Plant Cellular Respiration Flashcards

1
Q

In plant metabolism, sugar can be in the form of ___ and ___.

A

sucrose
starch

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2
Q

Disaccharide: _____
Polysaccharide: ______

A

sucrose
starch

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3
Q

Sucrose consists of ___;
Starch consists of ____.

A

glucose + fructose
many glucose units

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4
Q

Where does sucrose accumulate? Where is it transported after?

A

cytosol
heterotrophic sink tissues (roots, stems, tuber)

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5
Q

What happens to starch during daytime?

A

stored at the vacuole; called “transitory starch” which is insoluble and dense.

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6
Q

At night, what happens to the transitory starch?

A

subjected to degradation

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7
Q

A part of a plant that produces or releases sugars, such as a leaf is called ___.

A

source

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8
Q

A part of a plant that receives or stores sugars, such as seeds, fruits, flowers, roots, and storage organs are called ____.

A

sink

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9
Q

What are photosynthates?

A

sucrose and starch

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10
Q

What part of the plant transports photosynthates?

A

phloem

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11
Q

During photosynthesis, the amount of photosynthates increases, which drives increased cellular metabolism and growth and development.

A

true

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12
Q

What is the second most abundant polysaccharide next to cellulose?

A

starch

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13
Q

Two types of starch

A

amylose
amylopectin

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14
Q

Where is starch synthesized and stored?

A

synthesized in the chloroplast;
stored in the vacuole

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15
Q

A type of starch that is linear; glucose units are connected by alpha - 1,4 glycosidic bond; has less than 1% branching.

A

amylose

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16
Q

A type of starch that is branching; branching pattern is facilitated by alpha - 1,6 glycosidic bond; 5-6% branching.

A

amylopectin

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17
Q

It is the reverse chemical reaction of photosynthesis.

A

cellular respiration

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18
Q

What are the various substrates of plants to fuel cellular respiration?

A
  1. disaccharides
  2. organic acids: pyruvate, malate
  3. phosphorylated sugar like triose phosphate
  4. lipids and proteins
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19
Q

What are the three main phases of cellular respiration?

A
  1. glycolysis
  2. TCA cycle/citric-acid cycle
  3. oxidative phosphorylation
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20
Q

The oxidation of sucrose can be grouped into 4 major processes. What are these?

A
  1. glycolysis
  2. oxidative pentose phosphate pathway
  3. citric acid cycle
  4. oxidative phosphorylation
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21
Q

The process by which sugar is split to produce glucose is called ____.

A

glycolysis

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22
Q

Where does glycolysis occur?

A

cytosol

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23
Q

When O2 is unavailable for glycolysis, it is followed by ____.

A

fermentative pathway

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24
Q

How does glycolysis in plants differ from animals?

A

variations in:
1. regulatory features
2. alternative enzymatic routes
3. a parallel partial glycolytic pathway in plastid

25
Q

What are the two pathways for splitting sucrose?

A
  1. invertase pathway
  2. sucrose synthase pathway
26
Q

Invertase pathway and sucrose synthase pathway: irreversible or reversible?

A
  1. invertase pathway: irreversible
  2. sucrose synthase pathway: reversible
27
Q

The existence of two different pathways that split sucrose and can replace each other without a clear loss in function is called ___.

A

metabolic redundancy

28
Q

What are the two phases of glycolysis?

A
  1. initial phase
  2. energy conserving phase
29
Q

What happens in the initial phase of glycolysis?

A

hexose is phosphorylated
twice and split, which produces 2 triose-P. this consumes 2 – 4 ATPs/ sucrose unit.

30
Q

The initial phase of glycolysis includes 2/3 irreversible reactions, catalyzed by ___ and ___.

A

hexokinase, phosphofructokinase.

31
Q

What happens in the energy conserving phase of glycolysis?

A

nad+ is reduced to nadh via 3-phosphate dehydrogenase.

32
Q

Products of glycolysis

A

2 molecules of Pyruvate
2 molecules of CO2
2 molecules of NADH

33
Q

An alternative pathway for the oxidation of
sugars.

A

oxidative pentose phosphate pathway

34
Q

Oxidative pentose phosphate pathway is carried out by the enzymes in ___ and ___.

A

cytosol and plastids

35
Q

Main idea of OPPP

A

glucose-p (hexose-p) is converted to ribulose-p (pentose-p); which is then converted to triose (g3p) to enter glycolytic pathway.

36
Q

Products of OPPP

A
  1. CO2
  2. NADPH
  3. Pentose-p
37
Q

Roles of oxidative pentose phosphate pathway in plant metabolism

A
  1. NADPH supply in the cytosol
  2. NADPH supply in plastids
  3. Supply of substrate for biosynthetic
    pathways
38
Q

Cytosolic reactions generate products that are transported into the mitochondria to feed the
citric acid cycle. True or False?

A

true

39
Q

Fates of PEP:
* Pyruvate → transported directly to
mitochondrion via pyruvate dehydrogenase
* Oxaloacetate → transported directly to
mitochondrion; converted to malate via PEP carboxylase & malate dehydrogenase → OAA, pyr

A

true

40
Q

Oxidizes organic acid → CO2, and transfer electrons to reduce NAD+ and FAD → NADH & FADH2 respectively.

A

citric acid / tca / krebs cycle

41
Q

Where does citric acid cycle take place?

A

mitochondria

42
Q

TCA can oxidize amino acid, but fatty acid oxidation occurs in peroxisome in plants (vs. animal mitochondrion). True or False?

A

true

43
Q

What are the unique features in Plant TCA cycle?

A
  1. ATP; animals: GTP
  2. malic enzyme ; animals have none
44
Q

What are the major events that take place in citric acid cycle?

A
  1. oxidation: OAA to citric acid
  2. reduction: NAD to NADH and FAD to FADH2
  3. phosphorylation (substrate-level): ATP
  4. decarboxylation: CO2 is released
45
Q

Components of Mitochondrial ETC found in the inner mitochondrial membrane

A
  1. protein complexes
  2. mobile electron carriers
  3. ATP synthase (complex v)
46
Q

The presence of __ and ___ are unique features of plant mitochondrial ETC.

A
  1. alternative oxidase
  2. NAD(P)H dehydrogenase
47
Q

A feature of plant mitochondrial ETC that is tightly bound to the inner mitochondrial membrane.

A

alternative oxidase

48
Q

Alternative oxidase transfers electrons from UQ → O2, which bypasses ___, generating ___ as a product.

A

cytochrome c oxidase; H2O

49
Q

Alternative oxidase: No proton translocation. True or False?

A

true

50
Q

A feature of plant mitochondrial ETC that is rotenone-insensitive and transfers electrons to UQ.

A

NAD(P)H dehydrogenase

51
Q

Where is NAD(P)H dehydrogenase located?

A

matrix and external sides of the inner
membrane/ ~intermembrane

52
Q

What kind of membrane protein is NAD(P)H dehydrogenase?

A

peripheral membrane protein

53
Q

NAD(P)H dehydrogenase: No proton translocation. True or False?

A

true

54
Q

The mitochondrial ATP synthase is almost the same as chloroplast ATP synthase. True or False?

A

true

55
Q

Mitochondrial ATP synthase is also called as ___.

A

FOF1 – ATP synthase; Complex V

56
Q

What kind of membrane protein is mitochondrial ATP synthase?

A

peripheral membrane protein

57
Q

The F0 subunit of mitochondrial ATP synthase promotes ____; while
The F1 subunit is the ____.

A

proton translocation
catalytic portion

58
Q

F0 subunit of mitochondrial ATP synthase: Peripheral membrane protein. True or False?

A

integral membrane protein