CELL STRUCTURE AND FUNCTION

General Biology Lecture

Chapter 4: Tour of the Cell

An overview of the cell theory and the history of microscopy leads into the detailed structure and function of both prokaryotic and eukaryotic cells, with special attention to the endomembrane system.

THE MICROSCOPIC WORLD OF CELLS

Organisms are either ___________________ or ___________________________. 

I. Microscopes as a Window on the World of Cells

The ____________________ microscope is used by many scientists.  ________________ passes through the specimen.  __________________ enlarge, or magnify the image.  ________________________ is the increase in the specimen's apparent size.  _____________________________ is the ability of an optical instrument to show two objects as being separate.

Cells were first discovered in 1665 by _________________________.  The accumulation of scientific evidence led to the ______________________________.

1. _______________________________

2. _______________________________

Cell Theory

Early concepts – late 1600’s.  Anton van Leeuwenhoek was a Dutch shopkeeper, discovered microscopic life.  Robert Hooke was an English scientist who coined term “cell” for empty compartments in cork.  Spontaneous generation, now an outdated theory that microbes (i.e. cells) ‘generate’ or arise from nonliving matter, was a widely accepted explanation for the occurrence of certain forms of life (especially microbes).  The theory of spontaneous generation stated that a vital force was required to create life from nonliving matter. 

The Cell Theory – 1800’s, three Germans:  Schleiden (botanist) and Schwann (zoologist) state that all animals and plants are composed of cells; Virchow states that cells come from preexisting cells, no vital force required, the mechanical process of cell division explains the occurrence of new cells. 

The _______________________________ uses a beam of electrons.  It has a higher ________________________ than a light microscope.  The electron microscope can magnify up to ___________________________.

The ___________________________________ is used to study the detailed architecture of the surface of the cell.

The ___________________________________ is useful for exploring the internal structure of the cell.

II. Two Major Categories of Cells

The countless number of cells on Earth fall into two categories:

1. __________________________________

2. __________________________________

Prokaryotic cells:

1. __________________________________

2. __________________________________

3. __________________________________

Comparison of prokaryotic and eukaryotic cells: http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_structure/cell_structure.htm

MEMBRANE STRUCTURE

The _________________________ separates the living cell from its nonliving surroundings. 

I.  The Plasma Membrane: A Fluid Mosaic of Lipids and Proteins

The membranes of cells are composed mostly of:

1. _____________________________

2. _____________________________

The lipids belong to a special category called _________________________.  Phospholipids form a two-layered membrane, called the __________________________.

Most membranes have specific __________________________ embedded in the phospholipid bilayer.

Membrane phospholipids and proteins can ________________ about in the plane of the membrane.  This behavior leads to the description of a membrane as a ____________________.  _________________________ can move freely within the membrane.  A diversity of _______________________ exists within each membrane.

II. Cell Surfaces

Most cells secrete materials for _____________ of some kind or another.  They are external to the _____________________________.  These extracellular coats help to ___________________________ and ________________________ cells and facilitate interactions between __________________________________________________.

Plants have __________________ which:

1. _____________________________________

2. _____________________________________

3. _____________________________________

Animals cells have a __________________________ which ___________________________________________________________________________________.

THE NUCLEUS AND RIBOSOMES: GENETIC CONTROL OF THE CELL

The ________________________ is the manager of the cell.  ___________________ in the nucleus store information necessary to produce proteins.

I.  Structure and Function of the Nucleus

The nucleus is bordered by a double membrane called the ____________________________.  It contains _______________________________________.

II. Ribosomes

Ribosomes are responsible for ___________________________________________.

III. How DNA Controls the Cell

DNA controls the cell by transferring its coded information into _______________.  The information in RNA is used to make ________________________.

THE ENDOMEMBRANE SYSTEM: MANUFACTURING AND DISTRIBUTING CELLULAR PRODUCTS

Many of the ________________________ organelles in the cell belong to the endomembrane system.

I.  The Endoplasmic Reticulum

The endoplasmic reticulum (ER):

1. ____________________________________

2. ____________________________________

A. Rough ER

The "roughness" of the rough ER is due to _______________________ that stud the outside of the ER. 

Functions of the rough ER include:

1. _________________________________

2. _________________________________

After the rough ER synthesizes a molecule, it packages the molecule into _____________________________________.

B. Smooth ER

The smooth ER lacks the surface _____________________ of ER and produces __________________________________________________.

II. Golgi Apparatus

The Golgi Apparatus:

1. _________________________________________

2. _________________________________________

III. Lysosomes

A lysosome is a _________________________________.  It contains:

1. ________________________________________

2. ________________________________________

Lysosomes have several types of ____________________________ functions. They fuse with _____________________________ to digest foods

They also break down _________________________________________.

Animation site: http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter5/animations.html#

IV. Vacuoles

Vacuoles are ___________________________________.  Two types are:

1. ___________________________________

2. ___________________________________

Chloroplasts and Mitochondria: Energy Conversion

Cells require a constant ____________________ supply to do all the work of life.

I. Chloroplasts

Chloroplasts are the site of ___________________________, the conversion of ___________________________ to _______________________________.

II. Mitochondria

Mitochondria are the sites of _________________________________, which involves the production of _______________ from food molecules.

Mitochondria and chloroplasts share another feature unique among eukaryotic organelles.  They contain their own __________________.

The existence of separate "mini-genomes" is believed to be evidence that __________________________________________________________________

THE CYTOSKELETON: CELL SHAPE AND MOVEMENT

The cytoskeleton is an infrastructure of the cell consisting of __________________________________________. 

I. Maintaining Cell Shape

One function of the cytoskeleton is _______________________________________________________________________________.

The cytoskeleton can also change the _______________ of the cell.  This allows it to _______________________.

II. Cilia and Flagella

Cilia and flagella are _____________________________________________.

____________________________ propel the cell in a whip-like motion.

____________________________ move in a coordinated back-and-forth motion.

Some cilia and flagella extend from _____________________ cells.  Examples include: _____________________________________________________.

Evolution Connection: The Origin of Membranes

__________________________________ were probably among the organic molecules on early Earth.

When mixed with water, phospholipids spontaneously form _______________________________.

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CHAPTER RELATED WEBSITES

 

To learn more about cells, click on: http://www.quia.com/jg/151161.html and http://www.nigms.nih.gov/news/science_ed/life.html

For a good tutorial on cells, click on http://www.cellsalive.com/

To tour a virtual cell, click on: http://personal.tmlp.com/Jimr57/tour/cell/cell.htm

Quiz yourself on cell transport: http://www.gen.umn.edu/faculty_staff/jensen/1135/webanatomy/wa_cell_chem/wa_cell_terms2.htm

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