Cellular Energetics and Photosynthesis: Key Concepts for Unit 3

What is ATP?

Adenosine triphosphate (ATP) is a molecule that carries energy within cells. It consists of an adenine base, a ribose sugar, and three phosphate groups.

How does ATP store energy?

ATP stores energy in the high-energy bonds between its phosphate groups. When ATP is converted to ADP (adenosine diphosphate) by losing a phosphate group, energy is released.

What is the Cellular Respiration Equation?

The equation for cellular respiration is C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP, indicating that glucose and oxygen are converted into carbon dioxide, water, and energy.

What occurs during Glycolysis?

Glycolysis is the process that breaks down glucose into pyruvate, producing 2 ATP and 2 NADH. It occurs in the cytoplasm and is anaerobic.

What is Fermentation?

Fermentation is an anaerobic process that converts glucose into energy without oxygen. The two types are alcoholic fermentation and lactic acid fermentation.

What happens in the Krebs Cycle?

In the Krebs Cycle, acetyl-CoA is broken down, producing ATP, NADH, FADH2, and releasing CO2. It occurs in the mitochondria.

What is the Electron Transport Chain (ETC)?

The ETC is a series of protein complexes located in the inner mitochondrial membrane that transfer electrons and pump protons to produce ATP.

How many ATP are produced in Cellular Respiration?

A total of approximately 36-38 ATP molecules are produced from one glucose molecule during cellular respiration, including glycolysis, Krebs cycle, and ETC.

What is the Photosynthesis Equation?

The equation for photosynthesis is 6CO2 + 6H2O + light energy → C6H12O6 + 6O2, indicating that carbon dioxide and water, using light energy, are converted into glucose and oxygen.

What occurs in Photosystem II?

In Photosystem II, light energy is absorbed, water is split to release oxygen, and electrons are energized and passed to the electron transport chain.

What occurs in Photosystem I?

In Photosystem I, light energy is absorbed, and electrons are re-energized and used to reduce NADP+ to NADPH.

What are the stages of the Calvin Cycle?

The Calvin Cycle has three stages: carbon fixation, reduction, and regeneration of RuBP. It uses ATP and NADPH to produce glucose.

What pigments are involved in Photosynthesis?

Chlorophyll a and b are the primary pigments in photosynthesis, absorbing light mainly in the blue and red wavelengths and reflecting green.

What are C3, C4, and CAM adaptations?

C3 plants fix carbon directly in the Calvin Cycle, C4 plants have a modified pathway to minimize photorespiration, and CAM plants fix carbon at night to conserve water.

What is metabolism?

Metabolism encompasses all chemical reactions in a cell, including catabolism (breaking down molecules) and anabolism (building molecules), regulated by enzymes.

What are feedback mechanisms in metabolism?

Feedback mechanisms are processes that regulate metabolic pathways, often involving the inhibition or activation of enzymes based on the concentration of products or substrates.

What factors influence enzyme activity?

Factors that influence enzyme activity include temperature, pH, substrate concentration, and the presence of inhibitors or activators.

What is the role of enzymes?

Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to occur.

What is NAD+ and NADH?

NAD+ is a coenzyme that accepts electrons during metabolic reactions, becoming NADH, which carries electrons to the electron transport chain.

What is G3P?

Glyceraldehyde-3-phosphate (G3P) is a three-carbon sugar produced in glycolysis and is a key intermediate in both glycolysis and the Calvin Cycle.