell RespirationA. Breaks down glucose and builds up ATP.

B. C6H12O6 + 6O2 6CO2 + 6H2O + ATP Energy

C. Begins in cytoplasm with Glycolysis

1. Turns glucose into pyruvic acid

2. Produces 2ATP

D. Fermentation

1. Processes that keep glycolysis going without oxygen

2. Lactic Acid fermentation

a) Converts pyruvic acid into lactic acid

b) Occurs in muscle cells when oxygen not available; causes pain

c) Used by bacteria that make yogurt, cheese, pickles

3. Alcoholic Fermentation

a) Converts pyruvic acid into ethyl alcohol and CO2

b) Occurs in bacteria and yeasts

c) Used to make beer, wine, and bread

E. Aerobic Respiration1. Need Oxygen2. Energy from Pyruvic Acid is

transferred to ATPa) In the Krebs Cycleb) In the Electron Transport

Chain3. Breakdown of glucose

yields 36 ATP

4. If O2 is not available to the cell, fermentation occurs.

Paper Chromatography