BIO 100 - Life on Earth
Chapter 1
Why Biology????
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It’s the science of life
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Helps us understand the human body
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Helps to better inform you of controversial and ethical issues
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Career opportunities
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Depends our appreciation of nature
Scientific Theory: A concept that joins together well-supported & related hypotheses. It’s a speculated
idea that is tested and proven to be facts or evidence-base
Scientific Process: Research and Investigations
1. Observation – phenomenon, natural event. Using inductive reasoning – creative thinking
2. Hypothesis – possible explanation for the natural event, making a prediction
3. Experiments – conducted and designed to collect data
4. Data – the results of the experiment, measured in statistical values
5. Conclusion – was the hypothesis supported by the data or not?
Level of Biological Organization:
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Atoms first, followed by molecules, cells, tissue, organ. Organ systems and Complex organisms.
Living things are organized from the smallest unit of life to the largest organism
Life
Living things are complex and organized. They are structured by non-living & living matter (atoms,
molecules, & cells)
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Living things grow & reproduce
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Living things respond to stimuli
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Acquire and use materials and energy
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Use DNA to store information
Diversity of Life
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Diversity of life (variety of life forms) occurs because of evolution
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Evolution changes groups of organisms from generation to generation
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Caused by natural selection – a process in which unequal survival and reproduction or
organisms, favor individual with particular traits causing them to become more common in a
population.
BIO 100 – Atoms, Molecules & Life
Chapter 2
Chemical Molecules
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Elements = a substance that can neither be broken down nor converted to other substances by
ordinary chemical means.
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Atoms are the basic building blocks of matter that make up everything (desk, air, tissue, even
you). Atoms combine to form molecules
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Components of the Atom are made up of 3 basic particles
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Protons – positive charge
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Neutrons – negative charge
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Electrons – negative charge
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Protons & Neutrons join together to form the nucleus – atomic nucleus
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Atomic number – the number of protons in nucleus
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Isotopes – atoms of the same elements, with diff. Number of neutrons
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Radioactive isotopes –lease energy that break apart forming diff. Types of atoms.
So How Do Atoms Form Molecules?
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By interacting between atoms when their outmost electron shells have a vacancy. This will
create a :
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Chemical bonds – that hold atoms together by gaining or losing a shared electron. This
type of bond has attractive forces that hold atoms together to form molecules. The
elements have chemical bonding properties arising from the arrangements of the outer
shell . There is inert (non-reactive) and reactive (unstable) chemical bonds.
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Chemical reactions – occurs during the making and breaking of chemical bonds
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Electron Shells
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Ions – positive or negatively charged atoms.
Molecules & Compounds come together through the formation of 3 types of bonds:
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Ionic bonds – occurs when atoms loose or gain electrons during a reaction; opposite charges are
electrically attracted between positive and negative charged ions. Easily broken bonds
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Covalent bonds – share electrons instead of loosing or gaining; uncharged ions. Strong bonds
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Hydrogen bonds – electrical attraction (polarized) between in water molecules; negative
charged O2 atoms is attracted to a positive charged H atom in water. Forms a weak covalent
bond.
Water and Living Things
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Water – is the most abundant life sustaining substance in living organisms. It comprises 60-70%
of the body weight. It is an essential inorganic molecule in - water, acids, and bases. It is the
universal solvent for biological chemical reactions. The polarity of water causes many
characteristics beneficial to life.
Characteristics of water polarity:
1. Liquid – remains liquid in our bodies.
2. Universal solvent – facilitate chemical reactions in/out of our bodies
3. 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
1. Ability to change temperature slowly – prevents drastic changes
2. Vaporization – keeping body temperature from overheating
3. Ability to freeze – becomes less dense and in weight.
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Acid – Base
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Water breaks up (dissociates) equal number of hydrogen (H) and hydroxide (OH) ions
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Acid solutions – release H. Example of acid solutions: tomato juice, coffee, vinegar.
They have a sharp, sour taste associated with indigestion
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Basic solutions - release Hydroxyl (OH) and gain Hydrogen (H). Milk of magnesium
(MOM), ammonia, household cleaners & detergents are examples of alkaline/base. It is
what gives the bitter taste, become slippery when wet
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pH Scale – it is used to indicate acidity or alkaline base. Neutral – 7.0 (H & OH ions are at equal
state). < 7.0 becomes an acid state and > 7.0 becomes a basic state. The pH needs to be
maintain in humans in order to maintain homeostasis (Internal balance).
Buffers stabilize pH within normal limits. They take up the excess H+ or OH- moledules to resist pH
changes. These are Bicarbonate ions; examples: Bufferin, shampoos, deodorants
Organic Molecules have Carbon in their molecular makeup. The carbon atoms will combines with other
atoms to form different molecules such as: Charbohydrates, Polysaccharides, Proteins, Fat, Starches &
glycogen
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Organic molecule Structure:
The molecules of life always:
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Are important to living organisms. They always contain carbon and hydrogen
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Macromolecules – (polymers) a large molecule structure containing many molecules
joined together
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Micromolecules - (monomers) simple organic molecule or a subunit of a polymer
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Polymers -Monomers
Polymers – are macromolecule, monomers that are linked or covalently
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Carbohydrate (starch)
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Protein
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Nucleic acid (DNA)
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Lipids
(a polypetide is a polymer of monomers called amino acids).
Monomers – are simple organic molecules, subunits of a polymer. They exist individually or in bonded
chains that form polymers (glucose is a monomer of starch)
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Monosaccharide, Amino acid and Nucleotide
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Carbohydrates break down into sugars
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Lipids into glycerol and fatty acids
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Proteins into amino acids
Cells use these monomers to build
their own macromolecules
Organic molecules synthesis and Degradation reactions in macromolecules
Dehydration synthesis – BUILDS UP a molecule straucture by linking together monomers to form a
polymer. For example: 2 hydrogens and an oxygen atom are removed from subunits creating covalent
bonds - the reaction of ions combine to form water. Water is also always a byproduct
Hydrolysis – BREAKS DOWN. A polymer is broken down to monomers – B. Water is required to
replace 2 hydrogens and the oxygen
Carbohydrates
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The General structure includes Carbon, hydrogen and oxygen. Carbs. are the most
important energy source for most organisms
1. Function of Carbohydrates:
a. Principal energy source for cells
b. First function for short term energy storage
Structural components in some cells
c. Cell to cell recognition- surface antigens
2. Simple carbohydrates are in the form of Monosaccharides and dissaccharides
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Monosaccharides: simple sugars such like glucose (blood sugar) and
fructose (fruits, corn sugar)
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Dissaccharides: are 2 monosaccharides bonded together such as sucrose
(glucose + fructose); lactose (milk sugar = galactose); galactose (glucose +
lactose); and maltose (glucose + glucose)
3. Polysaccharides
Starch & glycogen
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Starch is already stored in the forms of glucose (glycogen). Glycogen is stored in the
liver. It is released in between meals to maintain blood glucose levels (0.1%)
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Cellulose is another starch molecule complex. It functions in plant cell wall structure.
Provides the tough plant structure that is unable to digest, acts as fiber or roughage
Lipids - the general characteristics of lip are extremely diverse group of organic molecules: come in the
form of fats, oils, steroids, waxes, phospholipids. The common characteristics include
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Non-polarity molecules, which are insoluble in water
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Contain more calories of energy per gram so are ideal energy storage molecules
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Also functions as structural components, insulation, cushioning of organs, and
hormones
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Fats and oils are the most common. 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 important in energy storage, they act as insulation against heat
loss and as a Protective cushion around major organs
Lipids – as an Emulsifier
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Saturated and Unsaturated fatty acids
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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
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Polyunsaturated have multiple double bonds- the more polyunsaturated the fatty acids,
the more liquid the fat will be at room temperature
The Good & the Bad and the Ugly side of cholesterol.
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Good cholesterol: is found in the form of HDL (high density lipids) and tend to have
more protein and less lipid. They circulates to the liver where it is removed from the
bloodstream
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Bad cholesterol: is found in the form of LDL (low density lipids), and have less protein
and more lipids. These circulates to cell (forming fat) and also deposit in artery walls
(causing atherosclerosis, arteriosclerosis, which lead to strokes and heart attacks).
Phospholipids – are attached to phosphates which gives it the “polarity” properties
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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
They have a hydrophilic (water-soluble) head and a hydrophobic (water-insoluble) tail.
These are important components of cell plasma membranes
Steroids – are composed of 4 carbon ring molecules. Cholesterol is a steroid that functions in cell
membrane structures and hormone synthesis.
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Proteins – the general characteristics of protein are composed of one or more amino
acids. There are 20 different amino acids which join by dehydration synthesis to form a
molecular chain. The Various functions – provide either a hormone, an enzyme or a
structural protein. They have up to 4 dimensional shapes, which gives proteins their
function: primary, secondary, tertiary , quantinary structures (these are the levels of
protein organization)
Protein Functions:
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Keratin – builds hair, nails and collagen
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Hormones – cellular metabolism
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Actin & myosin – movement of cells and muscular contractility
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Hemoglobin – transports oxygen in blood
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Antibodies – bind foreign subtances to prevent the destruction of cells
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Enzymes – speed up chemical reactions in the body
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Peptides - The bonds between amino acids called peptide bonds. Peptide bonds are polar
covalent bonds
Protein structure
The final shape of a protein molecule is often critical to its function - its what enables it to perform its
function. Extreme conditions (exposure to heat; pH) can change the shape of the protein molecule
Denaturation = irreversible change in the protein shape. It is a disruption of the proteins shape
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When normal bonding between the R groups have been disturbed, denaturation has occurred
Once protein loses its normal shape it become dysfunctional.
Nucleic Acid Molecule
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Deoxyribonucleic (DNA) Acid Molecule & Ribonucleic Acid (RNA)
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DNA is in every cell of your body and is contained in the nucleus of the cell, where genetic
material (instructional Manual for your body) is found
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Mostly composed of carbon, hydrogen, nitrogen and phosphorus
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Role of DNA: to reproduces & build proteins in the body
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Nucleic Acids - Long chains of similar, but not identical, nucleotides. All nucleotides have carbon sugars (ribose or deoxyribose), Phosphate, and Nitrogen. They form DNA and RNA
Basic Chemistry
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Matter is composed of element. There are ever 110 elements in the periodical chart. Each
element - composed of one type atom
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Atoms have:
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mass dependent upon protons & neutrons
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chemical properties dependent upon the number of electrons
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React with one another forming ionic, covalent or hydrogen bonds
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Molecules: Inorganic molecules constitute nonliving matter; are necessary for living
things. Examples: water and salt
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Organic molecules: are important to living organisms and are necessary for living
things. Always contain carbon and hydrogen. They Include:
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Charbohydrates
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Polysaccharides
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Proteins
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Fats
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Starches & glycogen