Cellular Respiration Overview

Stages of Cellular Respiration

• Cellular respiration is broken down into three main stages: Glycolysis, the Citric Acid Cycle (Krebs Cycle), and Electron Transport.

Sequence of Cellular Respiration

• Glycolysis is the first step in cellular respiration.

Cellular Respiration Formula

• The chemical equation for cellular respiration is: C6H12O6C_6H_{12}O_6C6​H12​O6​ + 6O26O_26O2​ → 6CO26CO_26CO2​ + 6H2O6H_2O6H2​O
• This equation represents the breakdown of glucose (C6H12O6C_6H_{12}O_6C6​H12​O6​) in the presence of oxygen (6O26O_26O2​) to produce carbon dioxide (6CO26CO_26CO2​), water (6H2O6H_2O6H2​O), and energy.

Cellular Respiration Energy Source

• Cellular respiration uses food molecules, such as glucose, as its primary source of energy.

Glycolysis Net Gain

• Glycolysis results in a net gain of two ATP molecules.

Krebs Cycle Starting Molecule

• Pyruvic acid is the starting molecule for the Krebs Cycle.

Electron Transport Chain Electron Donors

• NADH and FADH₂ are two molecules that donate high-energy electrons to the electron transport chain.

Cellular Respiration Stages

• Cellular respiration is broken down into three main stages: glycolysis, the citric acid cycle, and electron transport.
• The process begins with glycolysis.
• Cellular respiration requires food molecules to release energy.
• The molecule C6H12O6C_6H_{12}O_6C6​H12​O6​ 6O26O_26O2​ → 6CO26CO_26CO2​ 6H2O6H_2O6H2​O represents the chemical formula.
• The net gain of glycolysis is two ATP molecules.
• Pyruvic acid is the starting molecule of the Krebs cycle.
• NADH and FADH₂ are involved in passing high-energy electrons to the electron transport chain.

Cellular Respiration Stages

• Cellular respiration has three main stages: glycolysis, the citric acid cycle, and electron transport.

Cellular Respiration Sequence

• Cellular respiration begins with glycolysis.

Cellular Respiration Formula

• Cellular respiration is summarized with the following chemical formula:
  • C6H12O6+6O2→6CO2+6H2OC_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2OC6​H12​O6​+6O2​→6CO2​+6H2​O
• This shows glucose (C6H12O6C_6H_{12}O_6C6​H12​O6​) reacting with oxygen (O2O_2O2​) to produce carbon dioxide (CO2CO_2CO2​) and water (H2OH_2OH2​O).

Cellular Respiration Fuel

• Cellular respiration breaks down food molecules to release energy.

Glycolysis Net Gain

• Glycolysis results in a net gain of two ATP molecules.

Krebs Cycle Starting Molecule

• Pyruvic acid is the starting molecule for the Krebs cycle.

Electron Transport Chain Electron Donors

• NADH and FADH₂ provide high-energy electrons to the electron transport chain.

Heterotrophs and Autotrophs

• Heterotrophs consume food for energy. Examples include dogs, birds, and fish.
• Autotrophs produce their own food through processes like photosynthesis. Examples include plants, algae, plankton, and certain types of bacteria.

Photosynthesis

• Photosynthesis is the process by which plants convert carbon dioxide, sunlight, and water into glucose and oxygen.
• Chloroplasts are organelles within plant cells that contain chlorophyll and are responsible for photosynthesis.
• Thylakoids are chlorophyll sacs found within chloroplasts.
• Granum refers to a stack of thylakoids.
• Calvin Cycle is a light-dependent reaction that produces glucose within chloroplasts. It uses carbon dioxide and ATP.

Cellular Respiration

• Cellular Respiration is the process by which glucose and oxygen are converted into carbon dioxide, water, and ATP (energy).
• Aerobic respiration requires oxygen. Examples include plants, mosses, insects, mammals, some algae, and bacteria.
• Anaerobic respiration does not require oxygen. An example is lactic acid fermentation.

Glycolysis

• Glycolysis is the first step of cellular respiration.
• During glycolysis, a glucose molecule is split into two molecules of pyruvic acid.

Krebs Cycle

• Krebs Cycle (Citric Acid Cycle) completes the breakdown of glucose.
• The enzymes for the Krebs Cycle are located in the fluid within the mitochondria.

Fermentation

• Lactic Acid Fermentation occurs when glucose is converted into lactic acid, primarily in human muscles during strenuous exercise when oxygen levels are low.
• Alcohol Fermentation is a biological process that converts sugars like glucose, fructose, and sucrose into cellular energy, producing ethanol and carbon dioxide as byproducts.

Heterotrophs and Autotrophs

• Heterotrophs obtain nutrients by consuming other organisms. Examples include dogs, birds, and fish.
• Autotrophs produce their own food through photosynthesis. Examples include plants, algae, plankton, and some bacteria.

Photosynthesis

• Photosynthesis is the process by which plants convert light energy into chemical energy (glucose).
• It occurs in chloroplasts, specifically in the thylakoids.
• Chloroplasts are organelles within plant cells that contain chlorophyll, a pigment that absorbs light energy.

Cellular Respiration

• Cellular Respiration is the process by which cells break down glucose to release energy (ATP).
• Glycolysis is the first stage of cellular respiration, where glucose is broken down into pyruvate.
• Krebs Cycle (Citric Acid Cycle) is the second stage, where pyruvate is further broken down.
• Electron Carriers are molecules that transport electrons during cellular respiration, such as NADH and FADH2.
• ATP is the primary energy currency of cells.
• Aerobic Respiration requires oxygen. It occurs in plants, mosses, insects, mammals, some algae, and bacteria.
• Anaerobic Respiration does not require oxygen. One example is lactic acid fermentation, which occurs in human muscles during strenuous exercise.

Fermentation

• Lactic Acid Fermentation occurs in human muscles when oxygen is limited, converting glucose into lactic acid.
• Alcohol Fermentation is a process used by yeast and some bacteria to convert sugars into ethanol and carbon dioxide.

Other Key Terms

• Granum is a stack of thylakoids within a chloroplast.
• Thylakoid is a chlorophyll-containing sac in chloroplasts where light-dependent reactions take place.
• Calvin Cycle is a series of light-independent reactions in photosynthesis that produce glucose.

Heterotrophs

• Definition: Organisms that must consume food to obtain energy, as they cannot make their own.
• Examples: Dogs, birds, fish.

Autotrophs

• Definition: Organisms that produce their own food through photosynthesis, using sunlight, water, and carbon dioxide.
• Examples: Plants, algae, plankton, bacteria.

Granum

• Definition: A stack of thylakoids within the chloroplast of plant cells.

Thylakoid

• Definition: Chlorophyll sacs within the chloroplasts, where light-dependent reactions occur.
• Location: Suspended in the stroma (of chloroplasts), interconnected membranous sacs.

Calvin Cycle

• Definition: A light-independent reaction in photosynthesis, where glucose is produced.
• Location: Occurs in the stroma of chloroplasts.
• Process: Uses carbon dioxide ($CO_2$) and ATP from the light-dependent reactions.

Lactic Acid Fermentation

• Definition: Anaerobic process where glucose is converted into lactic acid when oxygen is limited.
• Location: Occurs in human muscles during intense exercise.

Cellular Respiration

• Definition: Process where glucose and oxygen are converted into carbon dioxide ($CO_2$), water ($H_2O$), and ATP (energy).
• Types:
  • Aerobic respiration: Requires oxygen.
  • Anaerobic respiration: Does not require oxygen.
• Examples of organisms that utilize cellular respiration: Plants, mosses, insects, mammals, some algae, bacteria.

Photosynthesis

• Definition: Process where plants convert sunlight, water, and carbon dioxide ($CO_2$) into glucose and oxygen.
• Purpose: Provides plants with food and energy.

Chloroplast

• Definition: Light-absorbing organelles where photosynthesis occurs.
• Location: Mostly found in the interior of leaves.
• Example: Cactus.

Glycolysis

• Definition: The first step of cellular respiration.
• Process: A molecule of glucose is split into two molecules of pyruvic acid.

Krebs Cycle (Citric Acid Cycle)

• Definition: Completes the breakdown of glucose.
• Location: Enzymes for the Krebs cycle are dissolved in the fluid (matrix) within the mitochondria.

Alcohol Fermentation

• Definition: A biological process that converts sugars (like glucose, fructose, and sucrose) into cellular energy, producing ethanol and carbon dioxide as byproducts.

Electron Carriers

• Definition: Molecules that transport electrons during cellular respiration.
• Examples: NADH and FADH2.
• Function: Carry electrons from the breakdown of glucose to the electron transport chain, where they are used to generate ATP.

This quiz covers the essential stages of cellular respiration, including Glycolysis, the Krebs Cycle, and the Electron Transport Chain. You'll explore the chemical processes, energy sources, and net gains involved in cellular respiration. Test your knowledge and understanding of these vital biological processes!