VIRUS

Virus
          - particles smaller than cells
          - noncellular
          - specific
          - DNA or RNA
Martinus Beijerinck
         - first to use the term virus


STRUCTURE
     - capsid- protein surrounding the DNA or RNA
     - bacteriophages - virus infecting bacteria

DNA viruses
          - hepa B, smallpox, cowpox, herpes
RNA viruses
          - AIDS, mumps, common colds, leukemia, measles

TAXONOMY

Taxonomy
         - science of naming, classifying, and identifying organisms
         - systematics

Levels of Classification (taxa)

     1. Kingdom          4. Order      7. Species
     2. Phylum             5. Family
     3. Class                 6. Genus

Phylogeny
          - natural system of classification that is based on the evolutionary history or genealogy shared by a group of organisms.

Phylogenetic Trees
         - show how related organisms evolved from common ancestors
Method:
     Cladistics
           - involves identifying shared derived traits

Carolus Linnaeus
     - binomial nomenclature
genus

• tells more about the organism
• always capitalized

species

• lower case

Genus and species form the scientific name.  It is either italicized or underlined.

Aristotle
          - father of animal classification
          - land, air, water
          - "species", belonging to the same kind

Artificial Systems
         - took into account only a few characteristics
         - Aristotle and Carolus Linnaeus

EVOLUTION

Early Concepts of Evolution

Aristotle: nature evolved gradually from the simple to the more complex and from imperfect to perfect

Lucretius: wrote an evolutionary explanation of the origin of plants and animals

Leonardo da Vinci: put forward the theory of catastrophism
                              explains that fossil found in rocks resulted from a succession of fires and flood
                              that destroyed all things some time in the prehistoric past

Theory of Uniformatarianism

James Hutton: concluded that the formation of sedimentary deposits was due to geological forces
                       of erosion, sedimentation, uplift, and disruption on that were working in the past
                       and one continuing to the present

John Playfair: further explained and supported Hutton's concept

Sir Charles Lyell: proved beyond reasonable doubt the idea of geologic evolution through
                          his book Principles of Geology

GENETICS

Mendel's Princples of Inheritance

1. The F1 generation showed only dominant traits
2. In the F2 generation, both the dominant and recessive traits reappeared
3. In the F2 generation, there were 3x as many plants with the dominant traits than plants with recessive traits

LAW OF SEGREGATION
          - Mendel inferred that the two factors determining a trait segregates when the sex cells are formed
          - Each gamete (egg cell or pollen) is equally likely to contain either traits
phenotypes: trait of a plant (tall)
genotypes: the pair of alleles for that trait (TT or Tt)

LAW OF DOMINANCE

LAW OF INDEPENDENT ASSORTMENT
          - alleles of the gene pair for a particular pair of traits segregate independently of the alleles of gene pairs for the trait

MEIOSIS

MEIOSIS
          - type of cell division involving reproductive cells

Phases

Meiosis I
     stages:

Prophase I

• two sister chromatids of each chromosome pair up with the chromatids of its homologue (synapsis)
• makes up 90% of the entire process
• forms a structure called tetrads
• chromatids of homologous chromosomes exchange segments (crossing-over)
• nucleoli and nuclear membrane start to disappear

Metaphase I

• homologous chromosomes align at the middle of the cell

Anaphase I

• movement of the chromosomes of each homologous pair toward the opposite poles of the cell
• individual chromosome still consist of two sister chromatids

Telophase I and Cytokinesis

• chromosomes are on each side of the pole
• chromosome still consist of two sister chromatids
• nucleoli and nuclear membrane reappear

Meiosis II
     stages:

Prophase II

• starts with haploid cells
• nuclear envelope starts to breakdown

Metaphase II

• chromosomes line up along the cell equator

Anaphase II

• chromosomes are pulled toward the opposite poles of the cell

Telophase II

• chromosomes finish their migration to poles
• nuclear membrane forms again and nucleolus reappear

Cytokinesis

• four new daughter cells are produced, each with a haploid number of chromosomes

MITOSIS

VOCABULARY :

• Cell Division - process by which cell reproduce
• Chromosomes - cell parts that determine what traits a living thing will have
• Chromatid - one strand of DNA, after replication, a chromosome is made up of two identical chromatids
• Daughter Cells - new cells produced by cell division
• Cytokinesis - a division of the cytoplasm of one parent cell into two daughter cells

Interphase
          - DNA has replicated but has not formed the condensed structure of chromosome. They remain as loosely coiled chromatin. The nuclear membrane is still intact to protect the DNA molecules from undergoing mutation.
   G1
   S - synthesis (DNA)
   G2

Early Prophase
          - the nuclear membrane breaks down
          - chromosomes shorten and thicken
          -centrioles are forming

Late Prophase
          - centriole pairs move apart
          - nuclear envelope starts to break up

Metaphase (midddle)
          - the chromosomes are lined up along the cell's equator
          - are attached to the mitotic spindle

Anaphase (away)
          - the newly formed chromosomes are pulled toward opposite poles of the cell

Telophase
         - the chromosomes have finished their migration to the poles
         - the plasma  membrane of the cell pinches down along the equator
         - the nuclear membrane forms again and the nucleolus reappears

Cytokinesis
         - after mitosis, two diploid daughter cells have formed
  

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