Section 2 Flashcards
Two Types of Cells
1- Eukaryotic
2- Prokaryotic
Examples of Eukaryotic cells
Make up non-mircroscopic like. 1- mammals 2- Fungi 3- algae 4- Plants 5- Protozoa
Prokaryotes
1- All Bacteria
2- Achaea
How many human eukaryotic cells genes are there
25,000
How many genes does bacteria cells have
5,000
Bacteria size
1/1000 the volume of our cells
Bacteria cells lack
1- internal membraned bound organelles 2- 70s Ribosomes 3- Complex Walls 4- 1000x smaller than human cells 5- circular dsDNA
Bacteria outer wall
Unique outer wall that covers the cell plasma membrane and protects from osmotic lysis.
Three major life forms
1- Bacteria
2- Archaea
3- Eucarya
measured by genetic similarity
Humans can be infected by Eukaryotic Pathogens
1- Fungi
2- Helminths
3- Portozoa
Prokaryotic microorganisms that infect humans
1- bacteria
2- a Few Archea
Bacteria can be decided into two categories
1- gram +
2- gram -
Gram + Bacteria
1- have thick outer cell wall with peptidglycan outside a single inner plasma membrane
Gram - Bacteria
1- have thin cell wall sandwiched between the cell membrane and a unique outer membrane.
2- the outer-membrane contains lipopolysaccharide (LPS)
Viruses two categories
1- enveloped
2- non-enveloped
Enveloped virus
much less hardy than non-enveloped
Prions
small infectious proteins
Bacteria protein synthesis
1- mRNA is transcribed directly in the presence of ribosomes, there is little lag in protein productions which means the bacteria can respond quickly to environmental changes.
Ribosome 70s
1- different than eukaryotic 80s
2- Target site for some antibiotics
Bacteria wall
1- regular bi-lipd cell membrane
2- rigid cell wall (another target for antibiotics)
Bacterial structures anchored to cell membrane or cell wall
1- Pili/Fimbrae
2- Flagella
3- Capsule
4- Lipopolysaccharide (LPS)
Pili/Fimbrae
1- used for attachment and conjugation
2- Leptin
Flagella
Locomotion
Capsule
1- protect from phagocytosis
2- Anti-phagocytic
1- Protect from PMNs and macrophages
Lipopolysaccharide
1- major virulence factor, found in the outer membrane of gram - bacteria
2- Inflammatory Toxin
3- Endotoxin
4- Activate macrophages
Bacteria secrete many digestive enzymes
to breakdown carbohydrates and proteins into small sugars and AA which are taken up by small pores
Digestive enzymes may cause
damage to human tissue which cause pathology
Bacteria must also steal
essential molecules (e.g. iron) from the host
Bacteria releases waste
into the immediate environment which could be used as nutrient source for other bacteria
Biofilms
Complex ecological bio-systems where bacteria live
Lectin
binds bacteria to host and other bacteria
Bacteria Cell Wall
1- essential, all enclosing, rigid, porous, protective-girdle that surrounds the bacterial cell
2- Protects the plasma membrane from osmotic pressure
Bacteria cell wall made of
polysaccharide chain cross linked by peptides
Polysaccharide chains
formed by repeating, modified glucose dimers called:
1- N-acetylglucosamine (NAG)
2- N-acetylmuramic acid (NAM)
Cell wall synthesis
1- Cytoplasm
2- short peptide is bound to a disaccharide (NAG-NAM-peptide)
3- transported through the cell membrane
4- joined to a growing peptidoglycan chain by a transport enzyme complex
5- 20 or so dimers are linked into a structural girder just outside the cell membrane, fall off the transport enzyme complex and bump into the inside of the existing cell wall.
6- Membrane bound enzyme Transpeptidase spot welds these girders into place by cross-linking the peptides hanging from the girders to peptides dangling from the existing wall.
Transpeptidase
spot welds peptidoglycan into place by cross-linking the peptides hanging from peptidoglycan to the existing wall.
Autolysins
degrades and synthesizes peptidoglycan
Small amount of LPS
Excellent at activating the innate immune reaction
Large amount or systemic amounts of LPS
1- Cause serious problems
2- In blood vessels clotting system is activated leading to disseminated intravascular coagulation
Disseminated Intravascular coagulation
Obstructed blood flow in the affected blood vessels, causing damage to death to the underlying tissue.
Macrophages when activated by LPS
1- LPS Binds to TLR-4 recpetor
2- secret NO compounds onto surrounding tissue which include proteases that breakdown extracellular matrix (collagen) - collegenase
3- PGE2 (Prostaglandin-E2) (Activates osteoclasts to resorb bone) and TNF alpha (Tumor Necrosis Factor) (signals endothelial cells to produce more NO, which causes pre-capillary sphincters to relax (inflammation)
1- Hypovolemic shock (septic shock)
1- too many capillaries in the body opened up at one time causing blood pressure to fall dramatically
Hypovolemic shock
1- Septic Shock
2- too many capillaries in the body opened up at one time causing blood pressure to fall dramatcially
Starch/Glycogen
1- Energy storage
2- Amylase (Pancreatic enzyme)
Cellulose
Structural
Peptidogylcan
1- Structural
2-Lysozyme
Lysozyme
Found in
1- Tears
2- Saliva
Chitin
Extracellular matrix
