Busy. Please wait.
or

show password
Forgot Password?

Don't have an account?  Sign up 
or

Username is available taken
show password

why


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.


Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.

Remove Ads
Don't know
Know
remaining cards
Save
0:01
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
Retries:
restart all cards




share
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Chapter 3

Cell Wall

QuestionsAnswers
Q: What gives the cell wall of bacteria its rigidity? A: Peptidoglycan (PTG)
Q: What is the basic structure of peptidoglycan (PTG)? A: An alternating series of two subunits, N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM), which form two glycan chains. The two glycan chains are held together by a string of four amino acids.
Q: The cell wall of gram positive bacteria is made up of how many layers of peptidoglycan (PTG)? A: As many as 30 layers making it a thick cell wall.
Q: What gives a bacterial cell its negaive charge? A: Teichoic acid.
Q: The cell wall of gram negative bacteria is made up of how many layers of peptidoglycan (PTG)? A: Two to three layers making it a thin cell wall.
Q: The peptidoglycan (PTG) of gram negative bacteria can be found where? A: In a region between the outer membrane and the cytoplasmic membrane know as the periplasm.
Q: True or false? In gram positive bacteria peptidoglycan (PTG) is sandwiched between an outer membrane and the cytoplasmic membrane. A: False! This is true only of gram negative bacteria.
Q: Aside from the cell wall, what can be found in the periplasm? A: Secreted proteins and proteins of the ABC transport system.
Q: The cell wall of gram negative bacteria has an outer membrane. What is it made of? A: The outer membrane (aka lipopolysaccharide layer or LPS layer) is a lipid bilayer made up of lipopolysaccharides.
Q: The outer membrane of the cell wall in gram negative bacteria serves as a barrier to large molecules but allows small molecules and ions through channels called _______. A: Porins.
Q: The outer cell membrane of gram negative bacteria has two portions, an inner and an outer. What are these portions called? A: The inner portion is “Lipid A” and the outer portion is called an “O-specific polysaccharide side chain”.
Q: True or false? Lipid A is considered an endotoxin. A: True!
Q: Whay are gram negative infections considered deadly? A: Because lipid A is an endotoxin.
Q: What anchors lipopolysaccharide molecules in the lipid bilayer and plays a role in recognition of infection? A: Lipid A.
Q: Which part of the outer membrane is used to identify certin species or strains? A: The O-specific polysaccharide side chain.
Q: True or false? Many antimicrobials, such as Penicillin and Lysozyme, interfere with the synthesis of peptidoglycan (PTG). A: True!
Q: Is Penicillin better against gram positive or gram negative bacteria. A: Penicillin is more effective against gram positive due to increased concentration of peptidoglycan (PTG).
Q: Penicillin is completely ineffective against gram negative bacteria. A: False! There are Penicillin derivatives produced to protect against gram negative bacteria.
Q: Name two places where lysozymes are produced. A: Lysozymes are produced in many body fluids including tears and saliva.
Q: What does a lysozyme do? A: Lysozymes destroy the integrity of the cell wall by breaking the bond linking NAG and NAM.
Q: Two examples of a lysozyme given in class were _______ and _______. A: Protease and nuclease.
Q: What accounts for differences in staining characteristics of gram negative and gram positive bacteria? A: The cell wall.
Q: When using a Gram stain, gram positive bacteria will stain _______ and gram negative bacteria will stain ______. A: Gram positive will be purple and gram negative will be pink.
Q: True or false? All bacteria have a cell wall. A: False! Some bacteria naturally lack a cell wall.
Q: If a bacterium lacks a cell wall, what is responsible for maintaining the cell shape? A: Sterols in the membrane.
Q: Give an example of a bacterium without a cell wall. A: Mycoplasma.
Q: Does Penicillin have any effect on mycoplasma? Why or why not? A: No, because mycoplasma have no cell wall.
Q: True or false? Bacteria in domain Archae contain peptidoglycan. A: False! Bacteria in domain Archae have a wide variety of cell wall types but NONE contain peptidoglycan (they contain pseudo-peptidoglycan).
Q: What causes the mild form of pneumonia known as "walking pneumonia"? A: Mycoplasma
Q: Together, the two layers outside the cell wall are referred to as ______? A: Glycocalyx (glyco = sugar / calyx = shell).
Q: There are two layers external to the cell wall of bacteria. What are they? A: The capsule and the slime layer.
Q: True or false? Bacterial capsules are a distinct gelatinous layer. A: True!
Q: True or false? Bacterial slime layers are irregular diffuse layers. A: True!
Q: Chemical composition of capsules and slime layers varies depending on bacterial species but most are made up of _______. A: Polysaccharide.
This MICROBIOLOGY stack covers the section of chapter 3 entitled CELL WALL. (blank)
Created by: PCC Microbiology