uptake of nutrients

Question 1

how do nutrients enter a cell

Answer 1

they have to cross the PM

Question 2

what can pass through the PM freely

Answer 2

small + non polar molecules (ie water, oxygen, co2, hydrocarbons)

Question 3

what cannot pass through the PM freely

Answer 3

large molecules, polar molecules, ions, or any molecule with an electrical charge

Question 4

how can the large/polar/charged molecules cross the Pm (ie what is needed)

Answer 4

special proteins are needed (called transporters or permeases)

Question 5

what are the two types of transporters/permeases

Answer 5

channel or carrier

Question 6

what are the two types of transport across the PM

Answer 6

passive and active

Question 7

describe passive diffusion

Answer 7

can be simple or facilitated (requires permeases), no energy is requires bc it’s with the gradient

Question 8

describe active transport

Answer 8

energy is requires bc it’s against the gradient, uses carrier proteins

Question 9

what type of transport (passive or active) do bacteria use primarily + why

Answer 9

active, because they’re usually in a low nutrient environment and need to bring nutrients in

Question 10

what three active transport processes happen in prokaryotes

Answer 10

primary active transport
secondary active transport
group translocation

Question 11

how are the three active transport processes of prokaryotes distinguished

Answer 11

distinguished based upon the energy used to drive transport and whether the solute is modified as it’s transported

Question 12

describe primary active transport

Answer 12

transport across the membrane is mediated by energy from ATP hydrolysis

Question 13

is the molecule modified in primary active transport

Answer 13

no

Question 14

what type of carrier protein is used in primary active transport

Answer 14

uniporters

Question 15

give an example of primary active transport

Answer 15

ABC transporters

Question 16

describe secondary active transport

Answer 16

transport across the membrane is mediated by the potential energy of ion gradients

Question 17

is the molecule modified in secondary active transport

Answer 17

no

Question 18

what type of carrier is used in secondary active transport

Answer 18

cotransporters – symport or antiport

Question 19

describe group translocation

Answer 19

molecules are modified as they cross the membrane

Question 20

give an example of group translocation

Answer 20

phosphoenolpyruvate: sugar phosphotransferase system (PTS)

Question 21

describe the PTS

Answer 21

the system is involved in transporting glucose, mannitol, fructose into E coli

Question 22

how is the molecule modified in PTS (group translocation)

Answer 22

it’s phosphorylated

Question 23

what is the P donor for the molecule in the PTS (group translocation)

Answer 23

phosphoenolpyruvate (PEP)

Question 24

T or F: almost all microbes require iron

Answer 24

true

Question 25

which form of iron is found in the evironment

Answer 25

Fe3+

Question 26

T or F: Fe3+ is soluble and easy to take into the cell

Answer 26

false; it’s insoluable

Question 27

how do cells combat Fe3+ being insoluble when they need iron

Answer 27

many bacteria secrete low molecular weight organic molecules called siderophores