amino acids, protiens and DNA Flashcards
What are the monomers of proteins?
Amino acids.
What two functional groups do amino acids contain?
- Carboxylic acid
- Primary amine
What is the property of amino acids that allows them to rotate plane polarized light?
Chirality.
What does it mean for amino acids to be amphoteric?
They have both acidic (COOH) and basic (NH2) properties.
How is the position of the amino group indicated in amino acid nomenclature?
With a number.
What is a zwitterion?
A dipolar ion with a permanent positive and negative charge.
What happens to amino acids at their isoelectric point?
They exist as zwitterions.
What occurs to the NH2 group of an amino acid in acidic conditions?
It accepts a proton to form NH3+.
What is the pH where the average overall charge of the amino acid is 0 called?
Isoelectric point.
What occurs to the carboxylic acid group in alkaline conditions?
It loses a proton to form COO-.
What is formed when amino acids react with each other?
Dipeptides through condensation reactions.
What is the process called that breaks peptide bonds between amino acids?
Hydrolysis.
What type of bonds are responsible for the primary structure of proteins?
Covalent bonds.
What type of structure involves coiling into alpha helices or beta-pleated sheets?
Secondary structure.
Which interactions stabilize the tertiary structure of proteins?
- Hydrogen bonding
- Ionic bonding
- Disulfide bridges
What is the final three-dimensional shape of proteins with more than one polypeptide chain?
Quaternary structure.
What technique is used to separate and identify amino acids?
Thin-layer chromatography.
What are enzymes?
Protein-based biological catalysts.
What hypothesis describes how enzymes and substrates interact?
Lock and key hypothesis.
What type of bond forms between nucleotides in DNA?
Phosphodiester bonds.
What is the structure of DNA?
A double helix made of two polynucleotide strands.
Which nitrogenous bases pair together in DNA?
- Adenine pairs with Thymine
- Cytosine pairs with Guanine
How many hydrogen bonds are formed between A-T and C-G pairs?
- A-T: 2 hydrogen bonds
- C-G: 3 hydrogen bonds
What is the action of the anti-cancer drug cisplatin?
It prevents DNA replication by forming bonds with guanine.
What is a side effect of cisplatin treatment?
Hair loss due to effects on rapidly replicating healthy cells.
Fill in the blank: The process of forming DNA involves __________ polymerization.
condensation
What is the role of water in the formation of phosphodiester bonds?
A molecule of water is lost for each bond formed.
What causes the selectivity of enzymes?
The specific tertiary structure of their active sites.
