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Introduction
Characteristics of Life
1. Carbon based, uses millions of molecular types.
2. Cellular composition
3. Development of metabolic activity (use energy to grow and reproduce)
4. Reproduction- all cells are preceded by other living cells.
5. Genetic identity- all life forms are unique and yet share countless common genetic traits; evolution proceeds as
changes in the gene pool
6. homeostasis- maintenance of internal environmental conditions
Article: It’s Alive and Question Sheet
Major Unifying Themes in Biology
ENERGY- most organisms tend to maximize energy input and minimize energy output (for maximum efficiency)
EVOLUTION- past characteristics are contained in the present
WHY questions are often answered by evolution
ECOLOGY- all organisms are ultimately connected with each other in the biosphere
ETHICS- the study of life is controlled by our moral voice
Organization of life
Cells tissues organs organ systems organisms populations communities ecosystems biomes
biosphere
Cell theory
1. The cell is the basic structural unit of life.
2. The cell is the basic functional unit of life.
3. All cells come from pre-existing cells.
1.1 The Molecular Basis of Life

review bonding (see handout), periodic table (see handout)
Types of Molecules
1. inorganic
2. organic
Inorganic Molecules

small, can be made without the assistance of a living organism (H20, CO2, O2)
Water- special properties that are a necessity of life

remains liquid over a wide temperature range, dissolves most substances, changes temperature gradually when
heated or cooled, provides a stable environment for cell reactions, the only pure substance that expands when
it solidifies, molecules cling together (cohesion) and stick to other substances (adhesion), polar

Handout: Unusual Properties of water
Organic Compounds
o always contain both H and C, sometimes contain O, N, S and P
o cannot be generated without life
o rings or chains of C with H bonded to the C
(Fig. 1.6)
Macromolecules- composed of smaller subunits (carbohydrates, lipids, proteins, nucleic acids)
Carbohydrates

function: short or long term energy storage

structure:- CH2O ratio is almost always maintained
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types:
o Simple Sugars

monosaccharide – 3-7 carbon atoms (glucose, fructose, galactose)
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disaccharide – 2 monosacccharides linked (sucrose, lactose)
o Complex Carbohydrates

polysaccharide –many simple sugars connected

plants- starch, cellulose
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animals- glycogen
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hydrolysis - when simple sugars bond, the O and the OH join to make water

dehydration - when complex sugars are broken apart, water makes the O and OH
MiniLab p. 11 Modelling Sugars
Lipids – don’t dissolve in water

function: energy storage (2.5x more E than carbs for same mass), insulation, cushioning, hormones, compose part of
cell membrane, dissolve fat soluble vitamins…

structure: glycerol chain with 3 fatty acid chains
o glycerol – 3 carbon chain with each carbon having an OH
o fatty acids- carbon chain ending COOH
o each fatty acid can be different

types:
o saturated- all single bonds (solid at room T)
o unsaturated- has double bonds where more H could join (liquid at room T)
Proteins

function : enzymes, transport substances, messengers, cell structures

structure : made from amino acids
o 20 amino acids
o 8 are essential- cannot be manufactured by the body (must be eaten)
o all amino acids have 2 C, 2 O, 4 H, 1 N in the following structure
o each has a different R group to distinguish it from other amino acids Eg. Figure 1.16 p. 14
o the shape of a protein determines its function

types:
o dipeptide- 2 amino acids joined

a peptide bond forms when OH from one amino acid joins to an H and water is released
o polypeptide- chain of amino acids, once there are over 30 amino acids they are twisted due to parts of the
functional group interacting to bind O and H
o Figure 1.19 p. 16

denaturing: changing the shape of the protein- caused by temperature, pH ..
CD Activity/Internet Mini Lab- p. 20
Investigation 1A p. 18-19
Nucleic Acids

function: direct the growth and development of every living thing by means of a chemical code, determine how the cell
functions and what characteristics it has

types: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)

how it works:
1. DNA composes genes
2. Genes direct the production of RNA
3. RNA directs the production of proteins

structure: made of nucleotides, phosphate, sugar and nitrogenous base

only 4 types of nucleotide, see Figure 1.20 p. 17

see Figure 1.22 p. 17


DNA- double helix
RNA - single chain
Section Review p. 20#1-10, Unit Investigation Prep
1.2 Cell Membrane Structure
The Fluid Mosaic Model (Figure 1.29 p. 24 and handout)

phospholipid bilayer

phospholipid structure (Figure 1.27 p. 23)
o polar head (glycerol) - attracted to water, water soluble
o non polar tail (2 fatty acids) - repels water
o bilayer has tails toward each other and head to the outside…this makes a water barrier in the middle to control the
movement of water in and out

proteins imbedded
o integral proteins- imbedded through the membrane- involved in movement of materials into and out of the cell
o peripheral proteins- stick out of the membrane to the inside- connect the cytoskeleton
o glycoprotiens- stick out of the membrane to the outside and identify the cell- protein
with a carbohydrate stuck to it

glycolipids- provide stability and mobility by reacting to temperature - lipid with a carbohydrate stuck to it
Section Review p. 24 #1-10
1.3 Through the Cell Membrane
homeostasis- maintaining a steady state
ECF- extracellular fluid- surrounds the cell
ICF- intracellular fluid-inside the cell
Types of Membranes- permeable, selectively permeable and impermeable

cell membrane is selectively permeable
o some molecules are small enough to fit between the phospholipids
o some molecules are too large (glucose)
o some molecules are insoluble in lipids (glucose)
o some molecules are charged (ions)
Passive Transport- NO energy is expended
Diffusion- the movement of molecules from a region of high concentration to a region of low concentration. (Down a
concentration gradient)

the molecules are constantly moving and collide and change directions..

Brownian motion- random movement

works well over short distances and with small molecules like O2 and CO2
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maximized efficiency when a cell has a high surface area to volume ratio
Mini-Lab p. 26
Osmosis- the diffusion of the solvent (usually water) across a biological membrane
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occurs down the concentration gradient (concentration of water)
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isotonic- concentration equal inside and outside
o water moves in and out at equal rate

hypotonic- concentration of water is greater outside than inside
o water moves into the cell

hypertonic- concentration of water is greater inside than outside
o water moves out of the cell
Figure 1.33 p. 27
Investigation 1B p. 28-29 Osmosis in a Model Cell
Facilitated Diffusion

carrier proteins (integral proteins) in cell membrane change shape to allow the molecule to cross the membrane

channel proteins (also integral) opens up to allow charged particles (ions) through if the particle is small and of the
correct charge (opposite to the charge of the channel)

movement is down the concentration gradient
Active Transport

movement against the concentration gradient (low to high concentration), requires energy

used to get rid of highly toxic waste or to keep nutrients inside

energy is used to run a Na-K pump p. 33 Figure 1.38
p. 34#16
Section Review p. 34#1-15
Section 1.4 Bulk Membrane Transport

some particles are too big or too polar to use any of the previous methods to enter or leave the cell
Endocytosis- cell membrane folds inward and creates vesicles containing the ingested particles

pinocytosis-cell drinking

phagocytosis- cell eating

receptor assisted- special proteins in cell membrane allow only certain molecules to attach to them and then be
ingested eg. cholesterol p. 37 Figure 1.41
Exocytosis- a vesicle containing particles fuses with the cell membrane and its contents are expelled
The Mystery of the Frozen Frogs
Mini Lab- Freezing Cells
Section Review p. 38#1-8
Chapter Review p. 39-41