Biology: Scientific Study of Life and Chemistry

• Exam 1 includes multiple choice, true/false, and matching questions.

Scientific Study of Life

• Properties of life and examples of homeostasis should be understood.
• The scientific method requires identifying the hypothesis, variables, theory, and control in an experiment.
• Life's complexity levels proceed from atoms to the biosphere.
• Cells make up tissues, tissues make up organs, organs make up organ systems, and organ systems make up an organism.

The Chemistry of Life

• Atoms are composed of protons, electrons, and neutrons.
• Electrons and their orbitals determine an atom's chemical properties.
• Atomic number is the number of protons or electrons, while atomic weight equals the number of protons plus neutrons.
• An atom with 8 protons, 8 electrons, and 7 neutrons has an atomic number of 8 and an atomic weight of 15.
• An ion is a charged atom, and an isotope is a variation of an element with a different number of neutrons.
• Radioactive isotopes are used in medicine and to date fossils.
• Ionic, covalent (polar and nonpolar), and hydrogen bonding are different types of chemical bonds.
• Sodium chloride uses ionic bonding.
• Polar molecules, like water, are hydrophilic, while non-polar molecules are hydrophobic.
• Hydrophilic substances are water-attracting, hydrophobic substances repel water.
• The pH scale measures acidity, alkalinity, or neutrality; buffers resist changes in pH.
• Acidity depends on the concentration of hydrogen ions (H+), and alkalinity on hydroxide ions (OH-).
• Hydrolysis involves the addition of water to break bonds, while dehydration removes water to form bonds.
• Macromolecules (polymers) consist of monomers.
• Proteins are made of amino acid monomers, each with a variable R group and constant carboxyl and amino groups.
• Nucleic acids are made of nucleotide monomers.
• A peptide bond holds amino acids together.
• Carbohydrates include glucose, sucrose, glycogen, starch, cellulose, and chitin.
• Some carbohydrates store energy, while others provide structure.
• Chitin and cellulose are structural carbohydrates found in specific cells or organisms.
• Saturated and unsaturated fats exist; examples include phospholipids and steroids.
• Protein structures include primary, secondary, tertiary, and quaternary forms.
• DNA and RNA differ in structure and function; DNA uses the base pairs A-T and G-C, while RNA substitutes Uracil (U) for Thymine (T).
• Practice finding a complementary sequence. GGAATT is complemented by CCTTAA

Cell Structure

• Prokaryotic and eukaryotic cells differ significantly.
• Bacteria, plant, and animal cells have different organelles.
• Organelles include the nucleus, mitochondria, chloroplast, cell wall, lysosomes, endoplasmic reticulum, ribosome, cilia, flagella, microtubules, centrioles, and chromosomes.
• Organelles each perform specific functions within the cell.
• Smooth and rough endoplasmic reticulum (ER) differ in structure and function due to the presence of ribosomes.
• Ribosomes are responsible for building proteins.
• Cytoplasmic movement is called cyclosis.
• Phospholipids are the main component of the cell membrane.
• Proteins are also found in the cell membrane.
• Proteins within the membrane of a cell have a specific function
• The fluid mosaic model describes cell structure.

Cell Energy

• Potential and kinetic energy differ; fats or sugar molecules possess potential energy.
• Metabolism is the sum of all chemical processes that occur in an organism.
• The first and second laws of thermodynamics describe energy conservation and entropy, respectively.
• ATP is a molecule that functions in structure and function.
• Enzymes catalyze reactions by lowering activation energy.
• The active site is where the substrate binds on an enzyme.
• Feedback inhibition is a way to regulate enzyme activity, it can be competitive or non-competitive.
• Factors like pH and temperature affect an enzyme's action.
• Coenzymes, like NAD, assist enzymes.
• Cellular transport systems include osmosis, diffusion, facilitated diffusion, active transport, endocytosis, exocytosis, pinocytosis, and phagocytosis.
• The sodium-potassium pump is an active transport example, and engulfing a bacterium exemplifies phagocytosis.
• Isotonic, hypertonic, and hypotonic environments affect cells differently depending on the amount of water.
• Red blood cells in water may burst depending on the environment.
• Water is hypotonic to red blood cells.
• A 10% salt solution is hypertonic to a cell.

Understand life's properties, homeostasis, and the scientific method. Learn atom composition, electron behavior, and atomic number vs. weight. Explore ions, isotopes, and radioactive isotopes in medical applications.