lec 3- introduction to macromolecules Flashcards
what are macromolecules?
large highly organized molecules that form the structure and carry out the activities of cells
what are the 4 types of macromolecules?
proteins, nucleic acids, polysaccharides, and lipids
are all macromolecules short lived?
no, only three are short lived, DNA lives long
what are carbohydrates?
sugar molecules that include monosaccharides, disaccharides, polysaccharides
what macromolecule is the most abundant form of organic matter on earth?
carbohydrates or polysaccharides
what is the structure of a sugar molecule?
it has a backbone of carbon atoms linked together in single bonds
what is a ketose?
a sugar molecule with the carbonyl group located at an internal position
what is an aldose?
a sugar molecule with the carbonyl group located at an external position
what formation does glucose always take in the body?
a ring structure
what does the 5th carbon in glucose do to the 1 carbon in a ring structure?
a nucleophilic attack
what configuration does D-glucose have when the primary carbon OH is below the plane?
alpha-D-glucose
what configuration does D-glucose have when the primary carbon OH is above the plane?
beta-D-glucose
what bond links sugar molecules together?
glycosidic bonds
how do glycosidic bonds form?
they are formed between two OH groups on two separate monosaccharides
what carbohydrate cannot be digested and why?
cellubiose, due to no enzyme existing for it
what monosaccharides does the disaccharide Sucrose contain?
glucose and fructose
what monosaccharides does the disaccharide lactose contain?
galactose and glucose
what can an anomeric carbon no longer do when it takes place in a glycosidic bond?
it can no longer mutarotate
what are the two types of glycosidic bonds?
O-glycosidic bond (attached with hydroxyl)
and N-glycosidic bond (attached with nitrogen)
do anomeric carbons always bond with a sugar?
no, they can bond with a protein as well
what do branched glucose polymers make in an animal?
glycogen
what do branched or unbranched glucose polymers make in a plant?
starch
what is amylose?
amylose is a linear polymer, with alpha (1–>4) linkages between glucose monomers
what is amylopectin and glycogen?
They are branched polymers, with alpha (1–>4) linkages and alpha(1–>6) linkages
amylopectin has a branch every 25th glucose, while glycogen has a branch every 10th glucose
what is starch made of?
amylose and amylopectin
what are the nutritional carbohydrates?
starch and glycogen
what are the structural carbohydrates?
cellulose, chitin, and GAGs
what is cellulose?
plant product made of unbranched polymers
what is chitin?
component of invertebrate exoskeleton made
what is GAGs?
composed of two different sugars and found in extracellular space
what is a glycan?
a carbohydrate with less than a dozen monosaccharides
what is glycomics?
the study of glycans produced by an organism
what are the types of lipids?
fats, steroids, and phospholipids
what are the characteristics of fats?
fatty acids are long, unbranched hydrocarbon chains
why can soaps dissolve grease?
because the nonpolar part of the fatty acid embeds itself into the grease while the polar part interacts with water, this causes the creation of a micelle where grease is on the inside and now can be washed away
what are the two forms of fatty acids?
saturated = single bonds
unsaturated = double bonds “kink”
what stores fat in the body
adipocyte cells
what are steroids made of?
built around 4 ringed hydrocarbon skeleton that is attached to cholesterol
do plant cells have cholesterol?
largely absent, so no, hence why vegetable oils are cholesterol free
what are phospholipids made of?
two hydrocarbon tails attached to a glycerol which is attached to a phosphate group which is also attached to a small polar group like choline
are phospholipids amphipathic?
yes
what are proteins?
are macromolecules that carry out cell activities
what are the 6 types of proteins?
-enzymes (catalyze reactions)
-structural proteins (provide mechanical support)
-signalling proteins (determine what a cell reacts to)
-regulatory proteins (determine how that signal is conveyed)
-filaments and molecular motors (provide biological movements)
-transport proteins (allow molecules in and out of the cell)
what are the 4 levels of organization of a protein?
primary (amino acid chain)
secondary (a-helix and B-sheets)
tertiary (folding)
quaternary (assembled subunits)
what are the two forms an amino acid can exist in?
D or L
what form are amino acids in the synthesis of a protein?
L form
what are amino acids made of?
an amine group, a carboxyl group, and a R group
why is the hydropathy index important?
useful in determining the hydrophobic interior portion and hydrophilic parts of a protein
what is protein secondary structure?
alpha helices and beta sheets
T or F:
alpha helices do not cross through lipid bilayers
false
what is a tertiary structure of protein?
folding
how can you determine tertiary protein structure?
by NMR spectroscopy or X ray crystallography
how are tertiary structures stabalized?
by noncovalent and covalent interactions
what are the two categories of shape for a protein?
fibrous = long
globular = compact
what is myoglobin?
a globular protein that stores oxygen
what is protein quaternary structure?
assembled subunits
what is a domain?
a substructure produced by any part of a polypeptide chain that can fold independently into a stable structure that has a function
what is src protein kinase?
it is an enzyme
how many domains does src protein have?
4 domains, 2 of the domains make kinase
what is a homodimer?
a protein with 2 identical subunits
what is a heterodimer?
a protein composed of 2 nonidentical subunits
what causes protein denaturation?
urea, detergents, organic solvents, radiation, heat
what do chaperones do?
bind to proteins and assist them in folding properly
what does misfolding of proteins do?
cause diseases like alzheimers
what are nucleic acids?
genetic information like DNA and RNA
what are nucleotides?
the polymers that make nucleic acids
what are nucleic acids made of?
a phosphate group, a sugar (deoxiribose in DNA and ribose in RNA) and a base