Introduction to Biology

Biological System of Classification

• Cells: Smallest unit of life, capable of independent existence

• Nutrition: Process of intake and conversion of food into protoplasm

• Respiration: Oxidation of food substances for energy release

• Excretion: Removal of metabolic waste

• Locomotion: Movement from one place to another

• Adaptation: Characteristics improving survival

• Reproduction: Production of offspring

• Classification: Grouping organisms by similarities and differences

  • Binominal System: Created by Carl Linnaeus, uses Latin names; Genus (capitalized) and species (lowercase)
    • Example: Felis domestica (Domestic Cat), Panthera tigris (Tiger), Panthera leo (Lion)
  • Classification order increases similarity among species

Cells & Organelles

• Cell Surface Membrane: Selectively permeable, regulates entry/exit, composed of lipids
• Cytoplasm: Medium for chemical activities, contains organelles
• Nucleus: Contains chromatin (stores DNA), nucleolus makes ribosomes
• Cell Wall: Present in plant cells, made of cellulose, provides shape and protection
• Rough Endoplasmic Reticulum (R.E.R): Synthesizes/modifies proteins, has ribosomes
• Ribosomes: Protein production, either free or attached to ER
• Smooth Endoplasmic Reticulum (S.E.R): Synthesizes lipids/steroids, detoxifies substances
• Golgi Apparatus: Modifies, processes, packages substances for secretion
• Vesicles: Lysosomes: Digest harmful material, integrate substances between organelles
• Mitochondria: Powerhouse, conducts cellular respiration, contains ATP
• Chloroplast: Double membrane, contains chlorophyll for photosynthesis
• Vacuole: Fluid-filled, stores substances, size differs in plant/animal cells
• Centrioles: Assist cell division, only in animal cells

Difference between Animal and Plant Cells

• Plant Cells: Have large vacuole, cell wall, chloroplast
• Animal Cells: Have multiple small vacuoles, centrioles

Specialized Cells

• Stem Cells: Unspecialized, quick reproduction, differentiate into specialized cells
• Red Blood Cells (RBCs): Contain hemoglobin, transport oxygen, no nucleus
• Root Hair Cells: Increase water/mineral absorption, no chlorophyll, found in plants
• Xylem Vessels: Transport water, provide structural support
• Nerve Cells: Transmit electrical impulses, have extensions to cover distance
• Cilia: In trachea/ears, help trap dirt, discern sound pitch
• Trachea Cilia: Move dirt away from lungs, secrete mucus
• Muscle Cells: Contract and expand, use ATP for energy

Levels of Biological Organization

• Cells → Tissues (Simple/Complex) → Organ → Organ System → Organism