Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
69 Cards in this Set
- Front
- Back
|
Chiral |
Objects that have handedness (mirror images of objects cannot be superimposed on each other, one does not completely fit on top of each other) |
|
|
Achiral |
Objects that lack handedness |
|
|
Chiral Carbon Atom |
- The central carbon atom is connected to 4 different groups |
|
|
enantiomers or optical isomers |
- two mirror-image forms of a chiral molecule |
|
|
Enantiomers are one kind of... |
stereoisomer - compounds that have the same formula and atoms with the same connections but different spatial arrangements |
|
|
Pairs of enantiomers have many of the same physical properties... |
...the same melting point, solubility in water, isoelectric point, and density |
|
|
Pairs of enantiomers often differ in their... |
...biological activity, odors, tastes, or activity as drugs |
|
|
Biochemistry |
study of molecules and their reactions in living organisms |
|
|
Principal classes of biomolecules are... |
...proteins, carbohydrates, lipids, and nucleic acids |
|
|
Proteins are....of amino acids |
polymers |
|
|
Central carbon of an amino acid |
- alpha carbon |
|
|
Amino acids in proteins are... |
...alpha-amino acids because the amine group in each is connected to the alpha carbon |
|
|
Priority of groups attached to the alpha carbon from highest to lowest |
carboxyl group→amine group→side chain→hydrogen |
|
|
Peptide Bonds |
- two or more amino acids can link together by forming amide bonds (peptide bonds when they occur in proteins) - Formed through dehydration reaction |
|
|
dipeptide, tripeptide, polypeptide |
dipeptide: 2 amino acids tripeptide: 3 amino acids polypeptide: many amino acids together (most, another name for protein) |
|
|
Primary Structure |
- sequence of amino acids in a protein chain (connected by peptide bonds) Along backbone - chain of alternating peptide bonds and alpha carbons Side chains - substituents along the backbone |
|
|
Secondary Structure |
- regular and repeating spatial organization of neighboring segments of single protein chains - alpha helix, beta sheet |
|
|
Tertiary Structure |
- the overall shape of a protein molecule produced by regions of secondary structure combined with the overall bending and folding of the protein chain - starts taking 3D shape - ball of alpha helix and beta sheets |
|
|
Quaternary Structure |
- refers to the overall structure of proteins composed of more than one polypeptide - together for functionality - EX: Na+/K+ pump |
|
|
Enzymes |
Function: catalyze biochemical reactions Example: Amylase - begins digestion of carbohydrates by hydrolysis |
|
|
Hormones |
Function: regulate body functions by carrying messages to receptors Example: insulin - facilitates use of glucose for energy generation |
|
|
Storage Proteins |
Function: make essential substances available when needed Example: myoglobin - stores oxygen in muscles to have resistance to move |
|
|
Transport Proteins |
Function: carry substances through body fluids Example: serum albumin - carries fatty acids in blood |
|
|
Structural Proteins |
Function: provide mechanical shape and support (give structure to cells) Example: collagen - provides structure to tendons and cartilage |
|
|
Protective Proteins |
Function: defend the body against foreign matter (antibodies) Example: immunoglobulin - aids in destruction of invading bacteria |
|
|
Contractile Proteins |
Function: myosin and actin - govern muscle movement |
|
|
Protein important in nutrition to... |
...replenish enzymes |
|
|
All proteins in living organisms are built from... |
...20 amino acids |
|
|
length of protein dependent on... |
...function |
|
|
function dependent on... |
...arrangement of amino acids |
|
|
What is the only amino acid that differs in more than just the side chain attached to the alpha carbon? |
Proline - secondary amine whose nitrogen and carbon atoms are joined in a 5 membered ring |
|
|
Interactions of side chains is the reason... |
...why proteins have a tertiary structure |
|
|
hydrophobic nonpolar side chains |
- to avoid aqueous fluids, nonpolar side chains gather into clusters to create a water-free environment - van der waals, london dispersion forces |
|
|
Hydrophilic, polar, acidic, and basic side chains |
- attractions between water molecules and hydrophilic groups on the surface of folded proteins impart water solubility to the proteins |
|
|
If amino acid as ammonium/amine |
= basic |
|
|
amino acids contain both an acidic group and a basic group |
acidic group: -COOH basic group: NH2 |
|
|
- COOH and NH2 group undergo what reaction to form a zwitterion? |
- intramolecular acid-base reaction NH2+H = ammonium ion (+) -COOH - H = carboxylate ion (-) Cancel eachother out = neutral |
|
|
Zwitterion |
- neutral ion with one positive charge and one negative charge and is thus, electrically neutral - charges give amino acids their functionality |
|
|
Zwitterion gives amino acids many physical properties of... |
...salts: crystals, high melting points, and water solubility |
|
|
In acidic solution, amino acid zwitterions... |
...accept protons on their basic -COO- groups to leave only the positive charged -NH3+ groups |
|
|
In basic solution, amino acid zwitterions... |
...lose protons from their acidic -NH3+ groups to leave only the negatively charged -COO- groups |
|
|
isoelectric point (pI) |
describes the pH at which a sample of an amino acid has equal numbers of (+) and (-) charges - net charge of all the molecules of that amino acid in a pure sample is zero - different for each amino acid due to influence of side chain |
|
|
Isoelectric point close to ____ for neutral amino acids, acids, bases |
neutral - pH 7 acids - pH 3 bases - pH 10 or 12 |
|
|
Side chain interactions are crucial to... |
proteins stability |
|
|
The carbon and nitrogen atoms along backbone lie in a... |
...zigzag arrangement with a tetrahedral bonding around alpha carbon. Angle=between 4 bonds = 109.5 degrees |
|
|
primary structure = carbonyl-group double bond electrons are shared with... |
...the adjacent C-N bond - sharing makes C-N bond sufficiently like a double bond that there is no rotation around it |
|
|
What forms the rigid planar unit in primary structure? |
- carbonyl group, N-H group bonded to it, and two adgacent alpha carbons |
|
|
Peptides and proteins are always written in... |
... amino-terminal amino acid (N-terminal) to carboxyl-terminal amino acid (C-terminal) |
|
|
Residues |
- individual amino acids joined in the chain |
|
|
Sickle-Cell anemia results from... |
- result of a single amino acid substitution that replacees one amino acid Glu with Val in hemoglobin - hydrophobic pocket is exposed to surface of hemoglobin and hydrophobic valine on another hemoglobin molecule is drawn into this pocket - insoluble fibrous chains are formed, forcing the cell into a sickle shape |
|
|
Protein malnutrition... |
... start breaking down proteins in body from muscle first |
|
|
essential amino acids |
9 of 20 amino acids that must be obtained in the diet |
|
|
Protein-energy malnutrition (PEM) |
- kwashiorkor - protein is deficient although caloric intake may be adequate. - enlarged livers and underdeveloped children - marasmus - result of starvation - severe muscle wasting, below-normal stature, and poor response to treatment |
|
|
Hydrogen bonds along backbone |
- form between hydrogen atoms in N-H group and oxygen atoms in C=O - secondary structure |
|
|
Hydrogen bonds of R groups with each other or with backbone atoms |
- some amino acids contain atoms that can form hydrogen bonds - can't connect different parts of a protein molecule - often hydrogen bonding side chains are present on surface of folded protein where they can form hydrogen bonds with surrounding water molecules |
|
|
Ionic attractions between R groups (Salt Bridges) |
- ionized acidic and basic side chains create salt bridges |
|
|
Hydrophobic interactions between R groups |
-van der waal/london dispersion - hydrocarbon side chains attracted to create water-free pocket - individual attractions weak but large number in proteins play a major role in stabilizing the folded structures |
|
|
Covalent Sulfur-Sulfur Bonds |
- cysteine residues can react to form sulfur-sulfur bonds(disulfide bonds) - disulfide bridges - stabilizing factor for 3D structure - adding heat can break yielding thiols |
|
|
alpha-helix |
- coil is held in place by hydrogen bonds between each carbonyl oxygen and the amide hydrogen four amino acid residues above - right-handed coil - hydrogen bonds lie parallel to verticle axis - viewed from top, side chains point to exterior of the helix |
|
|
beta-sheet |
- hydrogen bonds stabilize interactions between neighboring protein chains - protein chains lay side by side so that alternating chains run from the N-terminal end to the C-terminal end and from C-N = antiparallel arrangement - Stacks stabilized by side chains |
|
|
Fibrous protein |
- tough insoluble protein whose protein chains form fibers or sheets Ex: wool, hair, fingernails = made from kearatins Ex: natural silk and spider webs are made of fibroin |
|
|
keratin |
- composed of alpha helices twisted together into small fibrils that are in turn twisted into larger and larger bundles |
|
|
Fibroin |
- composed of beta-sheets. R- groups small so fibroin contains regions of alternating glycine and alanine |
|
|
Globular Protein |
- water soluble protein whose chain is folded in a compact shape with hydrophilic groups on the outside - structure vary wildly and aren't regular - sections of both beta and alpha pressent - hydrophilic sidechains on outside - allow them to travel through body fluids - overall shapes = tertiary |
|
|
Native Protein |
a protein with the shape in which it functions in living systems - dictated by primary structure |
|
|
simple protein |
a protein composed only of amino acid residues |
|
|
Conjugated proteins |
aided in their function by an associated non-amino acid unit - oxygen-carrying portion of myoglobin has a heme group embedded within the polypeptide chain |
|
|
polypeptides are primarily held together by... |
...noncovalent forces, but covalent bonds and non-amino acid portions may also be incorporated |
|
|
Heme |
organic molecule that is completely insoluble and need an amino acid to go through |
