Test 3 Review Flashcards

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1
Q

-where does substrate level phosphorylation occur

A

A smaller amount
of ATP is formed directly in a few reactions of glycolysis and
the citric acid cycle by this mechanism

This mode of ATP synthesis
occurs when an enzyme transfers a phosphate group from a
substrate molecule to ADP, rather than adding an inorganic
phosphate to ADP as in oxidative phosphorylation.

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2
Q

What are the end products for glycolysis

A

2 pyruvate, 2 net gain ATP (4 total), and 2 NADH

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3
Q

How many molecule of ATP produced from 1 glucose

molecule

A

For each molecule of glucose degraded to CO2
and water by respiration, the cell makes up to 32
molecules of ATP

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4
Q

Which parts of cellular respiration/photosynthesis occurs in

the cytosol

A

glycolysis

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5
Q

glycolysis

A

Glycolysis (“sugar splitting”) breaks down glucose
into two molecules of pyruvate and two molecules of water

Glycolysis occurs in the cytoplasm and has two
major phases

Energy investment phase

Energy payoff phase

Glycolysis occurs whether or not O2 is present

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6
Q

fermentation

A

catabolic partial degra-
dation of sugars or other organic fuel that occurs without the
use of oxygen

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7
Q

anaerobic

A

occurs without the use of oxygen as a reactant (fermentation)

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8
Q

aerobic

A

catabolic process that occurs with oxygen as a reactant

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9
Q

What type of reaction is the breakdown of glucose?

A

Exergonic (it can happen spontaneously and doesn’t require the input of energy)

It has a negative free energy change because the products store less energy than the reactants

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10
Q

redox reactions

A

transfer of one electron from one reactant to another

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11
Q

oxidized

A

the first reactant becomes oxidized and transfers to the first product

loses electrons

C6H12O6 is oxidized to become 6CO2

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12
Q

Reduced

A

The second reactant becomes reduced to become the second product

addition of electrons (number of protons are reduced)

6O2 is reduced to 6H2O

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13
Q

oxidizing agent

A

the second reactant is the oxidizing agent because it oxidizes the first reactant

6O2

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14
Q

Reducing agent

A

is the first reactant

C6H12O6

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15
Q

what role does oxygen play in cellular respiration

A

it’s the oxidizing agent

and it serves as the final electron acceptor in the Electron Transport Chain

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16
Q

What are the reactants in glycolysis

A

C6H12O6, 2NAD+,2ADP+2pi

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17
Q

What are the products of the Krebs Cycle?

A

ATP, CO2, FADH2, NADH

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18
Q

What are the reactants of the Krebs Cycle?

A

Acetyl CO.A, NAD+, FAD+, ADP+Pi

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19
Q

Roles of NADPH/NAD- what do they carry and how are

they used in the metabolic processes

A

electrons

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20
Q

facultative anaerobes

A

Yeast and many bacteria

they can survive
using either fermentation or cellular respiration

pyruvate can lead to cellular respiration via O2 or ethanol lactate or other products without O2 (fermentation)

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21
Q

Athletes and scarce O2

A

Human muscle cells use lactic acid fermentation to

generate ATP when O2 is scarce

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22
Q

Energy released by the electron transport chain is used to

pump H+ into which location in eukaryotic cells

A

from the mitochondrial matrix into the intermembrane space

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23
Q

The synthesis of ATP by oxidative phosphorylation, using
the energy released by movement of protons across the
membrane down their electrochemical gradient, is an
example of ?

A

chemiosmosis

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24
Q

During aerobic respiration, H2O is formed. Where does the

oxygen atom for the formation of the water come from?

A

Oxygen from the air we breathe (from photosynthesis) and food

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25
Q

Where are the proteins of the electron transport chain

located?

A

in the mitochondrial membrane (cristae)

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26
Q

In the presence of oxygen, the three-carbon compound pyruvate
can be catabolized in the citric acid cycle. First, however, the
pyruvate (1) loses a carbon, which is given off as a molecule of
CO2, (2) is oxidized to form a two-carbon compound called
acetate, and (3) is bonded to coenzyme A. The three listed steps
result in the formation of ?

A

Acetyl CoA`

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27
Q

When a glucose molecule loses a hydrogen atom as the result

of an oxidation-reduction reaction, the molecule becomes ?

A

CO2

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28
Q

Most of the CO2 from the catabolism of glucose is released

during ?

A

Citric acid or krebs cycle

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29
Q

During aerobic respiration, electrons travel downhill in which
sequence, i.e from where to where?

A

when they’re being oxidized and pass the electrons down to their more electronegative neighbor (to the Iron Sulfur FeS protein in complex 1) which is in chemiosmosis

From the electron transport chain to ATP Synthase in chemiosmosis

This proton gradient that forms is called the proton motive force

The carrier protein downhill from oxygen to water

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30
Q

electron transport chain

A

a collection of molecules em-
bedded in the inner membrane of the mitochondrion in eu-
karyotic cells. (cristae)

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31
Q

If the the free energy for the oxidation of glucose to CO2 and
water is -686 kcal/mol and the free energy for the reduction
of NAD+ to NADH is +53 kcal/mol. Why are only two
molecules of NADH formed during glycolysis when it
appears that as many as a dozen could be formed?

A

Because we only use 34% of glucose for ATP; the rest is released as heat

32
Q

alcohol fermentation

A

pyruvate is

converted to ethanol, releases CO2

33
Q

lactic acid fermentation

A

pyru-
vate is reduced directly by NADH to form lactate as an end
product, with no release of CO2

34
Q

beta oxidation

A

breaks
the fatty acids down to two-carbon fragments, which enter
the citric acid cycle as acetyl CoA. NADH and FADH2 are also
generated during beta oxidation

35
Q

• Carbohydrates and fats are considered high-energy foods

because they___

A

They have high energy levels of electrons

A gram of fat oxidized by respiration produces
more than twice as much ATP as a gram of carbohydrate.

36
Q

acetyl Coenzyme A

A

which links glycolysis to the citric acid cycle

joins the cycle by
combining with oxaloacetate, forming citrate

37
Q

Allosteric regulation

A

uses an enzyme to keep the “pace” of cellular respiration

It monitors ATP and when ATP reaches a certain number, it stops glycolysis

it also monitors citrate, so it keeps each cycle consistent

38
Q

Where is chlorophyll located

A

Green pigment that gives leaves their color and is found inside the thylakoid membrane of the chloroplast

39
Q

When oxygen is released as a result of photosynthesis, it is a
direct by-product of ?

A

The chloroplast splits water into hydrogen and oxygen

It incorporates the electrons of hydrogen into sugar molecules and then releases oxygen as a byprouduct

The Oxygen comes from water

40
Q

Difference between autotrophs and heterothrophs

A

autotrophs are self-feeders and sustain themselves without eating anything

heterotrophs are biosphere’s consumers because they consume compounds produced by other organisms

41
Q

Engelman’s experiment

A

Used aerobic algae to test which wavelengths were the most suitable for photosynthesis

The wavelengths that were suitable to photosynthesis caused the algae to expel excess O2 and then the aerobic bacteria would congregate around it.

42
Q

In What wavelength of light photosynthesis takes place

A

400-500 nm and 600-700 nm is the best for chlorophyll a

it can happen anywhere from 400-700

43
Q

If the plant leaves appear reddish-yellow what wavelength

are being absorbed

A

everything except yellow, red

so orange, violet, blue, and green

44
Q

What is the relationship between the wavelength of light and

the quantity of energy per photon?

A

The only photons absorbed are those whose energy is
exactly equal to the energy difference between the ground
state and an excited state, and this energy difference varies
from one kind of molecule to another. Thus, a particular
compound absorbs only photons corresponding to specific
wavelengths, which is why each pigment has a unique ab-
sorption spectrum.

45
Q

Water and electron donation to photosystem II

A

H2O is split by enzymes and the electrons are transferred from the hydrogen atoms to P680+ thus reducing it to P680 (O2 is released as a byproduct)

46
Q

Linear electron flow

A

Linear:

  1. Photon hits the pigment and the energy is passed from pigment molecules until it excites P680
  2. An excited electron from P680 is transferred via the primary electron transport (P680+)
  3. H2O is split by enzymes and the electrons are transferred from the hydrogen atoms to P680+ thus reducing it to P680 (O2 is released as a byproduct)
  4. Each electron “falls” down an electron transport chain to from the primary electron acceptor of PS 2 to PS 1
  5. Energy released by the fall drives the creation of a proton gradient across the thylakoid membrane (diffusion of H+ across the membrane drives ATP synthesis)
  6. In PS 1 transferred light energy excites P700 which loses an electron (P700+ accepts an electron passed down from PS 2 through the transport chain)
  7. Each electron falls down the chain from the primary electron acceptor in PS1 to ferredoxin (fd)
  8. The electrons are then transferred to NADP+ and reduced to NADPH

NADPH is then available for the Calvin cycle

This also removed H+ from the Stroma

47
Q

Cyclic electron flow

A

Electrons cycle back from Fd to PS1 reaction center

Uses only PS 1 and produces ATP, but no NADPH

Don’t release O2

Ie purple bacteria which have PS1 but not PS2

Evolved before linear flow and may protect the plant from light damage

48
Q

Where’s ATP synthase found

A

in the stroma? But it is kind of embedded in the thylakoid membrane

49
Q

P680+

A

Photon hits the pigment in PS 2 and the energy is passed from pigment molecules until it excites P680 and becomes 680+

50
Q

Calvin cycle/carbon cycle

A

Similar to the citric acid cycle because it regenerates its starting material after molecules enter and leave the molecule

It builds sugar from smaller molecules using ATP and reducing the power of electrons via NADPH

Carbon enters as CO2 and releases as glyceralhyde three phosphate G3P (has to go through Calvin cycle three times for this to occur

51
Q

RuBp molecule and rubisco

A

Rubisco catalyzes carbon fixation in the calvin cycle and regenerates CO2 acceptor by RuBp

52
Q

What compound provides the reducing power for Calvin

cycle reactions

A

ATP is involved, but it’s mostly NADPH

53
Q

C3 plants

A

most plants

initial fixation of CO2,
via rubisco, forms a three-carbon compound
3-phosphoglycerate

54
Q

C4 plants

A

minimize the cost of photorespiration by
incorporating CO2 into four-carbon compounds

two distinct types of cells in the leaves
of C4 plants:
Bundle-sheath cells
mesophyll cells

  1. The production of the four carbon precursors is
    catalyzed by the enzyme PEP carboxylase in
    the mesophyll cells
    PEP carboxylase has a higher affinity for CO2
    than rubisco does; it can fix CO2 even when CO2
    concentrations are low
  2. These four-carbon compounds are exported to
    bundle-sheath cells
  3. Within the bundle-sheath cells, they release CO2
    that is then used in the Calvin cycle
55
Q

CAM plants

A

what succulent plants use to fix carbon

open their stomata at night,
incorporating CO2 into organic acids

Stomata close during the day, and CO2 is released
from organic acids and used in the Calvin cycle

56
Q

Photorespiration

A

rubisco adds O2 instead of
CO2 in the Calvin cycle, producing a two-carbon
compound

consumes O2 and organic fuel
and releases CO2 without producing ATP or sugar

In many plants, photorespiration is a problem
because on a hot, dry day it can drain as much
as 50% of the carbon fixed by the Calvin cycle

57
Q

Cleavage furrow and cell plates

A

Cleavage furrow happens in cytokinesis of animal cells

Cell plates form in plant cells during cytokinesis

58
Q

Centromeres

A

narrow “waist” of the
duplicated chromosome, where the two
chromatids are most closely attached

59
Q

G1 phase

A

First gap - longest stage of interphase

60
Q

G2 phase

A

second gap

shortest time in interphase

61
Q

S phase

A

synthesis (where DNA is copied and synthesized) middle length stage of interphase

62
Q

Mitotic phase

A

10 % of the total reproductive cycle of the cell and includes cytokinesis and PMAT and prometaphase between pro and meta

63
Q

prophase

A

dna starts to condense

early mitotic spindle begins to form

become two sister chromatids

64
Q

prometaphase

A

nuclear envelope begins to disassociate

kinetochores attach to the sister chromatids

kinetochore tubules attaches to kinetochores

non kinetochore microtubules also form

65
Q

Kinetochores

A

Kinetochores are protein complexes associated

with centromeres

66
Q

metaphase

A

sister chromatids line up along the metaphase plate

67
Q

anaphase

A

The microtubules shorten by depolymerizing at

their kinetochore ends

68
Q

telophase,

A

genetically identical daughter nuclei

form at opposite ends of the cell

69
Q

density-dependent inhibition,

A

crowded cells

will stop dividing

70
Q

anchorage dependence

A

to divide, they must be attached to a substratum

71
Q

Cancer cells

A

don’t exhibit anchorage dependence or density-dependent inhibition

72
Q

MPF

A

(maturation-promoting factor) is a cyclin-Cdk
complex that triggers a cell’s passage past the G2
checkpoint into the M phase

73
Q

cyclins and cyclin-dependent

kinases (Cdks)

A

Two types of regulatory proteins are involved in

cell cycle control

74
Q

checkpoints

A

in G1, G2 and m phases

G1 is most important, if it receives the go ahead from G1, it will usually continue to do the rest

75
Q

M phase checkpoingt

A

without chromosomes being attached to microtubules, mitosis won’t proceed