Section 3Biochemical Concepts

Mr. McCammon

Biology I and SSR

Section 3.1I. Characteristics of Living Things

A. One or more cells

B. Have a way to reproduce

C. Grow and develop

D. Universal genetic code

E. Obtain material and use the energy from it.

F. Maintain a stable internal environment (homeostasis)

G. Respond to changes in the environment

H. Change over time

Section 3.1 Practice

Complete 1-8 on a sheet of paper Turn the sheet into the box.

Section 3.2 II. Chemistry of Life

A. Atoms make up all matter in the universe.B. Atoms are made up of:

1. Protons – positive charge and found in the nucleus (center) of the atom.

2. Neutrons – no charge and found in the nucleus (center) of the atom.

3. Electrons – negative charge and found orbiting the nucleus (center) of the atom.

Comparing Electrons, Protons, and Neutrons

Sub-atomic Particle

Charge Location Mass

Proton + Nucleus 1

Neutron 0 Nucleus 1

Electron - Electron Shells

0

Section 3.2

II. Chemistry of Life (con’t)

C. Electrons closer to the nucleus are held tighter than those further away.

1. Atoms can gain, lose, or share electrons with other atoms.

2. This is the basis for chemical reactions.

Section 3.2

II. Chemistry of Life (con’t)D. Chemical reactions

1. Making and/or breaking chemical bonds.

2. Chemical bonds are formed when outer electrons are attracted, shared, or transferred from one atom to another in order to fill outer shell electrons.

Section 3.2

II. Chemistry of Life (con’t)

E. The periodic table

1. All known elements

2. 92 natural occurring elements

3. Metals, non-metals, metalloids

4. Atomic mass, atomic number, symbol, and name.

Section 3.2

Section 3.2II. Chemistry of Life (con’t)

F. Making electron diagrams

1. Find the element on the periodic table and note the atomic number.

2. Atomic number is the number to protons.

3. The number of protons = the number of electrons.

Section 3.2II. Chemistry of Life (con’t)

F. Making Electron diagrams (con’t)

4. Helium’s atomic number is 2 therefore it has 2 protons and 2 electrons.

5. Draw protons in the center and electrons orbiting nucleus.

a. 2 electrons in 1st energy level

b. 8 electrons in 2nd energy level

c. 8 electrons in 3rd energy level

Section 3.2

F +9

1. Place the number of protons in the nucleus.

2. Put 2 electrons in the 1st level, 8 in the second. 3. Continue until all the electrons are

accounted for.

Section 3.2

Write the electron diagrams for:

1. Chlorine

2. Sodium

3. Lithium

4. Carbon

5. Boron

Turn them into the box.

Section 3.2

II. Chemistry of Life (con’t)

G. Two types of Bonds

H. Ionic bonds result from atoms that gain or lose electrons.

1. When an electron is lost, a + results.

2. When an electron is gained, a – results.

Section 3.2

II. Chemistry of Life (con’t)

H. Ionic bonds (cont)

3. Goal is to fill an outer shell. To reach the magic number of 8 (or 2 for the 1st energy level)

4. Positive and negative attract.

5. When an atom gains or loses an electron it is called an ion.

Section 3.2

II. Chemistry of Life (con’t)

I. Covalent Bonds result from the sharing of electrons.

1. Outer shell electrons overlap

2. Form molecules.

3. Organic molecules, water, complex macromolecules are examples.

Section 3.2

Complete Practice 1-6 on page 71 Turn it into the box.

Section 3.3

III. The Chemistry of Water

A. Chemical formula is H20 – made up of two molecules of hydrogen and one oxygen.

B. Most abundant compound in living organisms.

C. Covalently bonded.

Section 3.3III. The Chemistry of Water

D. Properties of Water (con’t)

1. Transparent to let sunlight through to aquatic organisms.

2. Can form ions.

3. Universal solvent – can dissolve many substances

4. Cohesion – Water sticks to water

5. Adhesion – Water sticks to stuff

6. Temperature stabilizer – Can absorb lots of heat before it changes temp.

Section 3.3

III. The Chemistry of Water (con’t)

E. The electrons are not shared evenly between the hydrogen and the oxygen molecules resulting in the oxygen end having a slight negative charge and the hydrogen having a slight positive charge. This makes water a polar covalent bond, having a slightly positive pole and a slightly negative pole.

Section 3.3

III. The Chemistry of Water (con’t)F. Since the slight positive end will attract the slight negative end, water molecules will stick together (cohesion).G. Water can form weak hydrogen bonds that can hold water to other materials (adhesion).H. Liquid at room temp. and floats when frozen

Section 3.3

III. The Chemistry of Water (con’t)

I. Water will dissolve most all materials except _____.

J. 65 to 70% of human body and up to 80% in some organisms.

Complete Practice on page 73 1-8

Turn it into the box.

Section 3.4

IV. pH

A. Water forms ions.

B. Water will split into H+ and OH-

C. pH measures the concentration of H+ in solution.

D. pH scale goes from 0 to 14 with 7 being neutral (H+ is equal to OH-)

Section 3.4

IV. pH (con’t)

E. Any solution less than 7 is an acid.

1. A compound that forms H+ in solution is an acid.

2. The lower the number the stronger the acid. 2.5 is a stronger acid than 4.5.

Section 3.4

IV. pH (con’t)

F. Any solution more than 7 is a base (or alkaline)

1. A compound that forms OH- in solution is a base.

2. The higher the number the stronger the base. 12.5 is stronger than 8.

Section 3.4

Complete 1-10 on page 74 and 1-8 on page 75.

Turn it into the box.