Question

For the last question "which says fill in the following.. ect" its chart in the second pic. Answer them all please!

Indicate whether each of the following is: associated with Gram positive or Gram negative cell wall structure AND its function STRUCTURE G + FUNCTION Teichoic Acid Porins Peptidoglycan O Antigen LPS Layer What is the difference between an endotoxin and exotoxin? Fill in the following chart indicating which type of cell would contain the structure. If both contain it, what are the differences in the structure between the two cell types.

Answer 1

Structure	Gm+Ve	Gm-Ve	Function
Teichoic acid	present	Absent	These are fibres of glycerol phosphate. They help the bacteria to adhere to the host surface and helps in pathogenesis.
Porins	In some gm+ve Mycobacteria.	Present	These are major outer membrane proteins, they act like an ion channel, these are wide water filled pores which helps in passively transporting hydrophilic molecules of various size across the membrane of the cell.
Peptidoglycan layer	They are thicker in gm +ve bacteria	They are thinner in gm-Ve bacteria	These are polymers of amino acids and sugars, they help in protecting bacteria from environmental shock, help in maintaining structure of bacteria, it acts as a barrier for cell taking much water by preventing much intake of water it protects bacteria from lysis.
O-antigen	Absent	present	These are found in the outer membrane of bacteria in lipopolysaccharides (LPS), O antigen is present on the outermost part of LPS, when O antigen present in LPS it is called rough, bacteria with rough LPS are more penetrable to hydrophobic antibiotics. As O antigen are present on Outer surface they are target for recognition by host antibodies. O antigen are toxic and responsible for virulence of Gm-Ve bacteria.
LPS layer	Usually absent but present only in one Gm+ve bacteria that is in Listeria monocytogenes.	Present	Lipopolysaccharide layer is the outermost membrane present in the cell wall of Gm-ve bacteria, it is an important characteristic feature of Gm-Ve bacteria. They gives structure to the cell wall and protects cell membrane from chemical attack. These are pyrogenic causes fever, also they give endotoxin shock.

q2)Difference between endotoxin and exotoxin.

Exotoxins:- these are toxins secreted by bacteria and released outside the cell.

Endotoxins:- These are the toxins having lipids found inside the cell, when bacteria ruptures or disintegrates they come out.

Exotoxin

Endotoxin

1. Found in Gm +ve and some gm -Ve bacteria. 2. These are released from the cell. 3. These are protein in nature. 4. These can be converted to toxoids. 5. They have strong immune reactions. 6. Do not cause fever. 7. It shows enzymatic activity. 8. On boiling it gets denatured. 9. It’s molecular weight is 10 KDa. 10. Its antigenicity is high. 11. These are specific to particular bacterial strain. 12. These are heat liable are destroyed beyond 60-80 degree celsius. 13. Their immune reaction strong.

1. Found in lysed Gm -Ve bacteria. 2. These are part of the cell. 3. These are lipopolysaccharide in nature. 4. They cannot be converted into toxoids. 5. They have weak immune reaction. 6. Causes fever. 7. It do not show enzymatic activity. 8. on boiling it cannot be denatured. 9. It’s mol.Wt. is 50-1000KDa. 10. It has poor antigenicity. 11. These are nonspecific in nature. 12. These are heat stable. 13. They have weak immune reaction.

Q3)

structure		Eukaryote		prokaryote
Cell wall		Found only in plant cells and fungi.		present
Cell membrane		present		present
DNA		Single loop of stable chromosomal DNA found stored in an area called nucleoid.		DNA is found on tightly bound organized chromosome.
Ribosome		Larger ribosome found		Smaller ribosome found
Mitochondria		present		absent
Nucleus		present		absent
cytoplasm	In eukaryotes it is Present, here cytoplasm is the substance present between plasma membrane and nuclear envelop. Membrane bound cell organelles are found here.		In prokaryotes it is present, here the total content found inside plasma membrane is cytoplasm.