Flashcards in Bio 4 Deck (49):
What colour are Gram-negative bacteria?
What colour are Gram-positive bacteria?
Describe the cell wall of Gram-positive bacteria
thick layer of peptidoglycan
Describe the cell wall of Gram-negatice bacteria
thin layer of peptidoglycan in the periplasmic space with an outer membrane with endotoxin outside it
How can endotoxins cause septic shock?
when bacteria die inside us and their disintegrated outer membranes are released into circulation
How is the prokaryotic flagellum different from a eukaryotic flagellum?
has a filament, hook, basal structure and rod (eukaryotic is 9+2 MTs)
requires large amounts of ATP to rotate rod
What are fimbriae?
like pill, but smaller
they are involved in adhering to surfaces
What are pilli?
long projections on the surface of bacteria that are used for attaching to different surfaces i.e. the sex pilus is used for conjugation
What are mesophiles?
like 30 degrees (i.e. us)
What are thermophiles?
survive at temperatures up to 100 degrees C
What are psychrophiles?
thrive at temps near 0 degrees C
What are autotrophs?
use CO2 as their carbon source
What are auxotrophs?
bacterium which cannot survive on minimal medium
What is a plaque in a bacterial lawn?
a clear area where the bacteria have died from lytic viruses or toxins
What is a facultative anaerobe?
use oxygen when its around, but don't need t
What is a tolerant anaerobe?
can grow in the presence of oxygen, but don't use in it their metabolism
What is an obligate anaerobe?
poisoned by oxygen
What is anaerobic respiration?
using something other than O2 as an electron acceptor i.e. SO4- or NO3-
What are endospores?
some Gram-positive bacteria can form tough, thick external shells made of peptidoglycan under unfavourable growth conditions
can survive above 100 degrees C
What is metabolic reactivation of endospores called?
Are bacteria that possess the F factor male or female?
How can conjugation with an Hfr cell transfer other genes?
since it is integrated into the genome, when it is replicated replication can continue into other genes and then they will be transferred too
What is the nuclear matrix or nuclear scaffolding?
insoluble mesh of protein left behind if you treat a nucleus with DNase and detergent
Which RNA polymerase makes rRNA?
RNA polymerase 1
What is a nuclear localization sequence?
sequence of basic amino acids that targets proteins larger than 60kDa to allow them through nuclear pores
What is a signal sequence?
N-terminal amino acid sequence on proteins that targets them to the rough ER via an SRP
on all proteins except the ones going to the nucleus, mitochondria, peroxisomes etc
What is the "default" pathway for proteins that go through the secretory pathway?
the plasma membrane
What is a targeting signal?
amino acid sequence on proteins that need to go somewhere other than the PM in the secretory pathway i.e. Golgi, ER or lysosome
What is a localization signal?
amino acid sequence on proteins that are made in the cytoplasm and need to be sent to an organelle that is not part of the secretory pathway i.e. nucleus, mitochondria, peroxisomes
What is crinophagy?
lysosomal degradation of unneeded secretory products
What is special about the mitochondrial inner membrane?
higher concentration of proteins than lipids
Where is glycosylation found?
on the extracellular surface of membranes only
What is molality? Why is it useful for measuring properties that involve temperature?
mol of solute / kg of solute
because it does not change with temperature
What do colligative properties depend on?
number of solute particles in the solution instead of the type of particle
What is vapour pressure? What happens to it as you add more solute to a solution?
the pressure exerted by the gaseous phase of a liquid that evaporated from the exposed surface of the liquid
higher vapour pressure = evaporates easier
adding more solute will decrease its vapour pressure (raises the boiling point)
Describe boiling-point elevation
boiling point is directly related to the number of particles in solution, more particles the higher the boiling point is
delta T = kbim
kb=solvent's boiling point elevation constant
Describe freezing-point depression
more particles in a solution, lower freezing point
delta T = kfim
kf=solvent's freezing-point depression constant
What is osmotic pressure?
the pressure it would take to stop osmosis from occurring
van't Hoff equation:
osmotic pressure = MiRT
Note: M is the osmolarity of the solution (not osmolality)
What are porins?
polypeptides that form pores in cell membranes
What does the Na+/K+ ATPase move in one cycle?
3 Na+ out of the cell and 2 K+ into the cell
(hydrolyzes ATP to do this)
What are the 3 types of endocytosis?
What is the secondary messenger used for epinephrine and glucagon?
When is the alpha subunit of a G-protein-coupled-receptor active?
when bound to GTP it will dissociate and activate or inhibit adenylyl cyclase or other enzymes
How large is the diameter of microtubules?
What is the diameter of intermediate filaments?
What is the diameter of microfilaments?
(these are actin filaments)
What do desmosomes do?
hold cells together tightly, but don't form a seal like tight junctions would
are found in the epithelial cells in the skin
anchored to the PM by keratin, attach to the intermediate filaments of the cytoplasm
What is another name for tight junctions?