Energy and Metabolism

A collection of flashcards summarizing key concepts from the Energy and Metabolism lecture notes.

What does the first law of thermodynamics state?

Energy cannot be created or destroyed, only transformed.

What is the equation for free energy (G)?

G = H - TS, where H is enthalpy, T is absolute temperature, and S is entropy.

What is activation energy?

The energy required to initiate a chemical reaction.

What is the difference between exergonic and endergonic reactions?

Exergonic reactions release energy, while endergonic reactions require an input of energy.

What role do enzymes play in chemical reactions?

Enzymes act as biological catalysts that lower the activation energy for reactions.

What is ATP and why is it important?

Adenosine triphosphate (ATP) is the energy currency of cells, providing readily available energy for biochemical reactions.

Define metabolism.

Metabolism is the total of all chemical reactions carried out by an organism.

What is feedback inhibition?

A process where the end product of a metabolic pathway inhibits an enzyme involved in the pathway, regulating the pathway’s activity.

What is the role of NAD+ in cellular respiration?

NAD+ acts as an electron acceptor and is reduced to NADH during glycolysis and Krebs cycle.

Describe the difference between autotrophs and heterotrophs.

Autotrophs produce their own organic molecules from inorganic substances, while heterotrophs obtain organic compounds by consuming other organisms.

What is the main function of the Krebs cycle?

The Krebs cycle oxidizes acetyl-CoA to produce ATP and electron carriers (NADH and FADH2) that are used in the electron transport chain.

What is chemiosmosis?

The movement of protons across a membrane, driving the synthesis of ATP via ATP synthase.

What is photorespiration?

A wasteful process where the enzyme rubisco oxygenates RuBP, leading to the release of carbon dioxide.

What are the two stages of photosynthesis?

Light-dependent reactions and light-independent reactions (Calvin Cycle).

How do C4 and CAM plants adapt to minimize photorespiration?

C4 plants have a spatial solution by fixing carbon in different cells, while CAM plants have a temporal solution by fixing carbon at night.

What is cellular respiration?

Cellular respiration is the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

What are the main stages of cellular respiration?

The main stages of cellular respiration are glycolysis, the Krebs cycle, and oxidative phosphorylation.

What is photosynthesis?

Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose.

What are the primary products of photosynthesis?

The primary products of photosynthesis are glucose and oxygen.

What is the formula for cellular respiration?

The formula for cellular respiration can be summarized as: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy.

What is the formula for photosynthesis?

The formula for photosynthesis can be summarized as: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.

How are cellular respiration and photosynthesis related?

Cellular respiration and photosynthesis are interconnected; the products of photosynthesis (glucose and oxygen) are the reactants for cellular respiration, and vice versa.

What is glycolysis?

Glycolysis is the initial stage of cellular respiration that breaks down glucose into two molecules of pyruvate, producing a small amount of ATP and NADH.

What occurs during pyruvate oxidation?

Pyruvate oxidation is the conversion of pyruvate into acetyl-CoA, which occurs in the mitochondria and produces carbon dioxide and NADH.

What is the Krebs cycle?

The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA, producing NADH, FADH₂, and ATP.

What is the electron transport chain?

The electron transport chain is a series of protein complexes located in the inner mitochondrial membrane that transfer electrons and pump protons to create an electrochemical gradient, driving ATP synthesis.

What is chemiosmosis?

Chemiosmosis is the process of synthesizing ATP using the energy from the electrochemical gradient of protons across the inner mitochondrial membrane, facilitated by ATP synthase.

What are light-dependent reactions?

Light-dependent reactions are the first stage of photosynthesis that captures sunlight energy to produce ATP and NADPH while splitting water and releasing oxygen.

What are light-independent reactions?

Light-independent reactions, also known as the Calvin cycle, use ATP and NADPH from the light-dependent reactions to convert carbon dioxide into glucose.

What are photosystems?

Photosystems are complexes of proteins and chlorophyll in the thylakoid membranes that capture light energy and initiate photosynthesis by passing excited electrons to the electron transport chain.