A. P. Biology (Photosynthesis and Cellular Respiration).

Photosynthesis

process by which plants convert light to chemical energy.

Autotroph

produces own food; produces organic and inorganic molecules from carbon dioxide.

heterotrophs

depends on producers for food and oxygen.

How are photosynthetic cells arranged?

enzymes and other molecules are grouped inside a membrane that allows for a efficient photosynthetic reactions.

Where do photosynthetic cells come from?

they evolved from photosynthetic bacteria.

Where are photosynthetic cells located in a plant?

the leaves.

Which tissue layer contains most of the chloroplasts?

the mesophyll (interior tissue of a leaf).

Where does carbon dioxide enter the leaf and where does oxygen leave the leaf?

the stoma (small openings on a plant).

Stroma

the dense fluid inside a chloroplast.

Thylakoid

connected membrane sacs

Grana

stacks of thylakoids.

What are the reactants in photosynthesis?

carbon dioxide and water.

What are the products of photosynthesis?

sugar (glucose) and oxygen.

What are the two stages of photosynthesis?

light reaction and the Calvin cycle.

Light Reaction process:

water is split, oxygen is released as debris, electron acceptor NADP+ is reduced to the molecule NADPH. ATP is generated from ADP by adding a phosphate group.

Process of the Calvin cycle:

ATP and NADPH that is produced by the light reaction is used to convert carbon dioxide into glucose. Process happens by carbon fixation.

Phosphorylation

the adding of a phosphate group to an ATP molecule.

What are two high energy molecules created by the light reactions?

ATP and NADPH

What is the wavelength and what does it determine?

distance between the crest of waves between electromagnetic energy. Determines the type of electromagnetic energy.

Photon

particle of light.

Pigments

substances that absorb light.

Why do leaves appear green?

chlorophyll reflects that color of light.

Chlorophyll A

absorbs violet blue to red; main photosynthetic pigment.

Chlorophyll B

absorbs a variety of wavelengths.

Carotenoids

absorb all excess light.

Photosystem

(1) consists of a reaction system (protein complex). (2) is a light harvesting complex, absorbs light energy.

Light harvesting complexes

complexes that have pigments that absorb energy from light.

Electron flow

the flow of electrons through both photosystems to produce ATP and NADPH.

Process of Photosystem 2:

(part of the light reaction step in photosynthesis). Photosystem 2 happens before photosystem 1. Sunlight is absorbed by chlorophyll A. Chlorophyll A uses that energy to activate an electron acceptor molecule called P680. At the same time, water is being split by enzymes into hydrogen and oxygen. Oxygen is released and electrons are transferred from hydrogen to the P680 molecule.

Process of Photosystem 1:

Electrons from photosystem 2 are passed down an electron transport chain where ATP is produced. Sunlight excites another electron acceptor molecule called P700. P700 molecule uses electrons from Photosystem 2 to change NADP into NADPH molecule.

Three phases of the Calvin Cycle:

(1). Carbon fixation- when carbon dioxide molecule is added to another organic molecule.

(2). Reduction- when a carbon molecule during carbon fixation is changed into a glucose molecule.

(3). Regeneration- when a original carbon molecule is regenerated and ATP and NADPH are fed back into the light reaction.

How do plants keep from dehydration or drying out?

by closing their stoma.

Photorespiration

when gas is used in the pace of carbon dioxide in the Calvin cycle. It is counter productive because it uses ATP and oxygen.

c3 plants

plants that are efficient in photosynthesis but not photorespiration; live in cool, wet places.

c4 plants

efficient in photorespiration due to specific enzymes that allow it to function with very little carbon dioxide, live in hot, dry places.

What do plants store excess sugar as?

starch (food).

What two products of photosynthesis are the reactants of cellular respiration?

glucose and oxygen.

Fermentation

partial breakdown of sugar in the absence of oxygen.

Aerobic respiration

consumption of organic molecules with oxygen to produce ATP.

Anaerobic respiration

formation of ATP from organic molecules without oxygen.

Redox reaction

reaction in which electrons are transferred and energy from that transfer is used to make ATP.

Oxidation

a substance loses an electron.

Reduction

a substance gains a electron.

During cellular respiration which molecule is oxidized and which is reduced?

glucose is oxidized; oxygen is released.

Three stages of cellular respiration:

glycolysis

Krebs cycle (citric acid cycle)

electron transport chain

Glycolysis

the breaking down of a glucose molecule into two pyruvate molecules.

Where does glycolysis take place?

in the cytoplasm and can happen with or without oxygen.

What is glucose converted into during glycolysis?

into two pyruvate molecules.

Process of the Krebs cycles (citric acid cycle):

The pyruvate from glycolysis is converted into a Aceytal co-enzyme A. The Aceytal co-enzyme generates 1 ATP, 3 NADH, and 2 FADH2. There are eight steps in the cycle and each are catalyzed by a different enzyme. NADH and FADH2 transfer electrons from original sugar molecules to the electron transport chain.

Oxidative phosphorylation

phosphorylation of ADP into ATP.

Process of the electron transport chain:

takes place inside the mitochondria at the cristae (inner folds). Most of the components that carry out the electron transport chain are proteins. Hydrogen ions are pumped across the membrane to create a gradient, those hydrogen ions then move through a protein called ATP synthase, this protein uses the hydrogen ions to change ADP into ATP or phosphorylation.

Where does the electron transport chain take place in the cell?

mitochondria at the cristae (inner folds).

What is the function of ATP synthase?

to phosphoryllate ADP into ATP.

Chemiosmosis

use of energy in a hydrogen ion gradient to drive cellular work.

Proton motor force

the gradient created by the hydrogen ions which drives the transport electron chain.

How many ATP are produced by cellular respiration?

32

What happens when no oxygen is present or the cell runs out of oxygen?

fermentation

Alcoholic fermentation process:

the pyruvate is converted into ethanol (alcohol), carbon dioxide is released, oxygen is not required but glycolysis still takes place.

Process of lactic acid fermentation:

the pyruvate ultimately becomes lactic acid or lactate; no carbon dioxide is released, no oxygen is required, and still has glycolysis. Muscles do this and cheese/yogurts are formed by this.

How many ATP are formed by fermentation?

2

Obligate anaerobe

organism that can only survive where there is no oxygen. Can only create energy through fermentation.

Facultative anaerobe

can use both cellular respiration and fermentation.