Unit 1 Macromolecules Flashcards
macromolecules
responsible for most of the form and order of living systems; generated by polymerization of small organic molecules (except lipids)
monomers
repeating units of macromolecules
types of macromolecules
protein (polymers of amino acids)
carbohydrates (polymers of sugars)
nucleic acids (polymers of nucleotides)
lipids
macromolecule synthesis
- monomer activation: must be activated, requires energy, attached to carrier molecules, directionality
- monomer condensation: each addition releases water, must have hydrogen and reactive OH on molecule
- polymerization
proteins
composed of nonrandom series of amino acids; sequence determines structure and thus function
protein functions
structure defense transport catalysis signaling
amino acid
20 usable by human body
carbon atom bonded to hydrogen plus amine and variable side chain
peptide bond
formed between amine group of one amino acid and carboxyl group of the next
monomeric protein
single polypeptide
multimeric protein
2+ polypeptides; dimers, trimers, tetramers
hemoglobin
tetramer with 2 alpha-subunits and 2 beta-subunits
protein primary structure
sequence of amino acids linked together by peptide bonds
protein secondary structure
determined by hydrogen bonding within polypeptide’ alpha helix, beta sheets
motifs
short stretches of alpha-helices and beta-sheets
tertiary structure
depends on interactions of R-groups; not repetitive; sum of hydrophobic/philic R-groups and similarly/oppositely charged R-groups
domains
compact units connected by short peptide chains; relatively independent on other domains
tertiary protein bonds/interactions
disulfide hydrogen ionic van der Waals hydrophobic
disulfide bonds
between the sulfur atoms of two cysteine residues
hydrogen bonds
form in water between amino acids in polypeptide chain via R-groups
ionic bonds
between oppositely charged R-groups
Van der Waals
molecules with non polar covalent bonds may have transient positively and negatively charged region
hydrophobic interaction
tendency of hydrophobic molecules to be excluded form interactions with water
protein quaternary structure
subunit interactions and assembly; mutlimeric proteins only
fibrous proteins
structural strand-like, water-insoluble, stable tertiary or quaternary provide mechanical support/tensile strength keratin, elastin, collagen
globular proteins
functional
compact, spherical, water-soluble, sensitive to environmental changes
tertiary or quaternary
specific function regions (active sites)
antibodies, hormones, molecular chaperones, enzymes
lipids
biochemically, structurally diverse hydrophobic stable in non polar solvents mostly hydrocarbon chains some have polar regions - amphipathic
If lipids are not formed by polymerization, why are they considered macromolecules?
because of their high molecular weight and their importance in cellular structures, particularly membranes
classes of lipids
fatty acids triglycerides phospholipids glycolipids steroids terpenes
fatty acids
components of several other kinds of lipids
long amphipathic unbranched chain with polar carboxyl group and non polar hydrocarbon tail
triacylglycerols
aka triglycerides
glycerol + 3 fatty acids via ester bonds (water removed)
glycerol
3-C alcohol with hydroxyl group on each C
phospholipids
2FA + phosphate group
glycolipids
2FA + carbohydrate chain
steroids
Three 6C ring plus one 5C ring; cholesterol most common
cholesterol
found in membrane
regulates membrane fluidity
involved in cellular signaling
source of all steroid hormones
terpens
synthesized from 5C compound isoprene; aka isoprenoids
isoprene
and derivatives produce vitamin A and carotenoid pigments
polysaccharides
long chain polymers of sugars
usually single repeating unit, sometimes alternating pattern of 2 kinds
glucose
disaccharide (2 monosaccharides covalently)
maltose (glucose + glucose)
lactose (glucose + galactose)
sucrose (glucose + fructose)
starch
energy storage polysaccharide in plant cells
glycogen
energy storage polysaccharide in animal cells and bacteria
cellulose
structural polysaccharide found in plant cell walls; indigestible to mammals
nucleic acids
store, transmit, express genetic information
linear polymers of nucleotides
protein synthesis (RNA)
nucleotides
nitrogenous bases
pentose sugars
phosphate
nitrogenous bases
purines (adenine, guanine)
pyrimidines (cytosine, thymine (DNA), uracil (RNA))
pentose sugars
ribose in RNA
deoxyribose in DNA
base paring
adenine with thymine (uracil) (2 hydrogen bonds)
cytosine with guanine (3 hydrogen bonds)
monomeric nucleotides
sources of chemical energy in cell (ATP)
cell signaling
