Question

Determine whether each process is anabolic or catabolic. a. photosynthesis b. cellular respiration c. fermentation

Short answer

a. Photosynthesis is an \(\textbf{anabolic}\) process. b. Cellular respiration is a \(\textbf{catabolic}\) process. c. Fermentation is a \(\textbf{catabolic}\) process.

Step-by-step solution

(a. Analyzing Photosynthesis)

Photosynthesis is a process in which plants, algae, and some bacteria convert light energy into chemical energy by synthesizing glucose from carbon dioxide and water. Since this process involves building complex molecules (glucose) from simpler ones (carbon dioxide and water), it is an anabolic process that requires energy input from sunlight.

(b. Analyzing Cellular Respiration)

Cellular respiration is the process by which organisms convert the energy stored in the chemical bonds of glucose or other organic molecules into a form that can be used by cells, such as ATP. In this process, glucose is broken down into simpler molecules, releasing energy. Thus, cellular respiration is a catabolic process that releases energy.

(c. Analyzing Fermentation)

Fermentation is an anaerobic process that occurs in the absence of oxygen, allowing organisms to generate energy through the partial breakdown of organic molecules such as glucose. Since fermentation involves the breaking down of complex molecules into simpler ones, this process is catabolic and releases energy. To summarize: a. Photosynthesis is an anabolic process. b. Cellular respiration is a catabolic process. c. Fermentation is a catabolic process.

Key concepts

Anabolic Processes

Anabolic processes are essential for the growth and repair of cells in living organisms. These processes build up complex molecules from simpler ones. For example, in photosynthesis, plants take in carbon dioxide and water to produce glucose, a simple sugar essential for their growth. This process utilizes energy, often from sunlight, and is crucial for storing energy in chemical bonds.

• Require energy input
• Build complex molecules
• Essential in growth, repair, and energy storage

Other examples of anabolic processes include protein synthesis, where amino acids link to form proteins, and the formation of nucleic acids from nucleotides. Anabolic processes are vital as they help organisms store energy that can be used for various cellular activities.

Catabolic Processes

Catabolic processes are the reverse of anabolic processes. They involve breaking down complex molecules into simpler ones and release energy in the process. This energy is then available for various cellular functions like movement, growth, and repair.

• Release energy
• Break down complex molecules
• Provide energy for cellular functions

A common example is cellular respiration, where glucose is broken down into carbon dioxide and water, releasing energy stored in ATP. Catabolic processes are crucial because they ensure that organisms have a steady supply of energy needed to sustain life.

Photosynthesis

Photosynthesis is a fascinating process through which plants, algae, and some bacteria transform sunlight into chemical energy. In simple terms, plants use light energy to turn carbon dioxide and water into glucose and oxygen.

• Occurs in the chloroplasts of plant cells
• Converts light energy into chemical energy
• Produces oxygen as a byproduct

The process happens in two main stages: the light-dependent reactions, where sunlight is captured, and the Calvin cycle, where carbon dioxide is converted into glucose. Since photosynthesis builds complex molecules, it is characterized as an anabolic process.

Cellular Respiration

Cellular respiration is a critical process for both plants and animals. It converts the energy stored in glucose into ATP, the energy currency of the cell. This conversion allows cells to perform various functions necessary for life.

• Occurs in the mitochondria of cells
• Breaks down glucose into carbon dioxide and water
• Releases energy stored as ATP

During cellular respiration, glucose undergoes glycolysis, the citric acid cycle, and the electron transport chain. This entire process is catabolic since it breaks down glucose and releases energy. The efficiency of cellular respiration lies in its ability to extract maximum energy from glucose.

Fermentation

Fermentation is an important process that enables cells to produce energy without the presence of oxygen. Typically occurring in yeast and some bacteria, fermentation breaks down glucose to produce energy, though less efficiently than cellular respiration.

• Occurs in the absence of oxygen (anaerobic)
• Partially breaks down glucose
• Produces products like ethanol, lactic acid, or other chemicals

There are several types of fermentation, such as alcoholic fermentation and lactic acid fermentation. For instance, in alcoholic fermentation, yeast cells convert glucose into ethanol and carbon dioxide. Meanwhile, lactic acid fermentation occurs in muscle cells, producing lactic acid, especially noticeable during intense exercise. Fermentation is classified as a catabolic process since it involves the breakdown of glucose to release energy.