Lipids and Membranes

Question 1

What is a plasma memebrane?

Answer 1

The bounday that seperates the living cell from its surroundings

Question 2

What does the plasma membrane serve as?

Answer 2

A selective barrier that allows chemical reactions to ocur effectively.

Question 3

What is the most abundant lipid in the plasma membrane?

Answer 3

Phospholipiods

Question 4

What is the structure of a phospholipid?

Answer 4

The hydrophilic head, which is “attracted” to water and the hydrophobic head, which “hides” from water

Question 5

What do phospholipids self asmenble to form?

Answer 5

Bubbles or micelle to form phosphlipid layers

Question 6

What building block moves less than phospholipids within the bilayer?

Answer 6

Proteins

Question 7

What kind of movement do unsaturated hydrocarbon tails have?

Answer 7

Fluid/rougher

Question 8

What kind of movement does saturated hydrocarbon tails have?

Answer 8

Viscous movement

Question 9

What is used in place of cholesterol for plants?

Answer 9

Sterols

Question 10

What is cholesterol used for?

Answer 10

It provides stability and acts as a temperature buffer quality for the membranee. Sterols for plants

Question 11

What model does the plasma membrane have?

Answer 11

The fluid-mosaic model

Question 12

What is the fluid phospholipid layer?

Answer 12

It is a layer where transmembrane proteins are partially or completely embedded, creating semi-permeable channels.

Question 13

What are the classes of membrane proteins?

Answer 13

Peripheral proteins and integral proteins

Question 14

What are peripheral proteins?

Answer 14

Proteins loosely bound to the surface of the membrane

Question 15

What are integral proteins?

Answer 15

Proteins that penetrate the lipid bilayer across the whole membrane

Question 16

What is another name for integral proteins?

Answer 16

Transmembrane proteins

Question 17

What type of protein is antigen?

Answer 17

A peripheral protein

Question 18

What type of protein are transport proteins?

Answer 18

Intergral Proteins

Question 19

What is the function of channel proteins?

Answer 19

Wide open passages

Question 20

What is the function of ion channels?

Answer 20

Gated passges

Question 21

What is the function of aquaporins?

Answer 21

Only lets water

Question 22

What is the function of carrier proteins?

Answer 22

Changes shape

Question 23

What is the function of transport proteins?

Answer 23

Requires ATP

Question 24

What are glycoproteins?

Answer 24

Recognition proteins

Question 25

What are hormones?

Answer 25

Receptor proteins

Question 26

What is the function of adhesion proteins?

Answer 26

Anchors

Question 27

Who discovered aquaporins?

Answer 27

Peter Agre (1991) and Roderick McKinnon (2003)

Question 28

Why are proteins the perfect molecule to build structures?

Answer 28

They alter structure and function

Question 29

What does a plasma membrane have to do to be a selectively permeable barrier?

Answer 29

A plasma membrane needs to import ions and molecules necessary for life while excluding ions and moleales that might damage it.

Question 30

What can be found inside the plasma membrane that anchors proteins?

Answer 30

Hydrophobic non polar amino acids

Question 31

What is found on the outer surfaces of membrane in fluid?

Answer 31

Hydrophobic polar amino acids

Question 32

What are the molecules that can get through the plasma membrane?

Answer 32

Hydrophobic molecules eg oxygen, carbon dioxide, nitrogen, steroids and small uncharged polar molecules eg water, glycerol, urea

Question 33

What are molecules that can't get through the plasma membrane directly?

Answer 33

Large uncharged polar molecules eg glucose, sucrose and ions (positive or negative)

Question 34

What are the ways of getting through the cell membrane?

Answer 34

Passive transport, facilitated transport and active transport

Question 35

What are the two ways of going from high to low concentration?

Answer 35

Passive and facilitated transport

Question 36

What is passive transport?

Answer 36

The diffusion of hydrophobic molecules (lipids)

Question 37

What is facilitated transport?

Answer 37

The diffusion of hydrophilic molecules through a protein channel

Question 38

What is the difference between passive transport and facilitated transport?

Answer 38

Passive transport is done on its own and facilitated transport is done with help.

Question 39

What is active transport?

Answer 39

The diffusion against the concentration gradient from low concentration to high concentration. Uses a protein pump and requires ATP

Question 40

What law is diffusion applied to?

Answer 40

The 2nd law of thermodynamics

Question 41

What helps facilitated diffusion?

Answer 41

Channels for ions/water and carriers for sugars/amino acids

Question 42

How do proteins open in the gated channels?

Answer 42

They only open in the presence of stimulus.

Question 43

' How are large molecules usually moved in and out of cells?

Answer 43

Through vesicles and vacuoles and endocytosis or exocytosis

Question 44

What is phagocytosis?

Answer 44

Cellular eating

Question 45

What is pinocytosis?

Answer 45

Cellular drinking

Question 46

What is osmosis?

Answer 46

The diffusion of water from high concentration to low concentration that occurs only when solutions are separated by a membrane that permits wate to cross but holds back some or all solutes

Question 47

What is the solute concentration for hypertonic solutions?

Answer 47

More solute, less water

Question 48

What is the solute concentration for hypotonic solutions?

Answer 48

Less solute more water

Question 49

What is the solute concentration for isotonic solutions?

Answer 49

Equal amount of solute and water.

Question 50

What does cell survival depend on?

Answer 50

Balancing water uptake and loss

Question 51

How are plant cells and animal cells in hypotonic solutions?

Answer 51

Animal cells- Lysed and burst while plants were turgid and normal

Question 52

How are plants and animals in isotonic solutions?

Answer 52

Animal cells are normal and plant cells are flaccid

Question 53

How are plants and animals in hypertonic solutions?

Answer 53

Animal cells are shriveled while plant cells are plasmolyzed

Question 54

What are salt water organisms compared to their environment?

Answer 54

Hypotonic

Question 55

Where are transmembrane proteins embedded?

Answer 55

In the fluid phospholipid layer

Question 56

What creates semi-permeable channels?

Answer 56

The embedding of transmembrane proteins in the phospholipid layer