Macromolecules Flashcards
Lipids
Hydrophobic
3 different type
neutral fats
phospholipids (polar because of phosphate group)
steroids
9.3Kcal/gm fats while carbohydrate 3.79Kcalm/gm
Neutral fats
Triglycerides
fats and oils in energy storage, acts as insulator
animals convert excess sugar into fats
cis or trans
tricylglyerol
not true polymers
made from glycerol and 3 fatty acids dehydration synthesis (acid comes from carboxyl group)
dehydration sythesis
saturated (solid), mono/polyunsaturated (liquid)
hydrogenation
double bonds broken and pressurized hydrogen molecules are inserted, may make fatty acid saturated or trans
digestion of triglycerides
because not soluble in water they cannot enter our bloodstream easily from digestrive track
1ry role of stomach is to break fats up
bile salts found in bile (synthesized by liver, stored in gall bladder) are amphipathic and break down fats into small droplets, process called emylsification
enzymes hydrolyze fats into fatty acids to be absorbed by the mucosal cells of the intestinal wall
once isnide they are reformulated bak into triglyferides packadeged into lipoproteins (trasport vessels) called chylomicrons
vehicles that keeps soluble so that it can be transported
then released into lymphatic system until they are returned into the bloodstream
chylomicrons lipoproteins
vehicles lipoproteins
outer shell if phospholipid
core of fats (cholesterol ex)
surface of proteins that allows tissues to recognize it
higher percentage of lipids, lower density (LDL) and higher percentage of proteins, higher density (HDL)
Atherosclerosis
the buildup of fats, cholesterol and other substances in and on the artery walls.
steroids
carbon skeleton with 4 fused rings, 3 contain 6 carbons and 1 contains 5
cholesterol is a precursor of most steroids (ex vitamin D, estrogen, testosterone, cortisol (blood sugar regulation) aldosterone (retaining salt and water) bile) also present in animal cell membranes
LDL HDL
LDL transports cholesterol to peripheral to make it available to tissues fir membrane or horone synthesis or storage
too much can lead to arteosclerosis (accumilatiom of LDL in the arteries
HDL can prevent atherosclerosis since they remove LDL plaques buildups and bring them back to the liver
phospholipids
2 fatty acids, glycerol, phosphate group which adds a negative charge to is
amphipathic
Polar hydriphilic head
non polar hydrophobic tail
important for phospholipid bilayers of cell membrane, trnaport of hydrophobic compunds in the blood,
sphingolipids
2 types of phospholipids in cellular membrane: phosphoglycerides and sphingolipids
long hydrocarbon tail and a polar doman that included an amino group
important component of lipid rafts because of how highly dynamic
lipid raft
can concentrate and segregate proteins withing bilayer
used for signal transduction, which is initiated by complex protein protein interractions
lipids raft can change their size and composition in response to stimuli to favour these interactions, acitvating signalling cascades
sphingomyelin
major constituent of cell membrane, mainly in myelin sheath (protects axon and increases speed or nerve impule)
Protein functions
Hormonal (ex insulin)
Receptor: response of cell to chemical stimuli
Contractile and motor proteins: actin
Structual protein: support ex keratin
enzymatic: accelerate chem reaction (ex digestive proteins)
Defensive proteins: antibodies
Storage proteins: storage of amino acids ex casein
Trasnport protein: hemoglobin
Proteins general
20 amino acids
alpha (a) carboon (bonded to 4 different substituent, each amino acid has H3N+, COO-, H and an R chain (R chain determines polarity)
amino acid roles
produce energy
acts as neurotransmitters
building blocks for proteins
L alanine and D alanine
because there are 4 different chemical groups bonded to the carbon, it is chiral (two mirror isomers can exist) (enantiomers)
these are the L and D, and L are almost exclusively present because protein synthesis machinery cannot use D amino acids
zwitterions
it is an ion possessing both positive and negative electrical charges. Therefore, zwitterions are mostly electrically neutral (the net formal charge is usually zero)
amino acids buffer
in low pH, COOH (carboxyl) accepts a proton
in high pH, HN3+ (amino group) donates a proton
so acts as a buffer
non polar and polar amino acids
non polar:
hydrophobic
resides in the interior of proteins because they repel aqueous environment
doesnt ionize or do H Bonds
Polar:
hydrophilic
help proteins dissolve in solutions
form H bonds
exterior surface of proteins or in reactive centers of enzymes
acidic and basic amino acids
acidic
side chain (R chain) that contains a carboxyl group
at cellular pH carboxyl group dissociates so that the R group has a negative charge
basic
has a protonation nitrogen in their side chain
very stable interractions known as salt bridges can occur when two oppositely charged side chains are in close proximity
alpha amino and alpha carboxyl groups can also participate in electrostatic interactions
essential amino acids
must be consumed, cannot be synthesized
plants must be able to synthesize all their amino acids
peptide bond
amino acids are likend by joining the amino end of one molecule and the carboxyl end of the other, and dehydrating to form a covalent bond (peptide bond) creating backbone chain from which side chains can come out of
at one end of the polypeptide these is a free amino acid and the other end a carboxyl group (N-terminus and C-terminus)
protein conformation
conformation determines how protein works
ex: antibodies which bind to foreign substances
hormones fitting into receptors
enzymes binding
Structural levels of a protein
primary: sequence of its amino acids, determined by the nucleotide sequence.
secondary: alpha helix and beta pleated (caused by hudrogen bonds between carboxyl and amino groups)
tertiary: final 3 dimentsional shape determined by (van der walls (repulsion of nonpolr chains), covalent bonds (disulfide) ionic bonds (salt bridges between cabroxyl group who lost its h and amino group positvely charged) and hydrogen bonds) (R group involved)
quartenary: two or more polypeptide
disulfide bridge
cystein monomers (amino acids with sulfhydryl) are brought close together
denaturation
loss of secondary or tertiary or quaternary structure due to disruption of non covalent/ disuldie bonds
heat, pH, mechnaical, inorganic salts, etc
can cause alzeihmers, cancer,
main fucntion carbohydrates
main energy source
energy storage as starch or glycogen
structural components of cells ex cellulose
ratio
1:2:1
carbon hydrogen oxygen
examples sacharrides
mono: glucose fructose galactose
di: sucrose lactose maltose
poly: starch glycogen cellulose chitin
aldose and ketose
isomers
glucose aldose (has cabronyl group at end of chain)
fructose ketose (carbonyl group in the middle)
alpha dn beta glucose
alpha: hydroxyde under hydrogen
beta: hydroxyde group over
in water, a and B interconvert and predominate
formula glucose
(CH2O)n
importance monosaccharides
major nutrients for cells (cellular respiration)
carbon skeleton serve as material for synthesis of small organic molecules like amino acid and fatty acid
unusual roles
chitin used to make strong and flezible surgicla thread on wounds that will decompose
peptidoglycan forms bacterial cell walls
vireous humour in eye has polysacharides, cartilage, cornea, cavities between bones
homeostasis glucose
nervous system requires steady and constant supply of glucose
regulated by isnulin (produced by beta cells of pancreas) and glucagon (produced by alpha cells of pancreas)
insulin
insulin: in response to high blood glucose, signal trasnduction cascade, increase ability to transport glucoe across plasma membrane.
liver: signal cascade to tranform glucoe into glycogen
deactivates cascade that breaks down glycogen into glucose
adipocytes (fat cells): signal cascade to tranform glucoe into glycogen
muscles cells: signal cascade to tranform glucoe into glycogen and uptake of amino acids
glucagon
by alpha cells of pancreas
liver cells: break down glygocen into glucose, deactivates cascade to produce glygogen
fat cells: brakdown stored fat and release fatty acids to be used as fuel for other cells other than nervous
muscles: cascade to breakdown protein to release amino acids and be sent to liver to be transformed into glucose for brain
diabetes mellitus
inability to produce or detect insule
high glucose levels, spills into the urine because kidney cannot reabsorb it fast enough
because more soluble into urine, water will follow the urine and dehydrate you
because cells cannot intake glucose without insulin, they breka down protein and fats, body weight declines
ketones are metabolites of fat breakdown and are acidic, so when accumulate into blood, can lead to acidosis and death
type 1: autoimune, destroys beta cells of pancreas so no insulin priduced
type 2: more common, normal production of insulin at beginning but body resistant to isnulien. can be faulty receptors
olgosaccharides
smal sugar polymers, 3-6 monosaccharides
often found in plasma membrane attached to glycoproteins and glycolipids, called glycoconjugates
role:
form cell coat outside cell membrane caled glycocalax, which is involved in celle-to-cell adherence, identification and protection
antigens on blood cells are usually glycoprotiens
polysaccharides
2 classes:
-easily broken down and used for energy storage (glycogen)
alpha linkages are for sugars that can be metabolized
-3d arrangement used for structural polysaccharides
beta linkages occurs in stuctural molecules (cellulose)
few organisms poses the enzymes to breka down b linkage
HDL LDL
higher percentage of lipids, lower density (LDL) and higher percentage of proteins, higher density (HDL)
