Test 2 shit Flashcards
1
Q
This is where photosynthesis takes place?
A
chloroplasts
2
Q
these membranous structures in chloroplasts are stack, flattened disks.
A
Thylakoids
3
Q
This is the principle photoreceptor in chloroplasts of green plants
A
chlorophyll A
4
Q
chlorophyll a contains this ion in the center of the tetrapyrrole
A
magnesium
5
Q
Plastocyanin requires this cofactor for activity
A
copper
6
Q
what is the prosthetic group of ferredoxin-NADP+ reductase
A
FAD
7
Q
This is one of the accessory pigments in plants
A
B-carotene
8
Q
this electron carrier of photosystem I is an iron sulfur protein
A
ferredoxin b
9
Q
Photosystems II responds to waves shorter than this value
A
680 nm
10
Q
the inner membarne of a chloroplast surrounds a space called the
A
stroma
11
Q
the process in which a positive charge forms on one molecule by the loss of a photo excited electron, and a negative charge forms on another by a gain of an electron is referred to as
A
photo induced charge seperation
12
Q
P700 is the pigment reaction center for___
A
photosystem I
13
Q
The manganese center of photosystem II converts __ to+___
A
H2O to O2
14
Q
electrons flow from photosystem I to photosystem II through the
A
cytochrome bf
15
Q
In the light reactions of photosynthesis, the cooperation between photosystem I and photosystem II creates a flow of electron from H2O to
A
NADP+
16
Q
The light induced electron transfer in photosynthesis result in the transfer of __ into the thylakoid space
A
H+ or prtons
17
Q
In ___, ATP is generated without the commitment of NADPH
A
cyclic phosphorylation
18
Q
The transfer of excitation energy from one molecule to one nearby through electromagnetic interactions is called
A
resonance energy transfer
19
Q
How is light used in photosynthesis?
A
The light is used to generate high energy electrons with great reducing potential
20
Q
How many chloroplasts does a typical plant have?
A
1 to 100
21
Q
Light absorbed by a chlorophyll a causes
A
an electron to move from ground state to an excited state
22
Q
Bacterial reaction centers a analogous to
A
Photosystem I and II
23
Q
The D1 and D2 subunits of photosystem II
A
span the thylakoid membrane
- are similar to each other
- are homologous to the L and Mchains of the bacterial center
24
Q
Light absorption induces electron transfer from P680 to__
A
Pheophytin
25
What is the original source of electrons used to neutralize the special pair in photosystem II?
H2O
26
The pathway of electron flow from H2O to NADP+ in photosynthesis is referred to as
Z scheme of photosynthesis
27
How many protons are transferred into the thylakoid lumen after absorption of four photons?
12
28
What are the light harvesting molecules?
Carotenoids
| Chlorophyll b
29
How is chloroplast similar to mitochondria?
both are site of ATP synthesis
- both have inner and outer membrane
- The thylakoids of chloroplast are analogous to membrane cristae structure
- both may have rise from symbiotic event
30
these organisms can synthesize glucose from CO2 and water
autotrophs
31
This is one of the products of photorespiration
phosphoglycolate
32
This is another name for ribulose 1,5-bisphosphate carboxylase/oxygense
rubisco
33
this is the pathway that ensures that sufficient amount of CO2 are available to minimize wasteful photorespiration
C4
34
the reduced form of this molecule is critical to reducing reactive oxygen species
glutathione
35
this enzyme is involved in both the Clavin cycle and the pentose phosphate pathway
transketolase
36
this metabolic adaptation is employed by plants living in hot dry climates
Crassulacean acid metabolism
37
This is a readily transportable and mobilizable sugar in plants
sucrose
38
these organisms obtain energy from chemical fuels
heterotrophs
39
This prosthetic group is tightly bound to the enzyme transketolase
TPP
40
The pentose phosphate pathway is also called
phosphogluconate pahtway
hexose monophosphate pathway
pentose shunt
41
the enzymes that catalyze the dark reaction of photosynthesis are located in the ___ of the chloroplast
stroma
42
The first of the Calvin cycle involves the addition of CO2 to ___to produce 2 molecules of 3-phosphoglycerate
ribulose 1,5-bisphosphate
43
The binding site of Mg2+ to rubisco involves the formation of a ___ group between lysine and Co2
carbamate
44
In photorespiration, the oxidation of glycol ate to glyoxylate occurs in the __
peroxisomes
45
The enzyme transketolase, transfers a ___ carbon fragment from a ketose to an aldose
2
46
In C4 plants, carbon dioxide is added to ____ to form oxaloacetate, which is reduced to malate, which carries CO2 to the bundle sheath cells
PEP
47
The oxidative phase of the pentose phosphate pathway produces ___which is required for lipid biosynthesis
NADPH
48
A ___ intermediate is formed between the carbonyl group of the ketose substrata and the 3-amino group of a lysine residue of transaldolase
Schiff base
49
Hemolytic anemia is caused by a deficiency of the enzyme
glucose 6-phosphate dehydrogenase
50
What is the source of carbons for the calvin cycle
Carbon dioxide
51
In the Calvin cycle, 3-phosphoglycerate is converted into which hexose phosphate?
Glucose 1-phosphate
Glucose 6-phosphate
Fructose 6-phoshate
52
Which sugars are converted into ribulose 5-phosphate by a single enzyme step
ribose 5-phosphate
| xylose 5-phosphate
53
Which form of thioredoxin activates certain Calvin cycle enzymes
reduced
54
Which coenzyme is required by glyceraldehyde 3-phosphate dehydrogenase in chloroplasts to convert 3-phosphoglycerate into glyceraldehyde 3-phosphte
NADPH
55
The C4 pathway is necessary in tropical plants because
at high temperatures, the oxygenate activity of rubisco is high
56
What is the energy cost of the C4 pathway
30 molecules of ATP are used per hexose molecule made
57
the purpose of the pentose phosphate pathway is to
generate NADPH
| synthesize 5-carbon sugars
58
Which of the following tissues does not contain the enzymes for an active pentose phosphate pathway
Skeletal muscle
59
Which cofactor is required in glutathione reductase to aid in the reduction of oxidized glutathione by NADPH
FAD
60
Why are components of the Calvin cycle called the "dark reactions"
unlike photosynthetic reactions the reactions of Calvin cycle do not depend on light to proceed
61
Describe the stages of the Calvin cycle
1) fixation of CO2 by reaction with ribulose 1,5-bisphosphate to form 2 molecules of 3-PG
2) the formation of hexose sugars from 3-PG
3) the regeneration of ribulose 1,5-Bisphosphate
62
most of the glucose residues in glycogen are linked by this type of bond
a-1,4 glycosidic bond
63
This is the activated form of glucose that is required for glycogen synthesis
UDP-glucose
64
This is the process by which a bond is cleaved by the addition of orthophosphate
phosphorylysis
65
This type of bond is located at the branch points in glycogen
a-1,6 glycosidic bonds
66
This is the liver enzyme that cleaves the phosphate from glucose 6-phosphate
glucose 6-phosphatase
67
this enzyme catalyzes the phosphorylation of glycogen phosphorylase
phosphorylase kinase
68
this enzyme is the 8 subunit of phosphorylase kinase
Calmodulin
69
This hormone signifies the starved state
glucagon
70
This protein serves as the primer used by glycogen synthase
glycogenin
71
this enzyme serves as the glucose "sensor" enzyme in liver cells
phosphorylase a
72
Phosphorylase requires the coenzyme ___ for activity
pyridoxal phosphate
73
phosphoglucomutase requires the intermediate ___ for the interconversion of glucose 1-phosphate and glucose 6-phosphate
glucose 1,6-bisphosphate
74
In skeletal muscle, the binding of ___converts phosphorylating b into the active form
AMP
75
Phosphorylase kinase becomes fully active by being phosphorylated and binding
calcium ions
76
____ stimulates glycogen breakdown in muscle by initiating a cAMP signal-transduction pathway
epinephrine
77
Glycogen synthase catalyzes the transfer of a glucose residue from UDP-glucose to one of the ____ ends of glycogen
non reducing
78
the glycogen branching enzyme moves a block of ___ or so glucose residues to form a branch point at least four residues from a preexisting branch
7
79
glycogen synthase is converted into the active form by the action of ___
protein phosphatase 1, PP1
80
The complete oxidation of glucose residues from glycogen produces ___ ATP
31
81
Insulin stimulates glycogen synthase by inactivating ___
glycogen synthase kinase
82
the major sites of glycogen storage is
Liver
| skeletal muscle
83
The key enzyme I glycogen degradation is
glycogen phosphorylasae
84
Conversion of glucose 1-phosphate to glucose 6-phosphate is carried out by the enzyme
phosphoglucomutase
85
what molecule must be excluded from the active site of glycogen phosphorylase
water
86
how is phosphorylase b converted into phosphorylase A
addition of a phosphate to a serine residue
87
Why is the T state of glycogen phosphorylase less active
the active site is partially blocked
88
what physiological conditions render phosphorylase b less active?
high ATP and low calcium ion levels
89
what is the function of liver glycogen degradation
for glucose export to other tissues when glucose levels are low
90
Phosphorylase kinase is regulated by
calcium ions
| cAMP activated PKA
91
two critical hormones that signal for glycogen breakdown are?
glucagon and epinephrine
92
the key regulatory enzyme in glycogen synthesis is
glycogen synthase
93
Why is glycogen branching important
branching increases the solubility of glycogen
| branching increases glycogen synthesis and degradation by increasing potential sites of action
94
Which of the following occur after a carbohydrate rich meal
blood glucose levels increase leading to glycogen storage in the liver
95
what is the normal glucose concentration in the blood?
80-120mg/100mL(4.4-6.7mM)
96
what are the 3 steps in glycogen degradation
1) release of glucose 1-phosphate from glycogen
2) remodeling of glycogen substrate
3) formation of glucose 6-phospahte from glucose1-Phosphate
97
Why can't glucose 1-phosphate diffuse out of the cell?
there is no membrane transporter
| -negative charge traps it
98
Triacylglycerols are stored in these cells in animals
adipose
99
the approximate energy yield from complete oxidation of fatty acids
9kcal/g
100
these amphipathic molecules facilitate the digestion of fats by incorporating dietary triacylglycerols into micelles in the intestine
bile salts
101
This molecule is the form in which triacylglycerols are transported rom the intestine to the rest of the body
chylomicrons
102
This molecule is required to translocate long chain fatty acyl groups in the mitochondria
carnitine
103
This is the pathway by which an acyl CoA is degraded into acetyl CoA
B oxidation (Fatty acid degradatino)
104
This is another name for vitamin B12
Cobalamin
105
The availability of this metabolite determines whether acetyl CoA, made from fatty acids can enter the citric acid cycle
Oxaloacetate
106
This compound is considered as one of the ketone bodies
D3-hydroxybutyrate
Acetoacetate
Acetone
107
this molecule is the form in which acetyl groups are carried across the mitochondrial membrane from the matrix to the cytoplasm
citrate
108
In eukaryotes the degradation of fatty acids occur in the
matrix of the mitochondria
109
The first step of B-oxidation is a ___ -linked oxidation of the fatty acyl chain
flavin
110
What stimulates the breakdown of triacylglycerols by activation of a hormone-sensitive lipase
Epinephrine
| glucagon
111
B-oxidation of odd numbered fatty acids produce
Acetyl CoA
| Propionyl CoA
112
The synthesis of fatty acids take place in ___ of the cell
cytoplasm
113
The coenzyme required for fatty acid synthesis is
NADPH
114
the commited step of fatty acid synthesis is the formation of
malonyl-CoA
115
What are the ketone bodies that are a major fuel source of the heart muscle
Acetoacetate and B-hydroxybutyrate
116
Prostaglandins and Thromboxanes are synthesized from __, a 20 carbon fatty acid
arachidonate
117
Fatty acids are the building blocks of
phospholipids
| glycolipids
118
Why are triacylglycerols an excellent design for energy storage
anhydrous and reduced
119
enzymes that digest the triacylglycerol into free fatty acids and monoacylglycerol are called
lipases
120
The hormone ___ induces lipolysis, where as the hormone ___ inhibits the process
Glucagon
| Insulin
121
The function of the enzyme acyl CoA synthetase is
ATP-dependent activation of fatty acids using CoA
122
What are the coenzyme(s) involved in the degradation of saturated fatty acyl CoA
FAD
| NAD+
123
How many round of B-oxidation would be required for a 16-C fatty acyl chain to be degraded to Acetyl CoA
7
124
What types of reactions do cobalamin enzymes catalyze
Intramolecular rearrangements
methylations
reduction of ribonucleotides to deoxyribonucleotides
125
How does the B-oxidation differ In peroxisomes
the initial dehydrogenation reaction is different in that electrons are transferred to O2 to yeild H2O2
126
What organs or tissues prefer to use ketone bodies such as acetoacetate as a fuel energy source instead of glucose
Heart muscle
| renal cortex
127
what is the commited step in fatty acid synthesis
synthesis of malonyl CoA
128
How is acetyl carboxylase globally regulated
Phosphorylation-off
| Dephosphorylation-on
129
How are fatty acid larger than 16 carbons formed
by elongation reactions catalyzed by the enzymes on the endoplasmic reticulum
