Heterotrophs and Autotrophs Quiz

Study Notes

Heterotrophs are organisms that cannot produce their own food and must consume other organisms to obtain energy.
Autotrophs are organisms that can produce their own food through photosynthesis, using sunlight, carbon dioxide, and water.

Photosynthesis is the process by which plants and other autotrophs convert light energy into chemical energy in the form of glucose.
Photosynthesis occurs in organelles called chloroplasts, which contain chlorophyll, a pigment that absorbs light energy.
Chloroplasts contain stacks of thylakoids, which are interconnected membranous sacs where light-dependent reactions take place. These sacs are stacked into grana.
Calvin Cycle is the light-independent stage of photosynthesis, where carbon dioxide is converted into glucose.
Glucose is a sugar that provides energy for plants and other organisms.

Cellular respiration is the process by which organisms break down glucose to release energy in the form of ATP (Adenosine triphosphate).
Aerobic respiration requires oxygen and produces carbon dioxide, water, and ATP.
Anaerobic respiration does not require oxygen and produces lactic acid or alcohol as byproducts.

Glycolysis is the first step in cellular respiration and occurs in the cytoplasm.
Glucose is broken down into two molecules of pyruvic acid, producing a net gain of 2 ATP.

The Krebs Cycle (also known as the citric acid cycle) completes the breakdown of glucose and occurs in the mitochondria.
Pyruvic acid is converted into acetyl-CoA, which enters the Krebs Cycle.
The Krebs Cycle produces ATP, NADH, and FADH2.

The electron transport chain is the final stage of cellular respiration and occurs in the mitochondria.
Electrons from NADH and FADH2 are passed down a chain of protein carriers, releasing energy that is used to produce ATP.
Oxygen acts as the final electron acceptor, forming water.

Fermentation is an anaerobic process that occurs when oxygen is not available.
Lactic acid fermentation occurs in human muscles during strenuous activity, producing lactic acid, which causes muscle fatigue.
Alcohol fermentation occurs in yeast and some bacteria, producing ethanol and carbon dioxide.