CHAPTER 5,6,7& 8 Q’S AND A’S
What is the monomeric unit of polypeptides? - ANSWER-Amino Acids
How many varieties of amino acids are there? - ANSWER-20
What bond is formed between the monomers of the polypeptide? - ANSWER-
Peptide bonds
What is the general structure of an amino acid? - ANSWER-A polypeptide is a
polymer of amino acids. Each polypeptide has a unique linear sequence of amino
acids, with a carboxyl end (C-terminus) and an amino end (N-terminus).
What parts are common to all amino acids? - ANSWER-A hydrogen, an amino
group, and a carboxyl group
What is the part of the amino acid that varies? - ANSWER-A R-Group
How are amino acids grouped? - ANSWER-...
Why are amino acids called "acids?" - ANSWER-They all contain the carboxyl group
(-CO2H), which is acidic.
What parts of the amino acids are joined with the peptide bond? - ANSWER-...
In what conditions does the carboxyl group (-COOH) ionize to (-COO-)? -
ANSWER-...
What is the difference between a polypeptide and a protein? - ANSWER-Proteins
are composed of α-amino acids linked together by peptide bonds into polypeptide
chains. An amino acid is characterized by an amino group (-NH2) and a carboxylic
acid group (-COOH) linked to a carbon, known as the α-carbon.
What is meant by "C-terminus" and "N-terminus?" - ANSWER-There's an amine
group on one end of the protein and a carboxyl group on the other. They call the end
with the amine on it the "N terminus" because the chemical formula for amine is NH2
while the end with the carboxyl group on it is named the "C terminal" because the
chemical formula of a carboxyl is CH2. The N terminus is the end that amino acids
are added onto when mRNA is translated in protein synthesis.
What level of protein structure do α-helices and β-pleated sheets form? - ANSWER-
Secondary structure
, What type of bonds do α-helices and β-pleated sheets depend on? - ANSWER-
Hydrogen Bonds
3 dimensional structure depends on interactions between the R groups, what type of
interactions contribute to tertiary structure? - ANSWER-Interactions among various
side chains (R groups).
What is denaturation and what causes it? - ANSWER-A process in which proteins or
nucleic acids lose the quaternary structure, tertiary structure and secondary structure
which is present in their native state. Alterations in pH, salt concentration,
temperature, or other environmental factors can cause a protein to unravel.
Folding is assisted by a group of proteins call________. - ANSWER-Chaperonins
Why is misfolding a problem? - ANSWER-They can lead to diseases such as
Alzheimer's, Parkinson's, and mad cow disease.
What are the 2 major nucleic acids? - ANSWER-1. Deoxyribonucleic Acid (DNA)
2. Ribonucleic Acid (RNA)
What is the monomeric unit of nucleic acid? - ANSWER-Nucleotides
What sugar is used in RNA? - ANSWER-Ribose
In DNA what is the sugar that is used and how is it different from the sugar used
RNA? - ANSWER-Deoxyribose,"Deoxy-" indicates one less oxygen in the ribose
sugar.
There are 5 nitrogenous bases in total, which 4 are used in DNA? - ANSWER-
Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).
There are 5 nitrogenous bases in total, which 4 are used in RNA? - ANSWER-
Adenine (A), Uracil (U), Guanine (G), and Cytosine (C).
What parts of the nucleotide form the backbone? (Rails or Ladders) - ANSWER-
Ladders
What parts of the nucleotides stick out away from the backbone? (Rails or Ladders) -
ANSWER-Rails
What is the structure of DNA? What is meant by "antiparallel?" - ANSWER-Double
helix, the 2 backbones run in opposite 5'-3' directions from each other, an
arrangement referred to as antiparallel.
What does the orientation relate (5'-3') to the structure of DNA? - ANSWER-Tells you
which way to read the sequence.