College Biology - Cellular Respiration Unit

Test 4

Why do we need oxygen? (COLLEGE LEVEL)

• To make ATP

• Energy from food “reloads” ATP

• Oxygen is the final electron acceptor in the making of ATP

ATP (Adenosine Triphosphate) - what it looks like

Fully charged battery

ADP (Adenosine Diphosphate) - what it looks like

Partially charged battery

Redox Reactions - two types

Oxidation AND Reduction 

Oxidation

Loses electrons

Reduction

Gains electrons

Redox Reactions - how they work

• In cells, when one substance is oxidized another is reduced

• Transfer of electrons from one molecule to another molecule

NAD (Nicotinamide Adenine Dinucleotide) - two types

NAD⁺AND NADH

NAD⁺

Empty bucket

NADH

Full bucket

NAD (Nicotinamide Adenine Dinucleotide) - traits

• Electron Carrier

• Referred to as a “bucket”

• Can carry 2 electrons

• Redox Reaction

Glycolysis - bullet list

• First to evolve

• Least efficient

• “Sugar splitting”

• Happens in cytoplasm

Glycolysis - diagram + “must knows”

MUST KNOW:

Glucose

Fructose-1,6-Diphosphate

PGAL

Pyruvix Acid

Glycolysis - net gain

2 ATP

2 NADH

Fermentation

If no oxygen is available

• Anaerobic respiration

• Alcoholic (yeast and bacteria)

• Lactic Acid (muscles and bacteria)

Krebs Cycle - bullet list

AKA “Citric Acid Cycle”

• Happens in Matrix of Mitochondria

• 2 turns per glucose (2 pyruvic acid)

Krebs Cycle - diagram + “must knows”

MUST KNOW:

Pyruvic Acid

Acetyl Co-a

Citric Acid

Oxaloacetic Acid

Krebs Cycle - net gain

Note: goes around twice, so double the diagram

2 ATP

8 NADH

2 FADH₂

ETC: Electron Transport Chain - bullet list

MAIN EVENT

• Happens in Cristae of Mitochondria

• Electrons from NADH and FADH₂ are used to make ATP

• ATP Synthase

ETC: Electron Transport Chain - diagram

Note 1: Electrons go down

Note 2: Pay attention to small details

ETC: Electron Transport Chain - net gain

32 ATP

Net Gain / Gain Summary - ETC

(Note: -2 ATP for Active Transport)

10 NADH — 30 ATP

2 FADH₂ — 4 ATP

How much ATP does 1 molecule of glucose yield in total?

36!

How much ATP is gained from all 3 steps?

• 2 ATP from Glycolysis

• 2 ATP from Krebs Cycle

• 32 ATP from Electron Transfer Chain

Cellular Respiration Formula

C₆H₁₂O₆ + 6O₂ — 6CO₂ + 6H₂O + 36 ATP

Cellular Respiration Formula (parts)

1. Glycolysis

2. ETC

3. Krebs Cycle

4. ETC

5. (ALL)

Photosynthesis

• Absorbs part of the visual spectrum

• Green plants reflect green light

• Pigments absorb light

  • Chlorophyll a

  • Chlorophyll b

  • Xanthophyl

  • Carotene

Chloroplast Review Traits and Diagram

1. Thylakoid

2. Stroma

3. Grana

4. Inner Membrane

5. Outer Membrane

Photosystems Traits

Pigments in the thylakoid membrane

Absorbs sun’s energy

Photosystems Steps (simplified)

1. Chlorophyll is oxidized … passes its electrons to the primary electron acceptor

2. Electrons are passed to electron acceptor instead of falling back to the original energy level

Light Dependent Reaction (LDR) - bullet list

1. Light energy is transferred to chemical energy

2. Happens in the thylakoid membrane

3. Electrons move through E.T.C.

4. Electrons are replaced by splitting water

Light Dependent Reaction (LDR) - net gain

Oxygen

NADPH

ATP

Empty Bucket - Plants

NADP+

Full Bucket - Plants

NADPH

Light Dependent Reaction (LDR) Diagram

Similar to E.T.C in Cellular Respiration

Compare: Stoma/Stomata and Stroma

They are both involved in the production of photosynthesis

Contrast: Stoma/Stomata and Stroma

However, stroma is the fluid in the chloroplast that LIR (Calvin Cycle) takes place in and stoma/stomata is the little mouth of the leaf that takes in carbon dioxide.

Calvin Cycle / LIR - bullet points

• Melvin Calvin

• C₃

• Fueled by ATP and NADPH

• Happens in stroma

• Uses CO₂ to make glucose…

Calvin Cycle / LIR - diagram and must knows

• CO₂

• Rubisco

• PGAL

• RUBP

Photorespiration

“Glitch” in the system

Rubisco binds with oxygen instead of carbon dioxide

Happens when it is hot

• Less carbohydrate

• Less plant growth

C₄ Plants

1. Do not use Rubisco the same way as C₃

2. CO₂ is fixed into a 4 carbon molecule

3. CO₂ is shuttled to the Calvin Cycle

C₄ Advantage

Avoids photorespiration

C₄ Disadvantage

Uses more ATP

CAM Plants

1. Warm and Dry climates

2. Close stomata during the day

CAM Plants - Night

C₄ - carbon storage during the night

CAM Plants - Day

Calvin Cycle during the day - when ATP is available

Photsynthesis Formula

6CO₂+ 6H₂O — 6O₂+ C₆H₁₂O₆

(FLIP OF CELLULAR RESPIRATION)

• — = light

• C₆H₁₂O₆ = glucose

Photoynthesis Formula (parts)

1. LIR

2. LDR

3. LDR

4. LDR

5. LIR

Aerobic vs Anaerobic Similarities

Both are biological processes that break down glucose to produce cellular energy

Aerobic vs Anaerobic Differences

However aerobic respiration uses oxygen as the final electron acceptor to break down a large amount of energy, while anaerobic respiration occurs without oxygen and produces less energy.

Lactic Acid Fermentation

Anaerobic metabolic process where sugars are converted into ATP and byproduct lactic acid

Alcoholic Fermentation

Microorganisms, primarily yeast, convert sugar (like glucose) into cellular energy, producing ethanol and carbon dioxide as byproducts, especially in the absence of oxygen