Atoms, Bonds, and Molecules Quiz

Atoms, Bonds, and Molecules

• Matter is anything that occupies space and has mass.
• Matter is made up of atoms.
• Atoms are the simplest form of matter that can't be broken down into simpler substances.
• Atoms are made up of protons, neutrons, and electrons.
• Elements are pure substances with a unique number of protons, neutrons, and electrons.
• Elements have predictable chemical behaviors.

Characteristics of Elements

• Atomic number is the number of protons.
• Mass number is the number of protons and neutrons.
• Isotopes are forms of an element with different mass numbers (different number of neutrons).
• Atomic weight is the average of the mass numbers of an element's isotopes.
• Electron orbitals are volumes of space surrounding the atom's nucleus where electrons are likely to be found.

Molecules and Bonds

• A molecule is a distinct chemical substance formed by two or more atoms.
• Compounds are molecules that are combinations of two or more different elements.
• Chemical bonds form when two or more atoms share, donate, or accept electrons to form molecules and compounds.
• There are three types of chemical bonds: covalent, ionic, and hydrogen.

3 Types of Chemical Bonds

• Covalent bonds: electrons are shared among atoms.
  • Polar covalent bonds: unequal sharing of electrons
  • Nonpolar covalent bonds: equal sharing of electrons.
• Ionic bonds: Electrons are transferred to one atom, creating positively charged cations and negatively charged anions.
• Hydrogen bonds: weak bonds between hydrogen and other atoms.

Biological Molecules

• Several important biological molecules are found in living organisms, including carbohydrates, lipids, proteins, and nucleic acids. These molecules have diverse functions and structures within cells.

Carbohydrates

• Carbohydrates are sugars and polysaccharides.
• They have the general formula (CH₂O)ₙ.
• Monosaccharides are the monomers (glucose, fructose).
• Polysaccharides are polymers of monosaccharides (starch, cellulose, and glycogen).
• Subunits in polysaccharides are linked by glycosidic bonds.
• Carbohydrates provide structural support and store energy.

Lipids

• Lipids are long or complex hydrophobic chains.
• Lipids include triglycerides, phospholipids, and steroids like cholesterol.
• Triglycerides are used for energy storage
• Phospholipids are major components of cell membranes.
• Steroids are components of cell membranes.

Proteins

• Proteins are the dominant molecules in cells.
• Proteins are made up of 20 different amino acids
• Amino acids are linked together by peptide bonds to form peptides, polypeptides, and proteins.
• Proteins fold into very specific 3-D shapes.
• Proteins have diverse functions, including support, enzymes, transport, defense, and movement.

Nucleic Acids

• Nucleic acids include DNA and RNA.
• Nucleic acids are made of monomers called nucleotides.
• DNA is deoxyribonucleic acid with nitrogenous bases A, T, C, G, and a double helix.
• DNA stores hereditary material.
• RNA is ribonucleic acid with nitrogenous bases A, U, C, G.
• RNA is involved in protein synthesis.

ATP: The Energy Molecule of Cells

• ATP is adenosine triphosphate, a nucleotide with adenine, ribose, and three phosphates.
• ATP is used for energy transfer and storage in cells.

Organic and Inorganic Compounds

• Organic compounds contain carbon.
• Inorganic compounds do not contain carbon.
• Macronutrients (needed in large amounts) include oxygen, carbon, hydrogen, nitrogen, phosphorus, potassium, magnesium, calcium, and sulfur.
• Micronutrients (needed in small amounts) include selenium and zinc.
• Air is made of nitrogen, oxygen, argon, carbon dioxide, and neon.
• Optimal amount of nutrients signifies the balanced quantity of nutrients for optimal health.