DO NOW- write in complete sentences

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DO NOW- write in complete sentences Powered By Docstoc
					   DO NOW- write in complete sentences
• 1. What is the evidence that led to
  the Cell theory?
  2. What are the 3 statements of the
  Cell Theory?
  3. What is surface to volume ratio?
• 4. Why are smaller cells better than
  large ones?
• 5. What are the basic parts of a cell?
      2 Basic Types of Cell Types
• PROKARYOTE                 • EUKARYOTE

  – No nucleus                 – Nucleus present
  – No membrane- bound         – Membrane-bound
    organelles.                  organelles.
  – DNA is floating in the     – Larger than prokaryotes
    cytoplasm                  – Ex. WBC, sperm, skin
  – Ex.Bacteria                  cell, most cells
     Features and the Functions
• 1. CELL WALL: protects and maintains shape
  of the cell.
  – Composed of carb-protein complex called
  – Some bacteria have extra layer of polysaccharide
    that helps it stick to things. Ex. Bacteria sticking to
    teeth, skin and food.
  2. The CELL MEMBRANE is just inside the cell
  – It controls the movement of materials in and out
    of cells.
• Prokaryotic cells reproduce by binary fission
  and the cell membrane plays a role in this.

• There are no compartments in bacterial cells
  so all cellular processes take place in the
• 3. PILI : Hair-like structures that are used for
  attachment. Main function is to join bacterial
  cells together for the transfer DNA from one
  cell to another.

• 4. FLAGELLA: longer than pili. Used for cell
  motility (movement).
• 5. RIBOSOMES: in all prokaryotic cells.
  Function to site of protein synthesis.

  – Gives electron microscope pictures a granular
• 6. NUCLEOID REGION: area within the
  bacterial cell that contains the circular threads
  of DNA.
Cheek Cell
Cheek Cell
Onion Cell
Onion Cell
   Cell Organelles and Functions
• 1. Plasma Membrane: also called the Cell
  – Allows only certain molecules to enter or
    leave the cell.
  – It separates internal reactions from outside
  – Also allows cell to excrete waste from the
• Made of PHOSPHOLIPIDS. Phospholipids
  have a polar end and a nonpolar end.
                2. NUCLEUS:
• Most functions of the cell are controlled by
  the nucleus.

• Functions: “Brain” of the cell.

• It houses and protects the cell’s genetic
• When the cell is not dividing, the DNA exists in
  long strands. While the cell is dividing, it coils
  up to form CHROMOSOMES.

• The nucleus is the site where DNA is
  transcribed into RNA.
• Nucleolus: dense part of the nucleus.

• Site where DNA is concentrated.
 • Nuclear Envelope: double layer that covers
    the nucleus. Also made of 2 phospholipid

• Nuclear Pores: holes in the nuclear envelope
  that allow passageways for RNA and other
  things entering and leaving the nucleus.
• 3. CYTOPLASM: area within the plasma
  membrane excluding the nucleus.
• 4. MITOCHONDRION: tiny, double-membrane
  organelles that transfer ENERGY from organic
  molecules to ATP.

• ATP powers most of the cell’s chemical

• Function: Powerhouse of the cell.
• Active cells have many mitochondrion. Ex.
  Muscle cells.

• Inner folds: CRISTAE. Cristae contain proteins
  that carry out energy-harvesting chemical
• 5. RIBOSOMES: small, spherical organelles.

• Function: make proteins.

• Don’t have a membrane.
• Assembly begins in the nucleolus and is
  completed in the cytoplasm.
• Consists of a large and small subunit.
Let’s Review