Digestion and Absorption

Questions and Answers

Which molecules are produced from the digestion of fats?

Glycerol and fatty acids (correct)

Monosaccharides

Polysaccharides

Amino acids

Some food molecules do not require digestion.

True

What are indigestible fibers that humans cannot break down?

Cellulose

What is the role of fiber in a balanced diet?

Helps to prevent heart disease Signup and view all the answers

The three stages of digestion are digestion, degradation, and complete oxidation to _, _, and energy.

CO2, H2O Signup and view all the answers

What does ATP stand for?

Adenosine triphosphate Signup and view all the answers

Hydrolysis of two phosphate groups from ATP releases more energy than hydrolysis of one phosphate group.

True Signup and view all the answers

What is the process that regenerates ATP in the body?

Phosphorylation Signup and view all the answers

Energy + 6 H2O + 6 CO2 → _ + 6 O2 represents the process of _

C6H12O6, Photosynthesis Signup and view all the answers

Match the following terms related to metabolism with their descriptions:

Catabolism = Breakdown of complex molecules to release energy Anabolism = Building large molecules from simple ones Metabolism = All chemical reactions providing energy and growth substances Signup and view all the answers

Study Notes

Digestion Overview

Digestion breaks down food into simpler molecules for absorption into the bloodstream.
Involves hydrolases that catalyze the hydrolysis of food components:
- Polysaccharides and disaccharides are converted to monosaccharides.
- Fats are broken down into glycerol and fatty acids.
- Proteins are decomposed into amino acids.

Absorption of Nutrients

Some substances do not require digestion and can be directly absorbed, including:
- Monosaccharides
- Inorganic salts
- Vitamins
These nutrients, being in their simplest form, easily cross cell membranes.
Indigestible substances, such as cellulose, cannot be absorbed.

Role of Fiber

Fiber is crucial for a healthy diet and helps prevent:
- Heart disease
- Diabetes
- Weight gain
- Certain cancers
It aids in lowering cholesterol levels and promoting digestive health.

Stages of Digestion

Stage 1: Digestion occurs in:
- Mouth
- Stomach
- Small intestine
- Bulk food is broken down into small molecules.
Stage 2: Degradation and Oxidation involves:
- Degradation of sugars, fatty acids, and amino acids to smaller molecules (mostly acetyl-CoA) in the cytoplasm.
Stage 3: Complete Oxidation produces CO2, H2O, and energy for ATP production.

Metabolism

Describes all chemical reactions that supply energy and materials for cell growth.
Catabolism: Breaks down complex molecules, releasing energy.
Anabolism: Builds large molecules from simpler ones using available energy.

Carbohydrate Origin

Carbohydrates are produced during photosynthesis:
- Formula: Energy + 6 H2O + 6 CO2 → C6H12O6 + 6 O2

ATP and Energy

ATP (adenosine triphosphate) is the primary high-energy molecule in cells, composed of:
- Adenine
- Ribose
- Three phosphate groups
Hydrolysis of one phosphate group releases energy of 7.3 kcal/mol (31 kJ/mol).
Hydrolysis of two phosphate groups releases energy of 7.7 kcal/mol (31 kJ/mol).
ATP drives energy-requiring reactions that cannot occur independently.
The body's ATP supply is limited; ATP is regenerated via phosphorylation.

Description

This quiz covers the essential processes involved in digestion and absorption of food molecules. Learn about the role of hydrolases and the breakdown of carbohydrates, fats, and proteins. Test your knowledge on how food is transformed into absorbable nutrients in the body.