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