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Biology 112
Biology 112
65
Biology
Undergraduate 1
10/04/2013

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Term
What are macromolecules?
Definition
Polymers with molecular weights exceeding 1,000 grams per mole.
Term
What are proteins formed from?
Definition
Proteins are formed from different combinations of 20 different amino acids.
Term
What are nucleic acids formed from?
Definition
Nucleic acids are formed from four kinds of nucleotide monomers linked together in long chains.
Term
How macromolecules function and interact with other molecules depends on the properties of certain chemical groups in their monomers called:
Definition
Functional groups.
Term
An optical isomer occurs when:
Definition
A carbon atom has four different atoms or groups attached to it.
Term
The functions of macromolecules is directly related to:
Definition
Their three-dimensional shapes and to the sequences and chemical properties of their monomers.
Term
Polymers are constructed from monomers by a series of reactions called:
Definition
Condensation reactions (dehydration reactions; both terms refer to the loss of water).
Term
Condensation reactions result in what type of bond between monomers?
Definition
Covalent bond.
Term
When polymers are formed, what is released?
Definition
Water molecules.
Term
The reverse of a condensation reaction is called a:
Definition
Hydrolysis reaction.
Term
Hydrolysis reactions result in:
Definition
The breakdown of polymers into their component monomers.
Term
What are enzymes?
Definition
Catalytic proteins that speed up biochemical reactions.
Term
What are defensive proteins?
Definition
Recognize and respond to non-self substances that invade the organism from the environment.
Term
What are hormonal and regulatory proteins?
Definition
Proteins that control physiological processes.
Term
What are receptor proteins?
Definition
Proteins that receive and respond to molecular signals from inside and outside the organism.
Term
What are storage proteins?
Definition
Proteins that store chemical building blocks--amino acids--for later use.
Term
What are structural proteins?
Definition
Proteins such as collagen that provide physical stability and movement.
Term
What are transport proteins?
Definition
Proteins such as hemoglobin that carry substances within the organism.
Term
What are genetic regulatory proteins?
Definition
Proteins that regulate when, how, and to what extent a gene is expressed.
Term
All proteins consist of one or more ____ chains.
Definition
Polypeptide.
Term
What is a polypeptide chain?
Definition
An unbranched (linear) polymer of covalently linked amino acids.
Term
The composition of a protein refers to:
Definition
The relative amounts of the different amino acids present in its polypeptide chains.
Term
What is a D-amino acid?
Definition
Right (dextro) amino acid.
Term
What is an L-amino acid:
Definition
Left (levo) amino acid.
Term
There are four levels of protein structure:
Definition
Primary, secondary, tertiary, and quaternary.
Term
The precise sequence of amino acids in a polypeptide chain held together by peptide linkages constitutes what?
Definition
The primary structure of a protein.
Term
The peptide backbone of the polypeptide chain consists of the repeating sequence:
Definition
-N-C-C-
Term
The carboxyl group in an amino acid carries what kind of charge?
Definition
A delta negative charge.
Term
The amino group in an amino acid carries what kind of charge?
Definition
A delta positive charge.
Term
The secondary, tertiary, and quaternary are derived from what?
Definition
The proteins primary structure--that is, the precise location of specific amino acids in the polypeptide chain.
Term
Primary structure is established by what kind of bonds?
Definition
Covalent bonds.
Term
A protein's secondary structure consists of:
Definition
Regular, repeated spatial patterns in different regions of a polypeptide chain.
Term
What are the two basic types of secondary structure?
Definition
The alpha helix and the beta pleated sheet.
Term
The interactions between R groups determine what structure?
Definition
Tertiary structure.
Term
Hydrogen bonding between the amino and carboxyl groups is responsible for what structure?
Definition
Secondary structure.
Term
Covalent disulfide bridges can form between what?
Definition
Specific cysteine side chains, holding a folded polypeptide in place.
Term
What type of bond between side chains help stabilize folds in proteins?
Definition
Hydrogen bonds.
Term
Ionic bonds can form between positively and negatively charged side chains forming what between amino acids?
Definition
Salt bridges.
Term
If a protein is heated slowly, the heat energy will disrupt only the weak interactions, causing what?
Definition
Secondary and tertiary structure to break down. This is known as denaturing.
Term
All the information needed to specify the unique shape of a protein is contained in its what?
Definition
Primary structure.
Term
Many functional proteins contain two or more polypeptide chains called what?
Definition
Subunits.
Term
A proteins quaternary structure results from what?
Definition
The ways in which subunits bind together and interact.
Term
What forces, interactions, and bonds help hold subunits together?
Definition
Hydrophobic interactions, van der Waals forces, hydrogen bonds, and ionic bonds.
Term
The weak nature of the bonds, interactions, and forces between subunits allow for what?
Definition
Small changes in the quaternary structure to aid the protein's function. Example: Hemoglobin's ability to carry oxygen.
Term
The specificity of protein binding depends on what two general properties?
Definition
Its shape and the chemistry of its exposed surface groups.
Term
What conditions can alter the weak, noncovalent interactions in a protein?
Definition
Increases in temperature, alterations in pH, high concentrations of polar substances, and nonpolar substances.
Term
Increases in temperature cause what in the structure of a protein?
Definition
Increases in temperature cause more rapid molecular movements and thus can break hydrogen bonds and hydrophobic interactions, thus weakening a protein's structure.
Term
Alterations in pH can affect a protein in what ways?
Definition
Alterations in pH can change the pattern of ionization of exposed carboxyl and amino groups in the R groups of amino acids, this disrupting the pattern of ionic attractions and repulsions.
Term
High concentrations of polar substances can do what to a protein's structure?
Definition
High concentrations of polar substances can disrupt the hydrogen bonding that is crucial to protein structure.
Term
How do nonpolar substances affect a protein's structure?
Definition
Nonpolar substances may disrupt normal protein structure in cases where hydrophobic groups are essential to maintain the structure.
Term
When does denaturation become irreversible?
Definition
Denaturation becomes irreversible when amino acids that were buried in the interior of the protein become exposed at the surface, causing a new structure to form or different molecules to bind to the protein. Example: boiling an egg is irreversible .
Term
When is a polypeptide in danger of binding to the wrong substance?
Definition
Following denaturation, and after a protein is made.
Term
Eukaryotic cells have special classes of proteins that act to counteract threats to three-dimensional structure called what?
Definition
Chaperones.
Term
What to chaperone proteins do?
Definition
Prevent inappropriate interactions and enhance the appropriate ones.
Term
What are carbohydrates?
Definition
Carbohydrates are a large group of molecules that all have a similar atomic composition but differ greatly in size, chemical properties, and biological functions.
Term
What are the three major biochemical roles of carbohydrates?
Definition
They are a source of stored energy that can be released in a form usable by organisms, they are used to transport stored energy within complex organisms, and they serve as carbon skeletons that can be rearranged to form new molecules.
Term
What are the four categories of biologically important carbohydrates?
Definition
Monosaccharides, disaccharides, oligosaccharides, and polysaccharides.
Term
Saccharide means what?
Definition
Sugar.
Term
Monosaccharides include what?
Definition
Glucose, ribose, and fructose.
Term
What are dissacharides?
Definition
Two monosaccharides linked together by covalent bonds.
Term
What are oligosaccharides?
Definition
Saccharides made up of several (3-20) monosaccharides.
Term
What are polysaccharides?
Definition
Polymers made up of hundreds or thousands of monosaccharides.
Term
`All living cells contain what monosaccharide?
Definition
Glucose.
Term
What is glucose used for?
Definition
Glucose is used to to transport energy in humans.
Term
Polysaccharides are connected by what?
Definition
Glycosidic linkages.
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