1. Cell Structure and Function
Chapter 4

2. Cell Theory 1) Every organism is composed of one or more cells
2) Cell is smallest unit having properties of life
3) Continuity of life arises from growth and division of single cells

3. Structure of Cells All start out life with: Two types: Plasma membrane
Region where DNA is stored
Cytoplasm
Two types:
Prokaryotic
Eukaryotic
Know table 4.2

4. Animal Cell Features Plasma membrane Nucleus Ribosomes
Endoplasmic reticulum
Golgi body
Vesicles
Mitochondria
Cytoskeleton

5. microfilaments
microtubules
components of
cytoskeleton
plasma
membrane
mitochondrion
nuclear enevelope
nucleolus
DNA + nucleoplasm
NUCLEUS
vesicle
lysosome
rough ER
ribosomes
(attached to
and free in
cytoplasm)
smooth ER
Golgi body
pair of
centrioles
Fig. 4.8b, p. 57

6. Lipid Bilayer Main component of cell membranes
Gives the membrane its fluid properties
Two layers of phospholipids

7. Bacteria Cells are unable to endocytose

8. Membrane Proteins Transport proteins Receptor proteins
Recognition proteins
Adhesion proteins

9. EXTRACELLULAR ENVIRONMENT
oligosaccharide groups
cholesterol
phospholipid
EXTRACELLULAR ENVIRONMENT
(cytoskeletal pro-teins beneatch the plasma membrane)
open channel protein
gated channel proten (open)
gated channel proten (closed)
active transport protein
RECEPTOR PROTEIN
LIPID BILAYER
ADHESION PROTEIN
RECOGNITION PROTEIN
(area of enlargment)
TRANSPORT PROTEINS
CYTOPLASM
PLASMA MEMBRANE
Fig. 4.4, p. 53

10. Functions of Nucleus
Keeps the DNA molecules of eukaryotic cells separated from metabolic machinery of cytoplasm
Makes it easier to organize DNA and to copy it before parent cells divide into daughter cells

11. Components of Nucleus Nuclear envelope Nucleoplasm Nucleolus
Chromosome
Chromatin

12. Nuclear Envelope Two outer membranes (lipid bilayers)
Innermost surface has DNA attachment sites
Pores span bilayer

13. Nucleolus Dense mass of material in nucleus May be one or more
Cluster of DNA and proteins
Materials from which ribosomal subunits are built
Subunits must pass through nuclear pores to reach cytoplasm

14. Chromatin Cell’s collection of DNA and associated proteins
Chromosome is one DNA molecule and its associated proteins
Appearance changes as cell divides

15. Components of Cytomembrane System
Endoplasmic reticulum
Golgi bodies
Vesicles

16. Endoplasmic Reticulum
In animal cells, continuous with nuclear membrane
Extends throughout cytoplasm
Two regions - rough and smooth
Ribosome
Cisterns

17. Rough ER Ribosomes on surface give it a rough appearance
Some polypeptide chains enter rough ER and are folded and modified
Cells that specialize in secreting proteins have lots of rough ER

18. Smooth ER No ribosomes on surface Lipids assembled inside tubules
Synthesizes steroids, such as estrogen and testosterone.
inactivates wastes, toxic chemicals and drugs

19. Golgi Bodies
Put finishing touches on proteins and lipids that arrive from ER
Package finished material for shipment to final destinations outside the cell.
Material arrives and leaves in vesicles

20. Vesicles Membranous sacs that move through the cytoplasm Lysosomes
Peroxisomes

21. Mitochondria ATP-producing powerhouses Double-membrane system
Carry out the most efficient energy-releasing reactions
These reactions require oxygen

22. Cytoskeleton Present in all eukaryotic cells
Basis for cell shape and internal organization
Allows organelle movement within cells and, in some cases, cell motility

23. Cytoskeletal Elements
intermediate
filament
microtubule
microfilament

24. Mechanisms of Movement
Length of microtubules or microfilaments can change
Parallel rows of microtubules or microfilaments actively slide in a specific direction
Microtubules or microfilaments can shunt organelles to different parts of cell