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Tortura Microbiology Ch. 4 and part of Ch.5


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What does the term prokaryote come from?
the Greek words meaning prenucleus
What does the term eukaryote come from?
the Greek words meaning true nucleus
Do viruses have a plasma membrane?
What is the defining structure of a cell?
the plasma membrane
What does the group prokaryote include?
bacteria and archaea
How are species of bacteria differentiated?
1. morphology (shape)
2. chemical composition (staining reactions)
3. nutritional requirements
4. biochemical activities
5. source of energy (sunlight or chemicals)
Most bacteria range from ____1___ to ___2____ in diameter and from ___3_____ to ____4_____ in length.
1. 0.2 micrometers
2. 2.0 micrometers
3. 2 micrometers
4. 8 micrometers
What are the basic shapes of bacteria?
1. spherical coccus
2. rod-shaped bacillus
3. spiral
Cocci are usually rounded but can be ___1_____, ____2_____, or ______3_________.
1. oval
2. elongated
3. flattened on one side
What happens when cocci divide to reproduce?
the cells can remain attached to one another
Cocci that remain in pairs after dividing are called _________.
Cocci that divide and remain attached in chainlike patterns are called _____________.
Cocci that divide in two planes and remain in groups of four are known as ____________.
Cocci that divide in three planes and remain attached in cubelike groups of eight are called _____________.
Cocci that divide in multiple planes and form grapelike clusters or broad sheets are called ___________.
Bacilli that appear as _________ after dividing.
single rods
Bacilli that appear in pairs after division are called __________.
Baccili that appear in chains after division are called __________.
Bacilli that appear oval and look like cocci after division are called ___________.
What is the plasma (cytoplasmic) membrane?
a thin structure lying inside the cell wall and enclosing the cytoplasm of the cell
What does the plasma membrane of most prokaryotes consist of?
primarily of PHOSPHOLIPIDS, which are the most abundant chemicals in the membrane, and PROTEINS
What does the plasma membrane of most eukaryotes consist of?
phospholipids, proteins, carbohydrates, and sterols
What is an example of a sterol?
Why are prokaryotic plasma membranes less rigid than eukaryotic plasma membranes?
because prokaryotic plasma membranes LACK sterols
What prokaryote does NOT have a cell wall?
The phospholipid molecules of the plasma membrane are are arranged in two parallel rows, called a ___________.
lipid bilayer
Is the outer membrane of a prokaryotic cell a plasma membrane?
NO! The plasma membrane is inside of the cell wall which is inside an outer membrane. The outer membrane is called an outer membrane because it has some features similar to the plasma membrane.
All cells contain what kind of protein?
peripheral proteins
What are peripheral proteins?
proteins that may function as: enzymes that catalyze chemical reactions, as a "scaffold" for support, and as mediators of changes in membrane shape during movement
What are integral proteins (also called transmembrane proteins)?
1. penetrate the membrane completely
2. channels that have a pore through which substances enter and exit the cell
The space outside the cell membrane is called the ___________.
Where does life end?
outside the cell membrane. Life is inside the cell membrane.
When does a cell die?
when it cannot maintain the cell membrane
What are glycoproteins?
proteins that are attached to carbohydrates
What are glycolipids?
lipids that are attached to carbohydrates
What function do glycoproteins and glycolipids serve?
both help protect and lubricate the cell and are involved in cell-to-cell interactions.
Each phospholipid molecule contains a _____1______, composed of a ____2______ and ______3_____ that is _______4_______ and ______5_____ in water, and ______6_____, composed of _____7_____ that are _______8_______ and ______9______ in water.
1. polar head
2. phosphate group
3. glycerol
4. hydrophilic (water-loving)
5. soluble
6. nonpolar tails
7. fatty acids
8. hydrophobic (water-fearing)
9. insoluble
Where are the polar heads located in the lipid bilayer?
on the two surfaces of the lipid bilayer
Where are the nonpolar tails located in the lipid bilayer?
in the interior of the bilayer
Draw a glycerol molecule.
What groups o the glycerol molecule are the most reactive?
the hydroxyl groups
What kind of acid is a fatty acid?
a carboxylic acid
What constitutes a fatty acid?
a carboxyl group plus oil (fat)
Draw a fatty acid.
What constitutes a triglyceride molecule?
3 fatty acids + 1 glycerol
What type of chemical reaction will form a glyceride molecule?
a dehydration reaction
How many fatty acids does it take to from a triglyceride molecule?
What are saturated fats?
where the carbons are at their full bond potential (4), there are NO double bonds.
What are saturated fats at room temperature?
What are unsaturated fats?
fats that are not at their full bond potential, have at least one double bond
What are unsaturated fats at room temperature?
What are some examples of saturated fats?
butter, crisco, lard, coconut oil, etc.
What are some examples of unsaturated fats?
corn oil, canola oil, olive oil, etc.
What are polyunsaturated fats?
fats that have more than one double bond
The lipid molecules of a saturated fatty acid are __________ packed.
The lipid molecules of an unsaturated fatty acid are ____________ packed.
What separates fatty acid chains?
sterol molecules such as cholesterol
What is the fluid mosaic model?
the dynamic arrangement of phospholipids and proteins in the lipid bilayer
What does amphipathic mean (referring to phospholipids)?
composed of BOTH polar and nonpolar regions
Are phospholipids in the lipid bilayer static (ie. can't move)?
NO! They can rotate and move laterally but CANNOT flip from one side of the membrane to the other.
The plasma membrane is a viscous as ____________.
olive oil
What is the most important function of the plasma membrane?
To serve as a selective barrier through which materials enter and exit the cell.
Define selective permeability.
this term indicates that certain molecules and ions pass through the membrane, but others are prevented from passing through it.
What is the inside of the cell mostly composed of?
Do eukaryotes have enzymes for ATP production in their plasma membranes?
NO! Only prokaryotes have the enzymes for ATP production located in their plasma membranes.
In some bacteria, pigments and enzymes involved in photosynthesis are found in infoldings of the plasma membrane that extend into the cytoplasm. What are these membranous structures called?
chromatophores or thylakoids
What are mesosomes?
one or more large, irregular folds in the plasma membrane of bacterial cells
What can damage a cell membrane?
alcohols, quaternary ammonium (detergents) and polymyxin antibiotics
Leakage of cell contents is defined as __________.
cell death

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