Physiology 1

Question 1

All biological membranes are composed of _____ and ______.

Answer 1

lipids
proteins

Question 2

What are the 3 major subtypes of lipids?

Answer 2

phospholipids
glycolipids
cholesterol

Question 3

Which subtype of lipids is present only in mammals? Where is it restricted to?

Answer 3

cholesterol

plasma membrane

Question 4

All of the membrane lipids are ______. Name the 3 membrane lipids

Answer 4

amphiphillic

phospholipids, sphingolipids, and cholesterol

Question 5

What does amphiphillic mean?

Answer 5

hydrophilic (polar) end and a hydrophobic (non-polar) end

Question 6

Head groups attach at ______ in phospholipids. What are some examples of head groups?

Answer 6

phosphate

serine, choline, ethanolamine, inositol

Question 7

Fatty acid tails attach to the polar head via _______. Tails are ____-______ in nature and have ___ tails

Answer 7

glycerol

non-polar

2

Question 8

Presence of double bonds in the tail means it is a(n) ________ fatty acid. No double bond means it’s a(n) ________ fatty acid

Answer 8

unsaturated
saturated

Question 9

What is the difference between phospholipids and sphingomyelin/glycolipids? Where is sphingomyelin/glycolipids found?

Answer 9

sphingomyelin has sphingomyelin INSTEAD of glycerol, and has a hydroxyl group

myelin sheath of nerves/nerve cells

Question 10

Where are glycolipids found exclusively in the lipid bilayer? Why are they called GLYCOlipids?

Answer 10

the non-cytoplasmic membrane

head contains sugars (galactose for example)

Question 11

Cholesterol is a _____. What is the definition?

Answer 11

sterol

rigid ring structure containing a polar hydroxyl group and a short nonpolar tail

Question 12

Cholesterol orients closer to ____ groups of phospholipids and resides ____ them.

Answer 12

polar
between

Question 13

Cholesterol is enriched in ______ cells but otherwise is very limited in the plasma membrane

Answer 13

nerve

Question 14

Having energetically favorable interactions with water is key to the formation of the…

Answer 14

bilayer

Question 15

Cholesterol can easily flip ACROSS the membrane because of…

Answer 15

their small polar head

Question 16

Phospholipids can move _____, as well as rotate and flex, but can’t flip due to _____ polar head. Requires a lot of _______

Answer 16

laterally
large
energy

Question 17

The plasma membrane is considered a “_____ _____” and shape depends on _____ and ______.

Answer 17

fluid mosaic
temperature
composition

Question 18

Shorter and kinked fatty tails allow for more ____ movement. Are these saturated or unsaturated tails?

Answer 18

free

unsaturated

Question 19

Long and straight fatty tails allow for more ____ movement. Are these saturated or unsaturated tails?

Answer 19

restricted

saturated

Question 20

At high temperatures, the lipid has greater ___ energy than interaction energy and is therefore in a more “_____” state

Answer 20

thermal

sol (liquid/solution)

Question 21

With low temperature and minimal movement, lipids are in the “_____ _____”

Answer 21

gel state

Question 22

Membranes are ____ and allow for transport

Answer 22

fluid

Question 23

Which lipid helps maintain membrane fluidity? How does it help exactly?

Answer 23

cholesterol

restrains the movement of the phospholipids and decreases permeability of the membrane.
-cannot be as well deformed or frozen

Question 24

Endocytosis is the process of…

Answer 24

bringing a particle INTO the cell

Question 25

Exocytosis is the process of...

Answer 25

vesicles fusing with membrane and releasing particles OUTSIDE the cell

Question 26

_______ forces inward curvature of the membrane. How is this helpful?

Answer 26

caveolin helps with endocytosis (cups to hold particles and bring them into cell) and helps plasma membrane expand (increases surface area as needed)

Question 27

Membrane fusion during neurotransmitter release at synapse is mediated by what 3 things?

Answer 27

1) V-SNARE 2) T-SNARE proteins 3) SNAP proteins

Question 28

Membrane lipids provide structure, while membrane _____ provide important functions

Answer 28

proteins

Question 29

Membrane proteins can be _____ or ______. What do each of those mean?

Answer 29

peripheral -loosely bound integral -covalent attachment

Question 30

Peripheral proteins can be knocked off the membrane by ______ effects like "salting out". What does salting out mean?

Answer 30

ionic protein precipitation due to change in hydrogen bonds with H2O and membrane

Question 31

Integral proteins are ____ in the plasma membrane

Answer 31

embedded

Question 32

All integral proteins are _______ proteins, which means...

Answer 32

transmembrane one end in ECM, middle embedded in membrane, and one end facing cytosol

Question 33

Integral proteins are amphiphilic, with the inner part being _____

Answer 33

hydrophobic

Question 34

Many membrane (integral) proteins are ______ and referred to as glycoproteins

Answer 34

glycosylated

Question 35

What are detergents? How do they work?

Answer 35

amphiphilic molecules that can solubilize proteins hydrophobic ends of both the detergent and protein bind. this displaces the protein, and the hydrophilic part of protein interacts with water and solubilizes

Question 36

What is a well-known example of a peripheral protein?

Answer 36

ankrin

Question 37

The biconcave structure of red blood cells is maintained by ____ _____

Answer 37

spectrin dimers

Question 38

What are 2 examples of integral proteins?

Answer 38

1) Band 3 2) glycophorin