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AP Bio Chapter 5: The Structure and Function of Macromolecules

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Macromolecule
-Large Molecules composed of smaller molecules that are complex in their structure and function; most are polymers built from monomers
Four Classes of Life
- The class's organic molecules are polymers 1) Carbohydrates 2) Lipids 3) Proteins 4) Nucleic Acids
Polymer
Long molecules consisting of many similar building blocks called monomers
Specific Monomers
Make up each macromolecule; example- Amino Acids are monomers of proteins.
Synthesis of Polymers
Lose an H2O Molecule; expends energy to carry out reaction; need enzymes to speed reactions in cells; dehydration synthesis.
Dehydration Synthesis
How monomers form larger molecules by condensation reactions; monomers are linked by covalent bonds.
Water in dehydration synthesis
1 monomer provides -OH Hydroxyl Group and 1 monomer provides -H Hydrogen
Breakdown of Polymers
Hydrolysis can disassemble polymers; the reverse of dehydration synthesis; H2O is added
Example of the Breakdown of Polymers
Digestion: Food = polymers in the digestive track -> enzymes attack the polymers -> released monomers enter the bloodstream -> then enter into cells -> reassemble into new polymers that perform specific functions.
The arrangement of monomers into polymers
is the basis of each organisms uniqueness, even though organisms share the same limited number of monomer types
Cells
Made of 1000's of different macromolecules
Variations in Polymers
cause differences in organisms; 40-50 monomers can make a limitless number of polymers
Small set of monomers
can build an immense variety of polymers, for example proteins are made of 20 different amino acids in chains
Carbohydrates
serve as fuel and building material for cells; includes sugars and their polymers (starch, glucose, etc.)
Monosaccharides
simples of sugars, can be used for fuel, can be converted into other organic molecules, can be combined into polymers; generally have molecular formulas that are multiples of CH2O
most common monosaccharide and an Aldose
Glucose
structural trademarks of a sugar
Aldose and Ketose are types of sugars dependent on the location of the carbonyl group, C=O
size of carbon skeleton in monosaccharides
3 to 7
Dissaccharides
consist of two monosaccharides joined by a glycosidic linkage
glycosidic linkage
covalent bond formed between two monosaccharides by a dehydration reaction
Maltose
Example of disaccharides; Glucose + Glucose
Sucrose
Most prevalent sugar "Table Sugar"; Glucose + Fructose
Polysaccharides
polymers of sugars with 100s and 1000s of monomers; some serve as storage material and other building materials to protect cells and organisms
Starch
storage polysaccharides of plants and a polymer consisting entirely of glucose monomers; stored energy that can be removed later by hydrolysis. Ex. potatoes, grains, corn
Forms of Starch
Amylose: simplest form - linear/unbranched
Amylopectin: complex form - branched
Plastid
cellular structures that contain granules of starch for plants
Glycogen: storage Polysaccharide
A polymer of glucose that is the major storage form of glucose in animals; has many branches and is stored mainly in the liver and muscles cells; usually depleted within 24 hours unless replenished by food.
Cellulose: Structural Polysaccharide
a polymer of glucose; major component of cell walls; produced by the 100s and billions of tons annually by plants; most common compound on earth
Difference between starch and cellulose
starch: glucose monomers are in alpha configuration -OH group below #1 Carbon
cellulose: glucose monomers are in beta configuration -OH group above #1 Carbon
Glycosidic Linkages: starch-helical; cellulose straight
Structure of Cellulose
molecules are straight and -OH groups form hydrogen bonds with other -OH groups.
Microfibrils
paralllel cellulose molecules held by hydrogen bonds; they are cable like structures and strong building units.
Human Digestion of Cellulose
humans cannot digest it, but it rubs against the wall of our digestive tracts and causes us to produce mucus to pass food through out systems.
Cows and termites
have microbes(enzymes) in their first stomach that allows them to digest cellulose; termites have microbes in its gut allowing it to digest cellulose.
Chitin: structural polysaccharide
used by arthropods to build an exoskeleton; purely, its leathery, but becomes hardened when encrusted with calcium carbonate, CaCO3 ,a salt; cell wall of fungi
Chitin and Cellulose
glucose monomer of chitin has nitrogen-containing appendage.
Lipids
diverse group of hydrophobic molecules, one class of large biological molecules that doesn't consist of polymers b/c mostly hydrocarbons
Fats
large molecules assembled by small molecules by dehydration reactions; constructed from 2 types of smaller molecules: glycerol and fatty acids.
Fatty Acids
long carbon skeleton, usually 16 or 18 carbon atoms in length; at one end is a carboxyl group
Making a Fat: triacylglycerol/triglyceride
3 fatty acid molecules join to glycerol by an ester linkage
why fats are hydrophobic
non polar C-H bonds in hydrocarbon chains of fatter acids
Saturated Fatty Acids
have the maximum number of hydrogen atoms possible, no double bonds btwn carbon atoms in chain, saturated with hydrogen. Ex. animal fats = saturated = solid @ room temp.
Cardivascular disease
plaque build up in walls of blood vessels, allowing less and less blood to flow through and reduces resilience of the vessels.
unsaturated fatty acids
-have one or more double bonds due to the removal of hydrogen from the carbon skeleton
-removal of hydrogen causes a "kink" in its hydrocarbon chain wherever a cis double bond occurs.
-source from fish and plants
phospholipids
has only two fatty acids attached to glycerol and a phosphate group instead of a third fatty acid.
phospholipid structure
hydrocarbon tails and phosphate group head: hydrophilic head and hydrophobic tail.
form a bi-layer arrangement found in cell membranes where heads are on outside and tails are inside two layers of heads.
cell membrane
separates what goes into the cell from what goes out.
Steroids
lipids characterized by a carbon skeleton consisting of four fused rings
Cholesterol
steroid found in cell membranes and a precursor for other hormones and steroids to synthesize. high levels
high levels of cholesterol
BAD for your system; contributes to cardiovascular disease (atherosclerosis)
Proteins
many structure = wide range of functions;
do most of work in cells; 50% of dry mass of most cells
Protein Functions
Enzymatic, structural, storage, transport, hormonal, receptor, contractile and motor, defense
Enzymes
type of protein that acts as a catalyst, speeding up chemical reactions
polypeptides
polymers (chains) of amino acids; proteins consist of one or more polypeptides that foil and coil into specific shapes.
Amino Acids
organic molecules possessing both carboxyl group and amino groups
R Groups
variable group of an amino acid that differs with each amino acid
structure of Amino Acid
alpha carbon, assymetric carbon atom, at the center, and has four partners, amino group, carboxyl group, Hydrogen, and R group
Amino Acid Polymer
linked by peptide bonds; when 2 amino acids are side by side, the carboxyl group of one is adjacent to the amino group of another=an enzyme joins them in dehydration reaction
Peptide Bond
covalent bond resulting from the formation of an amino acid polymer
polypeptide
multitudes of peptide bond linkages
Fredrick Sanger
attended Cambridge University; determined the amino acid sequence of proteins needed on a cellular level while researching insulin
Protein Conformation and Function
proteins specific shape determines how it functions.
structure of protein
one or more polypeptides precisely twisted, folded, or coiled into a specific shape
Amino Acid Sequence
determines the 3D shape of the protein
Four Levels of Protein Structure
Primary, Secondary, Tertiary, and Quarternary
Primary Structure of Protein
the unique sequence of amino acids in a polymer.
Transthyretin
globular protein that transports vitamin A and thyroid hormones
Secondary Structure of Protein
the folding and coiling of the polypeptides into repeating configuration
alpha helix
a coil due to a hydrogen bond between every 4th amino acid
beta pleated sheet
polypeptide chains side by side connected by hydrogen bonds between backbones
core of globular proteins
alpha helix and beta pleated sheet
Tertiary structure
The overall three-dimensional 3D shape of a polypeptide resulting from interactions between the R Group/side chain and the amino acids
Hydrophobic Interaction
polypeptide folds into its functional shape, amino acids w/ hydrophobic side chains end up in clusters (core) of the protein.
H2Ophobic interaction and water molecules
h2o forms hydrogen bonds with each other and w/ hydrophilic parts of protein, in turn excluding nonpolar substances.
Quarternary Structure
The overall protein structure that results from the aggregation of two or more polypeptide subunits.
collagen
helical subunits intertwined in a triple helix makes it really strong and found in connective tissue
Hemoglobin
oxygen-binding protein of red blood cells that moves iron and oxygen around; a globular protein
Sickle-Cell Disease
change in primary structure; a substitution of amino acid (valine) not glutamic acid in the protein hemoglobin causing cells to deform and clog blood vessels
Determiners of Conformation Proteins
chemical and physical conditions of the proteins environment: temperature, pH, etc.
Denaturation
a protein unravels and loses its native conformation(shape) causing proteins to be biologically inactive
The Protein Folding Problem
most proteins go through several intermediate states on their way to a stable conformation; denatured proteins no longer work in their unfolded conditions
Chaperonins
protein molecules that assist in the proper folding of other proteins
X-ray crystallography
used to determine a proteins three-dimensional structure
Nucleic Acids
Stores and transmits hereditary information
Genes
the units of inheritance that program the amino acid sequences of polypeptides; they are made of nucleotide sequences on DNA
2 types of nucleic acids
deoxyribonucleic acid and ribonucleic acid
Deoxyribonucleic Acid (DNA)
found in the nucleus of the cell, DNA stores information for the synthesis of specific proteins; DNA is inherited from parents; it is encoded with info that programs cell's activities but does not directly run the operation of a cell
Chromosome
contains one long DNA molecule that consists 100 to 1000 genes
tools for biological functions
proteins are the molecular hardware of the cell
DNA Function
directs RNA synthesis (transcription), directs protein synthesis through RNA (translation)
Flow of genetic information
DNA -> RNA -> protein
Ribosomes
cellular structures of actual sites of protein synthesis
mRNA
messenger RNA moves instructions for creating proteins from the nucleus to the cytoplasm.