Biology Unit 3 Notes
Biol GOD Notes.
First Edition
1 L. Leong 2012
Chapter 1: Molecules of Life
Cell Theory
∝ All living things are composed of cells and the products of cells ∝ Cells are the basic functional unit of life ∝ All cells arise from pre-existing cells
Living Things
Unicellular: consisting of one cell Multicellular: composed of many cells ∝ All living things: grow and develop, regulate metabolic processes, move, respond to stimuli, reproduce AUTOTROPHS: manufacture their own organic carbon compounds from inorganic material ‒ Phototrophic: use light as an energy source for the production of organic molecules eg. All green (chlorophyll-containing) plants are phototrophic ‒ Chemosynthetic: derive energy from chemicals for use in the manufacture of organic molecules eg. some bacteria HETEROTROPHS: rely on consuming an external source of organic molecules eg. All animals, fungi and most bacteria
Chemicals of Life
All cells (therefore all living things) are composed of chemicals, which fall into two different categories: » » Organic chemicals: Molecules that contain carbon in a complex form eg. glucose Inorganic chemicals: do not contain carbon in a complex form eg. Water, carbon dioxide
Maintaining a Constant pH in the Body It is vital to keep blood pH within its narrow limits. Deviations from the normal range are corrected using a buffering system. CO₂ + H₂O H₂CO₃ HCO₃⁻ + H⁺
Bicarbonate ions and hydrogen ions react with acids/bases in the bloodstream to maintain a constant pH.
2
L. Leong 2012
The Water Molecule
∝ Versatile solvent due to polarity, molecules held together by hydrogen bonds ∝ Substances dissolve in water due to positive ion attracted negative oxygen, and vice versa, which in enough to dissociate the substance » Hydrophilic: substances that readily dissolve in water (polar) » Hydrophobic: substances that tend to be insoluable in water (non-polar)
Biomacromolecules (a.k.a. organic molecules) Carbohydrates
∝ Chemicals
First Edition
1 L. Leong 2012
Chapter 1: Molecules of Life
Cell Theory
∝ All living things are composed of cells and the products of cells ∝ Cells are the basic functional unit of life ∝ All cells arise from pre-existing cells
Living Things
Unicellular: consisting of one cell Multicellular: composed of many cells ∝ All living things: grow and develop, regulate metabolic processes, move, respond to stimuli, reproduce AUTOTROPHS: manufacture their own organic carbon compounds from inorganic material ‒ Phototrophic: use light as an energy source for the production of organic molecules eg. All green (chlorophyll-containing) plants are phototrophic ‒ Chemosynthetic: derive energy from chemicals for use in the manufacture of organic molecules eg. some bacteria HETEROTROPHS: rely on consuming an external source of organic molecules eg. All animals, fungi and most bacteria
Chemicals of Life
All cells (therefore all living things) are composed of chemicals, which fall into two different categories: » » Organic chemicals: Molecules that contain carbon in a complex form eg. glucose Inorganic chemicals: do not contain carbon in a complex form eg. Water, carbon dioxide
Maintaining a Constant pH in the Body It is vital to keep blood pH within its narrow limits. Deviations from the normal range are corrected using a buffering system. CO₂ + H₂O H₂CO₃ HCO₃⁻ + H⁺
Bicarbonate ions and hydrogen ions react with acids/bases in the bloodstream to maintain a constant pH.
2
L. Leong 2012
The Water Molecule
∝ Versatile solvent due to polarity, molecules held together by hydrogen bonds ∝ Substances dissolve in water due to positive ion attracted negative oxygen, and vice versa, which in enough to dissociate the substance » Hydrophilic: substances that readily dissolve in water (polar) » Hydrophobic: substances that tend to be insoluable in water (non-polar)
Biomacromolecules (a.k.a. organic molecules) Carbohydrates
∝ Chemicals