Chapter 6 Final Study Guide

Glycolysis is a metabolic pathway that is common to both fermentation and cellular respiration. It is the initial step in both processes and occurs in the cytoplasm of cells. During glycolysis, glucose is broken down into two molecules of pyruvate, producing a small amount of ATP and NADH. In fermentation, pyruvate is further metabolized without the presence of oxygen, while in cellular respiration, pyruvate enters the mitochondria and undergoes further oxidation to generate more ATP. Therefore, glycolysis serves as a crucial metabolic pathway in both fermentation and cellular respiration.

The final electron acceptor in the electron transport chain in mitochondria is O2. During cellular respiration, electrons are passed down the electron transport chain, which generates a proton gradient across the inner mitochondrial membrane. This gradient is used to produce ATP. At the end of the electron transport chain, O2 accepts the electrons and combines with protons to form water. This process is essential for the production of ATP and the efficient functioning of cellular respiration.

Lactic acid is produced in the muscles when they are functioning anaerobically, meaning when there is not enough oxygen available for the muscles to produce energy aerobically. Monitoring the buildup of lactic acid can help the sports physiologist determine the point at which the muscles switch to anaerobic metabolism. This information is important for optimizing training programs and performance of athletes at the Olympic training center.

Autotrophs are organisms that can produce their own food using energy from sunlight or inorganic compounds, while heterotrophs rely on consuming other organisms for their energy needs. This distinction is correctly captured in the statement that only autotrophs can live on nutrients that are entirely inorganic. Autotrophs have the ability to convert inorganic substances into organic compounds through processes such as photosynthesis, allowing them to sustain themselves without the need for consuming other organisms. Heterotrophs, on the other hand, require organic compounds from the environment as a source of energy.

Glucose is the correct answer because it is a source of energy for cells through the process of cellular respiration. Glucose is broken down in the presence of oxygen to produce ATP, which is the main energy currency of cells. NADH, pyruvic acid, and carbon dioxide are intermediate products or byproducts of cellular respiration, but glucose is the initial molecule that provides the most chemical energy.

In glycolysis, glucose is oxidized, meaning it loses electrons, while NAD+ is reduced, meaning it gains electrons. This process is a crucial step in the breakdown of glucose to produce energy in the form of ATP. During glycolysis, glucose is converted into pyruvate, and NAD+ is converted into NADH. This reduction of NAD+ to NADH is important because NADH carries the electrons to the electron transport chain, where further energy production occurs.

Cellular respiration is the process by which cells break down glucose and other organic molecules to produce energy in the form of ATP. This process requires oxygen and is known as aerobic respiration. Aerobic consumers, plants, and human muscle cells are all capable of undergoing aerobic respiration. However, obligate anaerobes are organisms that cannot survive in the presence of oxygen and therefore do not undergo cellular respiration. Instead, they rely on alternative metabolic pathways, such as fermentation, to generate energy.