Atoms and Molecules Quiz

Atoms and Molecules

• Atoms are the fundamental units of matter, composed of protons, neutrons, and electrons.
• Chemical bonds form when atoms share or transfer electrons, creating molecules.
• Covalent bonds involve sharing electrons, while ionic bonds involve transferring electrons.
• Hydrogen bonds are weaker attractions between a hydrogen atom with a partial positive charge and another atom with a partial negative charge.
• Water is a crucial molecule for life, due to its polarity and ability to form hydrogen bonds. This allows it to act as a solvent, a transport medium, and a temperature buffer.
• Many important biological molecules are composed of carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (CHONPS).
• Carbohydrates, lipids, proteins, and nucleic acids are essential macromolecules in living organisms.

Carbohydrates

• Carbohydrates are composed of carbon, hydrogen, and oxygen atoms.
• Monosaccharides are simple sugars (e.g., glucose, fructose).
• Disaccharides are formed by joining two monosaccharides (e.g., sucrose).
• Polysaccharides are long chains of monosaccharides (e.g., starch, glycogen, cellulose).
• Carbohydrates serve as a primary source of energy and structural components in cells.

Lipids

• Lipids are composed mainly of carbon and hydrogen with a smaller proportion of oxygen.
• They are insoluble in water due to their hydrocarbon structure.
• Fats and oils are important energy storage molecules.
• Phospholipids are crucial components of cell membranes, with a hydrophilic head and hydrophobic tails.
• Steroids have a complex ring structure, including cholesterol and hormones.
• Lipids play a role in energy storage, insulation, and membrane structure.

Proteins

• Proteins are polymers of amino acids.
• The 20 different amino acids combine in various sequences to form a diverse range of proteins.
• Proteins have complex three-dimensional shapes, crucial for their function.
• Proteins perform diverse functions, including enzymes, structural components, transport proteins, and antibodies.
• Protein structure is organized into primary, secondary, tertiary, and quaternary structures.

Nucleic Acids

• Nucleic acids (DNA and RNA) store and transmit genetic information.
• DNA (deoxyribonucleic acid) is a double helix composed of nucleotides (adenine, thymine, guanine, cytosine).
• RNA (ribonucleic acid) is a single-stranded molecule involved in protein synthesis.
• Nucleotides are composed of a sugar, a phosphate group, and a nitrogenous base.