1.3.1 membrane proteins; movement of molecules across membranes Flashcards

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1
Q

what do regions of hydrophobic R groups allow

A

they allow strong hydrophobic interactions that hold integral membrane proteins within the phospholipid bilayer

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2
Q

what do integral membrane proteins interact extensively with

A

the hydrophobic region of membrane phospholipids

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3
Q

what are some integral membrane proteins known as

A

transmembrane proteins

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4
Q

what type of R groups do peripheral membrane proteins have

A

hydrophilic

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5
Q

where are peripheral membrane proteins bound

A

the surface of membranes

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6
Q

what are the main bonds that allow peripheral membrane proteins to bind with the membrane

A

ionic and hydrogen bonds

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7
Q

what do many of the peripheral membrane proteins interact with

A

the surfaces of integral membrane proteins

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8
Q

what is the phospholipid bilayer

A

a barrier to ions and most uncharged polar molecules

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9
Q

what are examples of small molecules that can pass through the bilayer by simple diffusion

A

oxygen and carbon dioxide

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10
Q

what is facilitated diffusion

A

the passive transport of substances across the membrane through specific transmembrane proteins

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11
Q

what features do different cell types have that allow them to perform specialised functions

A

different channels and transporter proteins

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12
Q

are most channel proteins in animal and plant cells highly selective

A

yes

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13
Q

what are channels

A

mutli subunit proteins with the subunits arranged to form water filled pores that extend across the membrane

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14
Q

how do gated channel proteins allow or prevent diffusion

A

by changing their conformation

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15
Q

what are ligand-gated channels controlled by

A

the binding of signal molecules

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16
Q

what are voltage gated channels controlled by

A

changes in ion concentration

17
Q

where do transporter proteins bind to

A

the specific substance to be transported and undergo a conformational change to transfer the solute across the membrane

18
Q

what do transporter proteins do

A

they alternate between two conformations so that the binding site for a solute is sequentially exposed on one side of the bilayer, and then the other

19
Q

what proteins does active transport use

A

pump proteins that transfer substances across the membrane against their concentration gradient

20
Q

what are pumps that mediate active transport

A

transporter proteins coupled to an energy source

21
Q

what is required for active transport

A

a source of metabolic energy

22
Q

what does ATPase do

A

hydrolyse ATP

23
Q

why do some active transport proteins hydrolyse ATP directly

A

to provide the energy for the conformational change required to move substances across the membrane