Carbohydrates/Proteins/Lipids/Enzymes

Identify/Define

Polymer – Long molecule consisting of many identical building blocks linked by covalent bonds.

Monomer – Small molecules that build up polymers.

Condensation Reaction – Reaction in which molecules are bonded, yielding a water molecule.

Hydrolysis – Reaction in which one water molecule is added in order to split apart molecules.

Monosaccharides – Single sugars (commonly with the chemical formula of C_xH_2xO_x).

Aldehyde Sugar – Linear sugars in which the carbonyl group is located at a terminal.

Ketose Sugar – Linear sugars in which the carbonyl group is connected to a central Carbon.

Disaccharide – a molecule consisting of two monosaccharides joined by a glycosidic linkage.

Glycosidic Linkage – Covalent bond formed between 2 monosaccharides by a condensation reaction.

Polysaccharides – Macromolecules, polymers with many monosaccharides joined by glycosidic linkages.

Starch – Storage polysaccharide of plants made of glucose monomers (helical).

Glycogen – Storage polysaccharide (polymer of glucose) that is extensively branched; stored in liver and muscle cells.

Cellulose – Structural polysaccharide (polymer of glucose) that makes up the microfibrils of plant cell walls.

Chitin – Structural polysaccharide that makes up exoskeletons of arthropods; also found in fungi (rather than cellulose).

Lipids – Insoluble compounds of one glycerol and 3 fatty acids; the glycerol terminal of a lipid is hydrophilic while the fatty acids are hydrophobic.

Fatty Acid – Long carbon skeleton connected to glycerol to form triglycerides (fats).

Triglyceride – One glycerol and three fatty acids connected via condensation bond.

Saturated Fatty Acid – Fatty acid with no double bonds between Carbons.

Unsaturated Fatty Acid – Fatty acid with at least one double bond between Carbons.

Phospholipids – Lipids with only two fatty acids; the glycerol end of the phospholipid is hydrophilic, the fatty acid end is hydrophobic.

Micelle – A grouping of phospholipids in which the heads are outward (hydrophilic) and the tails are inward (hydrophobic).

Steroids – Lipids characterized by carbon skeletons consisting of 4 fused rings.

Cholesterol – A steroid prevalent in membranes; precursor from which all steroids are generated.

Conformation – Three-dimensional shape of proteins.

Polypeptides – Polymers of amino acids.

Amino Acids – Organic molecules consisting of a unsymmetrical Carbon with a carboxyl group attached, an amine group attached, a hydrogen attached, and a generalized R group attached.

Peptide Bond – A condensation bond between two amino acids, formed between an amine and a carboxyl.

Primary Structure – A representation of a protein as a series of amino acids.

Secondary Structure – A representation of a protein as an alpha helix or a beta pleated sheet.

Alpha Helix – A helix formed by amino acids (with relatively small, nonpolar R groups); Hydrogen bonds occur between amines and carboxyls.

Beta Pleated Sheet – A jagged sheet of amino acids (with larger, polar R groups); hydrogen bonds occur between amines and carboxyls.

Mutation – A change in DNA coding, often caused prior to birth; most are inconsequential.

n-Terminal End – Amine group of an amino acid.

c-Terminal End – Carboxyl group of an amino acid

Amine Group – The nitrogen and two oxygens on an amino acid.

Carboxyl Group – A carbon double bonded to an oxygen and covalently bonded to an alcohol group on the end of an amino acid opposite the amine.

Alcohol Group - OH

Tertiary Structure – Structure depicting the formation of a chain of amino acids, noting bonds that hold together the polypeptide in certain shapes.

Hydrophobic Interaction – Congregation of amino acids with hydrophobic side chains that hold together tertiary structure.

Van der Walls Attractions – Attractions that hold together the hydrophobic interaction of tertiary structure.

Disulphide Bridges – Bonds between sulfhydryl groups (-SH) on cystine monomers; this is the strongest bond in tertiary structure.

Quaternary Structure – A three-dimensional representation of the shape of two or more polypeptide chains; Can be fibrous or globular.

Heme Group – One of four groups in the protein hemoglobin; there are 2 identical pairs of heme groups in one hemoglobin protein, and as such one heme is not considered a protein.

Denaturation – Damage to quaternary structure that causes bonds to break and the structure to split.

Chaperone Proteins – Proteins that direct shaping and bonding of proteins.

Enzymes – Catalytic proteins that cause lower activation energy for reactions; always reusable; substrates determine specificity.

Competitive Inhibitor – A molecule structurally similar to an enzyme’s specific substrate that binds to the active site and prohibits substrate binding.

Competitive Inhibition – The process of a competitive inhibitor’s impersonating a substrate to bind to an enzyme’s active site in order to inhibit substrate binding.

Non-Competitive Inhibition – The binding of a molecule to an enzyme at a location other than its active site; this causes a decrease in catalytic activity.

Active Site – The site on an enzyme to which a substrate binds.

Substrate – A specific substance on which an enzyme works; substrates attach to enzymes’ binding sites.

Enzyme-substrate specificity – This is the ideal that enzymes have specific receptor sites for specific substrates; like a key-and-lock model.

Induced Fit – Induced fit is the altering of an active site if charges from a substrate alter the position of charges within the site.

Allosteric Site – A site seperate from the active site on an enzyme which allows molecules to bind to itself to change the shape of the active site, making the enzyme more or less receptive to substrates.

Allosteric Inhibitors – Allosteric inhibitors mimic allosteric molecules and bind to the allosteric site, thus preventing binding of allosteric molecules; example: poison.

Short Answer

What properties of water are significant to living organisms?

Transparency (light in oceans, photosynthesis in water plants); Cohesion (water binds to itself in the water column of xylem molecules in plants and works against gravity to hydrate the plant); Universal Solvent (acts as solvent for minerals in plants); Thermal Properties (stable temperature allows for ocean life); Transport Medium (water moves urea across membranes in nephron); Coolant (sweat); pH (stays above 7.8, allows for human life); Surface Tension (high, allows some animals to walk on water).

Give the ring structure for Glucose.

Give the ring structure for Ribose.

Give the structure of a generalized amino acid.

Draw with structure of a generalized triglyceride.

Show a condensation reaction between 2 generalized amino acids forming a dipeptide.

State 3 functions of lipids.

Energy storage source; Form plasma membranes (phospholipid bilayers); Insulate the body (in the form of fat).

Give 1 example of a fibrous protein and 1 example of a globular protein.

Fibrous = Keratin

Globular = Hemoglobin

Explain the four levels of protein structure.

Primary Structure is a representation of a protein as a series of amino acids. Secondary Structure is a representation of a protein as an alpha helix or a beta pleated sheet. Alpha Helix is a helix formed by amino acids (with relatively small, nonpolar R groups); Hydrogen bonds occur between amines and carboxyls. Beta Pleated Sheet is a jagged sheet of amino acids (with larger, polar R groups); hydrogen bonds occur between amines and carboxyls. Tertiary Structure is the structure depicting the formation of a chain of amino acids, noting bonds that hold together the polypeptide in certain shapes. Hydrophobic Interaction is the congregation of amino acids with hydrophobic side chains that hold together tertiary structure. Van der Walls Attractions are the attractions that hold together the hydrophobic interaction of tertiary structure. Disulphide Bridges are bonds between sulfhydryl groups (-SH) on cystine monomers; this is the strongest bond in tertiary structure. Quaternary Structure is a three-dimensional representation of the shape of two or more polypeptide chains; Can be fibrous or globular.

What determines polarity of amino acids?

Amino acids are generally polar is there is an oxygen in the R group. Furthermore, other elements such as sulfur or nitrogen could cause polarity.

Differentiate competitive and non-competitive inhibition.

Competitive inhibition occurs when a competitive inhibitor structurally like the substrate of the enzyme binds with the enzyme’s active site and inhibits substrate binding. Non-competitive inhibition is the binding of a molecule to an area of the enzyme that is not the active site.

Why do enzymes lower activation energy of chemical reactions?

Chemical reactions necessitate collisions between molecules to break bonds. Enzymes weaken these bonds and thus, less energy is needed.

What are the monomer units of triglycerides?

1 Glycerol and 3 Fatty Acids

What are the monomer units of carbohydrates?

Sugars (often glucose)

Give the ionized form of Serine.

Why do alpha helixes and beta pleated sheets form in secondary protein structure?

Alpha helixes are made of consecutive patterns of amino acids with small, nonpolar R groups (note that the specific R group does not influence shape). Beta pleated sheets are made of amino acids with other R groups.

What bonding occurs in tertiary structure?

Hydrogen Bonding, Disulfide Bonding, Hydrophobic Interactions, van der Waals attractions

What is the primary role of enzymes?

Enzymes are proteins that act as catalysts, lowering activation energy for chemical reactions.

List the 8 types of proteins.

Structural; Storage; Transport; Hormonal; Receptor; Contractile; Defensive; Enzymatic

Show the hydrolysis of a maltose disaccharide to 2 glucose monosaccharides.

Show lipase acting on a generalized triglyceride resulting in hydrolysis reaction.