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Biology Chapter 2 What is Life?
Biology is the study of LIFE.
Living Things have 5 Characteristics according to this
Chapter.
1. Movement; 2. Sensitivity; 3. Development;
4. Complexity; 5. Death 
All Living Things also have:
1. Cellular Organization
2. Metabolism – using energy to grow and move.
3. Homeostasis – To maintain stable internal conditions.
4. Heredity – To pass genetic information…sometimes
genetically similar; sometimes identical.
Slime Molds are living.
Slime molds possess both animal and plant like
characteristics. They form three main groups, none
of which are closely related. Most of their lives are
spent as microscopic amoebas, some with flagella,
roaming independently through the forest feeding
on organic matter, bacteria, and other microscopic
morsels. During food shortages, slime molds
swarm and aggregate into an enormous single cell,
as shown in this photograph from the Sol Duc
Valley. The single cell has thousands of nuclei, and
contains no cell wall. This creature can cluster
using a very decentralized strategy, without any
known "leader" involved.
Slime Molds eat bacteria. When needed slime molds form a SLUG without
Any leader. The SLUG can migrate. When the SLUG finds a new spot it
“SETTLES DOWN” and splits into a “Head”; a “STALK” and a “BASE”.
2-2
Basic Chemistry
Know these Terms:
1.
Atom: The smallest particle that retains its chemical
properties.
2. Element: is a substance composed of only one type
of atom.
3.
Atoms are composed of Electrons, Protons and Neutrons.
4.
Ions: An atom with an Electric Charge. This atom has
gained or lost electrons. It is charged.
Chemical Bonds:
1.
Ionic means electron transfer. Atoms become ions and gain either
a positive or a negative charge. Salts, acids and bases form mainly
ionic bonds. Water can easily dissolve most of these types of compounds
2.
Covalent means electron sharing. Proteins, fats(lipids), sugars,
carbohydrates form from Covalent bonds. Water does not dissolve
these compounds.
3.
Molecule: A group of atoms held together by chemical bonds. Many of
the molecules studied in biology are covalently bonded.
2-3 Molecules of Life
Organic Molecules have Carbon has the MAIN atom forming them.
1.
2.
3.
Macromolecules: Fats(Lipids); carbohydrates; proteins; nucleic
acids(DNA and RNA also called
Deoxyribonucleic acid and Ribonucleic acid).
Chemical Reaction: The forming and breaking of chemical bonds.
Carbohydrates: Form from sugars. Also called starch and glycogen and
Polysaccharide.
The human body can only absorb the sugar GLUCOSE.
All starch is broken down into Glucose by the digestive
system.
Starch
molecules
Cellulose provides structural support for many plants.
Think of celery and lettuce. The human body does not do a
Good job digesting Cellulose.
Lipids also make up FATS. Lipids do not dissolve in water.
Lipids dissolve in oil. Fats contain at least twice as much
Energy as Carbohydrates and sugars. Fats insulate our nerves
And allow us to retain HEAT too.
Saturated Fats: Are loaded with Hydrogen. These tend to be a
Solid at Room temperature.
Unsaturated Fats: Are “missing” some Hydrogen. These tend to be
A liquid at Room Temperature.
Saturated Fats TEND TO BE
SOLID AT ROOM TEMPERATURE
Unsaturated Fats TEND
TO BE LIQUID AT
ROOM TEMPERATURE
Proteins: Composed of a long chain of subunits called AMINO ACIDS.
Proteins function as Structural molecules – Hair for example
And Proteins function as ENZYMES.
Nucleic Acids: Are made up of Nucleotides. The Nucleotides are the
Genetic Code.
DNA is in the shape of a DOUBLE HELIX.
RNA is one Strand of DNA. RNA helps synthesis PROTEINS.