Bio 20A, Study Guide 4

Front 1

Three major types of cytoskeleton:

Back 1

microtubules, microfilaments, intermediate filaments

Front 2

Microtubules are made of:

Back 2

tubulins

Front 3

tubulin

Back 3

rigid tubes within cells that form microtubules

Front 4

alpha + beta tubulin =

Back 4

tubulin heterodimer

Front 5

heterodimers link end to end to form a:

Back 5

protofilament

Front 6

protofilaments are arrange into:

Back 6

a ring w/ 13 strands

Front 7

How large are microtubules?

Back 7

25 nm in diameter (they're the largest)

Front 8

What is the function of microtubules?

Back 8

Serve as tracks along which other cell components move (e.g., vesicles, organelles, chromosomes)

Front 9

most microtubules originate from the:

Back 9

centrosome/MTOC

Front 10

What are the ends of microtubules referred to as?

Back 10

minus and plus ends

Front 11

When are microtubules rearranged? What do they form?

Back 11

mitosis; mitotic spindle

Front 12

mitotic spindle

Back 12

separates chromosomes during mitosis

Front 13

Microfilaments are a polymer of

Back 13

protein actin

Front 14

Microfilaments size?

Back 14

7 nm across

Front 15

The microfilaments structure is:

Back 15

flexible, thin

Front 16

Microfilaments function:

Back 16

>serves as a cable holding parts together
>cell movement
>cell shape

Front 17

What do amoeba use to crawl?

Back 17

Microfilaments

Front 18

In non muscle cells _______ have a dynamic polymerization and
depolymerization cycle that gives cell shapes

Back 18

Microfilaments

Front 19

What gives shape to the microvilli in intestinal epithelial cells?

Back 19

microfilaments

Front 20

microfilaments serve what role in cytokinesis?

Back 20

pinching cells in two

Front 21

Intermediate filaments are made of...

Back 21

made of several types of proteins, e.g., keratin

Front 22

Intermediate filaments size:

Back 22

10 nm

Front 23

Intermediate filaments structure:

Back 23

not dynamic, fixed

Front 24

Intermediate filaments function:

Back 24

strong cables, giving strength to tissues

Front 25

epithelial sheets get their strength from:

Back 25

intermediate filaments

Front 26

molecular motors

Back 26

interact with the cytoskeleton

Front 27

Kinesin and dynein move along _____________

Back 27

microtubules

Front 28

kinesin moves towards:

Back 28

plus end

Front 29

dynein moves towards:

Back 29

minus end

Front 30

molecular motors require:

Back 30

use of ATP --> ADP + Pi

Front 31

molecular motors are responsible for:

Back 31

the placement and movement of organelles and vesicles inside the cell

Front 32

molecular motors cause:

Back 32

heads to release, move forward and rebind

Front 33

during mitosis, motors are responsible for:

Back 33

pulling the sister chromatids apart

Front 34

ATP hydrolysis walks...

Back 34

the motor heads along the microtubules.

Front 35

Myosin

Back 35

similar in function as the microtubule motors, but is used to walk along
the microfilaments.

Front 36

Heads walk along

Back 36

actin fiber, use ATP for energy

Front 37

molecular motors are responsible for

Back 37

muscle contraction & cell shape

Front 38

sperm tails are

Back 38

flagella

Front 39

lungs use ____ to remove debris

Back 39

cilia

Front 40

___ line the fallopian tube

Back 40

cilia

Front 41

in the fallopian tube, ____ move eggs from the ovaries

Back 41

cilia

Front 42

cilia are composed of:

Back 42

9 outer doublet microtubles, two central singlet microtubules

Front 43

In cilia, the protein dynein causes:

Back 43

one set of outer doublet microtubules to move along another, bending the structure and creating a whip-like movement

Front 44

1st law of thermodynamics

Back 44

energy in a reaction is neither created nor destroyed

Front 45

2nd law of thermodynamics

Back 45

disorder tends to increase - essentially states that not all energy in the system is
available for work

Front 46

Enthalpy

Back 46

total energy = H

Front 47

Gibbs free energy

Back 47

energy available for work = G

Front 48

Entropy

Back 48

energy that is disorganized for work = S

Front 49

H=

Back 49

G + S

Front 50

entropy increases
with:

Back 50

temperature

Front 51

ΔG =

Back 51

ΔH − TΔS (T = the absolute temperature)

Front 52

In a chemical reaction, if ΔG is positive, the reaction is

Back 52

endergonic and will require
energy input

Front 53

If ΔG is negative, then the reaction is

Back 53

exergonic and will release energy.

Front 54

Catabolic reactions

Back 54

exergonic: complex molecules --> free energy + small molecules

Front 55

Anabolic reactions

Back 55

endergonic: free energy + small molecules --> complex molecules

Front 56

The formation of phosphate bonds between the
phosphates requires _______and serves as a _____ for energy in the cell.

Back 56

energy; storage unit

Front 57

Pi

Back 57

inorganic phosphate

Front 58

Breakage of these bonds to release ADP + Pi (inorganic phosphate) or
AMP + PPi (pyrophosphate) releases approximately ______ of energy.

Back 58

7.3 kcal/mol

Front 59

Luciferin + O2 + ATP -->

Back 59

oxyluciferin + AMP + PPi + light

Front 60

at rest, an average person produces and
hydrolyzes ______ of ATP in a day.

Back 60

40 kilograms

Front 61

the average ATP molecule cycles
between ADP and ATP ______ times a day

Back 61

10,000

Front 62

we really only have ___ of ATP
turning over in a person

Back 62

4 grams

Front 63

Pumps and molecular motors are driven by:

Back 63

ATP

Front 64

enzymes

Back 64

catalyze reactions

Front 65

The reason why all exergonic reactions don't go to completion automatically even though
the products have less free energy than the reactants is because :

Back 65

the transition state
between the two is a high energy state.

Front 66

The role of a catalyst is to:

Back 66

lower the energy for the transition state of a reaction.

Front 67

The free
energy of the reactants and products don't change, but the ability to get from one state to
the other is enhanced by _____

Back 67

a catalyst.

Front 68

Proteins serve as catalysts by:

Back 68

having binding sites on their surfaces for the reactants that
can bring the reactants in close proximity to each other and stabilize the transition states
as covalent bonds are broken and formed.

Front 69

The summary of a glycolysis reaction:

Back 69

C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O

Front 70

In glycolysis, ΔG =

Back 70

-686 kcal per mole

Front 71

Glycolysis

Back 71

breakdown of glucose produces ATP, which is the key energy currency.

Front 72

ADP + Pi --> ATP, ΔG =

Back 72

+7.3 kcal per mole

Front 73

Optimal yield of glycolysis:

Back 73

36 - 38 ATP

Front 74

Efficiency of glycolysis:

Back 74

40% efficiency

Front 75

NADH carries:

Back 75

two high-energy electrons

Front 76

NAD+ 2 e- + H+ -->

Back 76

NADH

Front 77

When bonds are broken down, high energy electrons are transferred to ____ along with
a ____ to make ____. These are fed into the _______ to produce more
____.

Back 77

NAD+; H+; NADH; electron transport chain; ATP

Front 78

Extracting energy from glucose consists of 4 phases…

Back 78

1.Glycolysis
2. Pyruvate Oxidation
3. Citric Acid Cycle
4. Electron Transport Chain/ATP synthase

Front 79

Does glycolysis occur in virtually all organisms?

Back 79

Yes.

Front 80

Glycolysis pathway has how many steps?

Back 80

ten

Front 81

phosphorylated

Back 81

has phosphates added to it

Front 82

pyruvate has how many carbons?

Back 82

three

Front 83

In glycolysis, glucose (6 carbons) is ________, rearranged and
broken down to yield two 3 carbon molecules of _____.

Back 83

phosphoylated; pyruvate

Front 84

Glucose - 6C is broken down into how many pyruvates?

Back 84

two pyruvates

Front 85

How many ATP are required to start glycolysis?

Back 85

Two (for steps 1 and 3) -- used to make initial phosphoylated intermediates

Front 86

Net yield of glycolysis:

Back 86

2 ATPs and 2 NADH

Front 87

Anaerobic organisms can get all of their ATP from _______

Back 87

glycolysis

Front 88

Anaerobic organisms

Back 88

organisms that don't require O2

Front 89

In fermentation, further ATP production after pyruvate requires ____, if ____ is low, then you get
______

Back 89

O2;O2; anaerobic metabolism

Front 90

One problem with glycolysis is that

Back 90

NAD+ gets quickly used up (reduced to NADH).

Front 91

NAD+ is present at low concentrations in the

Back 91

cytoplasm

Front 92

How to get the electrons off of NADH to recover NAD+ in humans :

Back 92

Pyruvate + NADH --> lactic acid + NAD+

Front 93

How to get the electrons off of NADH to recover NAD+ in yeast:

Back 93

Step one: Pyruvate --> acetylaldehyde + CO2

Step two: Acetylaldehyde + NADH --> ethanol + NAD+

Front 94

In glycolysis, if O2 is available, then the high energy electrons can be given to O2 and much more
energy can be derived from _____.

Back 94

pyruvate

Front 95

When oxygen is unavailable for pyruvate, _____ occurs

Back 95

fermentation

Front 96

pyruvate oxidation reaction

Back 96

Pyruvate + NAD+ + Coenzyme A --> CO2 + NADH + acetyl Coenzyme A

Front 97

in pyruvate oxidation ___ high energy ____ are put on ____

Back 97

two; electrons ; NAD+

Front 98

breath out a CO2 molecule caused by

Back 98

decarboxylation of glucose

Front 99

Coenzyme A serves as a carrier for

Back 99

acetyl

Front 100

pyruvate oxidation takes place :

Back 100

inside the mitochondrion

Front 101

pyruvate oxidation takes pl ace in the:

Back 101

mitochondrial matrix

Front 102

the citric acid cycle takes place in the:

Back 102

mitochondrial matrix

Front 103

the citric acid cycle:
Uses the ____ group from acetyl CoA to make more ____

Back 103

acetyl ; ATP

Front 104

How many enzymes are used in the citric acid cycle?

Back 104

eight

Front 105

How many steps in the pathway are there in the citric acid cycle?

Back 105

eight

Front 106

In step one, 2C Acetyl group + 4C OAA -->

Back 106

6C citrate in first step

Front 107

In the citric acid cycle...

2 C + 4C --> 6 C -->

Back 107

5 C + CO2 --> 4C + CO2

Front 108

For each Acetyl CoA that goes in, the citric acid cycle produces

Back 108

2 CO2, 1 ATP, 3
NADH and 1 FADH2

Front 109

FADH2 serves as a

Back 109

high energy electron carrier

Front 110

NADH and FADH2 have high energy

Back 110

electrons

Front 111

For each glucose, Glycolysis, pyruvate oxidation and the citric acid cycle yield a total
of…

Back 111

6 CO2
10 NADH
2 FADH2
4 ATP

Front 112

NADH and FADH2 accumulated during glycolysis, pyruvate oxidation and the citric acid
cycle carry _____

Back 112

high energy electrons

Front 113

NADH + H+ + ½ O2 ------->

ΔG =

Back 113

NAD+ + H2O

ΔG = -53 kcal/mol

Front 114

ΔG for ATP synthesis ADP + Pi --> ATP is about

Back 114

7.3 kcal/mol

Front 115

Peter Mitchell in 1961 proposed

Back 115

"chemiosmotic hypothesis" based initially on studies
of bacteria, but later proven applicable to the inner membrane of mitochondria.

Front 116

Electrochemical gradient is used to drive

Back 116

ATP synthesis

Front 117

Three main points of chemiosmotic hypothesis:

Back 117

1-components of the electron transport chain are proton pumps
2- need closed vesicle to make ATP
3- H+ gradient is used to drive synthesis of ATP

Front 118

Complexes I, III and IV are

Back 118

H+ pumps driven by the moving electrons.

Front 119

Complex II is
there to receive e- from

Back 119

FADH2

Front 120

Ubiquinone (Q) and cytochrome C

Back 120

carry electrons from one complex to the next

Front 121

In complex IV, the electrons are given to

Back 121

O2 to form H2O. This is the lowest energy
state of the electrons.

Front 122

RESULTS OF ELECTRON TRANSPORT
For each pair of electrons donated by NAD+,

Back 122

3 to 4 H+ pumped out of matrix by
complexes I, III and IV.

Front 123

How is the elctrochemical gradient used to make ATP?

Back 123

The ATP synthase couples transport of H+ down electrochemical gradient to synthesis of
ATP.

Front 124

ATP synthase constitutes _____ of the protein in the mitochondrial inner membrane

Back 124

15%

Front 125

f1 is made of

Back 125

5 types of polypeptides and it synthesizes ATP.

Front 126

f0 is made of

Back 126

3 types of integral membrane proteins which form a proton channel.

Front 127

Protons passing through the channel down their electrochemical gradient are used to

Back 127

drive synthesis of ATP.

Front 128

alpha and beta subunits

Back 128

alternating three of each in ring in f1.

Front 129

Gamma subunit

Back 129

attached to c proteins in membrane which form a complex that spins as
electrons pass through the channel. This causes the gamma subunit to spin inside of alpha
and beta subunit ring when electrons flow.

Front 130

gamma subunit spinning inside of alpha and beta subunits causes

Back 130

conformational change
of beta subunits which drives ATP synthesis.

Front 131

Beta subunits bind _____ and then a conformational change in beta subunit caused
by rotation of gamma subunit brings these close enough together to form ___.

Back 131

ADP and Pi; ATP

Front 132

beta subunit exists in _____ states and the position of the gamma subunit
rotating _____ through this process drives the production of ATP.

Back 132

three ; 120°

Front 133

f1 subunit

Back 133

3 alpha,
2 beta and one gamma proteins

Front 134

pyruvate/H+ symport

Back 134

used to import pyruvate into the matrix

Front 135

Pi/H+ symport

Back 135

used to import Pi into the matrix

Front 136

Antiports exist in inner membrane to

Back 136

exchange ATP out for ADP into the mitochondrial
matrix

Front 137

cell cycle

Back 137

process by which a cell, which has arisen from the division of
two cells, grows, replicates its chromosomes, and divides in two to form two daughter
cells.

Front 138

cancer is basically a disease that is caused when

Back 138

the cell cycle is not
regulated

Front 139

Cytokinesis

Back 139

dividing the cell in two

Front 140

M phase stands for

Back 140

mitosis

Front 141

mitosis

Back 141

process by which the chromosomes are
separated into the two daughter cells and the two cells divide

Front 142

S phase stands for

Back 142

synthesis

Front 143

S phase

Back 143

phase of the cell cycle in which the DNA in the
genome is completely replicated. It is also the phase in which the centrosome
(microtubule organizing center) is duplicated.

Front 144

G was initially used to stand for

Back 144

gap since it was not clear initially what the cells were
doing during the G phases

Front 145

Now people commonly refer to G as the

Back 145

growth phases of the
cell.

Front 146

G1 is the phase in which

Back 146

most growth occurs

Front 147

G2 is the phase

Back 147

after the DNA is replicated
during which more growth can occur and in which the cell has twice as much DNA as it
does at the other times

Front 148

G0

Back 148

refers to cells that stop dividing

Front 149

quiescence

Back 149

G0

Front 150

terminally differentiated cells

Back 150

remain at G0 until they die

Front 151

interphase

Back 151

refers to cells in G1, S or G2 because they look the same
under the microscope; they have a nucleus.

Front 152

How did S phase get discovered?

Back 152

tritiated thymidine in pulse-chase experiments

Front 153

Time of M phase Mitosis

Back 153

1 -2 hours

Front 154

Time of G1 phase Gap 1

Back 154

~8 hours

Front 155

Time of S phase synthesis

Back 155

~8 hours

Front 156

Time of G2 phase Gap 2

Back 156

~5 hours

Front 157

In a typical animal cell in culture, interphase lasts

Back 157

21 hours

Front 158

6 stages of mitosis:

Back 158

1) prophase
2) prometaphase
3) metaphase
4) anaphase
5) telophase
6) cytokinesis

Front 159

prophase

Back 159

Chromosomes condense, centrosomes migrate and begin assembly of mitotic spindle

Front 160

prometaphase

Back 160

Nuclear envelope breaks down, chromosomes attach to spindle

Front 161

metaphase

Back 161

Chromosomes align at the equator

Front 162

anaphase

Back 162

Sister chromatids synchronously separate and are pulled slowly towards the
spindle poles

Front 163

telophase

Back 163

Chromosomes arrive at the poles, begin to decondense. Nuclear envelope
reassembles.

Front 164

cytokinesis

Back 164

Contractile ring pinches the cell in two.

Front 165

chromosomes

Back 165

long strands of DNA packed up in proteins

Front 166

if our classroom is the size of a human nucleus, there would be ______ of DNA that
would have to be organized in it, completely replicated during _____, lined up at the
_______, and separated by the ______.

Back 166

3000 miles; S phase; metaphase plate; mitotic spindle apparatus

Front 167

chromatin

Back 167

DNA and associated
proteins

Front 168

DNA is wrapped ____ around:

Back 168

2x; an octamer of proteins
called histones an octamer of proteins
called histones arranged in a structure called the nucleosome

Front 169

histones

Back 169

an octamer of proteins
arranged in a structure called the nucleosome

Front 170

Approximately ______ of
DNA are found around one nucleosome and the spacer between the next one.

Back 170

200 BP

Front 171

mitotic spindle

Back 171

a rearrangement and specialized function of the microtubule
organizing center

Front 172

In mitosis, the microtubule network ____, the centrosome ________, and the microtubule networks______

Back 172

breaks down; duplicates and migrates
to opposite sides of the nucleus ; grow out to form the
mitotic spindle apparatus

Front 173

Minus ends of the microtubules are embed in the

Back 173

centrosome

Front 174

Plus ends grow...

Back 174

out to the cell edge, towards the chromosomes and towards each other.

Front 175

Polar microtubules

Back 175

reach across the center and interact with microtubules from the other
pole

Front 176

centromere

Back 176

The constriction of the mitotic chromosome where the two sister chromatids are held
together

Front 177

kinetochore

Back 177

a protein plaque at the centromere

Front 178

plus ends of some of the microtubules are attached to the

Back 178

kinetochore

Front 179

cohesins

Back 179

proteins attaching the sister chromatids together at the
centromere

Front 180

what happens to cohesins during anaphase?

Back 180

destroyed and the daughter chromosomes separate.

Front 181

daughters travel to

Back 181

the poles of the mitotic spindle

Front 182

PPi

Back 182

pyrophosphate

Front 183

Decarboxylation

Back 183

a chemical reaction which releases carbon dioxide (CO2)