General Biology 1

• MATTHIAS SCHLEIDEN studied numerous plant parts under the microscope and declared “ALL PLANTS ARE MADE OF CELLS!”
• RUDOLF VIRCHOW observed living cells dividing and declared “ALL CELLS COME FROM OTHER LIVING CELLS!”
• GOLGI BODY


  • Modifies, sorts, tags, packages, and distributes lipids and proteins
• ANTON VAN LEEUWENHOEK used a simple microscope to look at pond water and was the first to observe microorganisms in pond water
• Cell structure: NUCLEUS


  • Control center of cell
  • Direct synthesis of ribosomes and proteins
  • Contains genetic material - DNA
• Cell structure: CELL WALL


  • Commonly found in plant cells & bacteria
  • Made of porous cellulose so it does not regulate what enters and leaves
  • Provides support and maintenance of cell shape
• Types of Cell: PROKARYOTIC


  1. Cells without true nucleus

  2. Have nucleoid

  3. Contain small, double-strands of separate DNA called plasmids

  4. Do not have structures surrounded by membranes

  5. Few internal structures/organelles

  6. One-celled organisms, Bacteria

  7. Cell division happens through binary fission

  8. Exocytosis and endocytosis are not observed in prokaryotes
• ADIPOSE CELLS are fat cells and are storage by nature
• Cell structure: VACUOLES


  • Membrane-bound sacs for storage, digestion, and waste removal
  • Contains water solution
  • Help plants maintain shape
• THEODOR SCHWANN used a microscope to observe numerous animal tissues and declared “ALL ANIMALS ARE MADE OF CELLS!”
• Cell structure: LYSOSOMES


  • Digestive 'plant' for proteins, fats, and carbohydrates
  • Transports undigested material to cell membrane for removal
  • Contain digestive enzymes
• Cell theory
• EPITHELIAL CELLS are very simple cells which form the covering of other cells, found in skin, scalp, respiratory tract, and buccal cavity surface, acting as barriers for pathogens, fluid loss, and mechanical injuries
• CONNECTIVE CELLS include CARTILAGE CELLS which are freely bendable and present in ear bone, in between large bones to help them bend and move freely like in between two ribs, spinal bones, and joints
• CONNECTIVE CELLS also include NERVE CELLS which are very long, have many branchings at either end, never multiply in one’s lifetime, and are found in plenty in the brain and the spinal cord
• Types of Cell: EUKARYOTIC


  1. Cells that have true nucleus

  2. The DNA of a eukaryotic cell is linear with histones

  3. Contain organelles surrounded by membranes

  4. Most living organisms

  5. Cell divides through either mitosis or meiosis

  6. Perform endocytosis and exocytosis
• ROBERT HOOKE used a compound microscope to look at cork (from bark of a tree) & he saw empty boxlike structures that he named “cells”
• MUSCLE CELLS are mostly long, large, and have the ability to contract and relax providing movements, including SKELETAL MUSCLES attached to long bones, CARDIAC MUSCLE present only in heart muscle, and SMOOTH MUSCLE present in the stomach, intestine, and blood vessel walls
• CONDUCTIVE CELLS include Nerve cells and muscle cells which have the ability to conduct an electric impulse from one region to another in the body
• Cell structure: CHLOROPLASTS


  • Usually found in plant cells
  • Contains green chlorophyll
  • Where photosynthesis takes place
• Cell structure: CELL MEMBRANE

  • Separates cell from external environment
  • Outer membrane of cell that controls movement in and out of the cell
• Cardiac muscle cells


  Present only in heart muscle and are responsible for heart beats
• Types of muscle cells

  • Skeletal muscle cells
  • Cardiac muscle cells
  • Smooth muscle cells
• Skeletal cells


  Bone cells, toughest body cells bound together by calcium and phosphate, provide strength, support, and framework to the body enclosing organs in the skeletal system
• Types of cells

  • Adipose cells
  • Blood cells
  • Storage cells
  • Skeletal cells
• Lateral Cell Modification

  1. Tight Junction - acts as barriers regulating movement of water and solutes, prevent leakage of ECF

  2. Gap Junction - channels connecting cytoplasm of adjoining cells allowing direct exchange of chemicals

  3. Adhering Junction - fasten cells to one another
• Cytokinesis


  Division of the rest of the cell after nucleus division
• Apical Cell Modification


  1. Flagella - long whiplike structures

  2. Villi - finger-like projections that increase surface area for absorption
• Blood cells


  Include RBC, WBC, and thrombocytes, always motile, have a limited lifespan, do not multiply to form new cells
• Meiosis


  Two divisions (Meiosis I and Meiosis II), produces gametes (sperm or egg) with half the number of chromosomes
• Interphase


  Period of cell growth and development, DNA replication occurs, cell grows and carries out normal activities, replicates organelles
• Skeletal muscle cells


  Attached to long bones and assist in their movement
• Adipose cells


  Fat cells that store fat, found in specific body areas, reduce friction to the body
• Meiosis


  Cell division producing gametes with half the number of chromosomes, occurs in gonads, sexual reproduction
• Cell Modification


  1. Apical

  2. Basal

  3. Lateral
• Basal Cell Modification


  Desmosomes - anchoring junctions on the basal surface of the cell, composed of keratin, integrins, and cadherins
• Smooth muscle cells


  Flexibly contract and relax, present in stomach, intestine, blood vessel walls aiding in movement of food through the gut
• Storage cells


  Secretory cells found in glands like pancreas and salivary glands, aid in production of enzymes and hormones
• Mitosis


  Division of the nucleus into 2 nuclei with the same number of chromosomes, occurs in somatic cells
• Cell Cycle


  1. Interphase

  2. Mitosis

  3. Cytokinesis

  4. Meiosis