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NATURE OF LIFE
LIVING ORGANISMSComposition and structure
Composed of tiny structural units Cells
Cells around bound by a semi-permeable living membrane Plasma membrane
Cells are rigid due to outer structure Cell wall
Cells communicate with each other through microscopic tunnels Plasmodesmata
LIVING ORGANISMSComposition and structure
Cells contain soupy liquid Cytoplasm
Cells contain genetic material to control activities and development DNA
DNA is housed inside a special structure floating in cytoplasm Nucleus
LIVING ORGANISMSGrowth
Increase in mass
LIVING ORGANISMSReproduction
Offspring resembles parents
Genetic variations drive evolution Natural selection
Environment favors certain characteristics
LIVING ORGANISMSResponse to stimuli
Interaction with environment
Plants respond to injury Production of callose Seal wound
LIVING ORGANISMSMetabolism
Biochemical reactions inside an organism Growth Repair damage Cell maintenance
Energy-releasing production (consumption) Respiration
Energy-production and storage process Photosynthesis
LIVING ORGANISMSMovement
Reactions to environment Leaves closing Cytoplasmic streaming inside cell Sunflowers turning
ELEMENTS OF MATTER Stuff of the universe
Occupies space Mass Composed of elements
Atoms Subatomic particles
Quarks Gluons Higgs boson
LARGE HADRON COLLIDER (LHC)
ATOM Nucleus contains two particles
Protons Positively charged particles
Neutrons No electrical charge
ATOM Electrons
Negatively charge particles Orit the nucleus
Same amount of electrons as protons Atom has no charge
(neutral)
ELEMENTS The number of protons and
neutrons determine the element Hydrogen (H)
1 proton Part of nearly all life
Carbon (C) 6 protons Skeleton of molecules
MOLECULES 2 or more atoms attached to each other
Molecule Random collisions of atoms Chemical reactions between atoms
MOLECULES Water
2 Hydrogen (H) 1 Oxygen (O)
Slight negative charge on one side, slight positive charge on other side Polar molecule
MOLECULES Water molecules polarity is reason for
cohesion and adhesion Hydrogen bonding
Attraction to each other (cohesion) Surface tension
Attraction to other negatively charge particles (adhesion) fibers
BONDS Covalent bonds
Atoms share electron
Ionic bonds One atom donates an electron to another atom The result are ions
Positively or negatively charged atoms
BONDS Ion
Number of electron does not equal protons Atom is negatively or positively charged
Ionic bonds +ion attracted –ion
BONDS Hydrogen bonds
Weak attraction of polarity
ACIDS AND BASES Acid solution
Surplus of hydrogen (H) ion (+)
Basic solution Surplus of hydroxyl (OH) ions
(-)
PH SCALE 0 to 14
7 pH is neutral
<7 pH Acidic
>7 pH Basic