Exam 1 - Lecture 4 Flashcards
what is one thing that archaea don’t do that bacteria do?
cause disease!
do archaea have 70S or 80S ribosomes?
70S
what are the components of the archaeal cell envelope?
- plasma membrane
- cell wall
- additional external layers
what is a major difference between archaeal and bacterial cell walls?
archaea do not have peptidoglycan
what is the five carbon building block for archaeal membrane lipids?
isoprene
match the following:
a.) archaeal lipids
b.) bacterial lipids
c.) eukaryotic lipids
1.) ether linkages to glycerol
2.) ester linkages to glycerol
3.) no linkages to glycerol
a1.) archaea have ether linkages
b2.) bacteria have ester linkages
c2.) eukarya have ester linkages
what do pentacyclic rings do in the archaeal membrane?
they increase rigidity by shrinking the membrane
what’s the differences between a monolayer and a bilayer?
monolayer: one amphipathic molecule with two hydrophobic ends, lined up next to one another
bilayer: two layers of amphipathic molecules exhibiting the hydrophobic effect
true or false: archaeal cell walls are more diverse than bacteria.
true, they come in so many flavors
all organisms have a __________________ surrounding their cytoplasm
plasma membrane
what is the most common type of archaeal cell wall?
S layer outside of the plasma membrane
what does the S layer consist of?
proteins or glycoproteins
what is pseudomurein?
a peptidoglycan-like polymer found in some archaeal cell walls
what are the two monomers of pseudomurein?
NAT and NAG sugars
what are the three differences between pseudomurein and peptidoglycan?
- NAT, not NAM sugar
- 1-3 linkage instead of 1-4
- L- amino acids, no D-
what type of archaeal cell wall normally stains like Gram-positive?
thick polysaccharide layer with plasma membrane
are archaeal ribosomal proteins more similar to bacteria or eukarya?
eukarya
what is the nucleoid? where is it found? is it usually membrane bound?
- an irregularly shaped region that is usually one circular dsDNA chromosome
- found in archaea and bacteria (some archaea have histones)
- it’s usually not membrane bound
what are three external structures that can be found in archaea?
pili
cannulae
hami (grappling hook like)
assign the following to archaea or bacteria:
thinner flagella
hollow flagella
growth of flagella occurs at base
thinner flagella: archaea
hollow flagella: bacteria
growth of flagella occurs at base: archaea
what two structures contribute to the strength of the plasma membrane bilayer in eukaryotes?
sphingolipids and cholesterols
what type of linkages do eukaryotic fatty acids have to glycerol?
ester linkages
true or false: eukaryotes lack a cell wall
true
what is the cytoskeleton and what is it’s role in eukarya?
- vast network of interconnected filaments within the cytoplasmic matrix
- plays a role in cell shape and cell movement
what are the three filaments that form the cytoskeleton in eukaryotes?
- microfilaments (actin filaments)
- microtubules
- intermediate filaments
how big are actin filaments in diameter?
what are the roles of actin?
- 4 to 7 nm
- roles in cell motion and shape changes
how big are intermediate filaments in diameter?
~10 nm
how big are microtubules in diameter?
what is its role?
- ~25 nm
- helps maintain cell shape
what is the role of lysosomes?
intracellular digestion
what is endocytosis?
when solutes or particles are taken up and enclosed in vesicles pinched from the plasma membrane
what is the role of ribosomes?
protein synthesis
how big is the eukaryotic ribosome? what are the two subunits?
- 80S
- 60S (large)+ 40S (small)
what are the rRNA molecules present in the 60S subunit? how many proteins are present?
- 28S, 5S, 5.8S
- 50 proteins
what are the rRNA molecules present in the 40S subunit? how many proteins are present?
- 18S
- 30 proteins
match the following:
a.) ER ribosomes
b.) free ribosomes
1.) cytoplasmic proteins
2.) secreted and membrane proteins
a2.) ER: secreted and membrane proteins
b1.) free: cytoplasmic proteins
what are two prominent external structures found in eukaryotic cells? what role are they both associated with?
- cilia and flagella
- motility
how long are flagella? what about cilia?
- flagella: 100-200um long
- cilia: 5-20um long
what kind of wave movement pushes flagella forward? which pulls the cell?
push: wave from base to tip
pull: wave from tip to base
what are the two phases of cilia movement?
the effective beat and the recovery beat (like rowing a boat)
