Biology Chapter on Experimental Design & Molecules

Experimental Design

• Independent Variable: The variable that is intentionally changed in an experiment.
• Dependent Variable: The variable that is measured; it responds to changes in the independent variable.
• Control Variable: Factors that remain constant throughout the experiment.
• Controlled Experiment: An experiment where only one variable is altered at a time.
• Hypothesis: A testable prediction typically structured as "If..., then..."

Biological Molecules

• Carbohydrates: Composed of carbon, hydrogen, and oxygen; includes sugars and starches; main energy source for living organisms; provides structural support in plants; notable types include glucose and glycogen.
• Lipids: Made up of carbon and hydrogen; consist of fatty acids and glycerol; store energy and form cell membranes; examples include fats and oils.
• Proteins: Composed of carbon, hydrogen, oxygen, and nitrogen; made of amino acids; essential for regulating cell processes, forming muscles and bones, transporting substances, and immune response; consist of enzymes.
• Nucleic Acids: Contains carbon, hydrogen, oxygen, nitrogen, and phosphorus; composed of nucleotides; store and transmit genetic information; includes DNA and RNA.

Cell Biology

• Enzyme Functions: Biological catalysts that speed up chemical reactions; highly sensitive to temperature and pH.
• Importance of Water: Vital for all life; acts as a universal solvent; polar molecule structure aids in biological functions.
• Cell Structures:
  • Nucleus: Control center of the cell; regulates activities.
  • Ribosomes: Site of protein synthesis.
  • Cell Membrane: Regulates entry and exit of substances; semipermeable.
  • Cell Wall: Provides structural support and protection primarily in plants.
  • Mitochondria: Powerhouse of the cell; generates ATP through sugar breakdown.
  • Vacuoles: Storage of water, sugars, and other substances.
  • Lysosome: Digests waste materials.
  • Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.
  • Chloroplast: Converts sunlight into chemical energy in plant cells.

Cell Organization and Types

• Hierarchy of Cell Organization: Organelles → Cells → Tissues → Organs → Organ Systems.
• Eukaryotic Cells: Complex cells with a nucleus and membrane-bound organelles.
• Prokaryotic Cells: Simpler cells without a nucleus; lack membrane-bound organelles.
• Plant Cells: Characterized by cell walls, large central vacuoles, and chloroplasts.
• Animal Cells: Feature small vacuoles, lysosomes, and centrioles.

Transport Mechanics

• Passive Transport: Movement of molecules from high to low concentration without energy; includes diffusion and osmosis.
• Active Transport: Movement of molecules from low to high concentration requiring energy; involves processes like endocytosis and exocytosis.

Cell Cycle and Division

• Interphase: Period of DNA replication and preparation for cell division.
• Meiosis: Type of sexual reproduction leading to four haploid daughter cells; involves two cell divisions.
• Mitosis: Asexual reproduction resulting in two diploid daughter cells; consists of one cell division.

Genetic Information and Protein Synthesis

• mRNA: Carries genetic information from DNA to ribosomes.
• rRNA: Constitutes the structural components of ribosomes.
• tRNA: Transfers specific amino acids to the ribosomes during protein synthesis.
• Codon: A triplet of bases in mRNA that codes for a specific amino acid.
• DNA Replication: Process of copying DNA; involves unzipping the DNA strands and creating two new strands.

Photosynthesis and Cellular Respiration

• Photosynthesis Formula: CO2 + H2O + Energy → C6H12O6 + O2; plants use sunlight to convert carbon dioxide and water into glucose and oxygen.
• Cellular Respiration Formula: C6H12O6 + O2 → CO2 + H2O + Energy; the process by which organisms convert glucose and oxygen into carbon dioxide, water, and energy.

Living Organisms and Viruses

• Characteristics of Living Things: Composed of cells, capable of reproduction, growth and development, energy usage, evolution, genetic material, maintain homeostasis, and respond to the environment.
• Homeostasis: Ability of organisms to maintain stable internal conditions despite external changes.
• Viruses: Considered nonliving; contain DNA but cannot reproduce independently; require a host cell for replication.

Factors Affecting Biological Processes

• Photosynthesis Rate Influencers: Light intensity, color of light, water availability, temperature, and carbon dioxide levels.
• Cell Cycle Regulation: Disruptions in enzyme production can lead to uncontrolled cell division and potential cancer development.

Test your knowledge on the fundamental concepts of experimental design and biological molecules. This quiz covers independent and dependent variables, controlled experiments, and key macromolecules such as carbohydrates, lipids, and proteins. Prepare to enhance your understanding of essential biological principles.