Cellular Respiration Overview

Study Notes

Cellular Respiration Overview

Cellular respiration is a metabolic process that breaks down organic molecules to release energy in the form of ATP (adenosine triphosphate). This energy is used for cellular activities.
It's a central process for all living organisms.
Two main types exist: anaerobic (without oxygen) and aerobic (with oxygen).

Anaerobic Respiration

This type of respiration occurs in the absence of oxygen.
It's less efficient than aerobic respiration, producing much less ATP.
It involves a substrate being broken down by enzymes to produce energy in the form of ATP and reduced products.

Aerobic Respiration

This type of respiration requires oxygen.
It's highly efficient, producing a large amount of ATP.
It involves a series of reactions, including glycolysis, the Krebs cycle, and the electron transport chain.

Two Types of Fermentation

Fermentation is an anaerobic process that follows glycolysis.
Alcohol fermentation: This involves the conversion of pyruvate to ethanol and carbon dioxide. Common in yeast and some bacteria.
Lactic acid fermentation: Involves the conversion of pyruvate to lactic acid. Found in animal muscle cells during strenuous exercise when oxygen supply is limited.

Glycolysis

Glycolysis is the first stage of both aerobic and anaerobic respiration.
It occurs in the cytoplasm of the cell.
It involves breaking down glucose (a 6-carbon molecule) into two molecules of pyruvate (a 3-carbon molecule).
This process yields a small amount of ATP and NADH (electron carriers).

Krebs Cycle (Citric Acid Cycle)

Occurs in the mitochondrial matrix (in eukaryotes).
Pyruvate from glycolysis is further oxidized to release carbon dioxide.
It produces ATP, NADH, FADH₂ (electron carriers), and some byproducts.
The cycle repeats for each original glucose molecule.

Electron Transport Chain (ETC)

Takes place in the inner mitochondrial membrane (in eukaryotes).
NADH and FADH₂ from glycolysis and the Krebs cycle donate electrons to a series of protein complexes.
The electron transfer releases energy, which is used to pump hydrogen ions (protons) across the membrane creating a gradient.
The movement of hydrogen ions back across the membrane through ATP synthase generates ATP.
Oxygen acts as the final electron acceptor, combining with hydrogen ions to form water.

Photosynthesis

Photosynthesis is the process by which plants and some other organisms convert light energy into chemical energy in the form of glucose.
Two main types of reactions: Light-dependent and light-independent (Calvin cycle).
Light-dependent reactions capture light energy and convert it into chemical energy stored in ATP and NADPH.
Light-independent (Calvin cycle) reactions use ATP and NADPH to convert carbon dioxide into glucose.
It occurs in chloroplasts.

Description

Explore the essential process of cellular respiration that enables living organisms to convert organic molecules into energy. This quiz covers both anaerobic and aerobic respiration, detailing their processes and efficiencies. Test your knowledge on the critical components, including glycolysis and fermentation.