Exam 1 - Lecture 4

Question 1

what is one thing that archaea don’t do that bacteria do?

Answer 1

cause disease!

Question 2

do archaea have 70S or 80S ribosomes?

Answer 2

70S

Question 3

what are the components of the archaeal cell envelope?

Answer 3

• plasma membrane
• cell wall
• additional external layers

Question 4

what is a major difference between archaeal and bacterial cell walls?

Answer 4

archaea do not have peptidoglycan

Question 5

what is the five carbon building block for archaeal membrane lipids?

Answer 5

isoprene

Question 6

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

Answer 6

a1.) archaea have ether linkages
b2.) bacteria have ester linkages
c2.) eukarya have ester linkages

Question 7

what do pentacyclic rings do in the archaeal membrane?

Answer 7

they increase rigidity by shrinking the membrane

Question 8

what’s the differences between a monolayer and a bilayer?

Answer 8

monolayer: one amphipathic molecule with two hydrophobic ends, lined up next to one another

bilayer: two layers of amphipathic molecules exhibiting the hydrophobic effect

Question 9

true or false: archaeal cell walls are more diverse than bacteria.

Answer 9

true, they come in so many flavors

Question 10

all organisms have a __________________ surrounding their cytoplasm

Answer 10

plasma membrane

Question 11

what is the most common type of archaeal cell wall?

Answer 11

S layer outside of the plasma membrane

Question 12

what does the S layer consist of?

Answer 12

proteins or glycoproteins

Question 13

what is pseudomurein?

Answer 13

a peptidoglycan-like polymer found in some archaeal cell walls

Question 14

what are the two monomers of pseudomurein?

Answer 14

NAT and NAG sugars

Question 15

what are the three differences between pseudomurein and peptidoglycan?

Answer 15

• NAT, not NAM sugar
• 1-3 linkage instead of 1-4
• L- amino acids, no D-

Question 16

what type of archaeal cell wall normally stains like Gram-positive?

Answer 16

thick polysaccharide layer with plasma membrane

Question 17

are archaeal ribosomal proteins more similar to bacteria or eukarya?

Answer 17

eukarya

Question 18

what is the nucleoid? where is it found? is it usually membrane bound?

Answer 18

• 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

Question 19

what are three external structures that can be found in archaea?

Answer 19

pili
cannulae
hami (grappling hook like)

Question 20

assign the following to archaea or bacteria:

thinner flagella
hollow flagella
growth of flagella occurs at base

Answer 20

thinner flagella: archaea
hollow flagella: bacteria
growth of flagella occurs at base: archaea

Question 21

what two structures contribute to the strength of the plasma membrane bilayer in eukaryotes?

Answer 21

sphingolipids and cholesterols

Question 22

what type of linkages do eukaryotic fatty acids have to glycerol?

Answer 22

ester linkages

Question 23

true or false: eukaryotes lack a cell wall

Answer 23

true

Question 24

what is the cytoskeleton and what is it’s role in eukarya?

Answer 24

• vast network of interconnected filaments within the cytoplasmic matrix
• plays a role in cell shape and cell movement

Question 25

what are the three filaments that form the cytoskeleton in eukaryotes?

Answer 25

• microfilaments (actin filaments)
• microtubules
• intermediate filaments

Question 26

how big are actin filaments in diameter?

what are the roles of actin?

Answer 26

• 4 to 7 nm
• roles in cell motion and shape changes

Question 27

how big are intermediate filaments in diameter?

Answer 27

~10 nm

Question 28

how big are microtubules in diameter?

what is its role?

Answer 28

• ~25 nm
• helps maintain cell shape

Question 29

what is the role of lysosomes?

Answer 29

intracellular digestion

Question 30

what is endocytosis?

Answer 30

when solutes or particles are taken up and enclosed in vesicles pinched from the plasma membrane

Question 31

what is the role of ribosomes?

Answer 31

protein synthesis

Question 32

how big is the eukaryotic ribosome? what are the two subunits?

Answer 32

• 80S
• 60S (large)+ 40S (small)

Question 33

what are the rRNA molecules present in the 60S subunit? how many proteins are present?

Answer 33

• 28S, 5S, 5.8S
• 50 proteins

Question 34

what are the rRNA molecules present in the 40S subunit? how many proteins are present?

Answer 34

• 18S
• 30 proteins

Question 35

match the following:

a.) ER ribosomes
b.) free ribosomes

1.) cytoplasmic proteins
2.) secreted and membrane proteins

Answer 35

a2.) ER: secreted and membrane proteins
b1.) free: cytoplasmic proteins

Question 36

what are two prominent external structures found in eukaryotic cells? what role are they both associated with?

Answer 36

• cilia and flagella
• motility

Question 37

how long are flagella? what about cilia?

Answer 37

• flagella: 100-200um long
• cilia: 5-20um long

Question 38

what kind of wave movement pushes flagella forward? which pulls the cell?

Answer 38

push: wave from base to tip
pull: wave from tip to base

Question 39

what are the two phases of cilia movement?

Answer 39

the effective beat and the recovery beat (like rowing a boat)