Cell Design and Function

Chapter 7

Cell Theory The Cell Theory States the Following: 1. All organisms are composed of

one or more cells. 2. The Cell is the basic unit of life. 3. All cells come from pre-existing

cells through Mitosis or Meiosis.

The Two Basic Cell Types •  Prokaryotes: the cells of most

unicellular organisms like bacteria lacking membrane-bound structures.image

• Eukaryotes: Most multicellular organisms that contain membrane-bound structures. image

CELLULAR ORGANELLES AND THEIR FUNCTION

The Plasma Membrane •  Maintains

homeostasis •  creates a barrier

for the cell. •  Protection •  semi-permeable

image

Plasma Membrane • Border of the cell. • Regulates what can enter and exit

the cell.

The Phospholipids •  The head is polar and hydrophilic

(hydro = water, phil = like, love). • Attached to the "head" of the

molecule are 2 fatty acid chains which are nonpolar and hydrophobic (phob = dislike). (TAIL)

Plasma Membrane 3 Proteins are also found in the cell

membrane:

1. Channel Proteins: These proteins create a tunnel through the membrane to move materials in and out past the nonpolar region.

Example- Tunnel from one place to another

Plasma Membrane 2.  Receptor Proteins: These

proteins stretch through the membrane and send information they receive outside the cell in the cell interior.

Example: Satellite dish on house

3.  Marker Proteins: These proteins act like nametags and serve to identify the cell

Example: Basketball Team Concepts

Plasma Membrane

The Nucleus •  Contains the genetic

info. (DNA) •  Assembles

Ribosomes •  Central Processing

Unit •  Nuclear Envelope

and pores

The Ribosomes •  A small, NON-membrane bound

organelle. •  Located in the cytoplasm and the rough

Endoplasmic Reticulum (ER). •  Produced in the nucleolus. •  rRNA functions to assemble proteins

from amino acids. •  Composed of both DNA and RNA.

Ribosomes

The Mitochondrion •  Produces cellular energy for the cell in

the form of ATP. (=Adenosine-P-P-P). •  Contains highly folded internal

membranes called cristae. •  Contains it’s own DNA (theorized to have

once been a single-celled organism) •  Contains an inner and outer compartment

The Mitochondrion (cont’d) •  Divides asexually (fission) similarly to that of

a prokaryotic organism. •  The # of mitochondria in a cell is determined

by that cell’s energy needs. •  (Ex: Muscle cells contain more mitochondria

than do skin cells.)

The Golgi Apparatus • Contains a single membrane. •  Is a stack of vessicles involved in

packaging macromolecules for transport through the cell.

• Golgi vessicles are involved in transporting material out of cell.

The Golgi Apparatus

BACK AK Small Vessicle

Large Vessicle

The Golgi Apparatus • Vessicle Contents: 1) hormonal/enzyme contents of

lysosomes. 2) Peroxisomes that breakdown toxic

hydrogen peroxide. 3) Secretory vessicles that transport

material via exocytosis. image

The Endoplasmic Reticulum •  Attached to the nucleus to form a transportation network for protein distribution. Two Types:

1) Smooth ER: Ribosome-free and produces lipids and membrane proteins.

2) Rough ER: w/ribosomes and produces other proteins.

Endoplasmic Reticulum

The Differences Between Plant

and Animal Cells

Ok, I understand animal cells now, but what about Plant cells?

Differences between Plant and Animal Cells

•  Larger than Animal Cells •  Contain a Cell wall made of

cellulose (glucose polymer). •  Contain 1 large sap vacuole. •  Contain Chloroplasts with

chlorophyll pigment. •  Photosynthesize = obtain

their energy from the sun.

DO NOT contain cell walls.

Plant Cell Characteristics

Fig. Chloroplast Interior

image

Now I understand it. Cells are the basic units of all living organisms. Plant cells are different from animal cells only in a few ways. Plant cells have cell walls and animal cells don’t, And Animal cells have many small vacuoles, while Plant cells have one large one. That’s easy.