Physiology of GI Tract Flashcards
Define anabolism.
Anabolism is the set of reactions in which smaller molecules are combined to make larger molecules.
How is the energy released from the breakdown of glucose used by the body?
The energy is released during the breakdown of glucose is used by the body to add a phosphate to an ADP molecule and make ATP.
Describe cellular respiration.
It is when glucose combines with oxygen to form carbon dioxide, water, and ATP.
Describe glycolosis.
when glucose is broken down into 2 pyruvic acid molecules, and 2 ATP molecules are formed.
Describe the citric acid cycle (TCA cycle).
the pyruvic acid product of glycosis is converted to carbon dioxide forming some additional ATP.
Describe the electron transport chain.
hydrogen atoms formed during glycosis and the TCA cycle are converted to water releasing energy which is used to add phosphate to ADP to form ATP.
How is energy released in the breakdown of glucose converted to a form usable by cells?
The energy released in the breakdown of glucose allows the body to add a phosphate to an ADP molecule and make ATP, which is then used by cells as a source of energy to perform cellular activities.
How does the energy formed in fat catabolism compare to that formed in carbohydrate metabolism?
Lipid metabolism yields twice the energy formed during glucose metabolism.
Name, tell the location of, and explain in detail the first stage of lipid breakdown.
Lipid metabolism occurs in the liver by a process called beta-oxidation to form acetic acid which is further catabolized by the TCA cycle to carbon dioxid forming some ATP.
Why are proteins not usually used as a body energy source and when are they used?
Proteins are the building blocks for cells and are therefore preserved by the body only being used to make ATP when carbohydrates and fats are unavailable to the body.
What is the first step in the oxidation of an amino acid formed from a protein?
When proteins must be used to form ATP, the amino group is removed from the protein to form ammonia.
Explain in detail how ammonia is removed from the body.
Ammonia is combined with carbon dioxide to make UREA which is excreted in the urine.
When does ingestion occur?
Ingestion is when food enters the mouth.
When does ingestion occur?
What are the two parts of ingestion?
Digestion or food breakdown occurs when food is moved, mixed, and exposed to enzymes along the gastrointestinal tract. Digestion can be divided into two parts: mechanical digestion and chemical digestion.
When does mechanical digestion occur?
Mechanical digestion occurs when food is physically broken down into smaller pieces. This occurs when the teeth chew food, when the stomach churns and mixes food, and as food is moved and squeezed along the gastrointestinal tract.
