Module 2.3: Carbohydrates, lipids, steroids and hormones Flashcards
what are carbohydrates?
Organic molecules containing carbon, hydrogen, and oxygen (CHO)
describe the features of carbohydrate in diet
Primary macronutrient in diet
* Energy source for living cells to generate
ATP (adenosine triphosphate)
* Essential for growth
* 2-3% of total body mass
what is the general formula for carbohydrates
(CH₂O)ₙ, where “n”= # carbon atoms
what are some examples of carbohydrates?
sucrose, starch, glycogen
what are the three major forms of carbohydrates?
- Monosaccharides
- Disaccharides
- Polysaccharides
describe monosaccharides
- Simplest form of carbohydrates
- Cannot be broken down into smaller sugars
- Used to build more complex carbohydrates
examples of monosaccharides?
5-carbon (Pentose) and 6-carbon (Hexose)
- Pentoses: deoxyribose (DNA), ribose (RNA)
- Hexoses: glucose, fructose, and galactose
how are disaccharides synthesized?
puts two monosaccharides together by
removing water and forming a glycosidic bond
how are disaccharides broken?
Disaccharide Hydrolysis: breakdown a disaccharide into two monosaccharides by adding water and breaking the glycosidic bond
describe polysaccharides
- Polysaccharides: long chain of monosaccharides bound together by glycosidic bonds
- Range from 10-1000’s of monosaccharides arranged in strings or chains
- Usually insoluble in water
what is an example of a polysaccharide?
Glycogen is a common polysaccharide
* Storage form of glucose in liver and skeletal muscle
* Not soluble in water, cannot pass in and out of cells unless it is broken down
* Useful as a storage molecule due to this insolubility
how are polysaccharides broken down?
Broken down by hydrolysis reactions into monosaccharides
* Require enzymes: glycosidases or
carbohydrase
describe starches and the different types
(polysaccharides)
Starches: glucose monomers formed by plants
* Amylose: linear chain of glucose
* Amylopectin: branched chain
* Both broken down by amylase
describe cellulose
(Polysaccharide)
Cellulose (fiber)
* Formed by plants
* Cannot be broken down by
humans
what are two examples of CHO-Induced Infant Digestive Disorders
Lactose intolerance due to lactase enzyme
deficiency
* Unable to digest lactose
Fructosemia: unable to break down fructose
* Due to aldolase B enzyme causing increased circulating fructose in blood
- Both conditions increase production of toxic
metabolites due to improper CHO digestion
leading to liver toxicity and failure - These are genetic disorders with recessive
inheritance
what are the functions of lipids?
Functions: storing energy in fat cells
* Protect vital organs as an insulator and shock absorber
* structural components of cell membranes, restrict water, ions, and other molecules in and out of cells
* Acts as chemical messengers through signaling as steroid hormones and prostaglandins
* Fat soluble vitamins A, D, E, and K regulate critical biological processes
what are the physical properties of lipids?
- Hydrophobic molecules
- Soluble in organic, non-polar solvents (i.e. ether, gasoline)
- Insoluble in water
what are the classes of lipids?
Fatty acids: mostly hydrocarbon chains with
terminal carboxyl (COOH) group
Lipids containing glycerol: typically, fatty acids combined with glycerol at the carboxyl terminal group
Steroids: Multi-ring hydrocarbon structures with functional hydroxyl, amide, or carboxyl groups are various positions around the ring structure
example of fatty acids?
Saturated or unsaturated fatty acids
example of lipids containing glycerol?
Mono-/di-/triglycerides and phospholipids
example of steroid
cholesterol
