Cell Biology Exam 2

Front 1

What is the product of the enzyme Pyruvate Dehydrogenase?

Back 1

NADH

Front 2

Plasma Membrane

Back 2

Outer boundary of the cell that separates it from the world

Front 3

How thick is the plasma membrane?

Back 3

5-10 nm

Front 4

All membranes have ______ layers of lipids

Back 4

2

Front 5

Cell Membrane

Back 5

Semi-permeable barrier that contains the cell cytoplasm

Controls movement of substances in and out of the cell

Front 6

Cell Wall

Back 6

Mostly mechanical role

Provides support (strength & rigidity) to cell

Some "filtering" capacity

Front 7

All cells have a cell ________, not all cells have a cell ________

Back 7

Membrane, wall

Front 8

Membrane Functions- Compartmentalization

Back 8

Membranes form continuous sheets that enclose intracellular compartments

Front 9

Membrane Functions

Back 9

Compartmentalization

Scaffold for biochemical activities

Selectively permeable barrier

Transporting solutes

Responding to external signals

Intracellular interaction

Energy transduction

Front 10

Membrane Functions- Scaffold for Biological Activities

Back 10

Membranes provide a framework that organizes enzymes for effective interaction

ex. Photosynthesis takes place at the

membrane of the thylakoid

Front 11

Membrane Functions- Selectively Permeable Barrier

Back 11

Membranes allow regulated exchange of substances between compartments

Also channels that allow selective molecules

Front 12

Membrane Functions- Transporting Solutes

Back 12

Membrane proteins facilitate the movement of substances between compartments

Front 13

Membrane Functions- Responding to External Signals

Back 13

Membrane receptors transduce signals from outside the cell in response to specific ligands

Front 14

Membrane Functions- Intracellular Interaction

Back 14

Membranes mediate recognition and interaction between adjacent cells

ex. Plasmodesmata

Front 15

Membrane Functions- Energy Transduction

Back 15

Membranes transduce photosynthetic energy, convert chemical energy to ATP, and store energy

ex. ETC and membrane of mitochondria

Front 16

The Fluid Mosaic Model

Back 16

Core lipid bilayer exists in a fluid state, capable of movement

Membrane proteins form a mosaic of particles penetrating the lipids

Front 17

The lipid and protein components of the membrane are bound together by __________ bonds

Back 17

Non-covalent (electrostatic)

Front 18

Cellular membranes contain __________, __________, and __________

Back 18

Proteins, lipids, carbohydrates

Front 19

3 Main Types of Membrane Lipids

Back 19

Phosphoglycerides

Sphingolipids

Cholesterol

Front 20

Membrane lipids are __________

Back 20

Amphipathic

Front 21

Phosphoglycerides

Back 21

Diacylglycerides with small functional head groups linked to the glycerol backbone by phosphodiester bonds

Front 22

Fatty Acids

Back 22

Long unbranched hydrocarbon chains

14-20 carbons

Carboxyl group at one end

Amphipathic

Front 23

Fatty acids have a hydrophobic __________ and a hydrophilic __________

Back 23

Hydrocarbon chain, carboxyl group

Front 24

Saturated Fatty Acids

Back 24

No double bonds

Front 25

Unsaturated Fatty Acids

Back 25

One or more double bonds

Front 26

An unsaturated fatty acid has a __________ melting point than a saturated fatty acid

Back 26

Lower

Front 27

Most phosphoglycerides have one __________ and one __________ fatty acid

Back 27

Saturated, unsaturated

Front 28

Sphingolipids

Back 28

Ceramides formed by the attachment of sphingosine to fatty acids

Major roles in protecting cell surface against harmful environmental factors

Signal transduction and cell-cell recognition

Front 29

Cholesterol

Back 29

Smaller and less amphipathic lipid only found in animals

Front 30

Cholesterol makes up __________ of animal membrane lipids

Back 30

50%

Front 31

In Cholesterol, the __________ group is oriented toward membrane surface

Back 31

-OH

Front 32

Membrane role of cholesterol

Back 32

Regulates fluidity of the membrane

Prevents regular packing of saturated fatty acyl chains

"Wedge effects"

Enhances mechanical rigidity of the membrane while preserving the fluidity

Front 33

Dynamic Properties of Plasma Membranes

Back 33

Movement

Division

Fusion

Front 34

Glycoproteins

Back 34

Short, branched carbohydrates for interactions with other cells and structures outside the cell

Front 35

Glycolipids

Back 35

Larger carbohydrate chains that function in cell-cell recognition sites

Front 36

Glycosylation

Back 36

Addition of a sugar to either a protein or lipid (Post-translational modifications)

Front 37

3 Classes of Membrane Proteins

Back 37

Integral Proteins

Peripheral Proteins

Lipid-Anchored Proteins

Front 38

Integral Proteins

Back 38

Penetrate and pass through lipid bilayer

Amphipathic

Front 39

Integral proteins make up _____________ of all encoded proteins

Back 39

20-30%

Front 40

Channel proteins have __________ cores that form aqueous channels in the membrane-spanning region

Back 40

hydrophilic

Front 41

Peripheral proteins

Back 41

Attached to the membrane by weak bonds and are easily solubized

Located entirely outside of bilayer on either side

Front 42

Peripheral proteins are associated with membrane surface by __________ bonds

Back 42

Non-covalent

Front 43

Lipid-Anchored Proteins

Back 43

Anchored to lipid membrane

Front 44

GPI Linked Proteins

Back 44

Glycophosphatidylinositol

Type of Lipid-Anchored protein

Can be released by inositol-specific phospholipases

Front 45

Lipid rafts

Back 45

Provide a favorable environment for cell-surface receptors and GPI-anchored proteins

Front 46

__________ and ___________ tend to pack together to form highly ordered lipid rafts

Back 46

Cholesterol and sphingolipids

Front 47

Why would is it so hard for lipids to pass through the other leaflet (flip-flop)?

Back 47

Must pass through internal hydrophobic sheet of the membrane

Thermodynamically unfavorable

May take hours or days

Front 48

Protein movements are __________ than predicted by protein size and membrane viscosity

Back 48

Slower

Front 49

Membranes are not readily permeable to __________ molecules and larger __________ molecules

Back 49

Polar, non-polar

Front 50

Diffusion

Back 50

Spontaneous movement of material from a region of high concentration to low concentration

Front 51

Diffusion of nonelectrolytes depends on __________

Back 51

Concentration gradient

Front 52

Diffusion of electrolytes depends on the __________

Back 52

Electrochemical gradient

Front 53

Osmosis

Back 53

Diffusion of water through a semipermeable membrane

Front 54

Plant cells develop __________ in hypotonic solutions

Back 54

Turgor

Front 55

Plant cells develop __________ in hypertonic solutions

Back 55

Plasmolysis

Front 56

Aquaporins

Back 56

Specialized protein channels that allow passive movement of water

Front 57

Why can't ions diffuse through the membrane?

Back 57

Electrical charge of ions make them repulsive to the hydrophobic core of the bilayer

Front 58

3 Kinds of ion channels

Back 58

Voltage-gated

Ligand-gated

Mechano-gated

Front 59

Large or hydrophilic substances require __________ diffusion

Back 59

Facilitative

Front 60

Facilitative Diffusion

Back 60

Passive, specific, saturable, and regulated

Front 61

Active Transport

Back 61

Maintains the gradients for ions across the cell membrane

Couples the movement of substances against gradients to ATP hydrolysis

Front 62

Sodium-Potassium Pump

Back 62

K+ outside, Na+ inside

Inhibited by ouabain

Ratio of Na+:K+ is 3:2

Front 63

Co-Transport

Back 63

Coupling active transport to existing ion gradients

Front 64

Secondary Transport

Back 64

Use of energy stored in an ionic gradient

Front 65

ABC

Back 65

ATP-Binding Cassette

Front 66

CFTR

Back 66

Cystic Fibrosis Transmembrane Conductance Regulator (CFTR)

Transports Cl-

Front 67

Metabolism

Back 67

Collections of biochemical reactions that occur within a cell

Front 68

Metbolic Pathways

Back 68

Sequences of chemical reactions

Each rxn is catalyzed by a specific enzyme

Usually confined to specific locations

Front 69

Catabolic pathways

Back 69

Break down complex substrates into simpler end products

Provide raw materials and chemical energy for the cell

Front 70

Anabolic Pathways

Back 70

Synthesize complex end products from simpler substrates

Use ATP and NADPH from catabolic pathways

Front 71

Oxidation-Reduction Reactions

Back 71

Oxidized molecule donates electrons to reduced molecule

Front 72

Where does Glycolysis occur?

Back 72

Cytoplasm

Front 73

Equation for Glycolysis

Back 73

C6H12O6 + 2ATP + 2Pi + 2NAD+ >> 2 Pyruvate + 2ATP + 2NADH + 2H+ + 2H2O

Front 74

Energy Investment Phases of Glycolysis

Back 74

Hydrolysis of ATP in 2 of the first 3 reactions

Front 75

Glycolysis Step 1

Back 75

Glucose is phosphorylated to Glucose-6-Phosphate by using ATP

Enzyme- Hexokinase

Free Energy- -4.0

Front 76

Glycolysis Step 3

Back 76

Fructose-6-Phosphate is Phosphorylated to Fructose 1,6-Bisphosphate using ATP

Enzyme- Phosphofructokinase

Free Energy- -3.4

Front 77

Which step of Glycolysis is considered the most important?

Back 77

3

Front 78

Glycolysis Step 6

Back 78

NAD+ is reduced to NADH when Glyceraldehyde 3-Phosphate is oxidized to 1,3-Bisphosphoglycerate

Enzyme- Glyceraldehyde Phosphate Dehydrogenase

Free Energy- +1.5

Front 79

Dehydrogenase

Back 79

Enzyme that oxidizes and reduces cofactors

Front 80

NAD+

Back 80

Nicotinamide Adenine Dinucleotide

Receives 2 electrons and 1 proton

Front 81

Glycolysis Step 7

Back 81

ATP is formed when 1,3-Bisphosphoglycerate is converted to 3-Phosphoglycerate

Enzyme- Phosphoglycerate Kinase

Front 82

Substrate-level Phosphorylation

Back 82

Occurs when ATP is formed by a Kinase enzyme

Front 83

Glycolysis Step 10

Back 83

3-Phosphoglycerate is converted to pyruvate, another Kinase phosphorylates ADP

Enzyme- Phosphoenolpyruvate

Free Energy- -7.5

Front 84

Does Glycolysis require oxygen?

Back 84

No- anaerobic pathway

Front 85

Net ATP production of Glycolysis

Back 85

2 ATP

Front 86

Fermentation

Back 86

Restores NAD+ from NADH

Front 87

The supply of NADPH represents the cell's __________

Back 87

Reducing power

Front 88

How is NADPH formed from NAD+?

Back 88

Phosphate transfer from ATP to NAD+ to form NADP+, then reduced to NADPH

Front 89

NADPH donates electrons to build __________

Back 89

Large biomolecules

Front 90

__________ pathways use NADPH

Back 90

Anabolic

Front 91

__________ pathways use NAD+

Back 91

Catabolic

Front 92

NADPH vs NADH

Back 92

NADPH is favored when energy is abundant

NADH is used to make ATP when energy is scarce

Front 93

Covalent modification of enzymes regulated by __________

Back 93

Kinases

Front 94

Feedback Inhibition

Back 94

The product of the pathway allosterically inhibits one of the first enzymes of the pathway

Front 95

__________ and __________ are the catabolic and anabolic pathways of glucose metabolism

Back 95

Glycolysis, Glucogenesis

Front 96

Cristae

Back 96

Inside mitochondria, series of invaginated memranous sheets

Front 97

Once formed, Acetyl CoA enters the __________

Back 97

Tricarboxylic Acid (TCA) cycle

Front 98

How is Acetyl CoA formed?

Back 98

After Glycolysis, Pyruvate is actively transported across the inner membrane and decarboxylated to form Acetyl CoA

Front 99

Acetyl CoA links __________ to __________

Back 99

Glycolysis, TCA Cycle

Front 100

TCA Cycle overview

Back 100

Acetyl CoA condensed with 4-carbon Oxaloacetate to form a 6-carbon citrate, oxidized to Oxaloacetate over a series of steps

Front 101

Oxidation-Reduction Reactions in TCA Cycle

Back 101

Steps 3, 4, and 8- NAD+ reduced to NADH + H+

Step 6- FAD reduced to FADH

Front 102

Purpose of the TCA Cycle

Back 102

Produces high energy carrier molecules to be used during oxidative phosphorylation to produce ATP

Front 103

Where does the TCA Cycle take place?

Back 103

Matrix of the mitochondria

Front 104

End Products of TCA Cycle

Back 104

Oxaloacetate, 3NADH, 3H+, 2CO2, FADH2, ATP

Front 105

Ligand-Gated Ion Channel

Back 105

Has a binding site, goes through conformational change

Front 106

Mechano-Gated Ion Channel

Back 106

Physical stress causes change

Front 107

In what stage of cellular respiration does the first oxidative phosphorylation occur?

Back 107

Step 7 of Glycolysis

Front 108

2 Steps of Oxidative Phosphorylation

Back 108

1. Electron transport chain

2. Flow of protons drives ATP production

Front 109

During Oxidative Phosphorylation, you can expect to receive about ______ ATPs per pair from NADH and ______ ATPs per pair FADH2

Back 109

3, 2

Front 110

5 Types of Electron Carriers in the ETC

Back 110

Flavoproteins

Cytochromes

Copper Atoms

Iron-Sulfur Proteins

Ubiquinone

Front 111

Flavoproteins

Back 111

Polypeptides with either FAD or FMN (prosthetic group)

Front 112

Cytochromes

Back 112

Contain heme prosthetic groups w/ iron

Alternates between Fe2+ and Fe3+ by gain/loss of electron

Front 113

3 Copper Atoms

Back 113

Located w/in a single protein complex, donate/accept an electron

Front 114

Iron-Sulfur Proteins

Back 114

Contain iron linked to non-heme sulfur centers

Capable of accepting/donating one electron

Front 115

Ubiquinone (Coenzyme A)

Back 115

No Prosthetic group

Lipid soluble

Can accept/donate 2 electrons and protons

Mobile electron carrier

From Complexes I and II to Complex III

Front 116

Fully reduced form of Ubiquinone

Back 116

Ubiquinol

Front 117

Carriers in the ETC are organized from __________ to __________ agent

Back 117

Strongly reducing, oxidizing

Front 118

The last electron acceptor in the ETC is

Back 118

O2

Front 119

Complex I: NADH Dehydrogenase Complex

Back 119

Catalyzes transfer of electron pair from NADH to Ubiquinone

Front 120

Complex II: Succinate Dehydrogenase Complex

Back 120

Transfers e- to Ubiquinone

Contains FAD

Not accompanied by proton transfer

Front 121

Complex III: Cytochrome bc1

Back 121

Accepts e- from Ubiquinol and passes to Cytochrome C

Front 122

Cytochrome C

Back 122

Peripheral protein associated with the surface facing the intermembrane space

Mobile carrier between complexes III and IV

Front 123

Complex IV: Cytochrome Oxidase

Back 123

Adds 4e- to O2 to form 2 molecules of H2O

Front 124

Peroxisomes

Back 124

Membrane-bound vesicles that contain oxidative enzymes

Oxidize very long chain fatty acids, and synthesize plasmalogens