Nutrients Flashcards
What are nutrients and what are the classes?
Nutrients are substances from food that are used by the body for its life functions. They provide energy, building blocks for cellular components, and molecules that aid chemical reactions
Classes:
1. Carbohydrates (first major nutrient)
2. Lipids (second major nutrient)
3. Proteins
4. Vitamins
5. Minerals
6. Water
What elements make up carbohydrates?
Carbon, Hydrogen, Oxygen
What are carbohydrates that are found individually, in pairs, and in long chains called? (based on rings)
Individually: monosaccharides (aka simple sugars)
In pairs: disaccharides
Long chains: polysaccharides
What is the most common carbohydrate?
Glucose (monosaccharide)
How are disaccharides formed?
Two monosaccharides undergoing dehydration synthesis
How are disaccharides broken down into monosaccharides?
A disaccharide undergoes hydrolysis
Dietary sources of carbohydrates?
Plants: starch, sucrose and cellulose
Animals: glycogen and lactose
to be absorbed, carbohydrates must be broken down into monosaccharides
Describe the body’s ability to store carbohydrates
The body has a limited ability to store carbohydrates and they are easily converted to glycogen (stored in liver and muscle) and fat (in adipose tissue) if not used
What are the effects of carbohydrate consumption in excess or reduction?
Excess carbohydrate intake can lead to obesity and elevated blood lipid levels (ex. atherosclerosis)
Reduced carbohydrate intake can lead to increased protein and fat metabolism, loss of muscle mass, and potential acidosis
What are lipids composed of?
Carbon, Hydrogen, Oxygen, Phosphorus (less oxygen than carbohydrates)
What kind of molecules are lipids?
Lipids are non-polar, hydrophobic molecules that are insoluble in water and soluble in other lipids
What are the 4 classes of lipids?
- Triglycerides (triacylglycerols, neutral fats)
- Fatty acids (including eicosanoids)
- Phospholipids
- Steroids (cholesterol, estrogen, testosterone)
What are triglycerides?
A storage lipid, and represent a vast energy reserve in adipocytes, muscle, and liver
They insulate, cushion, and protect vital organs
Excess triglyceride is a cause of obesity
What is the composition of triglycerides?
Triglycerides are made up of 1 glycerol and 3 fatty acid chains
What is glycerol?
Glycerol is a molecule made up of 3 carbon atoms (one per fatty acid)
What are fatty acids?
Fatty acids are long chains of carbon atoms bound with hydrogen atoms (hydrocarbons)
Chain length varies but is typically around 16-20 carbons long
Each fatty acid has a carboxylic acid tail at the end, giving the chain its acidic properties (-COOH)
What determines the solidity of fatty acids at room temperature?
The type of carbon-to-carbon bonds and length
What is the different between saturated and unsaturated fatty acids?
Saturated: if all bonds are single bonds in the chain
Unsaturated: if there is one double bond in the chain
Polyunsaturated: if there are more than one double bond in the chain
What type of fatty acid (saturated/unsaturated) is more stable at room temperature?
Saturated
Where do saturated fatty acids come from?
Primarily from animal sources and are solid at room temperature (called fats)
Where do unsaturated fatty acids come from?
Found in plant sources, and are liquid at room temperature (called oils)
Which type of fatty acid is healthier?
Unsaturated fats / oils
What are hydrogenated oils?
Chemically altered oils in which some double bonds are converted to single bonds by the addition of hydrogen -> more saturated and solid at room temperature (ex. margarine)
What are essential fatty acids?
Linoleic acid or linolenic acids
essential fatty acids are fats that cannot be synthesized by the human body and must be consumed through dietary sources
What reaction does glycerol and 3 fatty acids undergo to become triglyceride?
Dehydration synthesis
What reaction does triglyceride have to undergo to become glycerol and 3 fatty acids?
Hydrolysis
What do hydrogenated oils do to the body’s LDL and HDL
Low density lipoproteins (Bad) are increased in levels in the blood
High density lipoproteins (Good) are decreased in levels in the blood
What are Eicosanoids?
Fatty acid signaling molecules that cannot be synthesized (essential fat) and must be obtained from diet
Derived from a fatty acid called arachidonic acid
types:
-leukotrienes (produced by leukocytes) that are active in the immune system
-prostaglandins: short-chain fatty acids, local hormones (chemical messages)
What are phospholipids composed of?
2 fatty acid chains, glycerol, and a phosphate group