1. Cells Chapter 5

3. Cell Theory
1. All organisms are made up of one or more cells and the products of those cells:
May be single cell
May be many celled
2. All cells carry on life activities
3. New cells arise only from other living cells by the process of cell division

4. Attributes of Cells A. Plasma or Cell membrane B. DNA C. Cytoplasm
D. Obtain energy and nutrients
from their environment

5. Plasma or Cell Membrane
Thin, flexible barrier around the cell, selectively permeable
Controls movement in & out of cells
Lipid bilayer (double layer)
Contains many lipids that cut through the membrane & proteins that lay on its surface

7. Cytoplasm Jelly-like substance fills inside of cells
Holds the organelles
Location for chemical reactions

8. Cell types
Prokaryotic—very small, no nucleus, scattered DNA, ribosomes
Eukaryotic—larger, nucleus with chromosomes/DNA, membranous organelles

9. Prokaryotic Cells Have no membrane-bound organelles
Include true bacteria
On earth 3.8 million years
Found nearly everywhere
Spores of bacteria in each breath; intestines
Naturally in soil, air, hot springs

10. nucleoid (DNA) ribosomes food granule cytoplasm cell wall
prokaryotic
flagellum
Figure: 04-10
Title:
A generalized prokaryotic cell.
Caption:
plasma membrane
cytoplasm
cell wall

11. Eukaryotic Cells: Nucleus
Have specialized membrane bound structures called organelles
Various types & forms found in:
Plants, animals, fungi, protists
Multicellular organisms have specialized cells

12. nuclear pore chromatin (DNA) nucleus nucleolus nuclear envelope
flagellum
cytoplasm
plasma
membrane
rough endoplasmic
reticulum
ribosome
lysosome
microtubules
smooth endoplasmic
reticulum
Figure: 04-02
Title:
A generalized animal cell.
Caption:
Golgi
Bodies
free ribosome
vesicle
mitochondrion
vesicle

13. (part of cytoskeleton)
microtubules
(part of cytoskeleton)
mitochondrion
chloroplast
Golgi Bodies
central vacuole
smooth endoplasmic
reticulum
vesicle
cell wall
rough endoplasmic
reticulum
Cell
membrane
Figure: 04-03
Title:
A generalized plant cell.
Caption:
nucleolus
nuclear pore
nucleus
chromatin
nuclear envelope
ribosomes
free ribosome

14. Eukaryotic cell structure: NUCLEUS
Nucleus is “control center” of the cell
1. Membrane bound (nuclear envelope with nuclear pores)
2. Contains Chromosomes which are
composed of DNA and proteins
3. Contains nucleolus- produces ribosomes

15. nucleolus Chromatin/ Chromosomes
nuclear
envelope
nucleolus
nuclear
pores
Figure: 04-04a
Title:
The nucleus.
Caption:
(a) The nucleus is bounded by a nuclear envelope. Inside are chromatin (DNA and associated proteins) and a nucleolus.
Chromatin/
Chromosomes

16. nucleus nuclear pores Figure: 04-04b Title: The nucleus. Caption:
(b) An electron micrograph of a yeast cell that was frozen and broken open to reveal its internal structures. The large nucleus, with nuclear pores penetrating its nuclear envelope, is clearly visible.

17. chromatin chromosome Figure: 04-05 Title: Chromosomes. Caption:
Chromosomes, seen here in a light micrograph of a dividing cell (on the right) in an onion root tip, are the same material (DNA and proteins) as the chromatin seen in nondividing cells adjacent to it, but in a more compact state.
chromosome

18. Eukaryotic cell structure: E.R.
Endoplasmic reticulum consists of folded membranes attached to the nucleus
Rough ER is covered with ribosomes
E.R. are involved in transport of materials throughout cell

19. rough endoplasmic reticulum smooth endoplasmic reticulum
ribosomes
0.5 micrometers
smooth endoplasmic reticulum
Figure: 04-07
Title:
Endoplasmic reticulum.
Caption:
There are two types of endoplasmic reticulum: rough ER, coated with ribosomes, and smooth ER, without ribosomes. Although in electron micrographs the ER looks like a series of tubes and sacs, it is actually a maze of folded sheets and interlocking channels.
0.5 micrometers
vesicles

20. Eukaryotic Cell Structure: RIBOSOMES
Ribosomes assemble amino acid into polypeptide chains i.e. protein synthesis
Can be found attached to the E.R. or floating freely in the cytoplasm

21. rough endoplasmic reticulum
ribosomes
Figure: 04-07R-1
Title:
Rough endoplasmic reticulum.
Caption:
rough endoplasmic reticulum
0.5 micrometers

22. Eukaryotic Cell Structure: GOLGI BODY
Golgi Bodies are membranous sacs associated with ER
Process, package, sort, in vesicles, substances synthesized by the cell for transport (secretion) out of the cell

23. vesicles from ER vesicles leaving Golgi Bodies Golgi Bodies
Figure: 04-08
Title:
The Golgi complex.
Caption:
The Golgi complex is a stack of flat membranous sacs. Vesicles transport material from the ER to the Golgi (and vice versa) and from the Golgi to plasma membrane, lysosomes, and vesicles. Departing vesicles bud off from the Golgi on one face; arriving vesicles join it on the opposite face.

24. Eukaryotic cell structure: LYSOSOME
Lysosomes (suicide sac) are Golgi-derived vesicles containing digestive enzymes
Enzymes may be secreted or may be used in a food vacuole to digest food in the cell
Breaks down old worn-out organelles
(autophagy)

25. Eukaryotic Cells: MITOCHONDRIA Energy sources for cell activities
Mitochondria are the sites for cellular
Respiration.
Provide/releases energy that powers cellular activities
Have their own DNA and ribosomes; self-replicate

27. 5 micrometers Figure: 04-E4-2d Title: An SEM photo. Caption:
(d) An SEM photo at much higher magnification, showing mitochondria, many of which are sliced open.
5 micrometers

29. Eukaryotic Cells: CHLOROPLAST
Chloroplast -- Site of photosynthesis
Green—contain chlorophyll pigment
Have their own DNA and ribosomes; self-replicate
Up to 100 per cell

32. Cell Wall (Plant cells )
Made of cellulose
Tough, flexible but sometimes fairly rigid layer (chain link fence)

33. Vacuole (Plant cells ) Fluid-filled membranous organelle
Central vacuole present in mature plant cells
If lack of water, vacuole will wilt (shrink)
Animal vacuoles: smaller, present in large numbers, some completely lack vacuole
In unicellular organisms: contractile vacuole
Gets rid of excess water

34. Cytoskeleton
Network of fibers that organizes structures and activities within cells
Consists of:
Microtubules
Microfilaments (Actin filaments)
Intermediate filaments

35. Microtubules Help maintain cellular shape Cell movement
Chromosome movement during cell division
Organelle movement

36. Microfilaments (Actin filaments)
Help maintain cell shape
Involved with changes in cell shape
Muscle contraction
Cytoplasmic streaming
Division in animal cells (cleavage furrow)

38. Intermediate filaments
Help maintain cell shape
Anchor nucleus

39. Plant & Animal Cells Similarities
Both constructed from eukaryotic cells
Both contain similar organelles
Both surrounded by cell membrane

40. Plant & Animal Cells Differences Plants have
Cell wall – provides strength & rigidity
Have chloroplasts, photosynthetic
Animals have
Lysosomes more common than plants
Centrioles, important in cell division (organize microtubules)
Less strength and rigid shape

41. Brief Look at Viruses
Infectious particle (genes packaged within a protein coat)
Not considered to be living (cannot reproduce or carry out metabolism outside of host cell)
Cause serious diseases in most organisms

43. Integrating Cell Structures
In order to understand how structures relate, you must understand that all of the processes performed are CHEMICAL in nature.
Chemical Rxns
Chemical reactions are controlled by ENZYMES
Each different chemical reaction is stimulated by a specific enzyme

44. Integrating Cells cont.
Enzymes are proteins
Some proteins are structural-some are enzymes

45. Integrating cont. Interaction of nucleus-ribosome
Nucleus is the control center of the cell-You already know this much
Now, what does it control?
It controls the chemical reactions that occur in the cell
This is done by controlling what enzymes are made at what time