Life Sciences 2 - Week 5 - Lipids Flashcards
Describe the key chemical properties of fatty acids.
Fatty acids are important lipids primarily used as fuel. They vary in chain length and saturation, which affects their physical properties:
o Saturated fatty acids: Have no double bonds, are linear, solid at room temperature, and have a high melting point (e.g., in pork, beef, butter).
o Unsaturated fatty acids: Have one or more double bonds, are liquid at room temperature, and can be further classified as monounsaturated or polyunsaturated.
What are the 5 major lipids and their biochemical functions?
*Free Fatty Acids: Used primarily as fuel and components of membrane lipids.
*Triacylglycerols: The storage form of fatty acids.
*Phospholipids: Key components of cell membranes, consisting of a polar head and nonpolar tails.
*Glycolipids: Important membrane components that are bound to carbohydrates.
*Steroids: Function as hormones (e.g., estrogen, testosterone), and cholesterol, a key membrane components.
What is the role of the liver, gallbladder and pancreas in lipid metabolism?
*Liver: Produces bile (about 1L/day) that helps emulsify fats, making them more accessible for digestion.
*Gallbladder: Stores and concentrates bile, releasing it into the duodenum to aid in lipid digestion.
*Pancreas: Secretes pancreatic lipases into the small intestine, which break down triglycerides into fatty acids and monoglycerides.
What is chylomicron formation?
- Chylomicrons are large lipoprotein particles formed in intestinal cells. They consist of reassembled triglycerides, cholesterol, and fat-soluble vitamins, surrounded by phospholipids and proteins (apolipoproteins), making them water-soluble. Chylomicrons transport dietary lipids from the intestines into the lymphatic system and eventually into the bloodstream.
Explain lipid metabolism in a fed state and fasted state.
*Fed State: Excess dietary fats and glucose are stored as triglycerides in adipose tissue through a process called lipogenesis when energy intake exceeds demands.
*Fasted State: Stored triglycerides are broken down into glycerol and fatty acids through lipolysis during periods of fasting (e.g., between meals, during exercise).
Understand lipid digestion in infants.
*Infants digest lipids efficiently due to several adaptations:
oThey have high levels of lingual and gastric lipases, which are more crucial in infants than adults.
oBreast milk contains lipases that are activated in the baby’s small intestine to assist in fat digestion.
oDespite low bile and pancreatic enzyme secretion, these adaptations help infants digest fats, which are crucial for growth and brain development.
