what's in a medicine (WM) Flashcards
What are amino acids and how are they amphoteric?
Amino acids have both acidic and basic properties. They contain an amino group (NH2) and a carboxyl group (COOH), which can both ionize, allowing them to act as both acids and bases.
What is a zwitterion?
A zwitterion is a molecule with both a positive and a negative charge but an overall neutral charge. It occurs when both the amino and carboxyl groups of an amino acid are ionized, typically at the isoelectric point.
What is the isoelectric point?
The isoelectric point is the pH at which an amino acid or protein exists as a zwitterion, with no overall charge.
How does high pH affect an amino acid?
At high pH, the carboxyl group of an amino acid loses a proton (ionizes), resulting in a negatively charged carboxylate group.
How does low pH affect an amino acid?
At low pH, the amino group of an amino acid becomes protonated (NH3+), resulting in a positively charged amino group.
What is the role of ninhydrin in paper chromatography?
Ninhydrin is used in paper chromatography to detect amino acids. It reacts with amino acids to produce a colored compound, allowing them to be visualized.
How are proteins formed from amino acids?
Proteins are formed by condensation polymerization, where amino acids are joined by peptide bonds between the amine group and the carboxyl group.
What is the structure of proteins?
Primary structure: The sequence of amino acids in the polypeptide chain.
Secondary structure: The folding into α-helixes or β-pleated sheets.
Tertiary structure: The 3D shape of the protein, stabilized by bonds like hydrogen bonds, ionic bonds, and disulfide bridges.
How do disulfide bonds form in proteins?
Disulfide bonds form between two cysteine amino acids, where the sulfur atoms in their thiol groups (–SH) bond together, stabilizing the tertiary structure of proteins.
What are the building blocks of DNA?
DNA is a polymer of nucleotides, each consisting of a pentose sugar, a phosphate group, and a nitrogenous base.
How are nucleotides linked together in DNA?
Nucleotides are linked by condensation polymerization, forming a phosphate-sugar backbone with ester bonds between the phosphate and deoxyribose sugar.
What is the role of hydrogen bonds in DNA structure?
Hydrogen bonds form between complementary bases: adenine (A) pairs with thymine (T) via two hydrogen bonds, and guanine (G) pairs with cytosine (C) via three hydrogen bonds.
How does DNA replication occur?
The hydrogen bonds between DNA strands break.
Free nucleotides pair with complementary bases.
DNA polymerase catalyzes the formation of the sugar-phosphate backbone, resulting in two identical DNA molecules.
What are codons in the context of mRNA?
Codons are groups of three nucleotides in mRNA that code for specific amino acids during protein synthesis.
What is the function of mRNA?
mRNA is a single-stranded RNA copy of a gene’s DNA sequence, which carries genetic information from the nucleus to the ribosome for protein synthesis.
Describe the process of translation in protein synthesis.
mRNA binds to the ribosome.
tRNA with a complementary anticodon binds to the mRNA codon.
Amino acids are added to the growing polypeptide chain until a stop codon is reached.
What is the lock and key model for enzymes?
The lock and key model suggests that enzymes have a specific active site shape that exactly fits the substrate, allowing for a specific biochemical reaction to occur.
How does enzyme concentration affect the rate of reaction?
As enzyme concentration increases, the rate of reaction increases, but it plateaus once all substrates are used up.
What are pharmacophores?
Pharmacophores are the part of a drug molecule responsible for its biological activity. They must fit into a specific receptor site to exert their effect.
What are optical isomers?
Optical isomers are non-superimposable mirror images of each other. They have chiral centers, meaning carbon atoms bonded to four different groups.
How do amines behave in chemical reactions?
Amines are basic due to the lone pair of electrons on nitrogen, which allows them to accept protons. They can react with acids to form ammonium salts.
What happens when amides are hydrolyzed under acidic conditions?
Amides undergo hydrolysis under acidic conditions to form a carboxylic acid and an ammonium salt.
What are the reactions of carboxylic acids?
Carboxylic acids are weak acids and only partially dissociate in water. They react with alkalis to form salts and with alcohols to form esters.
How do you name esters?
Esters are named by combining the alkyl group from the alcohol with the acid part from the carboxylic acid.
