Lecture 15 Membrane Structure (ch11) Flashcards

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1
Q

What is more abundant, proteins or lipids in the cell membrane? (and by how much)

A

Lipids are 50x more than proteins

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2
Q

What makes up 50% of the membrane mass and does most of the cell membrane’s functions?

A

Protiens! Because they are bigger they take up more mass

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3
Q

What is an example of an anchor protein?

A

Integrin

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4
Q

What is an example of an ion channel proteiN?

A

K + leak channel (K+ can leave cell)

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5
Q

Which portion of the membrane associated proteins are hydrophobic?

A

The part that is inside the membrane.

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6
Q

Which portion of the membrane associated proteins are hydrophillic?

A

The part that is in the cytosol or outside the cell (interstitial space)

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7
Q

What type of protein is peripheral?

A

Protein attached protein (1 protein attached to another)

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8
Q

Which protein is integral but not in the membrane?

A

Lipid linked protein

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9
Q

What conformation is a protein that crosses the cell membrane (most cases)? What is this protein called?

A

Alpha helical; transmembrane protein

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10
Q

A multipass transmembrane protein with multiple alpha helices is oriented how? If this is the case it is called a ____ ___

A

Each of the pieces face their hydrophobic side in and hydrophilic side out; a nuclear pore

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11
Q

If there is a multipass transmembrane protein with beta sheets, what does it form? What is an example?

A

A beta barrel; porin proteins

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12
Q

What do porin proteins form?

A

Channels holding water in the outer membrane of bacteria

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13
Q

How can we take out a protein forma membrane to study its function? What is the con?

A

Detergent; Can disrupt the protein structure :(

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14
Q

What is an alternative to detergent?

A

Cryonelectromicroscopy- study proteins while still IN membrane

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15
Q

What are two commonly used detergents?

A

SDS and triton X100

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16
Q

What do detergents from?

A

Micells (little balls that look like dandelions)

17
Q

What is the main component of the RBC cortex? Mutations of this would cause ___

A

Spectrin; anemia

18
Q

How is spectrin attached to the RBC membrane?

A

Actin moves transmembrane proteins to connect spectrin — membrane

19
Q

What side foes the protein cortex attach to of the membrane? WHat is its job?

A

Protein cortex —cytosol side of membrane; biconcave disc shape

20
Q

Other than RBCs, other human and animal cells have a cortex composed of ____ and ___

A

actin and myosin

21
Q

What organisms have a cell wall instead of a cortex?

A

Plants, yeasts, and bacteria

22
Q

What did the mouse -human hybrid cell experiment tell us?

A

Proteins can move laterally in each single layer of the bilayer (most proteins)

23
Q

What is it called when a membrane protein is ‘grounded’ to its spot?

A

A membrane domain

24
Q

Give examples of how a cell can be restricted movement by tethering?

A

To the cortex, the extracell matrix, to to other proteins of another cell’s surface

25
Q

How do diffusion barriers work?

A

They make a (tight junction) barrier between the apical and basal laminas in epithelium

26
Q

The tight junctions (diffusion barriers) in the gut ET are important for __ ___

A

nutrient absorption

27
Q

What is the surface of the cell coated with? What do they do?

A

A layer of carbs; they help cells recognize each other, attract water ->slimy, and protect from damage

28
Q

If a lipid has a sugar added on it, it is called a ___

A

glycolipid

29
Q

If a protein has a sugar added on it, it is either a __ or ___

A

glycoprotein (attach to short chains oligosach) or proteoglycan (to long chains polysach)

30
Q

What is cell to cell recognition and adhesion mediated by? Give 2 examples

A

Lectin proteins; sperm reognizes egg or WBC recognizes where an infection is