Day 2 Headstart year 15 – Bio 1
Day 2Headstart year 15 – Bio 1
Origin of life
Abiogenesis vs. Biogenesis
Abiogenesis vs. Biogenesis
• Biogenesis: Bio – life; Genesis – to form;• Biogenesis – the process that states that living things can only
be produced by another living thing, and not by a non-living thing.
• A – the process that states that living things can be produced by non-living things.
Chemosynthetic theory
Chemosynthetic theory
• States that the very first microscopic life could have evolved as a result of a series of chemical reactions
• Amino acids ++ peptides and proteins• Hydrocarbons + sugars = fat molecules• Carbohydrates ++ starch & complex sugars• coacervates – aggregate of molecules• Nucleic acids help in development of coacervates
Cell
Cell theory
The Cell Theory
• All living organisms are composed of cells. They may be unicellular or multicellular.
• The cell is the basic unit of life.
• Cells arise from pre-existing cells.
Cell structure and Function• Nucleus• Cytoplasm• Cell membrane• Cell wall• Golgi Apparatus • Endoplasmic Reticulum• Lysosome• Mitochondria• Lysosome• Vacuoles • Chloroplast
Nucleus• Control / command center of the cell• Stores genetic material
Cytoplasm, Cell wall, and Cell membrane
• Cytoplasm – ‘matrix’ of the inner layer of the cell. Cytosol – liquid portion
• Cell wall – rigid structure above cell membrane that is thicker and more rigid
• Cell membrane – semi-permeable structure which controls the passage of materials in and out of the cell
Cell structures and function• Golgi Apparatus – flattened sacs that store, modify, and
package products that are to be secreted by the cells• Lysosome – bag-like cells that digest dead organelles, organic
and inorganic materials, food, etc.• Mitochondria – powerhouse of the cell; contains and produces
ATP• Vacuoles – storage for nutrients, water, or waste• Chloroplast – contains pigments that store energy.
• Vesicle – contains an aqueous solution using a lipid bilayer • Ribosome –contains RNA and proteins. Assembles protein in
the cell. 2 types: Free and bound• Cytoskeleton – provides support in the cell. Microfilaments
and Microtubules.• Centrioles – aids and functions
at cell division. Made of microtubules• Flagellum – spins woaaa
Prokaryotic and Eukaryotic cells
Pro Eu
# of cells Single Single or Multi
Size Tiny Relatively larger
Organelles No Yes
DNA Circular Chromosomal
Examples Bacteria Fungi, Animal, plant
Plants and Animal cells
• Animal cells do not have cell walls• Animal cell round; Plant cell rectangle• Centrioles are present in all animal cells while only a few in the
plant cells.• Animal cells do not have chloroplasts• It is very rare for plant cells to have cilia.
Types of plant cells• Vascular:• Xylem • Phloem
• Ground:• Parenchyma• Collenchyma• Sclerenchyma
Diseases
• A change in the system, excluding an injury, that causes a disruption on normal body functions• Pathogens/ Infectious agents• Environmental factors• Genetic
• Pathogens:• Bacteria• Viruses• Protists• Large parasites• Fungi• Prions
• Virion
• Rapid multiplication• Destruction of body cells and tissues• Production of poison or toxins
Koch’s postulate• Pathogen should always be found in a sick organism• Pathogen should be isolated and grown in pure culture• When purified pathogens are placed in new host, the same
disease should appear.• When infected pathogen is isolated, it should be identical to
the original pathogen
Germ Theory of Disease• Infectious disease is caused by
germs or pathogensNames to remember:• Ignaz Semmelweis• washing hands
• Louis Pasteur• pasteurization
• Joseph Lister – used sterile equipment, antiseptics, and anesthetics in surgery
• Robert Koch – worked on bacili and proved diseases were caused by bacteria and that it could infect any organism despite harsh conditions
• Dmitri Ivanovsky – credited as the discoverer of viruses
Infection – modes and agents
• Airborne• droplets of pathogen
• Foodborne• Tape worms• amoebiasis
• Waterborne • Carriers or vectors• Actual contact
Pathogen What it is What it causes
Viruses Noncellular particles that invade living cells
AIDS, polio, smallpox, measles, colds, influenza, chicken pox,
SARS, bird flu
Bacteria Unicellular prokaryotes; from Domain Bacteria
gonorrhea, botulism, pneumonia, strep throat, boils/acne, tuberculosis,
meningitis, cholera, tetanus
ProtistsAny eukaryote that is
NOT a plant, an animal, or a fungus; from Kingdom Protista
malaria, amoebiasis/amoebic dysentery, African sleeping
sickness
Fungi Eukaryotic heterotrophs w/ chitinous CWs; from Kingdom Fungi
ringworm, athlete’s foot, San Joaquin Valley fever (lung disease), histoplasmosis
Worms Parasitic animals from the phyla Platyhelminthes & Nematoda
schistosomiasis, beef tapeworm
Prions*Misfolded proteins that cause other
normal proteins to misfold and cause widespread damage
Mad-cow disease, Creutzfeldt-Jakob disease,
scrapie
Defenses – vaccines, immunity, etc.• Two types of Immunity: • Innate• Acquired
Acquired (specific):• Humoral response• Cell-mediated response
Innate (Nonspecific)• External• Skin• Mucous membranes• Secretions
• Internal
• Phagocytic cells• Antimicrobial proteins• Natural killer cells• Inflammatory response