Chapter 3 Section 1: Chemistry of Life 7th Grade Science Minersville Area School District

1. Chapter 3
Cell Processes
Section 1:

2. I. Chemistry of Life
A. Nature of Matter
1. Matter: anything that has mass and takes up
space.
2. Energy: anything that brings about change.
a. Energy can hold things together or break things
apart.

3. I. Chemistry of Life
B. Atoms
1. Matter is made up of atoms
a. Atoms are the smallest unit of anything.
2. The center of an atom is called the nucleus.
a. The nucleus contains two atomic particles called
protons and neutrons.

4. I. Chemistry of Life
3. Atoms are made up of three smaller
particles.
a. Protons: positive charge; found in nucleus.
b. Neutrons: neutral charge; found in nucleus.
c. Electrons: negative charge; found in electron
cloud.

5. ATOMIC MODEL

6. I. Chemistry of Life
4. The charge of the nucleus of an
atom is positive because it has
only protons (+) and neutrons (0).

7. I. Chemistry of Life
5. Electrons are important because they are the
parts that are involved with all chemical
reactions.
6. Electrons are the smallest particle in an
atom.
7. Atoms are usually neutral (they do not have
a charge).
a. This is because the protons in an atom usually
equals the electrons.

8. Noah and Noah working on their
virus paper!!!!

9. I. Chemistry of Life
C. What is an Element
1. An element is matter that is made up of only
one kind of atom.
2. Cannot be broken down into simpler forms.
3. Each element is given a 1, 2, or 3 letter
symbol.
a. Some symbols are from Latin names.
b. Some symbols are from common names.
c. Examples given in class!!!! Pay attention

10. I. Chemistry of Life
4. There are currently 118 Elements.
a. 90 are natural elements, 28 are man made
elements.
D. The Periodic Table of Elements
1. A list of all elements by size (atomic
number), the smallest are in the upper left
(Hydrogen), the heaviest are at the bottom
right (#118)
2. The table shows the name, symbol, and how
many protons it has.

11. PERIODIC TABLE

12. I. Chemistry of Life
E. Elements of Life
1. 99% of all living matter is made up of six
elements.
2. Humans
a. O-oxygen=65%
b. C-Carbon= 18.5 %
c. H-Hydrogen = 9.5%
d. N-Nitrogen = 3.2%
e. Ca-Calcium = 1.5%
f. P-Phosphorus = 0.4%
g. See entire chart on page 67 of your textbook

13. I. Chemistry of Life
F. What is a Compound?
1. A compound is a substance made up of 2 or more
elements combined chemically in exact
proportions.
2. EX: WATER is always 2 H to 1 O or H2O.
3. Compounds act and appear differently than the
original elements.
a. Hydrogen is explosive, and a poisonous gas.
b. Oxygen is a gas needed for combustion in its elemental
form.
c. When they combine they make vital liquid water.

14. I. Chemistry of Life
G. Molecules (type of compound #1)
1. Molecules: Group of atoms held together by
energy of chemical bonds.
a. Formed when different atoms share their
outermost electrons.
b. Sharing of electrons is called COVALENT
BONDING.
c. Water is an example of a molecule because the 2
hydrogen share electrons with 1 oxygen.

15. I. Chemistry of Life
H. Ions (Type of Compound #2)
1. Compounds that form when atoms of opposite
charges called ions connect.
a. Ions are atoms with a positive or a negative charge.
2. Anion
a. When an atoms has more electrons than protons giving
the atom an overall negative charge.
3. Cation
a. If the atom has more protons than electrons; the atom
now has a positive charge.

16. I. Chemistry of Life
4. Ions of opposite charges attract one another
and form IONIC COMPOUNDS.
5. Example: Na+ + Cl- = NaCl (Table Salt)
6. Ions are very important inside the human body.

17. I. Chemistry of Life
I. Mixtures
1. When two substances join together but keep
their own properties.
a. This is different than a compound!!!
b. Examples: Blue and Red Marbles in a bag, Small
rocks in river water, Iced Tea, etc.
c. Mixtures can be separated by physical means!!
d. We will discuss in class why compounds and
mixtures are different!!! PAY ATTENTION!!

18. I. Chemistry of Life
J. Solutions (Type of Mixture)
1. A solution is a special type of mixture.
2. A solution is when two or more substances are
mixed together EVENLY.
a. One substance is dissolved in another substance.
b. Examples: Soda, Iced Tea, etc.
c. A solution can be separated by physical means.

19. I. Chemistry of Life
K. Suspensions (Type of Mixture)
1. When two or more substances are mixed
together but will eventually settle out over time.
a. Example: Italian Salad Dressing will separate into
oil and vinegar over time.
b. Suspensions are different than solutions because
solutions should not settle out over time!!!

20. I. Chemistry of Life
L. Food Pyramid
1. A chart explaining the types of foods and the
amounts a person should have on a daily
basis.
2. A balanced diet consists of several types of
ORGANIC COMPOUNDS.

23. I. Chemistry of Life
M. Organic Compounds
1. Substance that contains Carbon and Hydrogen
and are associated with living things.
2. Exceptions: Things that are non-living but
were made from once living things.
a. Example: Coal is made from dead and decaying
plant materials.

24. I. Chemistry of Life
3. There are four kinds of organic compounds.
a. Carbohydrates
b. Lipids (Fats)
c. Proteins
d. Nucleic Acids

25. I. Chemistry of Life
N. Carbohydrates
1. Made up of sugars and starches.
2. Job/Function: to supply energy for cell processes.
a. The main energy source for the cell.
3. Examples: Potatoes, vegetables, fruits, breads, rice,
and pasta.
4. Food Pyramid: most important part of diet in terms of
quantity. (Eat more carbs than any other food group).
5. If a person or cell is active the carbohydrates you eat
will be completely burned up during the course of the
day.

26. Carbohydrates

28. I. Chemistry of Life
O. Lipids
1. Function/Job: An energy backup for cells.
2. If not used they are stored as a fat called cellulite.
a. Once stored it is very hard for the body to lose.
3. Fats and Oils are examples of lipids.
4. Foods rich in lipids: Mayo, Salad Dressing, Ice
Cream, Dairy products, Chocolate, Oil, Butter, Etc.
5. A human only needs a very small amount of lipids
per day.

29. Lipids

31. I. Chemistry of Life
P. Proteins
1. Function: Responsible for all chemical
reactions that occur inside the human body!!
2. Made up of amino acids (20 common amino
acids)

32. I. Chemistry of Life
3. Special kinds of proteins called ENZYMES
regulate the rate of chemical reactions.
a. Example: Saliva helps break down carbohydrates in
the mouth faster.
b. Lactase helps break down milk products.
4. Foods rich in proteins: Meats, fruits, veggies,
fish, eggs, peanut butter, nuts.
5. Vegetarians NEED to be careful to make sure
they get enough protein in their diet!!

33. Proteins

34. I. Chemistry of Life
Q. Nucleic Acids
1. Function: Responsible for all genetic information
in cells.
2. Two Types of Nucleic Acids
a. DNA (Deoxyribonucleic Acid): Carries all the genetic
information for the cell. FOUND IN THE NUCLEUS!!
b. RNA (Ribonucleic Acid): Carries the DNA (plan) to all
cell parts; also makes proteins and enzymes.
3. Nucleic Acids are the most complex of all organic
compounds!!!

35. DNA

36. I. Chemistry of Life
R. Inorganic Compounds
1. Made from other elements besides water.
2. Normally they are simpler than organic
compounds.
3. See chart page 71 to see the important inorganic
compounds in the human body.
4. WATER is the most important INORGANIC
compound for living things!!
5. Life is composed of at least 50% water.
6. Human cells are made of at least 70% water.

37. I. Chemistry of Life
S. Importance of Water
1. Animals can live for only days without water but
weeks without food!
2. Every chemical reaction in the body needs to be in
a water-like solution.
a. Example: Blood
3. Water is composed of 2 hydrogen atoms and 1
oxygen atom.
a. Because of this water has a positive and negative side!!
b. Don’t worry…we will discuss this in 8th grade!!!

38. Water: The Mickey Mouse
Molecule!!!

39. Images needed for the quiz