Exam 2 Flashcards
Monomer
->molecule, that if bonded together forms a polymer
-> smaller molecules together, often using repeating units of the same kind of molecule
Polymer
->Biological macromolecules are made by assembling monomers together
-> these macromolecules together are called polymers
-> polymers create something new
Dehydration synthesis
putting little things together to make big polymers
-> removes a water molecule (H2O)
(water is a product)
when dehydrated you don’t have a lot of water so dehydration synthesis removes H2O
Hydrolysis
breaks down a polymer
-> adds a water molecule, which breaks down a bond
Ex. eating snickers bar and digesting it
(water is a reactant)
4 Types of Biological Macromolecules
carbohydrates, nucleic acids, lipids, proteins
Carbohydrates
Carbohydrates are sugar-based molecules
-> Single sugar monomers are connected by glycosidic linkages (using dehydration synthesis) to make disaccharides or polysaccharides
alpha glycosidic linkages
starch in plants or glycogen in animals are large polysaccharides with many branches used to store glucose for energy. These are connected by alpha glycosidic linkages that are digestible by eukaryotes.
Alpha=big strong energy!!
beta glycosidic linkages
Cellulose is polysaccharide made by glucose molecules connected with beta glycosidic linkages that are not digestible by eukaryotes, and are used for structural support in plant cell walls.
b=bad
bad for eukaryotes to digest
CELLulose=CELL walls
Nucleic acids
made by combining nucleotides (monomers) together using phosphodiester bonds (by dehydration synthesis) to make polynucleotides including DNA and RNA.
3 Parts of Nucleotides
Base, Sugar, Phosphate
Lipids
hydrophobic molecules, including the triglycerides, phospholipids, and steroids
Triglycerides
consist of three fatty acids attached to a glycerol molecule (dehydration synthesis again). and can be solid (fats) or liquid (oils) at room temperature.
Saturated fatty acids
lack double bonds and form straight molecules that can pack closely together so they are solid at room temperature (fats)
Unsaturated fatty acids
have one or more double bonds and are bent, so they push each other further apart making them fluid (oils).
Phospholipids
have a glycerol with two very hydrophobic fatty acid “tails” and one very hydrophilic phosphocholine “head.” The balance between these components is just right, making phospholipids amphipathic. Groups of phospholipids can be arranged in a bilayer in water.
Steroids
not macromolecules but they are hydrophobic. An important steroid for membrane structure-function relationships is cholesterol.
Cholesterol
moderates fluidity
-> makes fluid membrane more viscous
->makes viscous membrane more fluid
Proteins
very large polymers made by connecting amino acids (monomers) together with peptide bonds to make polypeptides.
The function of a protein is dependent on its shape.
Primary Structure of Protein
the sequence of amino acids
There are 20 naturally occurring amino acids, each with a different “R-group”
->different properties such as hydrophilic, hydrophobic, charged, polar, acidic, or basic
Secondary Structure of a Protein
->repeated folding of protein backbone
2 ways:
-> folds sections of polypeptide into beta sheets
->coils into alpha helices
Tertiary Structure of a Protein
->folding a single polypeptide into complex 3D shape. ->Having the correct shape is key to proper protein function.
Quaternary Structure
->multiple 3D polypeptide shapes put together to form large one
->forms larger protein molecules
How do Proteins change shape?
Proteins are able to change shape under different conditions because they are largely held together by weak interactions such as hydrogen bonds and ionic bonds.
Ligand
signal molecule that binds to larger molecules receptors
Cell communication
Reception: ligand binds to a receptor protein, causing a change in the shape of the protein.
Signaling: proteins inside the cell recognize the change in shape of a receptor bound by ligand and trigger a signal transduction cascade. Cells determine what proteins are in the signal transduction cascade to ensure appropriate response to a signal.
Response: create a diversity of responses among cells
Receptor tyrosine kinases
->transmembrane receptors that have the ligand binding part outside the cell and an enzyme part inside the cell on a single protein.
->RTKs dimerize, causing autophosphorylation, which activates the kinase enzyme function and triggers a signal transduction cascade.
G-protein coupled receptors
transmembrane receptors that have separate proteins for ligand binding and enzymatic response. These proteins are “coupled” by a G-protein that becomes activate on ligand binding by the receptor and in turns activates an enzyme that triggers a signal transduction cascade.
Gated ion channels
normally closed but will open and allow facilitated diffusion when bound by a signaling molecule.
Phagocytosis
creates large vesicles and can bring in large amounts of material
Pinocytosis
creates small vesicles that are used to transport water
Receptor mediated endocytosis
uses transmembrane receptor proteins to selectively bring in large amounts of the same solute very specifically.
How to recognize Active transport?
-directly from chemical energy in ATP
-from high-energy electrons
-from energy in a gradient of another solute
Channel Proteins
create aqueous pathways for the diffusion of ions
Carrier Proteins
move larger molecules across the membrane by changing shape
Coupled Transport
Symport: move more than one solute at a time in the same direction
Antiport: move more than one solute at a time in different directions
