ENERGY AND LIFEChapter 8

ATP in a moleculeA. Cell Energy

1. Energy is essential to life. All living things must be able to:a. produce energy from the environment

b.store energy for future usec. use energy in a controlled manner

2. Some cell processes that need energy are:a. active transportb. cell divisionc. Movement of cilia and flagella

d. Production of proteins (esp. enzymes)

3. Adensosine Triphosphate or ATPa. This is the energy molecule which is transformed from food in the mitochondria of cells

b. This energy is stored in the chemical bonds of the ATP molecule and can be used quickly and easily by the breaking of the bonds

B. Forming and Breaking Down ATP

1. Phosphate groups are charged (polar and hydrophilic) molecules.

A. AMP or Adenosine Monophosphate is formed when only one phosphate group is attached and only a small amount of energy is required (the chemical bonds do not store much energy).

B. ADP or Adenosine Diphosphate is formed when a second phosphate is added to AMP and when more energy is required to force the 2 phosphates together, yielding more energy when bonds are broken.

C.ATP or Adenosine Triphosphate is formed when the third phosphate is added to ADP.1. tremendous amounts of energy are required to force the third phosphate close to the two others.

2. This 3rd phosphate is so eager to get away from the other two that when the bond is broken a great amount of energy is released forming ADP

3. The energy of ATP becomes available when the molecule is broken down

4. ADP can reform ATP by bonding with another phosphate group.

The addition and release of a phosphate group on ADP creates a cycle of ATP formation and breakdown.

As long as phosphate molecules are available, the cell has an unlimited supply of energy.

C. How can cells tap into the energy stored in ATP?

1. Proteins have specific sites where ATP can bind so that when energy is released cells can capture and use the released energy efficiently and energy is not wasted.

2. When the phosphate bond is broken and the energy is released, the cell can use the energy for activities such as making proteins or transporting molecules through the plasma membrane.

3. The binding sites on proteins are necessary for cells to use this energy produced from ATP

INTRO-PHOTOSYNTHESIS

Structure of leaves

The primary function of leaves is to trap light energy for

photosynthesisPhotosynthesis is the process plants

use to trap the sun’s energy and build carbohydrates called glucose,

that store energy (ATP). Leaves are relatively flat so sunlight can penetrate to the photosynthetic tissues beneath the surface.

Structure of leaves:A. Mesophyll is the photosynthetic tissue

of the leaf (2 Types):1)palisade mesophyll made up of column-

shaped cells containing chloroplast; found under upper epidermis; most photosynthesis takes place here

2) spongy mesophyll composed of loosely packed irregularly shaped cells and air spaces so that carbon dioxide, oxygen, and water vapor can freely flow into and out of the stomata openings in the cuticle of the leaf

B. Dermal Tissue or Epidermis functions much like the skin of an animal; covering and protecting the body of the plant. Epidermal cells produce a waxy cuticle that helps prevent water loss.

C. Stomata helps control water loss; controls exchange of gases

D. Guard cells controls the opening and closing of the stomata regulates the flow of water vapor form the leaf tissue; takes in water by osmosis.

E. Chloroplast cell organelles that capture light energy and produce food to store for a later time (3 parts):

1)Disk-like compartments called thylakoids

2) Inner stacks called grana3)Fluid surrounding called stroma

2.

1.

3.

F. Chlorophyll embedded in the membrane of and is light trapping pigment

Autotrophs-producers (produce own food, plants, they use photosynthesis)

Heterotrophs-consumers (gain energy by eating autotrophs (plants), animals)

Leaves are the primary sites of photosynthesis

Transpiration is the process in which water and oxygen are lost in leaves through the stomata, which are regulated by guard cells

The broad, flat portion of a leaf is the blade, which is attached to the stem by a petiole

1. Cuticle thin waxy layer that prevents the loss of water.

2. Upper epidermis single protective layer of cells along the top edge of the leaf

3. Palisade layer rectangular photosynthetic cell below the upper epidermis (normally green). Where most photosynthesis occurs.

4. Vascular bundle loosely arranged photosynthetic cells below the palisade layer

5. Spongy layer groups of thick wall cell forming round rubes within the spongy layer. Responsible for transporting water and food

6. Stomata openings along lower epidermis that allow gas exchange

7. Guard cells cells surrounding the stomata that control stomata opening and closing

8. Air space large empty space within the spongy layers

9.lower epidermis thin, protective single layer of cells along the bottom edge of the leaf

Leaves

simple compound Double compound

Gymnosperm vs Angiosperm

BIOLOGY

Ch 8PHOTOSYNTHESIS

Photosynthesis is the process in which plants use to trap the sun’s energy and build carbohydrates.

6CO2 + 6H2O C6H12O6 + 6O2

This is accomplished in 2 phases:

Photosynthesis: Trapping of the sun’s energy

LIGHT

LIGHT DEPENDENT REACTIONS-which converts light energy from the sun into chemical energy; occur in the thylakoid sacs-chloroplast

Steps of the Light-Dependent Reactions:

1) Sunlight strikes and light energy transfers to chlorophyll

2) Chlorophyll passes energy down through the ELECTRON TRANSPORT CHAIN- providing energy that will:

Split (photolysis) H2O O2 + 2H + NADPH (from NADP+)

Bond PO4 to ADP forming ATP3)NADPH and ATP are used in the

Light-Independent reactions

Electron Transport

B. LIGHT INDEPENDENT REACTIONS (Calvin Cycle)-produces glucose; takes place in the stroma; does not require light.

Steps of the Light-Independent Reactions:

1) Carbon fixation 1 Carbon atom is added to a 5 Carbon sugar (RuBP)

2) PGA-the 6 carbon sugar formed in Step 1 is split to form 2 PGA molecules

3) NADPH + ATP from the Light Reactions convert PGA into PGAL (still a 3 Carbon sugar)

4) After 6 rounds of Calvin cycle - 1 GLUCOSE is formed

5) ATP and P replenish RuBP to begin the cycle again

The Calvin CycleThe Calvin Cycle

PhotosynthesisPhotosynthesis

PhotosynthesisPhotosynthesis

Photosynthesis: uses the energy ofPhotosynthesis: uses the energy ofsunlightsunlight to convert to convert waterwater and and carboncarbondioxidedioxide into high energy into high energy carbohydrates carbohydrates

6CO6CO2 2 + 6H+ 6H22O ---O ---lightlight C C66HH22OO6 6 + 6O+ 6O22

Carbon dioxide + water --- Carbon dioxide + water --- lightlight sugars + oxygen sugars + oxygen

Formula:

II. Electron Transport Chain- membrane around the thylakoid

CELLULAR RESPIRATION & FERMENTATION

Ch 9

Cellular Respiration

Process by which mitochondrion breaks down food to produce ATP

C6H12O6 + 6O2 6CO2 + 6H2O + energy

glucose plus oxygen produces carbon dioxide plus water

and gives off energy

Has 3 Stages:

1. 2. 3.

1. GLYCOLYSIS Anaerobic, uses no oxygen Occurs in the cytoplasm of the

cell Glucose breaks down to 2

Pyruvic acids (3 carbon sugars) 2 ATP used, 4ATP produced, 2

ATP net gain Uses an e- carrier NAD to form

NADH

Glycolysis

2) CITRIC ACID CYCLE (KREB CYCLE)

Aerobic, requires oxygen glucose is further broken down One ATP is produced with every

turn of the cycle 2 electron carriers are used

NAD + FAD

Citric Acid Cycle

3) ELECTRON TRANSPORT CHAIN

Aerobic, requires oxygen Occurs in the inner membrane of

the mitochondria Similar to ETC of the thylakoid

membrane Oxygen is the final electron

acceptor to form water Produces 32 ATP molecules

Electron Transport Chain

Fermentation

Anaerobic process-uses no O2

Means of producing ATP until O2 is available

2 types:1)Lactic Acid Fermentation

2 molecules of pyruvic acid is used to form lactic acid

2 ATP molecules are formed for each glucose

Causes muscle fatigue

LACTIC ACID FERMENTATION

2) Alcoholic Fermentation Used by yeast to produce

CO2 and ethyl alcohol Yields 2 ATP molecules

ALCOHOLIC FERMENTATION