SBI4U - Unit 1 - Biochemistry

electronegativity (En)

atom's attraction to shared electrons -- more orbits/electrons = less electronegativity

polar bond

covalent, En less than 1.7, nonequal En, nonequal sharing of electrons -- like other polars, do not like nonpolar

nonpolar bond

covalent, En less than 1.7, equal En, equal sharing of electrons

ionic bond

giving or taking electrons, En greater than 1.7

cohesion

water forms hydrogen bonds with each other

adhesion

water forms hydrogen bonds with other molecules -- good for transportation (ex. up xylem)

buffer

weak acids or bases that release or absorb H+ ions to compensate for changes in pH -- must be weak because strong acids or bases dissolve completely in water

functional groups

initiate chemical reactions, determine molecule's function, often ionic or strong polar

alcohol

functional group

carboxyl

functional group

aldehyde (carbonyl)

functional group

ketone (carbonyl)

functional group

amino

functional group

sulfhydral

functional group

phosphate

functional group

dehydration

water is removed from two molecules which then join up to form a larger molecule

hydrolysis

water is added to a larger molecule, which breaks up into smaller subunits

polymerization

process of smaller subunits joining together

saturated fat

single bond, animal fats

unsaturated fat

double bond, oils

fatty acid vs fat

fatty acid: long straight chain, carboxyl acids // fat (triglycerol): 3 fatty acids + glycerol

when fatty acid -- fat

glycerol removes carboxyl acid from fatty acid when it joins to form a fat

steroids

uses: growth, hormonal signalling, regulation of metabolic processes

lipid

nonpolar, do not dissolve in water

protein

many amino acids joined by peptide bonds

amino acids

carboxyl group + aminon group

denaturation

loss of structure + function of protein -- usually occurs as a result in change of temperature or pH level

protein primary structure

the linear structure of amino acids

protein secondary structure

folds (β-pleated) or coils (α-helix) that are formed through interactions between atoms in the backbone

protein tertiary structure

3D shape of polypeptide chain formed through interactions between R groups

protein quaternary structure

2 > polypeptides joining together

nucleotide

building block of nucleic acid -- 5 carbon sugar + nitrogenous base + 1-3 phosphate groups

pyrimidines nitrogenous bases

single organic ring: uracil (U), thymine (T), cytosine (C)

purine nitrogenous bases

double organic ring: adenine (A) and guanine (G)

DNA nitrogenous pairs

A+T / C+G

RNA nitrogenous pairs

A+U / C+G

enzyme

biological catalyst -- jumpstarts chemical reactions without being used up

competitive inhibition

where a molecule mimics a substrate and binds to the active site of an enzyme so that the actual substrate cannot bind there

noncompetitive inhibition

inhibitor binds somewhere that isn't the active site, changing the shape of the enzyme and changing the active site so that the substrate cannot fit

allosteric site

where regulatory molecules bind to enzymes

allosteric regulation

one site on a protein is affected by the binding of a molecule to a different site (ie noncompetitive inhibition)

endomembrane system

group of interacting organelles b/w the nucleus and plasma membrane -- nucleus (DNA with instructions for creating proteins -> RNA -> cytosol) --> rough ER (ribosomes turn RNA into proteins -> rough ER packages them) --> vesicles (carry proteins to golgi body OR from rough ER to smooth ER) --> smooth ER (proteins from rough ER get packaged and sent to golgi / others become enzymes which create lipids) --> golgi body (proteins are modified and sent to plamsa membrane) --> plasma membrane (vesicles fuse with and let proteins/lipids out to the exterior of the cell)

vesicles

many different types and functions -- ie vacuoles: huge trashcans, isolate/dispose of water/debris/toxins / in plant cells: maintain cell shape/rigidity // lysosomes: contain digestive enzymes, kill the cell

microtubule

long hollow cylinder w/ tubulin protein -- within flagella and cilia -- form pseudopods (false feet)

sterol

steroid with an OH group at one end and a non polar hydrocarbon on the other -- prevent fatty acids from forming a gel at normal temperatures

integral membrane protein

a protein that is embedded in the lipid bilayer

peripheral membrane protein

a protein on the surface of the membrane

passive transport

movement of a substance across a membrane without expending energy -- diffusion

simple diffusion

movement of small/non polar substances to move across a membrane unassisted

facilitated diffusion

transport of ions/polar substances across a membrane via proteins

transport protein

proteins that help substances move across the membrane

channel protein

pathway for water and ions to pass through the membrane like a gate

carrier protein

bind to a specific solute and change shape in order to allow solutes through

hypotonic

lower solute / higher water concentration than what is in it

hypertonic

higher solute / lower water concentration than what is in it

osmosis

diffusion from higher solute (hypertonic) to lower solute concentration (hypotonic)

active transport

movement of a substance across a membrane against the concentration gradient using energy

primary active transport

result of chemical reaction: ATP -> ADP + phosphate group, phosphate group binds to carrier protein and tricks it into binding with a substance it otherwise would not

secondary active transport

transport using the ion concentration gradient created by the primary active transport

exocytosis

secretory vesicles bind with plasma membrane which opens up to release components from the vesicle to the exterior of the cell

endocytosis

plasma membrane folds in and either takes in the extracellular water and whatever's in it or components bind to receptors and the folded membrane pinches off and releases the stuff within the vesicles into the cell