Biology Unit 5

Metabolism

Metabolism

the combination of all chemical reactions through which an organism builds up and breaks down materials.

Aerobic

metabolic processes need oxygen

Anaerobic

metabolic processes don’t need oxygen

Electron Carriers

Metabolic processes often use ATP, but there are several other molecules in the cell that can be used as energy currency.  Instead of using their chemical names, these molecules will be referred to as________, Examples include ATP, NADH, and FADH2

Energized Molecules

ATP, Energized electron carriers.

Ex: NADH and FADH2

De-energized Molecules

ADP, De-energized electron carriers.

Ex: NAD+ and FADH

Adenosine Triphosphate (ATP)

an electron carrier which provides energy for many cellular processes

Cristae

the folds of the inner mitochondrial membrane

Matrix

inner compartment of mitochondria

Cellular Respiration

the process by which the chemical energy of food molecules is converted into useful energy, Divided into three metabolic processes: Glycolysis, The Krebs Cycle, The Electron Transport Chain

Glycolysis

Anaerobic, found in the cytoplasm, glucose is split into 2 molecules called pyruvate (aka pyruvic acid) This change is accompanied by a NET gain of 2 ATP molecules and some energized electron carriers.

The Krebs Cycle

Aerobic, found in matrix, it uses 2 Acetyl CoA to produce energized electron carriers, including 2 ATP.  The non-ATP energized electron carriers will be used in the electron transport chain. More CO2 is released. There is a NET gain of 2 ATP.

The Electron Transport Chain

Aerobic, found in Inner Mitochondrial Membrane, The ETC allows the release of a lot of energy stored in electron carriers from the Krebs Cycle to make ATP. Approximately 34 ATP are produced in this step.

Fermentation

anaerobic, occurs in cytoplasm, occur after glycolysis when oxygen isn’t available to continue the Krebs Cycle and ETC. Different organisms undergo different types of fermentation. Plants and yeast cells undergo alcoholic/yeast fermentation. Animals undergo lactic acid fermentation

Photosynthesis

light energy from the sun is used to make chemical energy.  Chemical energy and CO2 are then used to make glucose.

Chloroplasts

trap light energy

Xylem

Water enters leaf through tubes called

Phloem

Sugar leaves leaf through tubes called

Leaves

are the site of photosynthesis

These capture light and are flat and numerous to increase surface area.

They have a cuticle and adjustable stomata to prevent water loss

Stems

are supporting structures that connect roots and leaves

• Carry water up and nutrients/glucose down

• Hold leaves up to the light

Roots

are underground plant organs that absorb water and minerals from soil.

• Anchor the plant and keep it upright.

Palisade cells

absorb most of the light coming into the leaf

Mesophyll cells

absorb most of the light coming into the leaf and contain many chloroplasts

Chloroplasts

double membrane structure with internal stacks of membranous discs \n site of photosynthesis, the process by which plants produce food \n (Only in plant cells)

Vascular Bundle

made of tissues that transport substances: xylem & phloem

Stomata

On the underside of leaves, surrounded by guard cells that allow them to open and close to allow in CO2 & prevent H2O loss

Guard Cells

each of a pair of curved cells that surround a stoma, becoming larger or smaller according to the pressure within the cells

Thylakoids

the structures where photosynthesis occurs

Grana

the stacks of thylakoids embedded in the stroma of a chloroplast

Stroma

fluid portion of the chloroplast

Light Reactions

Light-dependent reactions, located in thylakoid, reactants: H2O and sunlight, products: ATP, O2, and energized electron carriers

Calvin Cycle

Dark reactions, light-independent reactions, located in stroma, Reactants: CO2, ATP, and energized electron carriers, Products: C6H12O6

To occur, the Calvin Cycle use ATP and NADPH created during the light reactions.  It also uses CO2 that enters through the stomata.

Three major processes occur during the Calvin Cycle:

1. Carbon fixation

2. Reduction

3. Regeneration

Glucose is produced.

Photolysis

Inside the thylakoid, water is split into oxygen, hydrogen, and electrons when sunlight strikes a pigment embedded in the membrane, Hydrogens are pumped out, powering another pump to make ATP. The electrons and the pumped-out hydrogens are used to make the electron carrier NADPH

Chemical Equation of Photosynthesis

Carbon Dioxide+Water+sunlight>glucose+oxygen

Chemical Equation of Cellular Respiration

glucose+oxygen>carbon dioxide+water+energy(ATP)