The Study of Life: Biological Organization
Bio 100 - Chp 1
Why Biology????
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It’s the science of life
– Helps us understand the human body
– Helps to better inform you of controversial and ethical issues
– Career opportunities
– Depends our appreciation of nature
Biological Organization
Living things are
organized from the
smallest unit of life
to the largest
organism
Level of Biological Organization
• Atoms
• Molecules
• Cell
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Tissue
Organ
Organ systems
Complex
organisms
The Organization of Life is dependent upon an Ecosystem.
Terrestrial and Marine Ecosystems require the following elements in order maintain life
within the ecosystem. These elements included:
 Atmosphere
 Environment
 Population
 Food Chain
 Chemical recycling
 Energy flow
 Organic materials
Scientific Theory: is a concept that joins together well-supported & related hypotheses. It’s
a speculated idea that is tested and proven as grounded truth. However, a theory can
further be strudied through experiemental processes to prove it as evidence-base truth.
Scientific Process invoves Research and Investigation through:
• Observation – phenomenon, natural event. Using inductive reasoning – creative thinking
• Hypothesis – possible explanation for the natural event, making a prediction
• Experiments – conducted and designed to collect data
• Data – the results of the experiment, measured in statistical values
• Conclusion – was the hypothesis supported by the data or not?
Basic chemistry of life
BIO 100 Chp 2
Inorganic (Chemical) and Organic Molecules
Inorganic molecules
• Matter is composed of element
• 92 elements (periodical chart)
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Each element - composed of one type atom
What are atoms? the basic building blocks of matter that make up everything (desk, air,
tissue, even you)
• Atoms combine to form molecules
• Atoms have: mass dependent upon protons & neutrons
Components of the Atom
Atoms are made up of 3 basic particles
• Protons – positive charge
• Neutrons – negative charge
• Electrons – negative charge
• Protons & Neutrons join together to form the nucleus
• Chemical properties dependent upon the number of electrons
• react with one another forming ionic, covalent or hydrogen bonds.
Molecules & Compounds
• Ionic bonds – a chemical bond in which atoms of opposite charge are held
together by electrostatic attraction. It occurs when atoms loose or gain electrons
during a reaction, as positive or negative charged ions.
• Covalent bonds – are atoms bonded together by sharing electrons instead of
loosing or gaining. The example below shows the formation of a covalent bond
between tw0 hydrogen atoms.
Hydrogen bonds – occur when covalent bonded hydrogen is positive and attracted
to negative charged atoms. For example, the formation of hydrogen bonds between
the hydrogen & water molecules. Hydrogen bond is a weak bond and can readily
change the structure of the molecules. (Causing water to change its state - liquid,
frozen, vapor/steam)
Water and Living Things
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Water, acids and bases –essential inorganic molecules
Water – most abundant molecule in living organisms
60-70% of body weight
Polarity of water causes many characteristics beneficial to life
The Characteristics of water polarity:
 Liquid – remains liquid in our bodies.
 Universal solvent – facilitate chemical
reactions in/out of our bodies
 Cohesive properties – helps water base- solutions fill blood vessels
 Without hydrogen bonding between water
molecules, body fluids would be a gaseous
form.
Characteristics of water polarity have the ability to:
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Change temperature slowly – prevents drastic changes
Vaporize – keeping body temperature from overheating
Freeze – becomes less dense and in weight.
Acid – Base
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Water breaks up (dissociates) equal number of hydrogen (H) and hydroxide (OH) ions
Acid solutions – release H
– Tomato juice, coffee, vinegar
– Sharp, sour taste associated with indigestion
Basic solutions – release OH and gain H
– Milk of Magnesium, ammonia, household cleaners & detergents
– Bitter taste, become slippery when wet
pH Scale
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Used to indicate acidity or alkaline base
Neutral – 7.0 (H & OH ions are at equal state)
< 7.0 becomes an acid state
> 7.0 becomes a basic state
pH needs to be maintain in humans in order to maintain homeostasis
What are Buffers and what do they do?
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They are Bicarbonate ions
That help Stabilize pH within normal limits
By taking up excess hydrogen (H) or hydroxide (OH) ions to resist pH changes
Some buffers include: Bufferin, shampoos, deodorants
REVIEW:
Inorganics Molecules
 constitute nnoliving matter
 knecessary for living things
 like water and salt
Organic Molecules
Organic molecules include:
Charbohydrates (starch)
Polysaccharides
Proteins
Fats (lipids)
Starches & glycogen
These molecules of life are always:
– Important to living organisms
– Contain carbon and hydrogen
– Formed into large Macromolecules – a large molecule structures containing many
molecules joined together (polymers)
– Simplified into smaller, subunit molecules called monomers
Polymers -Monomers
Polymers (many macromolecule), are monomers linked or covalently bonded together
• Carbohydrate
• Protein
• Nucleic acid (DNA)
• Lipids
For example: a polypetide is a polymer of monomers called amino acids
Monomers – simple organic molecules, subunit of a polymer.
• Monosaccharide
• Amino acid
• Nucleotide
For examlple: monomers exist individually or in bonded chains that form polymers
Glucose is a monomer of Starch
polymers
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• Carbohydrates
• Lipids
• Proteins
break down into -
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monomers
sugars
glycerol and fatty acids
amino acids
Cells use these monomers to build their own macromolecules in order to maintain
their existance
Organic molecules: the Synthesis and degradation reactions in macromolecules
(combines molecules)
(separates molecules)
Dehydration synthesis
– Links monomers together to form a polymer
– 2 hydrogens and an oxygen removed in the reaction and unite to form water
– Water is also always a byproduct
• Hydrolysis
– Polymer is broken down to monomers
– Water is required to replace 2 hydrogens and the oxygen
Carbohydrates
• General structure
– Ratio of hydrogen atoms to oxygen atoms is 2:1
– Characteristic atomic grouping of H-C-OH
– “hydrates of carbon”
• Functions
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Principal energy source for cells
First function for short term energy storage
Structural components in some cells
Cell to cell recognition- surface antigens
Simple carbohydrates
Monosaccharides and dissaccharides
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Monosaccharides: simple sugars such as
• glucose (blood sugar)
• fructose (fruits)
• lactose (milk products)
– Dissaccharides: 2 monosaccharides bonded together
• sucrose (glucose + fructose)
• galactose (glucose + lactose)
• maltose (glucose + glucose)
Polysaccharides - Long-chain polymers
1. Starch & glycogen
• already stored forms of glucose
• stored in the liver
• Released in between meals to maintain blood glucose levels (0.1%)
2. Cellulose
• functions in plant cell wall structure
• unable to digest, acts as fiber or roughage
Lipids (Fats)
• General characteristics
– Extremely diverse group of organic molecules:
fats, oils, steroids, waxes, phospholipids
– Common characteristic - nonpolar molecules which are insoluble in water
– Contain more calories of energy per gram so are ideal energy storage molecules
Also function as structural components, insulation, cushioning of organs, and hormones
• Fats and oils (are the most common)
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Oils tend to be liquid at room temperature and are usually of plant origin
Fats tend to be solid at room temperature and are usually of animal origin
Fats are often called triglycerides - they are composed of one glycerol and 3 fatty acids
Synthesis of a triglyceride yields 3 water molecules as byproducts
Fats are important in energy storage
Insulation against heat loss
Protective cushion around major organs
• Emulsification
– Fats are nonpolar; they do not dissolve in water and tend to form “globules” (oil and vinegar
dressing)
– Emulsifier breaks down the globules of fat into smaller droplets
– Emulsifiers have a nonpolar end which attaches to the fat, and a polar end which interacts with
water molecules so that the droplets can disperse
• Saturated and unsaturated fatty acids
– Saturated have no double bonds between carbon atoms, and tend to be more solid at
room temperature
– Unsaturated have at least one double bond between carbons
– Polyunsaturated have multiple double bonds- the more polyunsaturated the fatty acids,
the more liquid the fat will be at room temperature
• Phospholipids
– Attached phosphate gives “polarity”
– Has a hydrophilic head and a hydrophobic tail
– Important components of membranes
Steroids
• Steroids
– “Skeleton” of 4 carbon rings
– Cholesterol is a steroid which functions in membrane structure and hormone synthesis
Proteins
• General characteristics
– Composed of amino acids
• Polymers with amino acid monomers
– There are 20 different amino acids
– The portion of the molecule that varies between the different types is called the R group
(“remainder”)
Various Functions of Proteins:
• Keratin – builds hair, nails and collagen
• Hormones – cellular metabolism
• Actin & myosin – movement of cells and muscular contractility
• Hemoglobin – transports oxygen in blood
• Antibodies – bind foreign subtances to prevent the destruction of cells
• Enzymes – speed up chemical reactions in the body
Peptides
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The bonds between amino acids called peptide bonds
Peptide bonds are polar covalent bonds
Levels of protein organization
Protein molecules have at least 3 levels of organization
• Primary - linear shape held together by peptide bonds
• Secondary - polypeptide coils to form an á-helix (pleated sheet) held together by
hydrogen bonds
• Tertiery – 3-dimensional bonded by R groups (ionic, covalent & hydrogen bonding all
together)
• Quaternary – arrangement of polypetides that form a 4-demensional protein structure
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The final shape of a protein molecule is often critical to its function
Extreme exposure of heat and pH can change the shape of the protein molecule
Denaturation = irreversible change in shape
When normal bonding between the R groups have been disturbed, denaturation
has occurred
• Once protein loses its normal shape it become dysfunctional.
DNA Molecule (Deoxyribonucleic Acid)
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DNA is in every cell of your body
Contained in the nucleus of the cell
Genetic material - Instructional Manual for your body
Mostly composed of carbon, hydrogen, nitrogen and phosphorus
Role of DNA: to reproduces & build proteins in the body