Molecular Biology Flashcards Lectures 1-7

Front 1

prokaryotes

Back 1

1 micron in diameter
very large surface to volume ratio
pili flagella, secretion needles
shape: cocci (spheres)
bacilli (rods)
spirilla (spirals)
have a glycocalyx
outer membrane and periplasm found in gram negatives only
cell wall present in all eubacteria except mycoplasma
p-bilayer present
cytoplasm: undifferentiated
organelles: not membrane bound,
DNA: circular chromosomes, sometimes linear
Cell division: binary fission
Endospores: formed predominantly in gram positive bacteria

Front 2

eukaryotes

Back 2

flagella
found in some species
no outer membrane or periplasm
don't contain component of peptidoglycan
has cytoskeleton and cytoplasmic streaming
always membrane bound organelles
DNA: paired chromosomes
Cell division: mitosis for growth, meiosis for reproduction
size: 10 microns

Front 3

unrestricted growth

Back 3

dn/dt=KN, growth is exponential

Front 4

balanced growth

Back 4

constant growth at a steady rate, rarely achieved in the microbial world

Front 5

phases of growth

Back 5

lag phase: time for bacterial cell to sense it's in the nutrient rich environment
exponential phase: very short, exhaustion of nutrients, buildup of toxic compounds
stationary phase: period of substantial cellular adjustments where cells can no longer grow (death and growth balanced)
death: constant rate of loss by cells

Front 6

bacterial habitats

Back 6

Everywhere, has commensal, symbiotic and parasitic relationships

Front 7

normal flora

Back 7

humans are made up of more bacterial cells than human cells

Front 8

probiotics

Back 8

live microorganisms that when administered in adequate amounts confer health benefit on host

Front 9

parasitic/pathogenic

Back 9

association of a microbe where host is harmed or killed

Front 10

biofilms

Back 10

complex communities of microbes that survive when subjected to environmental insult

Front 11

strict aerobes

Back 11

pseudomonas, depend only on oxygen

Front 12

strict anaerobes

Back 12

sensitive to oxygen (Bacterioides, Clostridium)

Front 13

Facultative anaerobes

Back 13

E. Coli, Strep. pneumoniae, can grow with or without oxygen. Aerobic metabolism yields 32 ATP,s anaerobic yields 2 ATP's

Front 14

Generation of ATP

Back 14

i). chemiosmosis: ATP production that is coupled to electron transport across a membrane
ii). substrate level phosphorylation: generation of a highly reactive phosphate bond as a metabolic intermeidate and transfer that bond to ADP to make ATP

fermentation: recycles NAD+ for use in oxidative phosphorylations

Front 15

prototrophs v auxotrophs

Back 15

bacteria have no requirements for organic compounds (proto)

bacteria that have more complex nutritional requirements (auxo)

Front 16

gram stain

Back 16

stain crystal violet meant to identify bacterial type

Front 17

gram positive

Back 17

thick cell wall, only inner membrane, stain gets retained in thick cell wall

Front 18

gram negative

Back 18

double membrane, thin cell wall, presence of periplasm place, presence of LPS and lipid A on outer membrane, more resistant to antibiotics and other degradative chemicals

Front 19

B subunit RNA pol

Back 19

catalytic activity

Front 20

B' subunit

Back 20

allows RNA pol to bind to and stay bound to DNA

Front 21

alpha subunit

Back 21

plays an important role in interaction with regulator proteins

Front 22

sigma factor

Back 22

necessary for recognition of promoter region

Front 23

actinomycin D

Back 23

binds to DNA, rendering it unusuable as a template

Front 24

rifampicin

Back 24

blocks translocation after first translation

Front 25

SOS response

Back 25

involves lexA, recA repressor gets activated in UV light and then degrades LexA repressor, along for SOS gene to be expressed

Front 26

gram (-) signaling molecules

Back 26

homoserine lactones

Front 27

gram (+) signaling molecules

Back 27

peptides

Front 28

Viruses

Back 28

Can be either double stranded DNA or RNA, or can be single stranded, consists of a protein coat (capsid) and maybe a lipid membrane derived from host. Contractile sheath, tail fibers!

Front 29

Viral Development

Back 29

1). Adsorption
2). Penetration (injection, receptor mediated endocytosis)
membrane fusion
3). gene expression of viral DNA
4). synthesis of proteins involved in nucleic acid replication
5). synthesis of structural proteins

Front 30

Phage Receptors

Back 30

Polysaccharides
O-antigen (LPS)
Porins
Sialic acid (eukaryotes)

Front 31

Adsorption

Back 31

Tail fibers make contact with capsid, porin, etc, reversible in contact. But once tail fibers flex, we have beginnig!

Front 32

Contraction

Back 32

Contractile sheath allow for injection of nucleic acids into periplasm, where they are transported by DNA transporters

Front 33

T4 bacteriophage

Back 33

binds to ompC porin (high osmolarity)

Front 34

MS2

Back 34

ssRNA, circular phage, rolls down pilus until it makes contact with the membrane

Front 35

PFU assay

Back 35

take bacteria and put on agar, make a bacterial lawn and then plate phages or bacterially infected cells on it

Front 36

bacterially infected cells plating on lawn

Back 36

have a sigmoidal curve, latent period

Front 37

phages infecting on the lawn

Back 37

have a curve that comes flat and has a faster period

Front 38

difference between eclipse period and latent period

Back 38

shows that there is a lag time, there is a need to produce various factors and proteins, including late and early DNA, and etc to form virions

Front 39

average burst size

Back 39

# PFU/infected cells

Front 40

T4 bacteria phage

Back 40

dsDNA linear, rollinc circle replication, T4 completed capsid swallows off more than one genome, duplicated genes results in possibilities for recombination

Front 41

phage lambda

Back 41

rolling circle, virus has certain 1 genome length, ssDNA complementary ends, sticky, area of religation is called cos site!

Front 42

bacteria and phage mutation dynamics

Back 42

bacteria try to fend themselves off with mutations in receptors, restriction endonucleases

viruses respond by mutating tail fibers, or finding means to avoid restriction endonucleases

Front 43

phage therapy

Back 43

panacea of therapies, 1940's goes against modern notion of antibiotics. However it can work! Still exploring possibilities.