Part 1 of our Cell lesson

1. 1
Organisms and Cells
d.
c.
b.
a.
50 m 140 m
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a: © Geoff Bryant/Photo Researchers, Inc.; b: Courtesy Ray F. Evert/University of Wisconsin Madison;
c: © Barbara J. Miller/Biological Photo Service; d: Courtesy O. Sabatakou and E. Xylouri-Frangiadak

2. Multicellular organisms are arranged from simple to complex
according to their level of cellular grouping.
cell tissue organ organ
system
organism
The Levels of Organization

6. Cells
Smallest living unit
Most are microscopic

7.  Cells have 3 main jobs
 make energy
 need energy for all activities
 need to clean up waste produced
while making energy
 make proteins
 proteins do all the work in a cell,
so we need lots of them
 make more cells
 for growth
 to replace damaged or diseased cells
The Jobs of Cells
Our organelles
do all these
jobs!
ATP

10. Principles of Cell Theory
 All living things are made of cells
 Smallest living unit of structure and function of all organisms is
the cell
 All cells arise from preexisting cells
(this principle discarded the idea of
spontaneous generation)

11. Why study cells?
 Cells  Tissues  Organs  Bodies
 bodies are made up of cells
 cells do all the work of life!

12.  Cells have 3 main jobs
 make energy
 need energy for all activities
 need to clean up waste produced
while making energy
 make proteins
 proteins do all the work in a cell,
so we need lots of them
 make more cells
 for growth
 to replace damaged or diseased cells
The Jobs of Cells
Our organelles
do all these
jobs!
ATP

13. Cell Size

14. Cell Types
Prokaryotic
Eukaryotic

15. Cell Type: Prokaryotes
 Prokaryotes, which includes all bacteria, are the simplest cellular
organisms. They have genetic material but no nucleus.
Typical bacteria cellBacteria cells

16. Cell Types: Eukaryotes
 Eukaryotic cells contain a membrane-
bound nucleus and numerous
membrane -enclosed organelles

17. Cell size comparison
Bacterial cell
Animal cell
 micron = micrometer = 1/1,000,000 meter
 diameter of human hair = ~20 microns
most bacteria
 1-10 microns
eukaryotic cells
 10-100 microns

18. Organelles
Organelles do the work inside cells
each structure has a job to do
keeps the cell alive; keeps you alive
Model Animal Cell
They’re like
mini-organs!

19. cytoplasm
jelly-like material holding
organelles in place

20. 20
Photograph of a Cell Membrane

21. KEY CONCEPT The cell membrane is a barrier that separates a cell from the external environment.

22.  Function
 separates cell from outside
 controls what enters or leaves cell
 O2, CO2, food, H2O, nutrients, waste
 recognizes signals from other cells
 allows communication between cells
 Structure
 double layer of fat
 phospholipid bilayer
 receptor molecules
 proteins that
receive signals
Cell membrane
lipid “tail”
phosphate
“head”

23. 3.3 Cell Membrane
Cell membranes are composed of two phospholipid layers.
• The cell membrane is selectively permeable.
Some molecules can cross the membrane while others
cannot.

24. copyright cmassengale
24

26. 26
Cell Membrane
Polar heads are hydrophilic “water loving”
Nonpolar tails are hydrophobic “water fearing”
Makes membrane “Selective” in what crosses

27. 27
Cell Membrane
Hydrophobic molecules pass
easily; hydrophilic DO NOT

28. What is the function of the protein channels?
They provide passageways for materials to cross the membrane.

29. Lesson Overview Cell Structure
But they can do much more

30. Nucleus
Control center of cell
Double membrane
Contains
Chromosomes
Nucleolus
The nucleus is a home to the cell’s chromosomes
and DNA. What are chromosomes you ask?
Chromosomes: They are genetic structures that
contain information to make new cells. Basically, the
instructions for how to make new cells.

31. Terms/Structures continued
Nucleus: The nucleus is a structure usually located near the
center of the cell.
The nucleus is a home to the cell’s chromosomes and
DNA. What are chromosomes you ask?
Chromosomes: They are genetic structures that contain
information to make new cells. Basically, the instructions for how
to make new cells.

32. Terms/Structures continued
Nucleolus: This structure is found inside the nucleus. It
is responsible for making ribosomes. We will get to this
term in a bit. Thanks for your patience!