Fermantation

FERMENTATION

• is the breakdown of pyruvic acid without the use of oxygen
• no ATP produced
• alcoholic and lactic acid

Alcoholic Fermentation
          - occurs in plant cells and some one-celled organisms (yeasts)
pyruvic acid + NADH + H ----------> CH3CH2OH + CO2 + NAD (returns to glycolysis)


Lactic Acid Fermentation
          - takes place when there is a short supply of oxygen in cells
pyruvic acid + NADH + H ----------> Lactic Acid + NAD (reused in glycolysis)


AEROBIC RESPIRATION

• large amount of energy is released from a glucose molecule
• takes place in the matrix and cristae (mitochondrion)
• occurs as a series of chemical reaction in which oxygen is used to convert the chemical energy stored in a organic food molecule to ATP and reduced H2 acceptor
• has 3 stages :

                                 - conversion of pyruvic acid to acetyl-CoA
                                 - Krebs cycle or Citric Acid Cycle
                                 - electron transport chain

1. Conversion of Acetyl-CoA
          - happens instead of lactic acid fermentation when you have enough oxygen
P.A. + CoA + NAD ----------> Acetyl-CoA + CO2 + NADH  + H
          1 glucose molecule = 2 molecules of Acetyl-CoA
          1 glucose molecule = 2 Pyruvic acid
                 1pyruvic acid  = 1 Acetyl-CoA


2. Krebs Cycle
          - From Sir Hans Adolf Krebs
          - The central biochemical pathway of aerobic respiration
          - Also called citric acid  cycle
          - Occurs in the inner matrix of the mitochondrion
          - Consists of :
                    - Dehydration (removal of water)
                    - Hydration (addition of water)
                    - Decarboxylation (removal of carbon dioxide)
                    - Dehydrogenation (removal of hydrogen)


3. Electron Transport Chain
         - oxidative phosphorylation
         - The breakdown of glucose is complete
         - 4 new ATP molecules are made
         - involves cytochromes (class of proteins that fuctions as electron transporter)
         - water is a by-product

CELL RESPIRATION

GLYCOSIS
          - the conversion of glucose into a reactive compound, pyruvic acid
          - occurs in the cytosol
          - has 4 major stages

                                                           GLUCOSE
                                                                   | phosphorylated
                                                                   |
                                                       Glucose-6-phosphate
                                                                   |
                                                                   |
                                                        Fructose-6-phosphate
                                                                   |
                                                                   |
                                                     Fructose1, 6 Diphosphate
                                                                 /  \
                                                                /    \
                                                               /      \
                                                              /        \
                                                       PGAL     PGAL
                                                        (3-C)      (3-C)
                                                            |              |
                                                         +P            +P
                                                           |               |
                                             Pyruvic Acid     Pyruvic Acid

PHOTOSYNTHESIS II

PHOTOSYNTHESIS

Two Raw Materials
          - Carbon Dioxide - stomata
          - Water - xylem vessels

                     CO2 + H2O + light ------------> C6H12O6 + H2O 

Two Processes

• Light Dependent or Photolysis
• Light Independent or Dark Reaction

LIGHT DEPENDENT
          - also called photolysis
          - occurs in the thylakoids
          - involves: Photosystem I
                          Photosystem II

Photosystem I
          - reaction center is 700
          - far-red region
          - more in chlorophyll a

Photosystem II
          - reaction center is 680
          - red region
          - in chlorophyll a and chlorophyll b

LIGHT ENERGY --------> chlorophyll a
                                (electrons excited)(P680)
                                                   |
                                                   |
                                      energized chlorophyll
                                                   / \
                                                  /   \
                                  splits water    adds P1
                                         / \                |
                                        /   \               |
                                     2H  O2     ADP(energy carrier)
                                       |                    |
                                       |                    |
                       NADP(H acceptor)    ATP
                                       |                    |
                                       |                    |
                                 NADPH          energy   
                                         \                   /
                                           \               /
                                    DARK REACTIONS

LIGHT INDEPENDENT
          - dark reactions
          - Calvin-Benson reaction
          - carbon fixation
          - occurs in the stroma

                                                      CO2
                                                          |
                                                          |
                                                   RuDP(CO2 acceptor)
                                                          |
                                                          |
                                           6-C sugar (very unstable)
                                                          | splits
                                                          |
                                 2 mols. of PGA (3 carbon compound) 
                                                          | combine
                                                          |    with
                                 2H from NADPH (from Light Reaction)
                                                        / \
                                                       /   \
                                                      /     \
                                             PGAL    H20 released as by products
                                                / \
                                               /   \
                                      RuDP    Glucose

External Factors that Affect Photosynthesis

1. light
2. Carbon Dioxide
3. temperature
4. water supply
5. minerals

Internal Factors

1. leaf structures
2. amount of photosynthetic products
3. enzymes    

PHOTOSYNTHESIS

PHOTOSYNTHESIS
          - a complex process that uses light energy to convert carbon dioxide and water into carbohydrates.


Discoveries on Photosynthesis


Jan van Helmont
          - Flemish botanist
          - first who studied photosynthesis
          - on 1630 he concluded that plants make their own organic materials and donot get these from the
             soil. 


Joseph Priestly
          - in 1772, he showed that a sprig of mint would restore air that had been injuredby a burning
            candle.
          - the results showed that oxygen gas, which is used up in burning, is released by plants.


Jan Ingenhouz         
          - supported the findings of Priestly
          - in 1779, he added that this air (oxygen) could only be restored by plants with sunlight.


Nicholas de Saussure
          - in1804, he made an experiment and its results showed that the increase in the dry weight of the plant
           was greater than the weight of the carbon dixide removed from the air.
          - concluded that aside from carbon dioxide, the other substance that contributed to the increase in the
           weight of the plant was water.


C. B. van Niel
          - in the 1930s, he was able to proved that light splits water, producing oxygen.


General Outline of Photosynthesis
carbon dioxide + water + light energy ----> organic material + oxygen + water


2 CLASSIFICATIONS


Heterotrophs
          - also called as "other-feeders"
          - cannot synthesize their own food and depend on autotrophs


Autotrophs
          - also called as "self-feeders"
          - synthesize their own food
          - has 2 main types:
               : photoautotrophs - include green plants and purple bacteria
               : chemoautotrophs - includes bacteria

 OXIDATION-REDUCTION PROCESS or REDOX REACTIONS
                     - involve the stable transfer of electrons between atoms.
It is said to be:

     Reduced - when an atom gains one or more electrons
     Oxidized - when it loses one or more electrons

CELLULAR TRANSPORT

Cellular Transport

2 Kinds:

ACTIVE TRANSPORT
          - requires energy
Examples:
     Sodium-Potassium pump
     Bulk Transport

Bulk Transport

Endocytosis
     - engulfs
     - 3 kinds:

Phagocytosis
     - solid
Pinocytosis
     - liquid
Reverse Mediated Endocytosis
     - specific molecules

Exocytosis
     - reverse


PASSIVE TRANSPORT
          - does not requires energy
          - 2 kinds:

Diffusion
     - movement of molecules from an area of high concentration to an area of low concentration

Factors Affecting the Rate of Diffusion

1. Size of the diffusing molecule
2. Molecular weight of the diffusing substance
3. Structure and composition of cell
4. Concentration gradient
5. Temperature
6. Other external factors

Osmosis
     - the diffusion of water through a semipermeable membrane

hypotonic - the cell bursts
hypertonic - the cell shrinks
isotonic - nothing happens to the cell  

PROKARYOTIC CELLS and EUKARYOTIC CELLS

Prokaryotic Cells

          - Greek, pro 'before' and karyon 'kernel'
          - unicellular organisms
          - lack nucleus and other membrane-bounded structures
          - bacteria and blue-green algae
          - DNA is coiled into a nucleus-like region(nucleoid)


Eukaryotic Cells

          - Greek, eu 'true' and karyon 'kernel'
          - plants, animals, protists, fungi
          - multicellular organisms
          - well-defined nucleus
          - DNA is bounded within a nucleus
          - with membrane-bounded organelles
          - with cytoskeleton

THREE BASIC PARTS of a EUKARYOTIC CELL

1. Plasma Membrane or Cell Membrane
2. Cytoplasm
3. Nucleus

CELLULAR STRUCTURES and FUNCTIONS

> The Cell Membrane

          - a thin layer of lipid and protein molecules held by noncovalent bonds
          - separates the cell contents from the surrounding medium
          - ranges from 5-10 nanometers
          - controls the entrance and release of substances in the cell
          - mainly composed of phospholipid molecules

PHOSPHOLIPID MOLECULE
          - composed of glycerol, two fatty acids, and one phosphate group
Polar or Amphipatic
          - 2 ends have different properties in water

• head - hydrophilic
• tail - hydrophobic

> The Nucleus

          - the control centre of the eukaryotic cell
          - surrounded by nuclear envelope (double layer)
          - contains the DNA
          - 2 main functions
               - directs chemical reactions in cells
               - acts as storage of genetic information and transfers such information

> The Cytoplasm

         - includes everything between the cell membrane and the nucleus
         - 2 main parts
               - Cytosol
                    - viscous colloidal substance of the cytoplasm
                    - where organelles are suspended
                    - site of major biological processes
               - Organelles

| THE ORGANELLES

Mitochondrion

• rod-shaped
• carries out process of cellular respiration
• "power-centre of the cell"
• has two compartments

           : Intermembrane Space
                 - inner and outer membranes
                 - highly folded (cristae)
           : Matrix

Endoplasmic Reticulum

• extensive network of membranes
• connects the nuclear envelope to the cell membrane
• 2 kinds :

      R.E.R

• has ribosomes attached on its surface
• makes more membranes
• transport proteins within a cell

      S.E.R.

• lacks ribosomes
• synthesizes lipids (fatty acids, phosholipids and steroids)

Ribosomes

• the protein factories of the cell
• attached to the E.R. (R.E.R.)

Golgi Apparatus

• from Camillo Golgi
• consists of a series of flat, membrane-bound sacs
• parallel to each other
• packages and secretes products of E.R.
• "packaging counter of the cell"
• one side receives from the E.R.
• inner sacs modify molecule
• other side transports out of the cell

Lysosomes

• is derived from the Greek word "breaking body"
• "suicidal bags of the cell"
• fuse with food vacuoles and digest the cell contains with the enzymes

     Lysosomal Storage Disease

• Pompe's Disease - accumulation of glycogen
• Tay-Sach's Disease - accumulation of lipids

Vacuoles

• fluid-filled cavities in the cytoplasm containing crystals, inorganic salts, sugars, insoluble particles, and excess water
• bounded by a membrane
• usually acts as storage organelles

Food Vacuoles
Contractile Vacuoles

In Plants:
     Centarl Vacuole - for growth
- contain pigments that attract insects
- contain toxic substances to protect from plant-eating insects

Peroxisomes
     - catalase
              - breaks down hydrogen peroxide
Hydrogen Peroxide
     - very toxic
     - product of cellular metabolism

ORGANELLES PECULIAR TO PLANT CELLS

1. Cell Wall
          - protection
          - 3 layers : primary layer
                              middle lamella
                              secondary layer
2. Plastids
          - pigment-containing storage organelles
Chloroplasts: red, yellow, green, violet, orange
Leucoplasts: colorless

Thylakoids  - disk-shaped structures
                     - stroma
                     - grana 

CELLS

THE CELL THEORY

Zacharias Jansen (1588-1631)
- invented one of the microscope's first prototype

Robert Hooke (1635-1703)
- reported some clear drawings of the plant cells
- introduced the term cell after observing boxlike structures from cork slices

Anton van Leeuwenhoek (1632-1723)
- reported the discovery of blood cells, sperm cells

*FORMULATED AFTER 200 YEARS AFTER THE INVENTION OF MICROSCOPE

Lorenz Oken (1779-1851)
- postulated that all organisms originate from and consist of cells

Robert Brown (1773-1858)
- discovered the nucleus

Felix Dujardin (1801-1860)
- sarcode, living substance within the cells was discovered (1835)
- the term was changed to protoplasm by Jan Evangelista Purkinje (1787-1869)

Matthias Schleiden (1804-1881)
- said that plants are made up of cells

Theodore Schwann (1810-1882)
- said that animals are made up of cells

Rudolf Virchow (1821-1902)
Concluded that
- the cell is the basic and structural unit of life
- every cell is formed from pre-existing cell


THREE PRINCIPLES OF THE CELL THEORY

• All organisms are composed of one or more cells
• Cells are the basic unit of organization of all organisms
• Cells arise only by division of a previously existing cell