Chapter 2 Flashcards
What are macromolecules? How are they organized?
large structures that make up all living organisms
lipids, carbohydrates, nucleic acids , and proteins
What are the characteristics of macromolecules?
they are organic molecules so they contain carbon, hydrogen and oxygen (may also have nitrogen, phosphorus, or sulfur)
they contain functional groups:
two or more atoms that exhibit specific chemical characteristics when found together in a molecule
some functional groups may act as an acid and release H while others may act as a base by binding H
they contain polymers-
molecules made of repeating monomers
carbohydrates contain sugar monomers
nucleic acids contain nucleotide monomers
proteins contain amino acid monomers
two monomers bonded together form a dimer
they undergo dehydration synthesis (condensation)
o Occurs during the synthesis (formation) of biomolecules
o One subunit loses H
o The other subunit loses OH
o New covalent bond is formed and water is produced.
o The equivalent of a water molecule is “lost” from the original structures
Undergo Hydrolysis
o The use of water during the breakdown of biomolecules
o H added to one subunit
o OH added to another subunit
What are lipids? What are its primary classes?
group of hydrophobic macromolecules
They are the only category of biological macromolecules that are not polymers because they are not formed from repeating monomers
Function as:
o stored energy
o cellular membrane components
o hormones
different classes
triglycerides
phospholipids
steroids
eicosanoids
what are triglycerides?
most common form of lipids in living things
stored in adipose tissue
form by the process of dehydration synthesis and from glycerol and three fatty acids
used for long-term energy storage in adipose connective tissue, structural support, cushioning, and insulation of the body
saturated, lack double bonds
unsaturated, one double bond
polyunsaturated, two or more double bonds
what is glycerol?
3 carbon molecules with a hydroxyl functional group attached to each carbon
what is lipogenesis and lipolysis?
lipogenesis- process of dehydration synthesis, formation of triglycerides when conditions of excess nutrients exist
lipolysis- breakdown of triglycerides when nutrients are needed
What are phospholipids?
amphipathic molecules that serve as chemical barriers of cell membranes
composed of glycerol, two fatty acids, a phosphate and various organic groups
glycerol, phosphate, and organic groups form a hydrophilic polar head
fatty acids form two hydrophobic nonpolar tails
function:
major components of membranes, including plasma membrane, which forms the chemical barrier between the inside and outside of a cell
What are steroids?
include cholesterol, steroid hormones, and bile salts
composed of hydrocarbons arranged in multi-ringed structure
differ in the side chains extending from the rings
function:
cholesterol- a component of animal plasma membranes and is precursor molecule for synthesis of other steroids
steroid hormones are regulatory molecules released by certain endocrine glands (testosterone and estrogen)
bile salts facilitate micelle formation in the digestive tract
what are eicosanoids?
four classes
prostaglandins, prostacyclins, thromboxanes, and leukotrienes
modified 20-carbon fatty acids
synthesized from arachidonic acid, membrane component
function:
locally acting signaling molecules associated with all body systems
have primary functions in both the inflammatory response of the immune systen and communication within the nervous system
what are carbohydrates?
main field source for all organisms
structure for plants
general chemical formula is CH2O
monosaccharides: simple sugar monomers (fructose, glucose, galactose)
disaccharides: formed from two monosaccharides (lactose, maltose, surcose)
polysaccharides: formed from many monosaccharides (glycogen, starch
what is glucose
- Six-carbohydrate (hexose monosaccharides)
- Most common monosaccharide
- Primary nutrient supplying energy to cells
- Concentration must be carefully maintained
What is glycogen?
- Liver and skeletal muscle store excess glucose, then bind glucose monomers together (glycogenesis)
- Liver hydrolyzes glycogen into glucose as needed (glycogenesis)
- Liver can also form glucose from noncarb sources (gluconeogenesis- synthesis/ generation of glucose)
What are disaccharides?
two simple sugars bonded together
Most common are sucrose (table sugar), lactose (milk sugar), and maltose (malt sugar)
All with glucose bonded to a second hexose monosaccharide
what are polysaccharides?
three or more sugars
* Glycogen most common in animals
* Starch and cellulose found in plants
Plant starch is a major nutritional source of glucose for humans
Cellulose is a source of fiber (nondigestible)
what are glycosaminoglycans?
(GAGs) are large carbohydrates with attached amine groups
* GAGs attached to proteins form proteoglycans
* GAGs and proteoglycans are found in the connective tissue
