Bonds Flashcards
(30 cards)
What is a hydrogen bond?
A weak interaction between a slightly positive hydrogen and a slightly negative atom like oxygen or nitrogen.
Hydrogen bonds are crucial for the structure and function of biological molecules, particularly in stabilizing the shapes of proteins and nucleic acids.
Where are hydrogen bonds found in biological molecules?
Between DNA base pairs and in protein secondary structures (-helices and β-pleated sheets).
These interactions play a key role in the stability and functionality of DNA and proteins.
What is an ionic bond in biology?
A bond formed by attraction between oppositely charged ions. Stabilises protein tertiary and quaternary structures.
Ionic bonds contribute to the overall shape and stability of proteins by forming interactions between different charged regions.
What is a covalent bond?
A strong bond formed when atoms share electrons. Found in the backbone of all biological molecules.
Covalent bonds are essential for maintaining the integrity of molecular structures in biological systems.
What is a peptide bond?
A covalent bond linking amino acids in a protein between the amino and carboxyl groups.
Peptide bonds are fundamental to protein structure and function, determining the sequence of amino acids.
What is a glycosidic bond?
A covalent bond formed between two monosaccharides in a condensation reaction.
Glycosidic bonds are critical for forming carbohydrates and polysaccharides, influencing energy storage and structural roles in cells.
What is an ester bond?
A bond between glycerol and fatty acids in lipids, formed by a condensation reaction.
Ester bonds are key to the formation of triglycerides and phospholipids, essential components of cellular membranes.
What is a phosphodiester bond?
A covalent bond between the phosphate of one nucleotide and the sugar of another in DNA/RNA.
Phosphodiester bonds are vital for the structural integrity of nucleic acids, enabling the formation of the sugar-phosphate backbone.
What is a disulfide bond?
A strong covalent bond between sulfur atoms of two cysteine residues, stabilizing protein structure.
Disulfide bonds play a significant role in maintaining the three-dimensional structure of proteins, particularly in extracellular environments.
What is a condensation reaction?
A reaction joining two molecules with the removal of water and formation of a bond.
Condensation reactions are fundamental in synthesizing larger biological molecules such as proteins, nucleic acids, and carbohydrates.
What is a hydrolysis reaction?
A reaction that breaks bonds by adding water.
Hydrolysis is a common reaction in biological processes, particularly in the digestion of macromolecules.
What bonds join glucose units in starch?
a-1,4 and a-1,6 glycosidic bonds.
Starch is a polysaccharide formed by the polymerization of glucose molecules.
What bonds join glucose units in cellulose?
b-1,4 glycosidic bonds.
Cellulose is a key structural component of plant cell walls.
What type of bond is broken during protein digestion?
Peptide bonds.
Peptide bonds link amino acids together in proteins.
How are phospholipids bonded?
By ester bonds between glycerol and fatty acids, with a phosphate group.
Phospholipids are essential components of cell membranes.
What maintains the primary structure of proteins?
Peptide bonds.
The primary structure refers to the linear sequence of amino acids in a protein.
What bonds contribute to tertiary protein structure?
Hydrogen bonds, ionic bonds, disulfide bonds, and hydrophobic interactions.
These interactions help stabilize the three-dimensional shape of the protein.
What are hydrophobic interactions?
Non-polar groups clustering away from water to stabilize protein structure.
Hydrophobic interactions play a crucial role in protein folding.
What bonds form between enzymes and substrates?
Temporary hydrogen bonds and ionic interactions.
These interactions facilitate the enzyme’s catalytic activity.
What bonds hold antibodies and antigens together?
Non-covalent interactions like hydrogen and ionic bonds.
These interactions are vital for the immune response.
What bond is formed during nucleotide polymerisation?
Phosphodiester bonds.
Phosphodiester bonds link the 5’ phosphate group of one nucleotide to the 3’ hydroxyl group of another.
What type of bond is formed in lipid synthesis?
Ester bonds.
Ester bonds are formed between glycerol and fatty acids.
How are polysaccharides broken down?
By hydrolysis of glycoside bonds.
Glycoside bonds are the linkages between sugar units in polysaccharides.
What bonds contribute to quaternary protein structure?
Hydrogen bonds, ionic bonds, and disulfide bridges.
These bonds help stabilize the complex structure of proteins made of multiple polypeptide chains.
