Chapter 3, Biological macromolecules - carbohydrates and lipids and Chapter 5, Plasma membrane

Hydrocarbon

an organic molecule that contains only caron and hydrogen atoms connected by covalent bonds

Lipid

a macromolecule that is non-polar and insoluble in water

Fatty Acid

• a carboxylic acid consisting of a hydrocarbon chain and a terminal carboxyl group, especially any of those occurring as esters in fats and oils.

• Fatty acids (w/1 CH chain) are conical; phospholipids (w/2) —→ straight

• Fatty acid tails of phospholipids can be straight or bent.

Saturated fatty acid

• long chain hydrocarbon with single covalent bonds in the carbon chain; the number of hydrogen atoms attached to the carbon skeleton is maximized

• these fatty acid tails look straight

• lipid bilayer with long and unsaturated hydrocarbon tails with lower permeability and fluidity

unsaturated fatty acid

• long-chain hydrocarbon that has one or more double bonds in the hydrocarbon chain

• can get stuck in our circulatory system (leading to heart disease)

• fatty acid tail appears bent

• lipid bilayer with short and unsaturated hydrocarbon tails with higher permeability and fluidity

polyunsaturated fatty acid

a type of unsaturated fatty acid that contain multiple double bonds between carbon atoms in their chemical structure

non polar

a molecule where electrons are distributed evenly between the atoms, creating no positive or negative poles.

Van Der Waals forces

weak, transient attractions between molecules arising from temporary, uneven distribution of electrons, leading to temporary dipoles.

Fat

a type of triglyceride, which are a subclass of lipids composed of a glycerol molecule and three fatty acids. (Lipids). essential nutrients that provide the body with energy, help absorb vitamins, and form cell membranes and hormones.

Oil

a type of lipid (or fat) that is liquid at room temperature, primarily due to its unsaturated fatty acid composition

Wax

lipid comprised of a long-chain fatty acid that is esterified to a long-chain alcohol; serves as a protective coating on some feathers, aquatic mammal fur, and leaves

Cholesterol

a lipid, or fat-like substance, that is essential for the proper functioning of the body.

Phospholipid

membranes major constituent; comprised of two fatty acids and a containing group attached to a glycerol backbone.

Phospholipid bilayer

the fundamental structure fo the cell membrane, formed by two layers of phospholipid molecules arranged with their hydrophilic (water-loving) heads facing outward and their hydrophobic (water-hating) tails facing inward.

Diffusion

passive transport process of low-molecular weight material according to its concentration gradient

Permeability

a biological membrane’s ability to allow certain substances to pass through it while restricting others

Fluidity (with respect to membranes)

the ability of a cell membrane’s components to move laterally within the bilayer, while membrane permeability is the membrane’s capacity to control the passage of substances

Hydrophobic

molecule that does not have the ability to bond with water; “water-hating”

fatty acids live here

Hypertonic

situation in which extracellular fluid has a lower osmolarity than the fluid inside the cell, resulting in water moving into the cell

Hypotonic

situation in which extracellular fluid has a lower osmolarity than the fluid inside the cell, resulting in water moving into the cell

Fluid Mosaic model of the membrane

describes the plasma membrane’s structure as a mosaic of components including phospholipids, cholesterol, proteins, glycoproteins, and glycolipids (sugar chains attached to proteins or lipids, respectively) resulting in fluid character (fluidity)

Hydrophilic

molecule with the ability to bond with water; “water-loving”

Polar head:

• polar group such as choline, phosphate, glycerol

Amphiphilic

molecule possessing a polar or charged area and a non polar or uncharged area capable of interacting with both hydrophilic and hydrophobic environments

Integral protein

a type of membrane protein that is permanently embedded within the lipid bilayer of a cell membrane

Peripheral protein

proteins that are loosely attached to the surface of a cell membrane, without penetrating into the lipid bilayer.

Diffusion

passive transport process of low-molecular weight material according to its concentration gradient

Passive Transport

method of transporting material through a membrane that does not require energy

Facilitated Transport

process by which material moves down a concentration gradient (from high to low concentration using integral membrane proteins)

Osmosis

transport of water through a semipermeable membrane according to the water’s concentration gradient across the membrane that results from the presence of solute that cannot pass through the membrane.

net movement of solvent molecules to equalize [solute]

• solute moves from lower osmolarity to higher osmolarity

Tonicity

amount of solute in a solution

Active transport (define and name two types)

method of transporting material that requires energy

Primary active transport:

• active transport that moves ions or small molecules across a membrane and may create a difference in charge across that membrane

Secondary active transport:

• movement of material that results from primary active transport to the electrochemical gradient

Bulk Transport

the active, energy-requiring process that cells use to move large quantities of substances like macromolecules, particles, or even whole cells across the cell membrane

Carbohydrate

• an organic compound such as a sugar or starch, and is used to store energy.

• carbon, oxygen, and hydrogen atoms: linear or ring conformations (with OH and C=0)

• stoichiometric formula (CH2O)n, where n is the number of carbons

  • C to H to O = 1 to 2 to 1

  • ‘carbo’ and ‘hydrate’

    • Monosaccharides (simple sugars) typically ahve 3-7 C’s

    • Polysaccharides typically have 8 or more C’s

• Have to remember

  • Glucose

    • linear form of glucose

    • ring forms of glucose

      • alpha glucose tastes sweet and we digest it

      • beta glucose is also sweet but is not digestible by humans

  • Galactose

  • Fructose

Monosaccharide

single unit or monomer of carbohydrates

Disaccharide

two sugar monomers that glycosidic bond links

Polysaccharide

long chain of monosaccharides; may be branched or unbranched

Alpha Glucose

a specific cyclic form form of the simple sugar glucose where the hydroxyl group no the first carbon (the anomeric carbon) points downward, or opposite to the hydroxymethyl group, in the six-membered ring

Beta Glucose

a cyclic form of the simple sugar glucose where the hydroxyl group on the first carbon atom points upward (above the plane of the ring)

Glycosidic linkage

a covalent bond that connects two monosaccharides (sugar units) to form a disaccharide, or connects multiple monosaccharides to form a complex polysaccharide, via a dehydration (condensation) reaction.

Alpha 1,4 linkage

a type of covalent bond that connects tow monosaccharide units in carbohydrates, specifically linking the anomeric carbon (C-1) of one sugar to the fourth carbon (C-4) of the next.

Beta-1,4 linkage

a type of glycosidic bond that connects two sugar molecules, specifically involving the C! carbon of one sugar and the C4 carbon of another, with the anomeric oxygen below the plane of the ring in a “beta” configuration

Starch

storage carbohydrate in plants

Glycogen

storage carbohydrate in animals

Chitin

type of carbohydrate that forms the outer skeleton of all arthropods that include crustaceans and insects; it also forms fungi cell walls

Peptidoglycan

a unique polymer found in the cell walls of most bacteria, forming a mesh-like, rigid layer that provides structural support and protection from osmotic pressure

Glycoprotein

combination of carbohydrates and proteins

Lipid Rafts

regions of high cholesterol (a special type of lipid) that sequesters specific ‘signaling’ proteins