Rev#1_Biology

• Biology


  The branch of science that deals with the study of living systems and life processes
• Cells

  • They are the basic unit of structure and function in living things
  • All living systems are composed of cells
• Cell structures

  • Cell wall/cell membrane
  • Nucleus
  • Cytoplasm
  • Mitochondrion
  • Chloroplast
  • Ribosome
  • Endoplasmic reticulum
  • Golgi apparatus
  • Lysosome
  • Protoplasm
  • Centriole
  • Microtubules and microfilaments
• Organelles


  Structures with specific functions found within living cells
• Nucleus


  The organelle that serves as the control center in which individual functions of the other organelles are coordinated
• Cell wall/cell membrane


  The cell wall in plant cells and in some monerans and protests provides rigidity for support to the cells and a characteristic shape for functionality and structure. The cell membrane on the other hand is selectively permeable.
• Mitochondrion


  The organelle that serves as the site where ATPs are abundantly synthesized
• Chloroplast


  The organelle that serves as the site of photosynthesis among plants and photosynthetic algae
• Ribosome


  The organelle that serves as the site of protein synthesis
• Endoplasmic Reticulum


  The organelles that serve as channels or passageways through which materials are transported to the different parts of the cell
• Centriole


  The organelle that serves for cytokinetic purposes and is very common among dividing cells
• Lysosome


  The organelle that is also called "suicidal bag" as it releases digestive juices
• Golgi apparatus


  The organelle that serves for selection and packaging of cellular materials
• Differences between plant and animal cells

  • Cell wall (present in plants, absent in animals)
  • Chloroplast (present in plants, absent in animals)
  • Centriole (absent in plants, present in animals)
  • Lysosome (absent in plants, present in animals)
  • Vacuole (one/large in plants, many/small in animals)
• The Cell Theory serves as the basis on which everything that we know about the cell is anchored
• Elements of the Cell Theory

  • All living things are made up of cells
  • Cells are the basic unit of structure and function in living systems
  • All cells come from preexisting cells
• Biomolecules that make up the cell

  • Carbohydrates
  • Fats/Lipids
  • Proteins
  • Nucleic Acids
• Carbohydrates


  Immediate source of energy
• Fats/Lipids


  Molecules that serve as another source of energy after carbohydrates
• Proteins


  Molecules that serve as sources of building materials
• Nucleic Acids


  Molecules that include the RNA's and the DNA's
• Types of cells based on complexity

  • Prokaryotic cells (no membrane-bound nucleus and organelles)
  • Eukaryotic cells (membrane-bound nucleus and organelles)
• Types of cell transport

  • Passive transport (does not require the expenditure of energy, moves particles through the concentration gradient)
  • Active transport (requires the expenditure of energy, moves particles against the concentration gradient)
• Diffusion


  The process in which molecules of solvent move from an area of high concentration to an area of low concentration
• Osmosis


  The diffusion of particles or molecules across selectively permeable membrane
• Types of cell division

  • Mitosis (division of somatic or body cells)
  • Meiosis (division of germ or sex cells)
• Mitosis


  The division of somatic cells, also referred to as equational division because the ploidy number of the daughter cells is equal to the ploidy number of the dividing cell
• Meiosis


  The division of germ cells, also referred to as reductional division because the ploidy number of the daughter cells is only half that of the parent cell
• Plants are autotrophic organisms capable of synthesizing their own food for growth and maintenance through the process of photosynthesis
• Major plant cell types

  • Parenchyma
  • Collenchyma
  • Sclerenchyma
• Parenchyma cells


  Usually large, thin-walled and are extremely variable in shape
• Collenchyma cells


  Have primary cell walls that are thickened irregularly by cellulose and pectin materials
• Sclerenchyma cells


  Have a comparatively thick primary cell wall bearing heavy depositions of lignified secondary substance laid down in a laminated pattern
• Tissues


  Aggregate of cells with similar structure and function
• Types of plant tissues

  • Meristematic tissues (composed of immature cells and regions of active cell division)
  • Permanent tissues (epidermis, periderm, vascular tissues)
• Epidermis


  Composed of tiny openings principally on the underside of the leaves that regulate the exchange of water and gases called stomates
• Periderm


  Constitutes the corky outer bark of trees
• Vascular tissues


  Composed of xylem and phloem; xylem functions for the transport of water and minerals upward from the roots while phloem functions for the transport of food materials
• Root


  The typically underground organ of the plant axis that functions principally for anchorage and absorption of water and minerals from the soil
• Stem


  Readily recognized by the presence of nodes, where leaves are born, with the intervening area between the nodes being an internode