Chapter 2 Flashcards
what do organic molecules contain?
carbon
what are biomolecules?
organic molecules living organisms
what are the four major groups?
carbohydrates, lipids, proteins, nucleotides
what do most molecules and bonds contain?
C, H, O, and N
N is the most common element on all proteins
basic functions of biomolecules
energy and building blocks
saturated fatty acids
- no double bonds btw carbons, so they are saturated with hydrogens. the more saturated a fatty acid is the more likley it is to be solid at room temp
- ex: animal fat
monosaturated fatty acids
- one double bond btw two of the carbons in the chain. for each double bond, the molecule has two fewer hydrogen atoms attached to the carbon chain
- liquid at room temp
- ex: plant liquids
polyunsaturated fatty acids
- two or more double bonds btw carbons in the chain
steroids
- lipid-related molecules whose structure includes four linked carbon rings
- cholesterol = steroid backbone
phospholipids
- have two fatty acids and a phosphate group
- cholesterol and phospholipids are important components of animal cell membranes
carbohydrates
- brain feeds off of this
- most abundant biomolecule
ribose
- forms the sugar-phosphate backbone of RNA
deoxyribose
- forms the sugar-phosphate backbone of DNA
fructose
- found in fruit
glucose (dextrose)
- found in any carbohydrate source
galactose
- only found in milk
glucose + fructose
- sucrose
- disaccharide
glucose + galactose
- lactose
- disaccharide
glucose + glucose
- maltose
- disaccharide
glucose is in what?
- in every disaccharide
polysaccharides
- glucose polymers
- all living cells store glucose for energy in the form of a polysaccharide
glycogen
- giant chain of glucose
- found in liver and muscles
peptide bond
- how amino acids connect to one another
- the amino group of one amino acid joins the carboxyl group of the other, with the loss of water
amino acids
- links that form tgthr to form proteins
9 essential amino acids
- arginine
- asparatic acid (aspartate)
- cysteine
- glutamic acid (glutamate)
- glutamine
- glycine
- tryptophan
- tyrosine
where can all 9 essential amino acids be found?
- in all meat and quinoa
homocysteine
- a sulfur-containing amino acid that in excess is associated with heart disease
y-amino butyric acid (gamma-amino butyric acid) or GABA
- a chemical made by nerve cells
creatine
- a molecule that stores energy when it binds to a phosphate group
- so you can lift more heavy weights
primary structure
- sequence of amino acids held tgthr by a peptide bond
- peptides range in length from two to two million amino acids
- oligopeptide: 2-9 amino acid
- polypeptide: 10-100 amino acid
- proteins: >100 amino acids
secondary structure
- created primarily by hydrogen bonds btw adjacent chains or loops
- covalent bond angles btw amino acids determine secondary structure
- alpha-helix
> DNA double helix
> single alpha helix: RNA - beta-strands form sheets
tertiary structure
- protein’s three dimensional shape
- can be a mix of secondary structures
- r groups bonding with one another
quaternary structure
- giving the protein a fxn
- multiple subunits combine with noncovalent bonds
- proteins bond with each other to form larger structures
- ex: hemoglobin
important cations of the body
Na+ = extracellular
K+ = intracellular
Ca2+
H+
Mg2+
important anions of the body
Cl-
HCO-3 = bicarbonate (extracellular)
HPO-2 4 = phosphate (intracellular)
SO-2 4
types of tertiary structure
- globular proteins
- disulfide bonds (S-S)
- fibrous proteins
why are molecular bonds critical?
critical in determining molecular shape
enzymes
- speed up chem rxn
membrane transporters
- help move substances back and forth btw intracellular and extracellular compartments
receptors
- proteins that bind signal molecules and initiate cellular responses
binding proteins
- bind and transport molecules
immunoglobulins
- protect the body from foreign invaders and substances
regulatory proteins
- turn cell processes on and off or up and down
ligand
- molecule or ion that binds to another molecule
- ligand binding: requires molecular complementarity
substrate
ligands that bind to enzymes and membrane transporters
specificity
- the ability of a protein to bind to a certain ligand or a group of closely-related ligands
affinity
- degree to which a protein is attached to a ligand
- more binding sites = affinity goes down
equilibrium
- rate of binding is exactly equal to the rate of unbinding
- equilibrium constant (Keg)
What does water always follow in the body?
Na
competitors
related ligands compete for the binding site
agonists
competing ligands that mimic each others actions
isoforms
closely-related proteins - function is similar but affinity for ligands differs
How are proteins activated following transcription/translation?
- posttranslational modification
- peptide bonds are spliced btw exons and introns
- cofactors like ions and small organic fxnal groups bind to the proteins affect how its folded and its functionality
introns
taken out
exons
expressed
chemical modulators
bind reversibly or irreversibly to proteins and alter their binding affinity or activity
competitive inhibitors
compete directly w ligand by binding reversibly to active sites
irreversible antagonists
binds to binding site and cannot be displaced
allosteric modulators
- binds to protein away from binding site and changes activity
- may be inhibitors or activators
covalent modulators
- binds covalently to protein away from binding site and changes its activity
physical modulators
- temp, pH
- the body regulates the amount of protein in cells
- up regulation: production of proteins
- down-regulation: programmed removal of proteins
reaction rate can reach a maximum
- concentration of ligand = determines magnitude of response
- saturation - maximum reaction rate (proteins are fully occupied)
pH < 7
acidic
pH > 7
alkaline
look at page 19
LOOK AT IT
look at page 20
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