Biology Cellular Respiration Quiz

Cellular Level of Organization

• The cellular level is the fundamental level of organization in living organisms.
• Objectives for study of cellular organization include outlining cellular respiration, describing the cell membrane and its functions, explaining cellular transport types, describing osmosis and solutions' effects on cells, and describing the factors contributing to resting membrane potential.

Cell Membrane

• The cell membrane is selectively permeable, regulating what enters and exits the cell.
• The membrane's structure consists of a phospholipid bilayer with embedded proteins and cholesterol molecules.
• Glycoproteins are present on the extracellular side of the membrane.
• Hydrophobic fatty acid tails are on the inside of the membrane, and hydrophilic phosphate heads are on the outside.

Cellular Respiration and Mitochondria

• Mitochondria are called the "powerhouse" of the cell.
• They use glucose to produce energy in the form of ATP.
• Mitochondria have an outer membrane and an inner membrane with folds called cristae.
• The intermembrane space is between the outer and inner membranes, and the inner matrix folds around cristae.

Metabolism Review

• Metabolism is the sum of all chemical reactions in a living organism.
• Anabolism refers to building up molecules, which requires energy.
• Catabolism refers to breaking down molecules, releasing energy.

ATP Structure and Function

• ATP (adenosine triphosphate) is a crucial energy molecule.
• Its structure includes an adenine base, a ribose sugar, and three phosphate groups.
• Energy is released when the terminal phosphate bond is broken (dephosphorylation).

ATP Review: Dephosphorylation and Hydrolysis

• Dephosphorylation is the process of breaking the high-energy phosphate bond in ATP to release energy.
• ATP hydrolysis involves adding water to the ATP molecule, separating the phosphate groups and releasing energy.
• ATPase is an enzyme that catalyzes this reaction.

ATP Re-making: Phosphorylation

• Phosphorylation is the re-making of ATP.
• It's the reverse process of dephophorylation.
• ATP synthase is the enzyme that re-makes ATP during cellular respiration.

Two Types of Phosphorylation

• Substrate-level Phosphorylation — a phosphate group is directly transferred from a substrate molecule to ADP in reactions, and it does not involve ATP synthase.
• Oxidative Phosphorylation — phosphate addition that uses energy from the electron transport chain and involves ATP synthase.

Aerobic and Anaerobic Respiration

• Aerobic respiration requires oxygen and produces a large amount of ATP from glucose (36-38).
• Anaerobic respiration does not require oxygen and produces less ATP from glucose (2).
• Anaerobic respiration produces lactic acid in animals.

Overall Equation for Cellular Respiration

• The overall equation for cellular respiration is C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (ATP).
• Glucose reacts with oxygen to produce carbon dioxide, water, and energy.

Cellular Respiration as a REDOX Reaction

• Cellular respiration involves oxidation and reduction reactions (Redox reactions).
• Glucose is oxidized (loses electrons) and oxygen is reduced (gains electrons).
• Oxygen is the final electron acceptor which produces water

Electron Carriers

• NAD+ and FAD+ are electron carriers that pick up electrons from glucose.
• They are reduced to NADH and FADH2, storing and delivering those electrons to the electron transport chain.

Stages of Cellular Respiration

• Glycolysis is the first stage, breaking down glucose.
• The Krebs Cycle is an intermediate stage, producing ATP and transferring electrons.
• The Electron Transport Chain (ETC) is the final stage, using electrons to generate a large amount of ATP.

Key Points of Glycolysis

• Glycolysis occurs in the cytoplasm and is an anaerobic process.
• Glycolysis starts with one molecule of glucose (6 carbons) and produces 2 molecules of pyruvate (3 carbons each).
• 2 ATP are used in the process, while 4 ATP molecules are produced, giving a net gain of 2 ATP molecules
• 2 NADH molecules are produced in the process.

Pyruvate Fate after Glycolysis

• If oxygen is present, pyruvate enters the mitochondria as acetyl CoA and undergoes further oxidation in the Krebs Cycle.
• If oxygen is absent, fermentation (lactic acid or alcoholic) happens.

Fermentation

• Fermentation is an anaerobic process that creates lactic acid or alcohol, depending on the organism.
• Fermentation happens when insufficient oxygen.

Krebs Cycle Summary

• The Krebs cycle occurs in the mitochondrial matrix in an aerobic environment.
• Two turns are needed for each glucose molecule.
• Pyruvate (from glycolysis) is used as input.
• The output is 2 ATP, 6NADH, and 2 FADH2, and 6CO2 per glucose molecule

Electron Transport Chain (ETC)

• The ETC occurs on the inner mitochondrial membrane.
• It uses electron carriers (NADH and FADH2) to create a proton gradient.
• This gradient drives ATP synthesis via ATP synthase.

Transmembrane Potential

• Transmembrane potential is the difference in charge across a membrane.
• It results from a concentration gradient of protons (H+).

ATP Synthase

• The ATP synthase is an enzyme that is involved in phosphorylation.
• It generates ATP from ADP and an inorganic phosphate which uses the energy stored in the electrochemical gradient of protons (H+).

How H+ Translates to ATP

• 4 H+ ions are required for one molecule of ATP to be made.
• Pumped across the membrane using ATP Synthase energy
• 10 H+ from NADH lead to 2.5 ATP
• 6 H+ from FADH2 lead to 1.5 ATP.

Cellular Respiration Summary

• The overall outcome of cellular respiration is a variable yield of ~30–38 ATP molecules per glucose molecule.
• ATP production depends on the cell type and specific enzymes.

Helpful Videos

• Crash Course on Cellular Respiration and various other videos are listed as useful resources for further learning or additional explanations on the subject.

Genetic Mutations Affecting Protein Structure

• Some diseases arise from mutations impacting essential proteins in the electron transport chain.
• Many genetic disorders are maternally inherited.

ETC Poisons

• Certain substances block the electron transport chain, inhibiting ATP production.
• Some examples of ETC poisons are rotenone, cyanide, and oligomycin.

Cyanide Poisoning

• Smoke inhalation is a typical cause of cyanide poisoning, as certain materials release cyanide when combusted.
• Symptoms such as immediate headaches, nausea, and dizziness can develop quickly, followed by respiratory failure and coma in serious cases.
• Treatment includes removing the source of cyanide exposure and seeking immediate medical care.

Test your knowledge on cellular respiration, including its processes, functions, and key reactions. Explore topics like glycolysis, the Krebs cycle, and the roles of various molecules such as ATP and FAD+. This quiz will challenge your understanding of energy production in cells.