Biochemistry questions

Question Answer
Which group on the Amino Acid determines its polarity? R- group
In which configuration are all amino acids in proteins? L- configuration
Any compound that is both an acid AND a base is called what? amphoteric
What are the two enantiomers or stereoisomers that all amino acids have? Dextro (D – right) and Levo (L – left)
What is the function of the amino acids trypsin and chymotrypsin? To break down proteins.
What is the tissue source that excretes amylase? The pancreas AND salivary glands.
What type of bond is the covalent bond between a primary amino acid groups of one amino acid and the carboxylic group of a second amino acid? Peptide bond.
What is the Henderson-Hasselbach equation used for? To predict the net charge and isoelectric point of a protein.
Proteins have a minimum of _____ to ______ amino acids. 30 to 50
What is the most important of all biological compounds to the body? proteins
Proteins are constructed from the same set of ____ amino acids. 20
Basic AA- contain amino groups and are fully pronated giving them a ______ charge. positive
Carboxylic acids (-COOH) CANNOT exist in the presence of what? a weak base
Compounds that have a positive charge on one atom and a negative charge on another atom are known as_______ Zwitterions
What are the four levels of structure for proteins, and what is each comprised of? Primary- sequence of amino acids
Secondary- sequences linked by hydrogen bonds (alpha helix, Beta- pleated sheet)
Tertiary- folds of twisted chains made by secondary structure
Quaternary- arrangement of polypeptide chains if unit has 2 or more subunits
The pH where an amino acid has an equal number of positively and negatively charged atoms is called the ________. Isoelectric point
How are proteins characterized? Size, Charge, Binding properties, and Solubility.
Which type of amino acid has hydrophobic rings and are found in the core of proteins? Aromatic Amino Acids
What equation is used to predict net charge and the isoelectric point of a protein? Henderson- Hasselbalch equation
Average nitrogen content in proteins is ___ % by weight 16%
What does adding a source of hydroxyl (OH-) do to the pH of a water solution of amino acids? Raises the pH
The amino acid residue with the free -COOH group is called the ____? C-terminal
What is one reason why the structure of proteins is important? The structure is linked to diseases
What increases solubility by adding low amounts
of salt (ammonium sulfate)?
"salting in"
What decreases solubility by adding large
amounts of salt?
"salting out""
At _____ pH's, amino acids have a negative charge. high

Hi there, would you like to get such a paper? How about receiving a customized one? Check it out