Biology 107 - Cell I
September 21, 2005
Prokaryotic
Cells and
Eukaryotic
Cells
Cell I
Student Objectives: As a result of this lecture and the assigned
reading, you should understand the following:
1.
The basic structural and functional unit of life is the cell.
2.
Cells may be classified as prokaryotic or eukaryotic, depending
upon their internal organization.
3.
Prokaryotic cells are typically smaller than eukaryotic cells, while
eukaryotic cells generally are structurally and functionally more
complex than prokaryotic cells.
Cell I
4.
A eukaryote ("true nucleus") has a membrane-bounded nucleus,
and possesses membranous organelles, each of which has a
particular function in the cell.
5.
Organelles are structures essential for the functioning of a cell.
Not all organelles are membranous. Examples of nonmembranous organelles are microtubules and ribosomes.
6.
The advantages of membranous organelles (compartments)
include: 1) metabolic processes in the cell that require different
specific chemical conditions may occur simultaneous and 2) an
increase in the cell's total surface area.
Cell I
7.
Organization of Cells - Common Structures and Functions
a. Cells are microscopic is size because of the surface area to
volume relationships
b. Membranes enclose and delimit cells
c. Cells have a “genetic control center” containing DNA
d. Cells have cytoplasm. The cytoplasm includes the organelles
(membranous and non-membranous) and the fluids and
dissolved substances; it excludes the nucleus of eukaryotic
cells.
Cell I
8.
The DNA genetic material in prokaryotes is concentrated in a
region called the nucleoid region. In eukaryotes the DNA is
enclosed in the nucleus.
9.
Most of the DNA is attached to proteins, forming chromatin. The
proteins associated with DNA assist in either the structural
organization of the genetic material and/or the regulation of the
use of the DNA.
Cell I
10.
The eukaryotic nucleus:
a. The nuclear material is enclosed by the nuclear envelope, a
double membrane structure with pores that allows the passage
of material into and out of the nucleus. Through the pores
travel mRNA, ribosomes, and various proteins used in gene
regulation and DNA maintenance.
b. Contains is a mass of fibers and granules called the
nucleolus. The nucleolus is a combination of DNA, RNA and
proteins, and it is where ribosomal subunits are assembled.
Prokaryotic Cell
Eukaryotic Cell - Animal
Eukaryotic Cell - Plant
Surface area to Volume Relationship
Relationship Between Surface Area and Volume
Eukaryotic Nuclei
Nucleus
Condensed Eukaryotic
Chromosomes
Chromatin
Chromatin – DNA + Proteins
Eukaryotic Nucleus
Eukaryotic Nucleus
Nuclear Envelope –
Double-membrane
structure with pores
Nucleolus