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• Cell


  Life's basic unit of structure and function
• Cell


  • Smallest unit of living material that can carry out all the activities necessary for life
• Light microscope


  Used to study stained or living cells, can magnify up to 1,000 times
• Electron microscope


  Used to study detailed structure of a cell, can magnify up to 250,000 times but can only observe killed cells of specimens
• Eukaryotic cell


  Contains a membrane-bound structure called a nucleus and cytoplasm, filled with tiny structures called organelles
• Prokaryotic cell


  Lacks both a nucleus and membrane-bound organelles, genetic material is one continuous, circular DNA molecule that lies free in the cell in an area called the nucleoid
• Prokaryotic cells


  • Bacteria
  • Rickettsiae
• Prokaryotic cell


  • In addition to a plasma membrane, most have a cell wall composed of peptidoglycan, may have ribosomes and a flagellum
• Diagram of a bacterial cell showing key structures
• Plasma membrane


  Complex double-layered structure made up of phospholipids and proteins, regulates movement of substances into and out of the cell
• Nucleus


  Control center of the cell, contains hereditary information-DNA-organized into chromosomes, houses the nucleolus
• Ribosomes


  Sites of protein synthesis, can be free floating or attached to the endoplasmic reticulum
• Endoplasmic reticulum (ER)


  Continuous channel that extends into many regions of the cytoplasm, rough ER has ribosomes and synthesizes proteins, smooth ER lacks ribosomes and makes lipids, hormones, and steroids
• Golgi bodies


  Process, modify, and sort proteins synthesized on the rough ER, package final products in vesicles to be sent out of the cell
• Mitochondria


  The "powerhouses" of the cell, convert energy from organic molecules into ATP
• Lysosomes


  Membrane-bound structures that carry digestive enzymes to break down old, worn-out organelles, debris, or large ingested particles
• Centrioles


  Small, paired, cylindrical structures found within microtubule organizing centers, active during cell division
• Vacuoles


  Fluid-filled sacs that store water, food, wastes, salts, or pigments
• Peroxisomes


  Organelles that detoxify various substances, produce and break down hydrogen peroxide
• Cytoskeleton


  Network of fibers, including microtubules and microfilaments, that determine the shape of the cell and enable movement
• Plant cells


  • Have a protective outer cell wall made of cellulose, contain chloroplasts for photosynthesis, have a large central vacuole, lack centrioles
• Comparison of structural characteristics of prokaryotic, plant, and animal cells
• Endocytosis


  Process where the cell membrane forms a pocket, pinches in, and engulfs large particles to form a vacuole or vesicle
• Cell metabolism


  Catabolism - cell breaks down complex molecules to produce energy and reducing power

  Anabolism - cell constructs complex molecules and performs other biological functions
• First law of thermodynamics

  Energy cannot be created or destroyed, the sum of energy in the universe is constant
• Second law of thermodynamics

  Energy transfer leads to less organization, the universe tends toward disorder (entropy)
• Adenosine triphosphate (ATP)


  The energy molecule in the cell
• Catabolism


  The cell breaks down complex molecules to produce energy and reducing power
• Anabolism


  The cell constructs complex molecules and perform other biological functions
• Energy cannot be created or destroyed. The sum of energy in the universe is constant. This rule is called the first law of thermodynamics.
• The second law of thermodynamics states that energy transfer leads to less organization. That means the universe tends toward disorder (or entropy).
• Adenosine triphosphate (ATP)


  A molecule consisting of a molecule of adenosine bonded to three phosphates. An enormous amount of energy is packed into those phosphate bonds, particularly the third bond.
• Sources of ATP


  1. Photosynthesis

  2. Cellular respiration
• Photosynthesis


  1. Light reaction (light-dependent reaction)

  2. Dark reaction (light-independent reaction)
• The light reaction produces ATP and NADPH, which are then used in the dark reaction (light independent) to make carbohydrates.
• Cellular respiration


  1. Aerobic respiration

  2. Anaerobic respiration
• Anaerobic respiration in muscle cells produces lactic acid, causing muscle aches.
• DNA


  The hereditary blueprint of the cell
• Chromosomes


  • Consist of DNA wrapped around proteins called histones
  • When in loose form (euchromatin), genes are active
  • When fully condensed (heterochromatin), genes are generally inactive
• DNA molecule


  Two strands that wrap around each other to form a double helix