Tuesday, September 16, 2008

Chapter 6: A Tour of the Cell

A Concept map for cells!

A Tour of the Cell: How We Study Cells

Light microscopes (LSs) are used to observe most plant and animal cells, bacteria, and some organelles like mitochondria and nuclei, although most cell organelles are too small to be seen with a light microscope. With these instruments, scientists can observe things from 1 mm in size.

Electron microscopes are used to study objects from about 0.1 nm to 100mm in size. They function by focusing a beam of electrons either through the specimen or onto its surface. There are two kinds of EMs: transmission electron microscope (TEMs) and scanning electron microscopes (SEMs)

A Panoramic View of the Cell

The best way to remember the main facts about prokaryotes and eukaryotes is to study a table of their major characteristics:

Characteristics

Prokaryotic Cells

Eukaryotic Cells

Plasma membrane

Yes

Yes

Cytosol with organelles

Yes

Yes

Ribosomes

Yes

Yes

Nucleus

No (It had a Nucleoid)

Yes

Size

1-10 micrometers

10-100 micrometers

Internal membranes

No

Yes

Prokaryotic cells include bacteria and archaebacteria, where as eukaryotic cells are animal and plant cells. Some details to remember about prokaryotes include:

  • No membrane bound nucleus—instead chromosomes grouped together in region called the Nucleoid
  • No membrane bound organelles
  • Smaller than eukaryotes
  • Consist of bacteria and archaebacteria

Some details to remember about eukaryotic cells include:

  • Membrane bound nucleus, which contains cell’s chromosomes
  • Membrane bound organelles in cytoplasm
  • Much larger that prokaryotes
  • Eukaryote cells make up the kingdoms protista, fungi, plantae, and animalia


The Nucleus and Ribosomes, the Endomembrane system, other membranous organelles, and the cytoskeleton.


Nucleus: A generally conspicuous membrane bound cellular organelle in a eukaryotic cell; contains most of the genes that control the entire cell.

Nuclear Envelope: A double membrane which encloses the nucleus in a eukaryotic cell.

Chromatin: Complex of DNA and histone proteins, which makes up chromosomes in eukaryotic cells; appears as a mass of stained material in nondivded cells.

Chromosomes: long threadlike association of genes composed of chromatin and found in the nucleus of eukaryotic cells.

Nucleolus: Roughly spherical region in the nucleus of nondividng cells, which consists of nucleolar organizers and Ribosomes in various stages of production.

Nuclear Organizers: Specialized regions of the same chromosomes, with multiple copies of genes for rRNA synthesis.

Ribosome: A cytoplasmic organelle that is the site for protein synthesis

Free Ribosomes: Ribosomes suspended in the cytosol

Attached Ribosomes: Attached to the outside of the endoplasmic reticulum (ER)


2 comments:

SMABiology said...

Great that you found a concept map of a cell! Excellent. This will help other students understand the connections.

Leigh said...

Aw! This concept map is so helpful!!! Thanks Kelsey!