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

CHEMICAL COMPOUNDS IN THE LIVING SYSTEM

Compounds
- a bigger molecule formed by atoms

2 Main Groups

Organic Compounds
- compounds that contain carbon atoms bonded to hydrogen or oxygen atoms

Inorganic Compounds
- compounds that lack carbon atoms


Inorganic Compounds

Water HOH
- 2/3 of our total body weight is water
- universal solvent

Acids
- releases one or more hydrogen ions (H+)
ex:
Hydrochloric acid (HCI)
Sulfuric acid (H2So4)

Base or Alkaline
- releases one or more hydroxyl ions (OH-)
ex:
Sodium hydroxide (NaOH)
Ammonium hydroxide (NH4OH)

pH Scale
- measures how acidic or how basic a substance is.
0-6 : substance is acidic
ex: battery acid
7 : neutral
ex: water
8-14 : substance is basic
ex: baking soda

buffers - resist changes in the pH of the chemical system
*Important Biological Buffers
- bicarbonates
- phosphates
- organic molecules (amino acid)

Salts
- form when an acid and a base react.
- hydrogen ion+hydroxyl ion = salt (table salt)+water

Neutralization Process - positive ion of an acid reacts with the negative ion of a base


Organic Compounds

Carbohydrates : compounds contaning carbon, hydrogen, and oxygen in the ration of 1:2:1

Monosaccharides - simplest form of carbohydrates
- glucose, fructose, and galactose are examples

Glucose
- most common hexose in the body
- sometimes reffered to as blood sugar, dextrose, and grape sugar
- indespensable component of blood

Fructose
- sugar that accounts for the sweeteness of ripened fruits

Galactose
- monosaccharides found in milk

Five-carbon sugars (pentose)

Ribose
- important component of ribonucleic acid (RNA)
Deoxyribose
- important component of deoxyribonucleic acid (DNA)


Disaccharides
- reffered to as the double sugars
- made up of two monosaccharide units
Dehydration Synthesis
- formation of a disaccharide from 2 monosaccharide units with the
removal of a water molecule

Examples:

Maltose (malt sugar)
-formed by the reaction of 2 glucose units

Sucrose
- common table sugar
- formed by the reaction of one molecule of glucose and one molecule of fructose

Lactose
- milk sugar
- formed when one molecule of glucose reacts with one molecule of galactose

Polysaccharides
- composed of a large number of monosaccharide units

Starch
- common component of plant protoplasms
- soluble in water

Glycogen
- found in bodies of animals
- excess glucose units stored temporarily

Cellulose
- similar to starch
- insoluble in water
- part of the plant cell wall


Lipids : composed of carbon, hydrogen, and oxygen but contain much less oxygen in proportion to carbon and hydrogen

2 Basic Units

Glycerol
Fatty acids

2 Kinds of Fats

Saturated Fats
- are solid at solid temperature
- examples are butter, lard, and animal fats
- promotes a condition called atherosclerosis

Unsaturated Fats
- remain liquid at room temperature
- not harmful to one's health
- examples are corn oil, olive oil , and other vegetable oils.


Proteins
- most diverse in the structure and function among organic compounds

peptide bond - formed between the amino group of amino acids and the carbon group of the next
amino acid.

Classes of Proteins

a. Structural Protein e. Transport Protein
b. Contractile Protein f. Hormonal Protein
c. Storage Protein g. Receptor Protein
d. Defensive Protein h. Catalytic Protein


Nucleic Acid
- serve as blueprints for proteins that ultimately control the chemical processes in a cell.
- nucleotide is composed of a five-carbon sugar, a phosphate group, and a
nitrogen-containing base pair.

THE LIVING CONDITION

THEORY OF SPONTANEOUS GENERATION



Spontaneous Generation (Abiogenesis)

- believed that living things may arise from nonliving substances.



Aristotle

- noted in his book Historia Animalium: mullet, a kind of fish, is the mud

of a dried-up pond that came to life spontaneously when rain filled the pond.



John Turberville Needham

- English biologist

- boiled mutton gravy, poured into a glass vial, and corked it. After a afew days,

the gravy was swarming with microorganisms.



F.A. Pouchet

- respected French scientist

- prepared hay infusion and introduced "artificial air". In a few days, the infusion

contained a rich variety of microorganisms.





THEORY OF BIOGENESIS



Biogenesis

- states that life comes only from life



Francesco Redi

- Italian physician

- proved that maggots were not spontaneously generated from rotting meat.



Lazzaro Spallanzani

- Italian biologist

- repeated Neddham's experiment but failed to obtain growth of organisms

by spontaneous generation

- he used vessels that are tightly closed.



Louis Pasteur

- one of the graetest biologist of all time from France.

- made an experiment which proved that air was a source of contamination.

- used flasks for his experiments.



Stanley Miller

- proved in his laboratory the possibility of forming amino acids and other organic

molecules from a mixture of hydrogen, methane , and ammonia.



Characteristics of Living Things

• Living things have a specific organization
• Living things undergo metabolic processes in their bodies
• Living things can move
• Living things can react to stimuli or changes in their surroundings
• Living things are capable of growth
• Living things can reproduce
• Living things can adapt to their environment