Biochem Chapter 8

Question 1

Cell membrane is what model

Answer 1

Fluid mosaic model

Question 2

What does cell membrane do 3 things

Answer 2

Protect interior

Regulates material exchange

Helps communication and signalling

Question 3

Hydrophobic fatty acid tail
Hydrophilic heads

Where they face

Answer 3

Hydrophobic fatty acid tails face inside

Hydrophilic heads face outside

Question 4

Phospholipids move into phospholipid layer how

Answer 4

They just do simple diffusion

Question 5

What are lipid rafts in phospholipid membranes

Answer 5

Specialized membrane rich in cholesterol, involved in signalling
They are attachment points for other bio molecules that’s why used in signalling

Question 6

What are flippases for

Answer 6

Move one leaflet to another leaflet of bilayer for lipids to maintain asymmetry

Question 7

Can membrane composition and receptor distribution change

Answer 7

Yes needed for survival

Question 8

Are flippases energetically favourable

Answer 8

No

Question 9

Most to least plentiful in phospholipid bilayer

Carbs
Protein
Lipids
Nucleic acid

Answer 9

Lipids most

Protein

Carbohydrates

Nucleic acid basically none

Question 10

Triacylglyeceorls are for

Answer 10

Fat storage mainly

Question 11

Why are triacylglycerols used for energy storage

Answer 11

Carbon atoms are more deuces than sugars

Triacylglycerols are hydrophobic

Question 12

Saturated fatty acids have single or double bonds

Answer 12

Single bonds

Question 13

Unsaturated fatty acids are usually single o double bonds

Answer 13

Has at least one or more double bonds

Question 14

Cis unsaturated fatty acids

Trans saturated fatty acids what they do to membrane fluidity

Answer 14

Trans allows tight packing, reduce membrane fluidity

Cis allows looser packing, increases membrane fluidity

Question 15

Building block of other subtypes of sphinsosine

Answer 15

Ceramide

Question 16

If glucose or galactose are added to ceramide what is made

Answer 16

Cerebrosides

Question 17

If you add sugars and sialic acid to ceramides what are made

Answer 17

Gangliosides

Question 18

If you add choline to ceramides what is made

Answer 18

Sphingomyelin

Question 19

What are three things sphingolipids do

Answer 19

Membrane stability
Signalling
Cell stability

Question 20

Steroids are derived from

Answer 20

Cholesterol

Question 21

Steroid have what rings

Answer 21

3 cyclohexane rings and 1 cyclypentane

Question 22

Low temperature
High temperature

How does it affect cholesterol and fluidity of membrane

Answer 22

Low temperature, more fluid
High temp, less fluid

Question 23

What are the 3 membrane proteins

Answer 23

Transmembrane proteins
Embedded proteins
Peripheral proteins

Question 24

What are transmembrane proteins for in cel membrane

• where are they, exposed to what environments
• what they do

Answer 24

They are on the entire lipid bilayer, exposed to extracellular and intracellular environments

Act as channels and transport

Question 25

What are embedded proteins -which side they face -what they do

Answer 25

Only on one side of membrane either or Signalling or anchoring structures to membrane

Question 26

What are peripheral proteins in membrane protein - where are they found -what they do

Answer 26

Loosely bound to space, doesn’t go through Electrostatiscally or binding to lipid rafts Signalling or maintain shape of cell by linking to cytoskeleton

Question 27

Integral proteins are which two proteins

Answer 27

Trans membrane and embedded proteins together

Question 28

Which membrane proteins can facilitate diffusion and active transport

Answer 28

Transmembrane proteins

Question 29

Where do carbs really attach to on membrane

Answer 29

Protein to make glycoprotein Lipids for making glycolipids

Question 30

Why are carbs attached to cell membrane

Answer 30

Hydrophilic nature attracts water so makes protective coat Act in cell recognition, identification and signalling

Question 31

What are tight junctions in cell membrane

Answer 31

Prevent molecules from passing Apical surface Prevents water and solutes transport

Question 32

What are desmosomes in cell membrane

Answer 32

Anchoring junctions bindt to adjacent cells like Velcro Using Cadherins To prevent mechanical stress

Question 33

What are hemidesmosomes

Answer 33

Cell to matrix anchors Protect tissues from mechanical stress

Question 34

Difference between desmosomes and hemidesmosomes

Answer 34

Desmosomes are found between 2 layers of epithelial tissue Hemidesmosomes is to attach epithelial cells to underlying basement membrane

Question 35

What are gap junctions - what do they allow to pass

Answer 35

Allow ions and small molecules to pass through form cell to cell , helping to synchronize activities

Question 36

What are examples of gap junctions

Answer 36

Channels Connexons

Question 37

How would gap junctions work under stress

Answer 37

They afffected by ph and concentrations and environment so they will close when under stress

Question 38

Do proteins go through gap junctions

Answer 38

No

Question 39

Animals the main cell to cell is what junctions

Answer 39

Tight junctions Desmosomes and gap junctions

Question 40

What are the only membrane proteins found on plants

Answer 40

Plasmodesmata

Question 41

Cell to cell junctions generally comprised of what protein

Answer 41

Cell adhesion molecules (CAMs)

Question 42

What is CAMs , cell adhesion molecules for in cell membrane, what they do

Answer 42

Help cells recognize one another Allows cell to connect properly or to take them to right positions Influence how cells mature and into what DIFFERENTIATION

Question 43

What is different between passive and active transport

Answer 43

Active uses energy, passive needs no energy, needs natural movement only

Question 44

What are the 3 types of passive transport

Answer 44

Simple diffusion Osmosis Facilitated diffusion

Question 45

What does passive transport use if not atp

Answer 45

Concentration gradients

Question 46

Whaat is simple diffusion work

Answer 46

Small non polar molecules just move through wihtout assistance

Question 47

What can move through simple diffusion

Answer 47

Oxygen and co2

Question 48

What is facilitated diffusion

Answer 48

No energy needed but carrier proteins and channels help move molecules across

Question 49

What moves through facilitate diffusion for example

Answer 49

Glucose and ions

Question 50

How does osmosis work

Answer 50

Semi permeable membrane Water moves from low solute concentration side to high concentration side

Question 51

Hypertonic solution what it look like

Answer 51

Lots of solutes outside of cell, water moves out of cell and the cell shrinks

Question 52

Hypotonic solution what doles it look like

Answer 52

Less solutes outside the cell, water will go inside cell, and thus swell

Question 53

What is osmotic pressure

Answer 53

Force that drives water in osmosis

Question 54

Why is osmotic pressure a colligative property, what htat mean

Answer 54

Only depends on concentration of dissolved particles and not on chemical identity of the dissolved particles

Question 55

Osmotic pressure is calculated by

Answer 55

(I)MRT I is vanhoff factor

Question 56

Active transport moves solute where

Answer 56

Against concentration gradient so needs energy

Question 57

What is primary active transport - what powers it - what helps out

Answer 57

Using ATP to power the transport Needs transmembrane ATPases to help out

Question 58

Sodium potassium pump is what type of active transport

Answer 58

Primary

Question 59

What is secondary active transport

Answer 59

Doesn’t use ATP directly,, it uses energy stored in electrochemical gradient of a primary transport to drive this

Question 60

Symport and antiport is part of which active transport

Answer 60

Secondary

Question 61

What does symport and antiport mean

Answer 61

Symport - both particles going same direction Antiport : opposite direction particles moving

Question 62

What is an example of secondary active transport

Answer 62

When kidneys use sodium to resorb and secrete solutes and filter out filtrate

Question 63

What is endocytosis

Answer 63

Cell membrane invaginates and engulfs material to bring into cell

Question 64

What are two types of endocytosis Also what they each mean

Answer 64

Pinocytosis : fluids Phagocytosis : large solids

Question 65

What is exosytosis

Answer 65

Secretory vesicles fuse with membrane to release material outside of cell

Question 66

What is membrane potential

Answer 66

Voltage difference across membrane due to ion distribution

Question 67

Why does maintaining membrane potential require energy

Answer 67

Because ions may passively disuse through the wall over time using leak channels

Question 68

What is solution to leak channels cause membrane potential to change and becomes imbalance

Answer 68

Ion transporter or pump regulated the concentration of ions

Question 69

What equation helps us calculate equiblitum portential of inside and outside of cell

Answer 69

RT/zF ln ( outside concentration/ inside concentration )

Question 70

What does Goldman Hodgkin Katz equation take into accounts that Nernst didn’t about cell membrane potential

Answer 70

Account for permeability of membrane to each major ion

Question 71

What is outer membrane of mitochondrial membranes like as compared to inner membranes

Answer 71

Outer membranes is permeable to small molecules Whereas inner membrane is impermeable.

Question 72

What is found in inner mitochondrial membranes (2)

Answer 72

ETC and ATP synthase

Question 73

How is inner membrane of mitochondrial membranes folded

Answer 73

Highly folded into crirtae

Question 74

Does inner mitochondrial membranes have cholesterol

Answer 74

No Allow mitochondria to produce ATP (outer) and inner side just does the enclosemnet.

Question 75

If given this Sodium Permeability 0.05 Intracellualr concentration 14mM Extracekllular concentration 140 mM Potassium Permeability 1 Intracellualr concentration 120 mM Extracekllular concentration 4 mM Chloride Permeability 0 Intracellualr concentration 12mM Extracekllular concentration 120 mM What is resting membrane potential of the cell

Answer 75

61.5 x log x ( 0.05x140)(1 x 4)(0 x 12) ————————————— (0.05 x 14) (1x120) (0x 120) = -60mV For the numerator , you use outside concentrations for sodium and potassium, and inside concentration of chlorine For denominator, you use inside concentrations for sodium and potassium, and outside concentration of chlorine