Atomic Structure and Bonding Quiz

Atomic Structure and Bonding

• Atoms are composed of subatomic particles: protons, neutrons, and electrons
• Protons and neutrons reside in the nucleus, while electrons orbit the nucleus
• Atomic number equals the number of protons in an atom
• Atomic mass is roughly the sum of protons and neutrons
• Electrons in the outermost shell determine the reactivity of an atom
  • An atom with 10 electrons will have 2 electrons in its outermost shell
• Isotopes are atoms of the same element with a different number of neutrons
• Forming bonds makes atoms more stable
  • Bonds occur to fill the outermost electron shell
• Ions form when atoms gain or lose electrons, becoming electrically charged
  • Atoms become ions when they gain or lose electrons
• Ionic bonds form between ions with opposite charges
• Covalent bonds form when atoms share electrons
  • Covalent bonds form when electrons are shared
• Hydrogen bonds are weak attractions between a hydrogen atom and an electronegative atom (like oxygen or nitrogen)
  • Hydrogen bonds are important in the structure of proteins and nucleic acids
• Compounds are substances formed by the chemical combination of two or more different elements

Molecules and Chemical Reactions

• A molecule is formed when two or more atoms bond together
• Chemical formulas represent the composition of a molecule
  • 3CO2 represents 3 molecules of carbon dioxide
• Water is a polar molecule due to the unequal sharing of electrons between oxygen and hydrogen atoms
• Polarity influences interactions between water molecules (hydrogen bonding).
• Hydrophilic molecules dissolve in water, while hydrophobic molecules do not.
• Hydrolysis breaks down a molecule by adding a water molecule
• Condensation joins two molecules by removing a water molecule

Cellular Components and Processes

• Organelles are compartments within cells
  • Organelles are compartments within cells
• Tissues are groups of similar cells with a common function
  • Tissues are groups of similar cells with a common function
• Organs are functional units composed of different tissues
  • Organs are functional units composed of different tissues
• Cells are the basic units of life
  • Cells are the basic units of life
• The levels of organization in biological systems (from least to most complex): atom, molecule, organelle, cell, tissue, organ, organ system, organism

Cellular Respiration

• Cellular respiration is the process of breaking down glucose to produce energy (ATP)
• Aerobic respiration requires oxygen and yields a large amount of ATP
  • The largest amount of ATP is generated by the electron transport chain
• Fermentation occurs in the absence of oxygen and produces less ATP
• NAD+ acts as an electron carrier in cellular respiration
• ATP production by chemiosmosis involves H+ concentration gradients across membranes

Cell Division

• Mitosis is a type of cell division that produces two identical daughter cells
• Mitosis has four phases: prophase, metaphase, anaphase, and telophase
• Cytokinesis is the division of the cytoplasm
• Meiosis is a type of cell division that produces gametes (sex cells) with half the number of chromosomes

DNA and Protein Synthesis

• DNA is composed of nucleotides containing a sugar, phosphate, and base
• DNA stores genetic information
• Transcription is the process of making RNA from a DNA template
• Translation is the process of making proteins from mRNA
• RNA is similar to DNA but contains ribose sugar and uracil instead of thymine
• tRNA carries amino acids to ribosomes for protein synthesis
• mRNA carries the genetic code from DNA to ribosomes