Study sheet: Photosynthesis and Respiration

📋 Course Outline

1. Photosynthesis Inputs and Products
2. Photosynthesis Sequence
3. Respiration and ATP Production
4. Photosynthesis Versus Respiration
5. Glucose Fate and Limiting Factors
6. Stomata and Gas Exchange
7. Hydrilla Photosynthesis Experiment

📖 1. Photosynthesis Inputs and Products

🔑 Key Concepts & Definitions

• Photosynthesis : the process by which green plants use sunlight to produce glucose and oxygen from carbon dioxide and water

📝 Essential Points

• Chlorophyll absorbs sunlight energy that enables photosynthesis in green leaves.

• The end products of photosynthesis are glucose and oxygen, while carbon dioxide is absorbed and oxygen is released from leaves in bright sunlight.

💡 Memory Hook

Sunlight absorbed by chlorophyll drives glucose and oxygen production.

📖 2. Photosynthesis Sequence

📝 Essential Points

• Photosynthesis involves absorbing solar energy by chlorophyll, splitting water into hydrogen and oxygen, converting solar energy into chemical energy, and reducing carbon dioxide to form glucose.

💡 Memory Hook

Absorb light → split water → store energy → reduce carbon dioxide.

📖 3. Respiration and ATP Production

★ Must-know

📌 Aerobic respiration occurs in the presence of oxygen and produces carbon dioxide, water, and 38 ATP, whereas anaerobic respiration occurs without oxygen and produces ethanol, carbon dioxide, and 2 ATP.

• Aerobic respiration follows $C_6H_{12}O_6 + 6O_2 \xrightarrow{enzymes} 6CO_2 + 6H_2O + 38\ ATP$.

Further detail

• Anaerobic respiration follows $C_6H_{12}O_6 \xrightarrow{enzymes} 2C_2H_5OH + 2CO_2 + 2\ ATP$.

💡 Memory Hook

Aerobic respiration uses oxygen and yields 38 ATP; anaerobic respiration lacks oxygen and yields 2 ATP.

📖 4. Photosynthesis Versus Respiration

★ Must-know

📌 Photosynthesis produces glucose using sunlight and removes carbon dioxide, whereas respiration breaks down glucose to produce ATP and returns carbon dioxide to the atmosphere.

• Respiration occurs in both plants and animals and supplies energy for cellular activities through ATP.

Further detail

• Most free oxygen in the atmosphere is produced by photosynthesis, and most living organisms depend on this oxygen for survival.

💡 Memory Hook

Photosynthesis builds glucose using sunlight, whereas respiration breaks glucose down to produce ATP.

📖 5. Glucose Fate and Limiting Factors

★ Must-know

• After photosynthesis, glucose may be stored temporarily as insoluble starch, transported through the plant as sucrose in solution through leaf veins, or converted into energy by respiration.

• The three most important factors are:

  • carbon dioxide concentration
  • light intensity
  • suitable temperature

Further detail

📌 Temperatures above 40 degrees Celsius can slow or stop photosynthesis by inhibiting enzyme action.

📌 Too much light can destroy chlorophyll, while low light, low carbon dioxide concentration, or below-optimal temperature lowers the rate of photosynthesis.

📖 6. Stomata and Gas Exchange

🔑 Key Concepts & Definitions

• Stomata : pores on the leaf surface that allow the exchange of gases such as carbon dioxide and oxygen

★ Must-know

📌 Stomata are important for photosynthesis because they permit carbon dioxide to enter and oxygen to leave the leaf.

Further detail

• The labeled parts are:
  • epidermal cells
  • chloroplasts
  • guard cells
  • the stoma

💡 Memory Hook

A pore between two guard cells opens in the leaf surface for gas exchange.

📖 7. Hydrilla Photosynthesis Experiment

★ Must-know

• In the Hydrilla experiment, oxygen released by photosynthesis collects as gas bubbles in the inverted test tube placed over the funnel in sunlight.

Further detail

📌 If the Hydrilla experiment is performed in darkness, bubbles do not form because photosynthesis does not occur without light.

💡 Memory Hook

Light enables photosynthesis, causing oxygen bubbles to collect.

📊 Synthesis Tables

Aerobic and Anaerobic Respiration

Feature	Aerobic respiration	Anaerobic respiration
Oxygen	Requires oxygen	Occurs without oxygen
End products	Carbon dioxide and water	Ethanol and carbon dioxide
Energy yield	38 ATP	2 ATP