Biology Chapter 2 What is Life?

1. Biology Chapter 2 What is Life? • Biology is the study of LIFE. • Living Things have 5 Characteristics according to this • Chapter. • Movement; 2. Sensitivity; 3. Development; • Complexity; 5. Death  • All Living Things also have: • Cellular Organization • Metabolism – using energy to grow and move. • Homeostasis – To maintain stable internal conditions. • Heredity – To pass genetic information…sometimes • genetically similar; sometimes identical.

2. Slime Molds are living.

3. 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. 

4. 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”.

5. 2-2 Basic Chemistry • Know these Terms: • Atom: The smallest particle that retains its chemical • properties. • 2. Element: is a substance composed of only one type • of atom. • Atoms are composed of Electrons, Protons and Neutrons. • Ions: An atom with an Electric Charge. This atom has • gained or lost electrons. It is charged.

6. Chemical Bonds: • 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 • Covalent means electron sharing. Proteins, fats(lipids), sugars, • carbohydrates form from Covalent bonds. Water does not dissolve • these compounds. • Molecule: A group of atoms held together by chemical bonds. Many of • the molecules studied in biology are covalently bonded.

7. 2-3 Molecules of Life • Organic Molecules have Carbon has the MAIN atom forming them. • 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

8. 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.

9. Saturated Fats TEND TO BE SOLID AT ROOM TEMPERATURE Unsaturated Fats TEND TO BE LIQUID AT ROOM TEMPERATURE

10. 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.