Biochemistry Chpt 10 And 11 Final

Front 1

lipids include many types of what?

Back 1

molecules

Front 2

Rather than lipids being defined by a ? they are defined by a ?.

Back 2

not by structure but by property

Front 3

Name 3 molecules defined by structure?

Back 3

proteins, carbs, nucleic acids

Front 4

The property which defines a lipid?

Back 4

they are largely insoluble in water, but relatively soluble in hydrophobic (organic) solvents

Front 5

The two options for lipids?

Back 5

either totally hydrophobic or amphiphilic (having both hydrophobic and hydrophilic parts)

Front 6

Fatty acids are aka what?

Back 6

storage lipids

Front 7

What can lipids store?

Back 7

energy (fat and oils)

Front 8

Many lipids contain ? acids.

Back 8

fatty

Front 9

Is the fatty acid the sole component of the lipid?

Back 9

it may be...or it may be linked to another entity by an ESTER or AMIDE bond.

Front 10

The 2 melting point trends?

Back 10

1. the longer the carbon chain, the higher the m.p.



2. dbl bds introduce kinks in chains...disrupt the association of adjacent chains...and so decrease the m.p. (b/c groups of molecules are less likely to associate to from solids)...and the more dbl bds (up to a pt.) the lower the m.p.

Front 11

So longer Carbon chains do what to mp?

Back 11

increase it

Front 12

So dbl bds do what to mp?

Back 12

decrease it (to a pt)

Front 13

How do you know according to table 10-1 when a FA is hydrophobic?

Back 13

it is more soluble in benzene than H2O

Front 14

Storage lipids : ? and ? : contain ?.

Back 14

storage lipids : fats and oils: contain fatty acids

Front 15

Larger molecules have ? mp and ? solubilites?

Back 15

higher mp...lower sol.

Front 16

A saturated fatty acid has no what?

Back 16

dbl bonds

Front 17

1 Dbl bond is aka what?

Back 17

mono-unsaturated

Front 18

2 or more dbl bds is aka what?

Back 18

poly-unsaturated

Front 19

Saturated fatty acids are generally what at room temp?

Back 19

(no dbl bds)

generally solids at room temp (and body temp)

Front 20

Unsaturated FAs are generally what at room temp?

Back 20

(dbl bonds)

generally liquid at room temp (and body temp)

Front 21

Which has the higher melting point sat. FAs or unsat. FAs?

Back 21

saturated FAs (remember they are solid at room temp)

Front 22

If two FA molecules had 16 carbons but only one had a dbl bd which one would have a higher melting point?

Back 22

the saturated one with no dbl bds would have a higher mp

Front 23

So increaed #C = an increase what?

But an increased dbl bd = what?

Back 23

more Cs gives a higher mp BUT more dbl bds give a lower mp

Front 24

What is reqd for transport of FAs?

Back 24

serum albumin

Front 25

Most FAs exist in our body as what?

Back 25

esters

Front 26

FAs are often incorporated into what?

Back 26

triaglycerols (includes, triglycerides, fats, TAG's)

Front 27

In vertebrates, what stores large amts of TAGs?

Back 27

adipocytes

Front 28

Triaglycerols = ? = ? = ?

Back 28

triaglycerols = triglycerides = fats = glycerol + 3 FAs (simple and mixed)

Front 29

Some advantages of storing in lipids (TAGs) instead of polysacchs?

Back 29

1. C atoms are highly reduced...this means that the energy density is 2X what it is in polysacchs

2. hydrophobic mol.s so not hydrated (no xtra water weight) (so you can carry energy in a more small, efficient area)

3. insulate against cold

Front 30

Which fats are healthier for you?

Back 30

unsaturated (dbl bds)(liq at room temp)

Front 31

Kearney's review sheet says triaglycerol's has ? density?

Back 31

low

Front 32

What is stored in adipocytes?

Back 32

triaglycerols = triglycerides = fats = glycerol + 3 FAs

Front 33

Advantages to storing energy in lipids?

Back 33

1. C atoms are highly reduced...high energy-density

2. no h2o of hydration for these hydrophobic molecules...lighter cells

3. insulation

Front 34

Fats in foods are generally mixtures of what?

Back 34

different triaglycerols with various FAs

Front 35

Describe composition of vegetable oil?

Back 35

high percentage of unsat. FAs...liquids

Front 36

Describe composition of Animal fats?

Back 36

higher percentage of saturated FAs...solids

Front 37

The two components of waxes?

Back 37

FAs + alcohol (so esters and long chain alcohols)

Front 38

The melting point of waxes is generally what?

Back 38

fairly high (60-100C)...solid at room temp

Front 39

Are waxes solid, liquid or vary?

Back 39

solid

Front 40

Why are biological waxes important for the wings of birds and insects?

Back 40

they are water repellant

Front 41

Why are bio waxes important for leaves?

Back 41

they prevent evaporation/dehydration

Front 42

What do bio. waxes protect plants and animals from?

Back 42

parasites

Front 43

Name three things that waxes are used in?

Back 43

lotions, ointments, and polishes

Front 44

Structural lipids are aka?

Back 44

membrane lipids

Front 45

2 types of structural (membrane) lipids?

Back 45

A. glycerophospholipids

B. Sphingolipids

Front 46

Describe structure of glycerophospholipids?

Back 46

A. glycerol backbone

B. with phosphate

C. 2 FAs + 1 polar group

Front 47

Describe structure of sphingolipids?

Back 47

A. sphingosine backbone

B. with or without phosphate

C. 1 FA + 1 polar group

Front 48

What do sphingolipids define?

Back 48

the human blood groups (A,B,O,)

Front 49

Membrane lipids are continually what?

Back 49

degraded and replaced, this is carried out by enzymes in lysozomes (which breakdown lipids)

Front 50

What genetic diseases are caused by defects in the enzymes that degrade and replace membrane lipids...what do they lead to?

Back 50

-lead to an accumulation of lipids (cuz can't breakdown)

1. Niemann-pick
2. Tay Sachs
3. Gaucher's
4. Fabry's
5. Sandhoff's

Front 51

Describe structure of sterols? (you are going to need to know this visually)

Back 51

4 fused rings

Front 52

Where are sterols found?

Back 52

in membranes of eukaryotes but not not prokaryotes (bacteria)

Front 53

What are the precursors to sterols?

Back 53

isoprene...(synthesized from isoprene/isoprenoids)

Front 54

What is the major sterol in animal tissue?

Back 54

cholesterol...an amphipathic (polar end and nonpolar end)

Front 55

Sterols are what overall?

Back 55

amphipathic

Front 56

Besides structural and storage lipids name 3 other functions of lipids?

Back 56

1. signals

2. cofactors

3. pigments

Front 57

Describe lipids as pigments?

Back 57

they absorb light...capture energy and give color...usually have conjugated dbl bds)

Front 58

The 3 levels of lipids as signals?

Back 58

1. Phosphatidylinositol (key)

2. Eicosanoids

3. Steroids

Front 59

Phosphatidylinositol is what kind of lipid signal?

Back 59

intracellular signal

-it and it's deriv.s regulate cell structure and metabolism

Front 60

Eicosanoids are what kind of lipid signals?

Back 60

(paracrine hormones)

-act on neighbor cells (have 20 carbons in molecule)

-so "nearby intercellular signals"

Front 61

Name 3 paracrine hormones that are eicosanoids?

Back 61

(20 C FA derivs)(act on cells near site of synthesis)

1. prostaglandins

2. thrombaxones

3. leukotriene

Front 62

What are eicosanoids derived from?

Back 62

arachidonic acid

Front 63

What do the prostaglandin (eicosanoid lipid signal) do?

Back 63

regulatory molecules...fever, pain, inflammation

Front 64

What do the thromboxanes (eicosanoid lipid signal) do?

Back 64

produced by platelets...act in clot formation

Front 65

What do the leukotriene (eicosanoid lipid signal) do?

Back 65

first found in leukocytes...role in asthma

Front 66

Steroids are aka what?

Back 66

oxidized derivatives of sterols

Front 67

Difference between sterols and steroids in structure?

Back 67

hydrophobic side chain of sterols replaced by a more polar group...sometimes an addnal polar group...polar groups make molecules easier to transport in aqueous environ.s (ex. blood)

Front 68

Where are steroids observed?

Back 68

1. sex hormones (testosterone, estradiol)

2. Adrenal cortex hormones (cortisol)

3. anti-inflammatory drugs

Front 69

What are vitamins?

Back 69

precursors of hormones, cofactors, light absorbers,etc.

-essential for vertebrates but not synthesized by them (except vit D)

Front 70

Which category of vitamins are we concerned with?

Back 70

fat-soluble (ADEK)
-soluble in nonpolar solvents

Front 71

Where are the fat-sol. vitamins derived from?

Back 71

from isoprene/isoprenoids (like cholesterol)

Front 72

5 aspects of vitamin D?

Back 72

1. transformed into a hormone important for Ca2+ uptake

2. precursor transformed into D3 by light (in the skin...light reqd)

3. liver and kidney reqd for full activation

4. absence leads to bone defects and rickets

5. found in milk and butter (D2 not D3)

Front 73

5 aspects of vitamin A?

Back 73

1. hormone and visual pigment

2. important for skin development

3. synthesis : precursor beta carotene>retinol>retinal(eyes, visual pigment)>retinoic acid(epithelial, skin cells)

4. found in milk, butter, etc

5. beta carotene (precursor) is found in yellow veggies (carrots) and dark green veggies

Front 74

What can a vit A deficiency lead to?

Back 74

dry skin, eyes, slow dev and growth, night blindness

Front 75

How is vit E important?

Back 75

an important anti-oxidant

Front 76

What is an anti-oxidant?

Back 76

ring in vit E destroys oxygen radicals

Front 77

How is vit K important?

Back 77

for promotion of blood clotting and as rat poison

Front 78

How is warfarin related to vit K?

Back 78

warfarin is an anticoagulant...and a derivative of vitamin K

Front 79

How does vit K work as a rat poison?

Back 79

causes them to bleed to death

Front 80

What are the 4 general principles of biosignaling?

Back 80

1. specificity

2. sensitivity

3. modification

4. integration

Front 81

Describe specificity of biosignaling?

Back 81

signal molecules fits binding site on its complementary receptor...other signals do not fit...specific

Front 82

Describe sensitivity of biosignaling?

Back 82

high receptor-signal affinity...cooperativity...and amplification

-a small amt of ligand (signal) leads to the occupation of a large fraction of the receptors binding sites

-cooperativity...like hemoglobin...them that has gets

Front 83

Describe modification of sensitivity of biosignaling?

Back 83

-Desensitization/Adaptation

-receptor activation triggers a feedback circuit that shuts off the receptor or removes it from the cell surface

Front 84

Describe integration of multiple signals of biosignaling?

Back 84

when 2 signals have oppo effects on a metabolic characteristic such as the [conc] of a 2nd messenger X, or the membrane potential Vm, the regulatory outcome results from the integrated input from both receptors

Front 85

Describe the typical concentrations of a gated ion channel?

Back 85

intracellular = higher K+

extracellular = higher Na+, Ca2+, Cl-

Front 86

What is unique about intracellular Ca2+?

Back 86

only one with <1mM (so a small change can be relatively large)

Front 87

What is a gradient involved in?

Back 87

active transport

Front 88

How is a gradient created?

Back 88

Na+K+ATPase (3 Na+ pumped out for every 2 K+ pumped in, creating an electrochemical gradient)

Front 89

The gradient created by Na+K+ATPase can do what?

Back 89

drive the passive transport, thru gated channels, of Na+ and Ca2+ to move into the cell, and K+ and Cl- out

Front 90

Where is the nicotinic acetylcholine receptor located?

Back 90

postsynaptic membrane

Front 91

What does the nicotinic acetylcholine receptor open in response to?

Back 91

to the binding of acetylcholine or nicotine

Front 92

What does the nicotinic acetylcholine receptor allow to move into the cell?

Back 92

allows Na+ and Ca2+ to move into the cell...depolarizing the membrane gradient

Front 93

Describe structure of nicotinic acetylcholine receptor?

Back 93

5 subunits each with 4 transmembrane helices

Front 94

When is nicotinic acetylcholine receptor closed? Open?

Back 94

closed when hydrophobic AAs line the central canal

open when subunits rotate so that polar residues line the channel

Front 95

In the nicotinic acetylcholine receptor when does desensitization result?

Back 95

if acetylcholine is not degraded

Front 96

What opens the voltage-gated Na+ channel?

Back 96

depolarization

Front 97

What happens when the voltage-gated Na+ channel opens?

Back 97

allows more Na+ ions to move into the cell...which results in further depolarization

Front 98

Describe structure of voltage gated Na+ ion channel?

Back 98

4 domain polypeptide, each with 6 transmembrane helices

Front 99

What happens in response to depolarization in the voltage-gated Na+ ion channel?

Back 99

helices move relative to each other, opening the central channel, allowing passage of Na+ ions

Front 100

What opens the voltage-gated Ca2+ channels?

Back 100

depolarization

Front 101

What is allowed when the volt-gated Ca2+ channel opens?

Back 101

allows Ca2+ to move into the cell

Front 102

When Ca2+ enters into the cell what does it do?

Back 102

triggers the release of acetylcholine to pass to next neuron

Front 103

What happens to the Na+ channel when transmembrane pot. changes?

Back 103

opens up and Na+ ions can pass thru

Front 104

What causes volt-gated K+ channels to open?

Back 104

depolarization

Front 105

What does the opening of the volt-gated K+ channels do?

Back 105

allows K+ to move OUT of the cell (the other channels allow movement in)

Front 106

Structure of K+ channel?

Back 106

4 subunits with 4 helices

Front 107

Where do the K+ ions pass thru?

Back 107

channel thru the center of the volt-gated K+ ion channel

Front 108

Describe receptor enzymes?

Back 108

ligand binds to extracellular binding site, triggering enzyme activity in the cytosol

Front 109

What is a protein kinase? give and example

Back 109

A receptor enzyme (ex. insulin receptor)

Front 110

Describe structure of protein kinase (insulin receptor)?

Back 110

1. 2 extracellular alpha chains include insulin binding sites

2. 2 transmembrane beta subunits have kinase activity on intracellular side of membrane

Front 111

Insulin binding on the protein kinase (insulin receptor) initiates what?

Back 111

conformational change...which leads to beta subunits autophosphorylation

Front 112

After the conformation change in the protein kinase (insulin receptor) and beta subunit autophosphorylation what occurs?

Back 112

the phosphorylated/activated enzyme phosphorylates IRS-1 (target protein)

Front 113

What is IRS-1 aka?

Back 113

insulin receptor substrate

Front 114

Once phosphorylated what does IRS-1 begin? (7)

Back 114

a chain rxn that leads

1. activation of RAF

2. phosphorylation of MEK

3. Phosphorylation of ERK

4. movement of ERK into nucleus

5. activation of genes (gene expression)

6. synthesis of new proteins

7. cell division

Front 115

Besides the chain rxn what else does IRS-1 cause?

Back 115

metabolic changes

1. inactivation of GSK3, leading to activation of glycogen synthase, leading to the synthesis of glycogen from glucose

2. mvmt of glucose transporter GLUT4 from 'storage' (vesicles) to the cell surface, leading to the transport of more glucose into the cell, reducing the blood glucose concentration

Front 116

What is Guanylyl Cylase?

Back 116

another type of receptor enzyme...synthesizes cGMP

Front 117

When is cGMP synthesized?

Back 117

When the ligand is bound on the extracellular surface, cGMP is synthesized inside the cell

Front 118

2 examples of guanylase cylase receptors?

Back 118

1. ANF receptor

2. Guanylin and Endotoxin Receptor

Front 119

What is ANF released by?

Back 119

stretched heart...goes to kidneys

(from heart>kidney>muscle)

Front 120

What does the release of ANF lead to? (2)

Back 120

1. rise in [cGMP], triggering release of Na+ and H2O, reducing blood volume

2. bounds to receptors in smooth muscles, leads to the relaxation of smooth muscle, allowing blood vessels to expand, decreasing blood pressure

Front 121

What activates the Guanylin and endotoxin receptors?

Back 121

activated by intestinal chloride secretion (guanylin)(elevates cGMP, which increases Cl- secretion in the intestine and modifies the retention of H2O)

also by an endotoxin produced by gram-negative bacteria (such as E coli)(leads to excess Cl- secretion, producing diarrhea)

Front 122

Give an example of a soluble guanylyl cylase?

Back 122

nitric oxide-activated GC

Front 123

What does a soluble GC (guanylyl cylase) increase?

Back 123

[cGMP]...so for an example an increased [NO] will increase [cGMP] thru synthesis

-reduces the forcefulness of heart contractions in response to NO or nitroglycerin

-so nitro can be used to tx angina

Front 124

An indirectly acting receptor protein?

Back 124

G Protein-Coupled Receptors
(GPCRs)

Front 125

The 3 components of the G protein-coupled receptors (GPCR)?

Back 125

1. plasma membrane receptor

2. guanosine nucleotide-binding protein (aka G protein)

3. in-membrane enzyme that generates an intracellular second messenger (ex. cAMP)

Front 126

How many GPCRs are there and what do the transduce?

Back 126

more than a 1000 and they transduce messages such as light, smells, taste, hormones, etc.

Front 127

What do more than half of all medicines prescribed today target?

Back 127

a GPCR

Front 128

Give an example of a typical GPCR receptor?

Back 128

Beta adrenergic receptors (BAR)....the prototype

Front 129

Describe structure of beta adrenergic receptor (BAR)?

Back 129

integral membrane protein with 7 hydrophobic transmembrane helices that weave back and forth across the membrane, with an extracellular epinephrine binding site

Front 130

The ? protein is associated with the beta adrenergic receptor?

Back 130

G protein (guanosine nucleotide binding protein)

Front 131

The G protein assoc. with the beta adrenergic receptor is what?

Back 131

stimulatory (Gs)

Front 132

How is the G protein activated?

Back 132

when epinephrine binds to the receptor, GDP is released and GTP is bound, thus activating the G protein

(so GDP before and replaced by GTP after)

Front 133

When the G-protein is activated what subunit seperates and where does it go?

Back 133

the alpha subunit of Gs(Gsa) seperates from the beta and theta subunits and moves to adenylyl cyclase (AC) and activates it, so that it catalyzes the synthesis of cAMP

Front 134

After activating Adenylyl cylase (AC) what does the Gsa (alpha subunit of the G protein) do?

Back 134

it inactivates itself by converting its bound GTP to GDP

(so back to GDP)

...then the Gsa dissociates from the AC, and reassociates with its beta and theta subunits and is ready to go again (Gs)

Front 135

The cAMP synthesized by the AC and alpha subunit can do what once the alpha subunit has dissociated?

Back 135

activates protein kinase A (PKA)...which then goes on to phosphorylate many cellular proteins

Front 136

The process of the indirectly acting receptor proteins, G proteins, GPCRs, ACs, Gs, Gsa, cAMP, etc is a good example of what?

Back 136

signal amplification

Front 137

The epinephrine cascade was described in the last few notecards...what is it a good example of?

Back 137

amplification

Front 138

cAMP is usually ? but ? can increase it's ?.

Back 138

cAMP is usually degraded but methyl xanthines (caffeine, theophylline) can increase it's half-life by blocking the degradation

Front 139

Describe desensitization?

Back 139

once the Gsa has gone off to do it's thing the beta and theta subunits of G can bind betaARK (BARK)...this phosphorylates BAR...then Barr binds to and blocks the phosphorylated BAR...then, finally, the BAR-Barr complex can be removed from the membrane

-so essentially after the binding epinephrine has had its effect, the receptor is blocked from further interaction with Gs...taken out of circulation, and...eventually returned to the membrane (resensitization)

Front 140

Desensitization broken down into 4 steps?

Back 140

1. BARK adds phosphoro group

2. BAR blocks the receptor

3. Receptor moves off membrane into the cell

4. cell can be resensitized

Front 141

cAMP is a what?

Back 141

2nd messenger for many regulatory molecules

Front 142

Besides cAMP what else is an important 2nd messenger?

Back 142

Ca2+

Front 143

How is Ca2+ an important 2nd messenger?

Back 143

-it's low intracellular conc. means that small changes (as initiated by various ion channels) are relatively large, and easily detected....when the conc. of calcium goes from 0.1 to 1mM it binds to calmodulin (an acidic protein) and changes it's conformation...this then changes the activity of various proteins which it can associate

(so calcium doesn't act directly, it acts on calmodulin which then acts on other molecules)

(so calmodulin signals to other proteins that Ca2+ has been released)