Gastrointestinal Lecture 4 Digestion and Absorption Part 1 Intro to Dietary Nutrients Flashcards
digestion
process of breaking down large particles of food and high-molecular weight substances into small molecules
absorbtion
movement of the products of digestion across the intestinal epithelium into the body
macronutrients
required to be present in the diet in large amounts
- carbs
- fats
- proteins
What maintains a healthy body?
balanced diet
carbohydrates energy
Major energy source for humans (4 calories/gram)
How is glucose obtained, stored and synthesized?
Glucose is an essential energy source for many human tissues
- obtained in the diet
- stored as glycogen
- synthesized via gluconeogenesis
major forms of carbs
- Monosaccharides
- Disaccharides
- Polysaccharides
non-digestible carbohydrates
dietary fiber
Monosaccharides
glucose, fructose… simple sugar
Disaccharides
Composed of two monosaccharide building blocks via hydrolysis
- sucrose, lactose, maltose
monosaccharides of sucrose, lactose, maltose,
sucrose → glucose + fructose
lactose → glucose + galactose
maltose → glucose + glucose
Polysaccharides
Polymers of sugar residues
- starch, glycogen
dietary fibre
polysaccharides >>> cellulose
- Glucose polymer with alternating orientation of glucose residues, linked by hydrogen bonds
fat energy
Major energy source for humans (9 calories/gram)
Most abundant type of dietary fat?
is triglyceride (~90%)
triglyceride structure
Different fatty acyl compositions
> Saturated fatty acids
> mono-unsaturated fatty acids
> poly-unsaturated fatty acids
fats
mixtures of triglycerides that are solid at room temperature
oils
mixtures of triglycerides that are liquid at room temperature are called oil
protein energy
Major energy source for humans (4 calories/gram)
What is protein major source of?
Major source of building blocks for numerous biological functions (new proteins, neurotransmitters, etc.)
Protein structures
> Primary structure
> Secondary structure
> Tertiary structure
> Quaternary structures
> Supramolecular protein assemblies
primary protein structure
(linear sequence of amino acids in a polypeptide chain)
secondary protein structure
structural motifs in the polypeptide chain; alpha-helices & beta-pleated sheets
tert protein structure
three-dimensional structure formed by polypeptide chain
quaternary protein structure
complexes with multiple polypeptide chains, hemoglobin
Supramolecular protein assemblies
protein complexes, myofilaments, collagen fibrils
Types of micronutrients
Vitamins
- Fat-soluble vitamins (A, E, D)
- Water-soluble vitamins (B complex, C)
Trace elements
- Iron, iodine, Zinc,….