NAS2 Study Guide Questions with Correct Answers

NAS2 Study Guide Questions with Correct Answers Name the building blocks of proteins - Answer-Amino Acids = 21 used to build protein for living organisms. Describe Aa's chemical structure (i.e. groups) - Answer-1. A central carbon 2. An amino group (- NH2) 3. A carboxylic acid group (-COOH) 4. A hydrogen atom (H) 5. An 'R' group Answer-physiological function Enzymatic Proteins: - Answer-Lower the activation energy required for initiating chemical reactions and speed up the rate of chemical reactions. Structural Proteins: - Answer-Make up cell membranes, bones, muscles, ligaments, tendons, hair, nails & skin Transport Proteins: - Answer-Carry oxygen in red blood cells (RBC); pump nutrients and ions across membranes Hormonal Proteins: - Answer-Regulate physiological process such as insulin regulates blood sugar levels Defensive Proteins: - Answer-Antibodies (Immunity) Contractile Proteins: - Answer-Movement Storage Proteins: - Answer-Amino acids can be used as a C & N source. (ex. Ovalbumin, casein) Receptor Proteins: - Answer-Membrane bound & receive chemical signals Name the elements found in proteins. - Answer-All contain C, H, O, N, (and some have S) State the difference between a nonessential amino acid and an essential amino acid. - Answer-Non-essential: Some can be made within the body. Essential: Have to be acquired through diet. Identify the one group that makes each amino acid unique - Answer-All amino acids are identical except for their 'R' group. Variable = chain of C with potentials other elements (N/O/S) Can contribute characteristics to Aa Hydrophobic, hydrophilic, positive or negative charges Name the specific bond between amino acids that form a protein. - Answer-Amino acids are linked by covalent bonds called peptide bonds The FUNCTION of a protein is determined by its... - Answer-Shape The SHAPE of a protein is determined by its... - Answer-Primary structure of the amino acids sequence. Explain how the STRUCTURE of a protein determines its function? - Answer-Shape is based on amino acid sequence. Shape also depends on the environment. The sequence of amino acids in a protein is determined by the SEQUENCE of... (hint protein synthesis) - Answer-Nucleotides in the gene (DNA) encoding it. Proteins have four levels of structure/shape what are the NAMES of these four levels? - Answer-Primary, Secondary, Tertiary, and Quaternary Primary structure - Answer-Linear polypeptide = string of Amino Acids Secondary structure (two forms) - Answer-1. Alpha-helix - O & H in a single chain can bond to make an 'a' helix. 2. Beta-pleated sheet - O & H in separate primary chains can interact making a 'B'- pleated sheet (Bonding occurs at regular intervals) (This secondary shape imparts particular properties to the protein) Quaternary structure - Answer-Two or more tertiary structures combine to form a functional protein (Held together by both hydrogen and covalent bonds) Name three examples of Quaternary structures and their functions - Answer-1. Hemoglobin: Transports O2 inside a RBC 2. Keratin: Waterproofs skin 3. Collagen: Supports many cells throughout the body Explain how sickle-cell disease is related to abnormal protein structure - Answer-A change in the amino acid sequence can render a protein inactive. Potentially this will cause the protein to fold differently. (Glutamate (Glu) which is hydrophilic is replaced by Valine (Val) which is hydrophobic) Define protein denaturation - Answer-Loses shape Causes of denaturation of a protein - Answer-Drop in pH (acidic) Increase in pH Increase in temperature Describe how the denaturation of a protein affects its function - Answer-Sometimes reversible under normal conditions. Sometimes irreversible. (Sometimes chaperone proteins are needed to help fold/re-fold proteins!) What are enzymes? - Answer-Globular proteins What are the functions of enzymes? - Answer-1. Lower the activation energy required for chemical reactions 2. Increase the speed of reactions 3. Cannot force reactions to occur that on their own would not react 4. Are not used up or altered 5. Specific enzymes for specific reactions 6. Most names of enzymes end with the suffix '-ase'