BIO Module 5 (exam 2)

Energy Transformation parts 1 and 2

Phototrophs

organisms that obtain electromagnetic energy from sunlight

(Energy Source)

Chemotrophs

Organisms that obtain Chemical energy from organic macromolecules

(Energy Source)

Autotrophs

Organisms that obtain carbon from inorganic sources (ex. Co2, vascular plants)

(Carbon Source)

Heterotrophs

Organisms that obtain carbon from organic macromolecules (ex. Carbohydrates, animals, most bacteria)

(Carbon Source)

what level of the trophic pyramid has the most energy?

Primary Producers

How much energy is lost as heat as you move up a trophic level?

10%

Each individual in higher levels needs more energy, resulting in fewer individuals and less biomass as you move up

First law of Thermodynamics

Energy is a cycle

Second Law of Thermodynamics

Disorganized energy (heat) contributing to entropy

• entropy of a system is constant or increasing but never decreasing

Exergonic reactions

Energy out

• reactants have more energy than products (ex. cellular respiration)

Endergonic reactions

Energy in

• products have more energy than reactants (ex. Photosynthesis)

Energetic Coupling

The energy released by a catabolic reaction is used to drive an anabolic reaction

• Less disorder: more chemical energy in bonds

ATP Hydrolysis

most common exergonic (catabolic) reaction that releases energy for use in endergonic I anabolic) processes

Enzymes

proteins that regulate hemical reactions and thus energy transfer

• energetic regulation

Macromolecules

Carbohydrates, proteins, fats, nucleic acids

Subunits

sugars, amino acids, fatty acids, nucleotides

Oxidation- reduction reactions

• Oxidezed

• Reduced

Oxidized (redox) reaction

Loses energy and electron

Reduced (redox) Reaction

Gains electron and energy

Enzyme - substrate complex

substrate (sucrose) binds to enzyme which puts stress on the glucose-fructose bond (breaks bond) ; products are released

Activation energy

All reactions require this input of energy to proceed

• EA

Energetic regulation

Cells produce molecules that affect enzyme activity and thus have ultimate control over energetic processes

Types of enzyme inhibitors

• Competitive

• Non Competitive

Competitive Inhibitor

Interferes with active site of enzyme so substrate cannot bind

Noncompetitive inhibitor

changes shape of enzyme so it cannot bind to substrate

Allosteric site

• Allosteric inhibition

• Allosteric Activation

Changes the shape of active site

Enzyme activity is affected by:

Environmental changes:

• temperature

• pH

• substrate concentration

• enzyme concentration

Primary function of photosynthesis

to produce carbohydrates

primary function of cellular respiration

to produce ATP

photosynthesis

• major entry point for energy into biological systems

• source of all food we eat and oxygen we breathe

  • 40% visible light

electromagnetic spectrum

left of the spectrum is higher energy

• more energy is violet light (400 nm) than infrared light (650ish nm)

Light Absorption

Pigments are oxidized(release high energy electrons) when they absorb light energy

Carotenoids

Blue

(light absorption)

Chlorophyll b

orange

blueish indigo

(light absorption)

Chlorophyll a

inidgo

red

( light absorption)

colors that are not absorbed well

yellow and green

Thylakoid membrane

part of chloroplast where pigments are found

• light dependent reactions happen here

The chloroplast parts

• outer membrane

• inner membrane

• thylakoid membrane

• grana

• thylakoid lumen

• stoma

mitochondria

where cellular respiration is conducted

Generalized Equation for photosynthesis reactions

H2O + CO2 + light —→ O2 + sugar

Stroma

light independent reactions (calvin cycle)

Light Dependent Reactions

1. Photosystem 2

2. Electron transport chain 1

3. Photosystem 1

4. Electron transport chain 2

5. ATP synthesis

1. Photosystem 2

• pigments receive electrons from the splitting of H2O which also produces oxygen and H+

• pigments absorb light energy which causes them to be oxidized and release excited electrons

2. Electron Transport Chain 1 (Pq, Cyt, Pc)

• cytochrome (Cyt) uses the energy from electrons the pump H+ from the stroma into the thylakoid lumen

3. photosystem 1

• pigments receive electrons from electron transport chain 1

• pigments absorb light energy which causes them to be oxidized and release excited electrons to electron transport chain 2

4. Electron Transport Chain 2 (Fd, NADP+ reductase)

• high energy electrons, NADP+, and H+ are used by NADP+ reductase to make NADPH

5. ATP Synthesis

• ADP, phosphate (Pi), and H+ are used by ATP synthase to make ATP

Light independent reactions

Calvin Cycle

1. carboxylation

2. Reduction

3. Regeneration of RuBP

1. Carboxylation

The addition of CO2 to the 5-carbon compound, RuBP, is catalyzed by the enzyme Rubisco

2. Reduction

ATP and NADPH provide the energy and high-energy electrons needed to reduce 3-PGA to triose phosphate

CO2 input

Carbon enters the calvin cycle as CO2

3. Regeneration of RuBP

3-carbon compounds are reorganized and combined to produce RuBP

Carbohydrate output

carbohydrates exit as 3-carbin compounds (G3P)

Aerobic cell respiration equation

sugar + O2 —→ Co2 + H2O + ATP

Aerobic cellular respiration

Role: to generate energy (ATP) from glucose and oxygen

Steps (location):

1. Glycolysis (cytoplasm)

2. Pyruvate Oxidation (mitochondrial matrix)

3. Citric Acid (Krebs) Cycle (mitochondrial matrix)

4. Oxidative phosphorylation (inner mitochondrial membrane)

1. glycolysis

Reactants: 1 glucose

Products: 2 NADPH , 2 ATP, 2 Pyruvates (fuel that powers the next step)

• happens in cytoplasm

2. Pyruvate Oxidation

Reactants: 2 pyruvates

Products: 2 CO2, 2 NADH, 2 Acetyl-CoA (fuel that powers the next step)

• occurs in the Mitochondrial Matrix

3. Citric Acid (Krebs) Cycle

reactants: 2 Acetyls

Products: 4 CO2, 6 NADH, 2 FADH , 2 ATP (fuel is gone)

• occurs in Mitochondrial Matrix

4, Oxidative Phosphorylation

Reactants: NADH FADH 2, Oxygen

Products: ATP, H2O

• Occurs in Inner Mitochondrial membrane

Anaerobic Cellular respiration

occurs when no oxygen is present

• recycling of NADH to NAD+ for use in Glycolysis

Lactic Acid Fermentation

reduction of pyruvate to lactic acid

Glucose —> pyruvate —> lactic acid

• Anaerobic

Alcoholic fermentation

Oxidation of pyruvate to acetaldehyde followed by reduction to ethanol

Glucose —→ pyruvate —→ acetaldehyde —> ethanol

• anaerobic