Cells and Life

1. Cells
Life
and

2. Understanding Cells
English scientist Robert Hooke first identified
cells over 300 years ago while looking at cork
under a microscope he built.

3. Cork is actually made of water-resistant cells that
separate the outer bark from the delicate interior bark.
Understanding Cells

4. Understanding Cells
•Cork has a unique set of properties not
found in any other naturally existing
material. It is:
•impermeable to gas and liquid
•lightweight
•rot resistant
•fire resistant
•termite resistant
•soft
•buoyant

5. Understanding Cells
•In the cork Hooke saw small openings similar
to a bee’s honeycomb. The openings
reminded him of the small rooms, called
cells, where monks lived.
•Hooke named these small structures cells.

6. Cell Theory
•Scientists made better microscopes than
Hooke’s.
•They looked for cells in places such as pond
water and blood.
•The newer microscopes made it possible for
scientists to see different structures inside cells.

7. •A scientist named Matthias Schleiden
looked at plant cells.
•Another scientist, Theodore Schwann,
studied animal cells.
•Later, Rudolf Virchow said all cells come
from cells that already exist.
•The observations made by these scientists
became known as the cell theory.
Cell Theory

8. The Cell Theory states:
1.All living things are made of one or more
cells.
2.The cell is the smallest unit of life.
3.All new cells come from pre-existing cells.
Cell Theory

10. •The cell theory raised more questions for
scientists. Scientists began to look into what
cells are made of.
•Cells are made of smaller parts called
macromolecules that form when many
small molecules join together.
•Macromolecules cannot function without
one of the most important substances in
cells - water.
Basic Cell Substances

11. •The main ingredient in every cell is water.
Making up more than 70 percent of a cell.
•Water also surrounds cells, helping to
insulate your body. This helps your body
maintain a stable internal environment, or
homeostasis.
•Water also is useful because it can dissolve
other substances, such as salt.
•For substances to move into and out of a
cell, they must be dissolved in a liquid.
Basic Cell Substances

12. •All cells contain other substances besides
water that help cells do what they do.
•There are four types of macromolecules in
cells. They are nucleic acids, proteins,
lipids, and carbohydrates.
•Each type of macromolecule has its own
function in a cell. These functions range
from growth and communication to
movement and storage.
Macromolecules in Cells

13. •Both deoxyribonucleic acid (DNA) and
ribonucleic acid (RNA) are nucleic acids.
•Nucleic acids are important because they
contain the genetic material of a cell. This
information is passed from parents to
offspring.
•Nucleic acids are macromolecules formed
when long chains of molecules called
nucleotides join together.
Macromolecules in Cells
Nucleic Acids

14. Macromolecules in Cells
Nucleic AcidsDNA

15. Macromolecules in Cells
Nucleic AcidsDNA

16. Macromolecules in Cells
Nucleic AcidsDNA

17. Macromolecules in Cells
Nucleic AcidsDNA

18. Macromolecules in Cells
Nucleic AcidsDNA

19. Macromolecules in Cells
Nucleic AcidsDNA RNA

20. •DNA includes instructions for cell growth, for
cell reproduction, and for cell processes
that enable a cell to respond to its
environment.
•DNA is used to make RNA. RNA is used to
make proteins.
•The order of nucleotides in DNA and RNA is
important. A change in the order of the
nucleotides can change the information in
a cell.
Macromolecules in Cells
Nucleic Acids

21. •The macromolecules necessary for almost
everything cells do are proteins.
•A protein is a macromolecule made of
long chains of amino acid molecules.
•RNA contains instructions for joining amino
acids together to build the protein.
Macromolecules in Cells
Proteins

22. Macromolecules in Cells
Proteins
Amino
Acids

23. Macromolecules in Cells
Proteins
Chain
of
Amino
Acids

24. Macromolecules in Cells
Proteins
Chain
of
Amino
Acids

25. •A protein can contain 100 to 10,000’s
amino acids.
•Cells have hundreds of proteins.
•Each protein has its own function. For
example some:
•help cells communicate with other cells
•move substances around inside cells
•help to break down nutrients in food
•make up supporting structures (like hair,
horns, and feathers)
Macromolecules in Cells
Proteins

26. •A lipid is a large macromolecule that does
not dissolve in water. Because lipids do not
dissolve in water, they protect cells.
•Lipids also are a large part of the cell
membrane.
•Lipids store energy for cells and help with
cell communication.
•Cholesterol and vitamin A are lipids.
Macromolecules in Cells
Lipids

27. Macromolecules in Cells
Lipids
Cell Membrane

28. •One sugar molecule, two sugar molecules,
or a long chain of sugar molecules make
up carbohydrates.
•Carbohydrates store energy, provide
structural support for cells, and help cells
communicate.
Macromolecules in Cells
Carbohydrates

29. •Sugars and starches are carbohydrates that
store energy. Fruits contain sugars. Bread
and pasta are mostly starch.
•The energy stored in sugars and starches
can be released quickly through chemical
reactions in cells.
•Cellulose is a carbohydrate in the cell walls
of plants.
Macromolecules in Cells
Carbohydrates

30. Macromolecules in Cells
Carbohydrate
Sugars

31. Macromolecules in Cells
Carbohydrate
Starch
chain of glucose

32. Macromolecules in Cells
Carbohydrate
Cellulose
many chains of glucose
bunched together