Polymers and life Flashcards
What is an amino acid?
Amino acids contain at least one amino (-NH2) group and one carboxylic acid (C=OOH) group.
What is the general formula of 2-amino acids?
H2N-CHR-COOH, where R represents a side chain specific to each amino acid.
What happens when two amino acids react?
A condensation reaction occurs, releasing water and forming a peptide bond (-CONH-) between the COOH of one amino acid and the NH2 of another.
What is a peptide bond?
A -CONH- link formed between amino acids during a condensation reaction.
How can proteins be hydrolysed?
Heat with a medium-concentration acid or alkali, or use enzymes as catalysts. This breaks peptide bonds to release amino acids.
What are the main steps of paper chromatography?
- Draw a pencil line near the bottom of the paper. 2. Spot the sample and reference samples onto the line. 3. Suspend the paper in solvent and cover the beaker. 4. Once the solvent reaches the top, remove and dry the paper.
What is the primary structure of a protein?
The sequence of amino acids in the protein chain.
What is the secondary structure of a protein?
Hydrogen bonds between peptide links form structures such as alpha-helices or beta-pleated sheets.
What is the tertiary structure of a protein?
The overall 3D structure formed by additional folding and coiling of the protein, stabilized by ionic, hydrogen, disulfide, and dipole-dipole bonds.
What is a disulfide bridge?
A covalent bond between two -SH groups on the Cys amino acid.
What are the monomers of DNA?
Nucleotides, which consist of a phosphate group, a sugar (deoxyribose), and a base (A, T, C, or G).
How are DNA strands held together?
Hydrogen bonds form between complementary bases: A-T with 2 hydrogen bonds, and C-G with 3 hydrogen bonds.
What is RNA
and how is it different from DNA?
What is the role of the genetic code?
It determines the sequence of amino acids in proteins using base triplets (codons), where each codon specifies an amino acid.
What is a receptor?
A site on a cell where specific molecules can bind due to complementary size, shape, orientation, and bonding groups.
What is a pharmacophore?
The part of a drug that interacts with a receptor site, determining its biological activity.
What is an enzyme?
A biological catalyst that speeds up reactions by lowering the activation energy. It has a specific active site for its substrate.
What happens when an enzyme denatures?
The active site’s shape changes due to non-optimal pH or temperature, preventing substrate binding.
What is a competitive inhibitor?
A molecule that binds to an enzyme’s active site without reacting, preventing the substrate from binding.
What happens to enzyme activity at high substrate concentrations?
The reaction becomes zero-order because all active sites are occupied, and adding more substrate does not increase the rate.
What is a zwitterion?
A molecule with both positively charged (H3N+) and negatively charged (COO−) groups, such as amino acids at neutral pH.
How do amino acids behave in acidic solutions?
The COO− group gains an H+ ion, forming COOH, and the molecule becomes positively charged.
How do amino acids behave in basic solutions?
The H3N+ group loses an H+ ion, forming NH2, and the molecule becomes negatively charged.
What is an amine?
An organic compound derived from ammonia (NH3) with one or more hydrogens replaced by carbon chains.
