Biological Principles of Human Medicine (Stoyanov)
Wichtiges zum merken aus den Kurs Biological Principles of Human Medicine
Wichtiges zum merken aus den Kurs Biological Principles of Human Medicine
What tree types of shape are common in bacterias?
Spherical cells
Rod shaped
spiral cells
Why is the cell wall for bacterias important?
The plasma membrane is very thin and would break on it's own. the Cell wall supports this structure
How big is a bacteria? how big is a eucaryotic cell?
Bacteria: around 1um
Eucaryot: around 10-20um
How do bacteries move around?
With the help of the flagellum
What is a fission and where is it used?
Fission is the last step of the BACTERIAL cell division.
Only used for bacterias
What are the 4 steps fo the bacterial cell division?
Replication
Translocation
Ingrowht of plasma membrane and cell wall
Cell division (Fission)
How can bacterias be classified? in what two categories?
Gram-positive: thick cell wall
Gram-negative: two membranes
Gram is a kind of stain that olors the cell wall purple
What ar the two different surface structures of bacteria and how are they called?
Flagelllum: used du move around, helical shaped
pilus: used to exchange genetic material, "spike" shaped
Why are most bacterias non pathogenic?
Phatogenic bacterias usually carry patogenic "islands" and are thus bigger than the nonpathogenic coresponding bacteria.
Bigger bacterias require more energy
What two mechanism are there for cells to take up bacteria (Phagocytosis)?
Zipper mechanism
and trigger mechanism
How can epithelia help to defend against microbial invasion?
It secrets antimicribial molecules
What can not be targeted by antibiotics?
The "Capsule", a slimy surface that protects the bacteria
What role play antibiotics in the mutation of bacteria?
They do not cause the mutation (mutation has always been there). But they select for them by killing the ones that are not mutated and thus now have more space and nutrients to grow even more
name two tools of genetric engineering?
Plasmids: rings of DNA that do not belong to the bacterial chromosome
Restriction of enzymes: cutting the dna either with sticky or blunt ends
What do all viruses have in common?
They have some kind of shell and inside the nucleic acid
But they vary greatly in shape and size
What do viruses posses (or better said not) that all other living cells have?
Viruses have either DNA OR RNA, but not both (all other cells have both)
Name two types of Viral genomes
Single-stranded RNA
Double-stranded circular DNA
What do virueses rely on to replicate?
They depend on ribosomes, enzymes and metabolities of the host cell to replicate (can't on theyr own)
What is a simple viral life cycle?
1: entry into cell and uncoat dna
2: replicate DNA or Transcribe DNA to RNA
3: Assembly new viruses and exit cell
Why is it difficult to generate a vaccine against HIV?
Because the surface proteins of the viral envelope of HIV changes very fast
What does an enzyme do?
It lowers the actication energy and makes reactions go faster.
What does GATC stand for?
G: guanine
A: adenine
T: thymine
C: cytosine
What is the role of hydrogen and covalen bonds in forming DNA?
Hydrogend bonds bring the DNA together, covalent bonds hold them together.
Like scotch (hydorgen bonds) to stick something to the wall and then screw (covalent bonds) it down
In which direction does the DNA replication flow?
Always from 5' to 3'.
The two strings develop in antiparalell direction
How is eucaryotic DNA packed?
Into 22 chromosomes (plus X and Y chromosome)
They consist of a centremere (where the genes get separated) and the telomere
What is the most common protein in DNA?
Histons
How many levels of DNA packaging are there in chromosomes?
Explain them
6 levels.
1. DNA double helix , 2. beads-on-a-string --> chromatin, 3. cromatin fiber of packed nucleosomes
4. section of chromosome, 5. condensed section of chromosome 6. entire mitotic chromosome
What is nucleodynamics?
If the DNA gets packed and unpacked in different configurations to allow acess to different parts at different times
Where does the DNA synthesis begin? Which way do they move?
At Replication origins and move in both directions
Where does the energy come from to drive the DNA synthetisation?
From deoxyribonucleoside triphosphates
What bases do connect together?
Adenine and Thymine
Cytosine and Guanine
What is a nucleotide?
A base (GAT or C) covalently attachet to a pentose and with a posphate group
How are the two stings of DNA connected?
Hydrogen bonds bring them together, covalent bonds fix them
Why are wome more reistent to genetic disesas?
They have two X chromosomes, which are long thus an error can be compensated.
Males with an X and a Y chromosome (which is shortter) can not fix mistakes that easyli
What does it mean that the DNA replication is Semiconservativ?
1 Strand is the template and one new strand gets syntetisized
In which direction is the DNA synthetisation going? and why?
From 5' to 3' direction.
It can only go this way because the molecule is Polar
What is an osaki fragment?
Fragments in the lagging strand of the DNA synthetization
Other strand is the leading strand
What does it mean if a chain gets nucleised?
The chain deforms back in to nucleotides
What do mutations do to the DNA sequence?
They change it
What is the DNA Polymeraze? What is different to the DNA Ligase?
Enzyme that catalyzes the DNA syntesition, and brings its own nucleotides
DNA Ligase is used for repair and therefore brings NO new nucleotide
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Cartes-fiches
Name two types of Viral genomes
Single-stranded RNA
Double-stranded circular DNA
What do virueses rely on to replicate?
They depend on ribosomes, enzymes and metabolities of the host cell to replicate (can't on theyr own)
What is a simple viral life cycle?
1: entry into cell and uncoat dna
2: replicate DNA or Transcribe DNA to RNA
3: Assembly new viruses and exit cell
Why is it difficult to generate a vaccine against HIV?
Because the surface proteins of the viral envelope of HIV changes very fast
