SC100 Unit 15: The Living Cell I' The Nature and Variety of Cells

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SC-100 Unit 15 The Living CellI. The Nature
and Variety of Cells

• A. What is a cell? The smallest physical unit
  capable of carrying on all of the activities that
  we associate with living things.
• B. Shape Depends on function rectangular/
  polygonal(plants), spherical(egg),
  rod/spiral(bacteria), elongated(muscle),
  fibrous(nerve),tailed(sperm)

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I. The Nature and Variety of Cells

• C. Size
• Typical 0.01mm, range 0.0001mm(bacteria) -ostrich
  egg yolk
• MICROSCOPES-optical,electron
• D. Functions
• 1. Provide framework for chemical reactions
• 2. Reproduce

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II. Elements of a Cell

• A. Elements common to all cells
• 1. Membrane
• 2. DNA (In nucleus if one, else in cytoplasm)
• 3. Cytoplasm Cell contents excluding nucleus(if
  any) inside membrane

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II. Elements of a CellB. Cell membranes

• 1. Function
• Defines the boundary/frontier of the cell inside
  vs outside
• Regulates flow of material between the inside and
  outside of the cell
• 2. Structure
• Double layer (bilayer) of phospholipids with
  proteins and other substances embedded in membrane

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II. Elements of a CellB. Cell membranes

• 3. Transportation across the membrane
• a. Diffusion --Down the Concentration Gradient.
  Water diffusion has the special name osmosis
• b. Engulfing (Endocytosis)-- Protein receptors,
  Forms a vesicle
• c. Active transport --Against the Concentration
  Gradient, requires energy expenditure

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II. Elements of a Cell

• C. Cell wall
• Plants typically surround the membrane with a
  wall of cellulose for strength

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II. Elements of a CellD. Nucleus

• An organelle containing the genetic material (as
  DNA) of the cell Reproductive Information
• Prokaryotic cells do not have a nucleus.
• Eukaryotic cell have a nucleus.
• Nucleus has a double membrane which suggests at
  one time in evolutionary process it was a
  separate cell of its own.

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II. Elements of a CellE. Other
Organelles(Little Organs)

• 1. Chloroplasts - Perform photosynthesis in
  green plants
• 2. Mitochondria - Glucose derivative reacts with
  oxygen to produce cells energy
• 3. Ribosomes - Spherical bodies forming sites
  for protein synthesis

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II. Elements of a CellE. Other
Organelles(Little Organs)

• 4. Endoplasmic reticulum - Channels dividing
  cell into regions, protein and lipid synthesis
• 5. Lysosomes - Contain digestive enzymes
• 6. Vacuole - Used in plants to store water and
  wastes

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(Adenine)
(Ribose)
ATP - Adenosine Triphosphate
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III Metabolism

• The process by which a cell derives energy from
  its surroundings.
• Catalyst
• Enzyme-Protein acting as a catalyst.
• Metabolic Pathways- Sequence of chemical
  reactions in a cell (enzyme driven)

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III Metabolism

• A. Anabolism
• Metabolic pathway in which larger molecules are
  synthesized by combining smaller ones.
• B. Catabolism
• Metabolic pathway in which larger molecules are
  broken down(digested)

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III Metabolism

• C. Photosynthesis
• The process by which plants convert the energy of
  sunlight into energy stored in carbohydrates.
• D. Respiration
• The main process by which animals retrieve the
  energy stored in glucose

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IV. Energy

• A. ATP
• ATP lt---gt ADP PO4 Energy
• Cells store the energy released in glycolysis and
  respiration temporarily in ATP

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IV. Energy

• B. Photosynthesis
• Energy CO2 H2O -gt glucose O2
• 1. Energy comes from sun (photon)
• 2. Location chloroplasts

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IV. Energy

• C. Glycolysis
• Glucose -gt pyruvate energy
• D. Fermentation (anaerobic)
• Pyruvate -gt alcohol or lactic acid energy

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IV. Energy

• E. Respiration (aerobic)
• Pyruvate -gt CO2 H2O ENERGY
• 1. Location mitochondria
• 2. All energy from glucose retrieved

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Glucose
Energy Content
GLYCOLYSIS
Pyruvic Acid (C3)
FERMENTATION
(Anaerobic)
PHOTO SYNTHESIS
YEAST
MUSCLE
RESPIRATION
(Aerobic)
Ethanol
Lactic Acid
Energy IN
Unrecovered Energy
CO2 H20
CO2 H20
METABOLISM
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V. Cell Division

• A. Chromosome - A long strand of genetic
  material (DNA)
• B. Mitosis - The resulting daughter cells have
  exactly the same number of chromosomes ad the
  mother cell.
• C. Meiosis - Used by cells involved in sexual
  reproduction. Each daughter cell has half the
  number of chromosomes of mother cell.