Lecture 10 - Nutrition Flashcards
What is nutrition?
The science that interprets the interaction of nutrients and other substances in food in relation to maintenance, growth, reproduction, health and disease of an organism
What is a nutrient?
A component in foods that an organism uses to survive and grow
What are macronutrients?
• nutrients that are required in large quantities by the body to maintain normal metabolic activities
Carbohydrates, fibre, fats, protein, and water
What are micronutrients?
• Nutrients that are required in small quantities by the body to maintain normal metabolic activities
Vitamins and minerals
What are essential nutrients?
Nutrients that are required by the body to carry out/maintain normal metabolic activities but our body is unable to synthesise them. Hence, we need to obtain them from the food we eat/supplements
What is the role of vitamins and minerals?
Assist the enzymes (cofactors to enzyme) that participate in the release of energy from carbohydrate, fat, and protein (enzymes required cofactors to stimulate their functions)
What is the digestion that occurs in the mouth?
Physical digestion: Teeth breaks down food mechanically
Chemical digestion:
Lingual lipase breaks down dietary fat/mainly triglycerides into medium or smaller fatty acid chains
Salivary amylase breaks down starch into maltose
What is the digestion that occurs in the stomach?
Stomach acid inactivates amylase and stops the digestion of starch
HCL in the stomach activates the enzyme pepsinogen to pepsin. Then the pepsin and HCL helps to break down proteins into smaller polypeptides and amino acids
Gastric Lipase in the stomach only hydrolyses a very small amount of fat
What is the digestion that occurs in the pancreas and small intestine?
Pancreas produce pancreatic amylase through the pancreatic duct into the small intestine, which breaks down starch into smaller polysaccharides and disaccharides. Then, the disaccharide enzymes on the surface of the small intestinal cells hydrolyse the disaccharides into its respective monosaccharides
Pancreatic and Intestinal protease hydrolyse polypeptides into tripeptides, dipeptides and amino acids. Then the Intestinal tripeptidases and dipeptidases hydrolyse the peptides into its respective amino acids
When fat enters the small intestine, it triggers the release of cholecystokinin, which signals the gallbladder to secrete bile. The bile then emulsifies the fat. This breaks down the fat into smaller fat globules which has a larger surface area for the enzymes to act on to increase the efficiency of digestion. Pancreatic lipase breaks down the emulsified fat (triglycerides) into monoglycerides, glycerol and fatty acids
What is the difference between active and passive transport?
Active transport requires energy (in the form of ATP) to open the channel in the plasma membrane.
Passive transport do not require energy (particles can pass through across the membrane via simple diffusion down a concentration gradient)
What is facilitated diffusion?
Passive transport of materials across the plasma membrane using the transport proteins
What is the function of micelle?
Trap fat within a water friendly environment to facilitate the transport of fat within our body)
What is the function of chylomicron?
A small fat globule made from protein and lipid
(outer layer is water friendly but the centre is the fat) transfer fat through the blood to be stored in our organs (need to be wrapped within a water friendly medium because fat is immiscible with water)
What is the benefit of fibre?
Reduce blood sugar levels
What are some examples of polyunsaturated fatty acids?
DHA/EPA (essential as our bodies are unable to synthesise these fatty acids)
