Exam #3 Flashcards
1
Q
There’s no input of energy in ________ transport.
A
passive
2
Q
What are the two modalities of passive transport?
A
Simple diffusion and facilitated diffusion
3
Q
What is the difference between simple diffusion and facilitated diffusion?
A
Simple diffusion: from high to low directly across a lipid bilayer without the assistance of any other molecule.
Facilitated diffusion: from high to low with the assistance of a transport protein
4
Q
Most of the substances we need to get into the cell are _____/and or _______
A
polar and or charged
5
Q
What are the two types of transport proteins?
A
Channels and carriers
6
Q
Ions, which you may know as electrolytes…move through _______ _______.
A
channel proteins
7
Q
Does water diffuse across a pure lipid bilayer?
A
Not easily, it is partially blocked
8
Q
What are the water channels called to help in water diffusion?
A
Aquaporins
9
Q
Water moves to areas of ______ solute concentration
A
higher
10
Q
Water moves to where the solutes are _____ in concentration
A
higher
11
Q
Water balance, also called ____________, is a primary level of homeostasis that all life must maintain
A
osmoregulation
12
Q
Protists maintain osmoregulation by expelling excess water using a ________ _______.
A
contractile vacuole
13
Q
As water comes in, the ____ ______ protects the cell from bursting
A
cell wall
14
Q
What’s the difference between a hypotonic and a hypertonic solution?
A
Hypotonic: low solute concentration, water flows into the cell
Hypertonic: high solute concentration, water flows out of the cell
15
Q
Which of the three (hypotonic, hypertonic, isotonic) environments does a plant prefer?
A
HYPOTONIC
16
Q
Channels are _____ protein completely spanning the membrane
A
integral
17
Q
Channels have a ________ pore that recognizes ____ type of solute
A
hydrophilic, ONE
18
Q
All proteins have an elaborate confirmation…but some proteins have the ability to…..
A
change confirmation
19
Q
A ______ protein can change its confirmation, and in so doing, it allows a solute to pass through
A
carrier
20
Q
Now, who MOVES into cells this way?
A
Sugars. Glucose….
21
Q
Now, who MOVES into cells this way? Sugars. Glucose….through the ______ transporter…fructose through the ______ transporter
A
glucose, fructose
22
Q
Do lipids need channels or carriers?
A
No, they go right through
23
Q
If we have this way of bringing sugar into the cell, why do we need active transport?
A
If the sugar is not high in the environment, which won’t always be the case…in which case WE GOTTA FORCE!
WE NEED THAT GLUCOSE! WE NEED IT NOW!
24
Q
Monosaccharides (sugars) and amino acids use _______
A
carriers
25
Carriers are ______ membrane protein..._____ and _____ molecules.
integral. polar and charged molecules
26
What are the two types of active transport?
Primary (1º) active transport
| Secondary (2º) active transport
27
Primary (1º) active transport is the way we concentrate _____ through via ____ ______
ions via ion pumps
28
What is the energy that drives ion pumps?
ATP
29
Where do you find a concentration of sodium about the cell? Inside or outside the cell?
OUTSIDE
30
In your body, your cells have more ______ outside, than inside.
sodium
31
Where do you find a concentration of potassium about the cell?
INSIDE
32
______ out, ________ in
Sodium, potassium
33
The sodium/potassium pump moves sodium ____ of the cell and potassium ____ the cell
out, into
34
What source of energy? (Na/K pump)
ATP
35
ATP has three phosphates on it...by breaking off a phosphate, you liberate _______
energy
36
So ATP becomes ___ and a _____ _______ _______
ADP, free inorganic phosphate
37
The Na/K Pump is essential to maintaining ___________ in animal cells
osmoregulation
38
Secondary (2º) active transport involves the movement of ____ substances.
two
39
What are those two substances?
1) The MOLECULE you're intending to transport
| 2) The ION that's driving the transport
40
Since two substances are always transported by secondary active transport, sometimes it's called "__________", since you're actually moving two substances across the membrane at the same time.
"co-transport"
41
How is the sodium providing energy for the glucose to come in? What's so energetic about this sodium ion?
It is arranged in a GRADIENT. There's more outside than inside, it wants to go down!
42
So how does the ion provide energy?
It's in a gradient
43
Does secondary (2º) active transport require ATP?
NOOOOOO
44
Is primary (1º) active transport driven by ATP?
YESSSS
45
Source of energy..... (direct/indirect ATP use)
Primary (1º) active transport:
Secondary (2º) active transport:
Primary (1º) active transport: direct ATP use
| Secondary (2º) active transport: indirect ATP use
46
Plant cells do it another way...they have primary active transport that pumps _______ outside of the cell.
protons
47
What fuels secondary active transport?
Proton gradient
48
It's always an ____ _______ providing that energy.
ion gradient
49
Channels can be referred to as "_____."
static
50
We have a way of forcing a substance up the concentration gradient. How does that work? Well, you provide ______,. Either the energy is ___, and that's going to generally pump ______ across the membrane.
Or the second way it could work is _________ _______ ______ where we use an ____ gradient as a source of energy.
energy, ATP, ions, secondary active transport, ion
51
We can move stuff out of the cell, or bring stuff in. If we move stuff out, we call that ________. If we move stuff in, we call that _________.
exocytosis, endocytosis
52
Exocytosis is simply ________
secretion
53
_________ is an example of endocytosis. "Eating"
Phagocytosis
54
Phagocytosis is generally ___-______. A lot of substances can come into the cell by phagocytosis
non-specific
55
Receptor mediated endocytosis depends upon a ______ in the cell membrane.
receptor. What type of molecule is a receptor? It's a PROTEIN.
56
So receptor mediated endocytosis is a very ______ mechanism of transport
specific
57
Energy that is available is called ______ _______.
free energy
58
What fuels metabolism?
Free energy
59
The building of biochemistry is what?
Anabolism
60
The breakdown of biochemistry is what?
Catabolism
61
Catabolism provides _______.
energy
62
_______ requires energy.
Anabolism
63
What is thermodynamics?
The study of energy transformation
64
A system that is capable of taking energy from the surroundings, or releasing energy into the surroundings is referred to as an _____ system.
open
65
What type is the cell?
Open system
66
What does the first law of thermodynamics say?
Energy cannot be created, it can only be transformed
67
What's one word that can describe the first law of thermodynamics?
Transformations
68
What does the second law of thermodynamics say?
In all those transformations, the universe will increase in its disorder
69
Any transformation, the universe will increase in disorder, which is symbolized by the letter _ which is referred to as what?
S, entropy
70
G = ?
Free Energy
71
H = ?
Total Energy
72
T = ?
Temperature
73
S = ?
Entropy
74
What is the equation to calculate free energy?
G = H - TS
| Free energy = Total Energy - Temperature*Entropy
75
If the energy of the product is less than the energy of the reactant, then the delta G value becomes ________, which means energy must have been _________.
negative, released.
76
If the energy of the product is greater than the energy of the reactant, then delta G becomes _________, which means energy must have been _________.
positive, absorbed
77
If Delta G is negative...
1) Endergonic or exergonic ?
2) H and S ( which increases, which decreases) ?
3) Stability
4) Favorable/Non favorable?
5) Spontaneous/Non spontaneous?
1) Exergonic
2) H decreases, S increases
3) More stable
4) Favorable
5) Spontaneous
78
If Delta G is positive...
1) Endergonic or exergonic ?
2) H and S ( which increases, which decreases) ?
3) Stability
4) Favorable/Non favorable?
5) Spontaneous/Non spontaneous?
1) Endergonic
2) H increases, S decreases
3) Less stable
4) Non favorable
5) Non spontaneous
79
If the system is at equilibrium... Delta G?
Delta G is 0, reached maximum stability and is no longer capable of doing work. Means death lol
80
If you breakdown starch...exergonic or endergonic?
Exergonic, release of energy
81
No process is perfect, we always lose some energy as _____.
heat
82
This is stated in the second law of thermodynamics, every process increases the S of the universe because.....?
you lose heat
83
What is an example of a catabolic process?
The hydrolysis of sucrose
84
Catabolism releases _______ energy in nutrients and provides that energy for _________.
chemical, anabolism
85
_______ fuels ________.
Catabolism fuels anabolism
86
Catabolism fuels anabolism but...it does not do so directly. You don't dismantle glucose every time you need energy. This is not efficient.
**Catabolism provides energy to make ____. *** Which in turn serves as the immediate source of energy for anabolism.
ATP
87
ATP is a _________.
nucleotide
88
ATP, in particular, is one of the four nucleotides used to make ___. The one with a in it...which is ?
RNA, adenosine (adenine ---> base)
89
What are the components of a nucleotide?
Base, sugar, phosphate
90
Three units of negative charge on the phosphates that are all in close proximity...what do they want to do?
Move apart. Like charges repel
91
They would like to repel and come apart, but they can't...because the ________ bond holds these phosphates together. The only way to liberate a phosphate is if you _____ the covalent bond...________ ATP...that's how the energy gets released.
covalent, break, hydrolyze
92
Adenosine refers to the base adenine plus the sugar ______.
ribose
93
ATP hydrolysis is endergonic/exergonic?
EXERGONIC, provides energy
94
What is Pi?
Inorganic phosphate
95
If you put energy on the product side, you show that this is ________. Delta G will be _______.
Exergonic, negative
96
___ kcal/mole is released when a mole of ATP is hydrolyzed
-7.3kcal/mole
97
How is the ATP used to do work?
ATP hydrolysis is coupled to endergonic reaction, allowing it to move forward
98
Delta G will be positive...endergonic..._____ kcal/mole
+3.4 kcal/mole
99
Would the hydrolysis of 1 mole of ATP provide enough energy?
YES. The absolute value of 7.3 is greater than 3.4, therefore there's enough energy.
100
If you add -7.3 + 3.4, you get a negative value. A negative value means...?
you have enough energy
101
How does coupling work?
Glutamic acid + ATP...when they react, a phosphate comes off of the ATP, which becomes ADP, and sticks onto the Glutamic acid. When it does that, the glutamic acid now becomes reactive. It's now easy to replace that phosphate with an amino group. And now you have glutamine
**It works through phosphorylation of a reactant.***
102
What does phosphorylation do?
Adding a phosphate covalently makes that compound unstable, makes it reactive...whenever you have a phosphate, that means you have energy.
103
How does the Na/K pump function?
Through conformational change
104
The Na/K pump was _________ in order to drive the conformational change
phosphorylated
105
Using ATP means _________ it.
hydrolyzing
106
What do we hydrolyze ATP into?
ADP and inorganic phosphate
107
Energy from catabolism is...
| Energy from anabolism is...
exergonic
| endergonic
108
Using ATP means breaking it down into ____ and ______ _______ and then making it again which means...
ADP and inorganic phosphate
| ...putting ADP and inorganic phosphate back together
109
We make ATP through _________
catabolism
110
What is the most efficient form of catabolism?
Cellular respiration
111
What is a less efficient, effective way of catabolism?
Fermentation
112
What do all reactions have in effect?
An energy barrier
113
The energy barrier is the energy to ______ bonds.
breaks
114
The barrier makes reactions _______.
slow
115
An energy barrier must be _______ for every single reaction.
overcome
116
How do we increase the rate of a reaction?
Use a catalyst
117
What's an example of a catalyst?
Heat
118
Why is it not a good idea to apply heat to cells?
1) denaturing proteins
| 2) no specificity
119
What is the biological solution/catalyst?
We accomplish catalysis with ENZYMES.
| Enzymes do not damage cells. Moreover...they're very specific for the reaction we desire.
120
T/F: There's an enzyme for every biochemical reaction
TRUE
121
How do enzymes work?
They will reduce the activation energy, allowing reactants to go to products at the ambient temperature of the cell
122
____ __ is unaffected by enzyme.
Delta G
123
Delta G is the change in energy from the _______ to the ______.
reactant, product
124
Enzymes reduce Ea without altering _____ __.
Delta G
125
By recognizing that enzyme doesn't alter delta G, we're saying it doesn't change the need for energy that _________ reactions have. Endergonic reactions where the reactant is here, and the product is here. This reaction has a delta G that is positive. Adding the enzyme doesn't take you there.
endergonic
126
The enzyme doesn't provide energy to a reaction that _______ it. If you're endergonic, you need a source of energy, ATP...and you need an ______ so that it happens quickly. So these are two separate requirements...the need for energy in a non spontaneous process...and the need for catalysis, so it happens quickly.
requires, enzyme
127
Do enzymes provide energy?
No, they lower Ea.
128
Who couples the endergonic to the exergonic?
Enzymes.
129
Enzymes enable ________.
coupling
130
Enzymes are ________. It is a requirement of a true catalyst.
reusable
131
T/F: An enzyme can be turned on and off. It's regulated.
TRUE
132
Enzymes are a type of _______.
Protein...typically...
133
What other alternative is there for an enzyme? Besides a protein...
Nucleic acids...can also serve as a catalyst. More specifically **RNA**
***RNA can be an enzyme***
134
The _______ is the reactant that binds to the enzyme.
substrate
135
Where it binds to the enzyme is called the _______ site.
active. It's where the reaction is catalyzed.
136
Enzymes often end in -____.
-ase
137
Sucrase is the specific hydrolase that hydrolyzes _______.
sucrose
138
How does the substrate bind to the active site? It binds how?
binds by weak interactions, forming an enzyme-substrate complex
139
Once the products of glucose and fructose are released, the enzyme is _______.
reused/recycled
140
How do enzymes accomplish this reduction of the Ea? What is actually happening to do that? (3)
Depends on the Enzyme...
1) Some enzymes will orient substrates so that the reaction can happen
2) Stress covalent bonds so that they may be broken
- That's what sucrase does to sucrose, the bond has been bent, which makes it easier to break the bond
3) Create a microenvironment
- You can get the electrons to begin to flow in the direction to allow the reaction to happen
141
T/F: Enzymes make endergonic reactions exergonic.
FLASE!!! Recall, if a reaction is endergonic, you need energy. You need fuel. You need another reaction that is exergonic so that it can be coupled. In addition to that, you need the enzyme which is what couples the reaction and makes it fast.
So the enzyme couples reactions, and speeds it up.
142
As the substrate concentration increases, the reaction rate _______.
increases. If there is more substrate, it will more often find and bind to the enzyme and convert to product more quickly
143
T/F: As long as you give more substrate, the reaction will always go faster.
FALSE! Once you're at a concentration that you've filled every single active site, the rate of the reaction will no longer increase
144
When you effectively max out the capacity of the enzyme. We say that the enzyme is then __________.
saturated
145
Is there anything we can do once the enzyme is saturated to make it go faster?
Add more enzyme, which will provide more active sites for the substrates to bind to
146
As the concentration of enzyme increases, so the ________ rate.
reaction
147
As the temperature increases, the reaction rate ________.
Increases
148
Our _____ temperature is the maximum rate for enzymes.
body
149
After 37 degrees C (98.6 deg F), the reaction rate drops off quickly. Why?
Denaturation of protein. If the temperature goes too high, you will break the weak interactions and the protein will unfold. There's no active site if the enzyme is denatured.
150
Every enzyme has an optimal _________.
Temperature. Every enzyme has an optimal temperature where they operate most efficiently
151
Enzyme function also depends on __.
pH. Important for enzyme conformation
152
The enzyme that functions in your stomach has an optimum pH of __.
2. That's where it's most active
153
Why does the stomach become acidic during digestion?
It's all about the digestion of protein. The stomach is for the digestion of protein. Which is typically in a globular form. A globular form is hard to digest. So you change the pH drastically so the enzyme denatures...and now the hydrolyses can now cut the protein because it's vulnerable.
154
The situation when a molecule is blocking the active site is called _________ _________.
competitive inhibition
155
If a molecule binds to an allosteric site, it changes the shape of the enzyme, which...
turns the enzyme off. It changed the shaped. Structure determines function.
156
Competitive inhibition involves an _______ site.
active
157
Noncompetitive inhibition involves an _________ site.
allosteric, means "other shape"
158
Allosteric regulation can either work _______ OR _______.
positively or negatively
159
If it's negative, we call that __________ __________.
noncompetitive inhibition
160
Which one may be countered by increasing substrate concentration? Competitive inhibition or noncompetitive inhibition?
Competitive inhibition. If the inhibition is working this way...**adding more substrate can outcompete the inhibitor.**
161
In biology, when we say "two molecules bind,"...they also _____ _____. Remember, weak interactions are ________. Bind, come apart, bind, come apart. Yes, the inhibitor is binding and blocking the active site, but a moment later it will come off. And if there's more substrate, guess who's going to bind next? Substate and not the inhibitor. It is possible to outcompete the inhibitor by adding more substrate.
come apart, reversible
162
Do all enzymes have active sites?
Every enzyme has an active site, it's not an enzyme without an active site
163
Do all enzymes have allosteric sites?
NO, that's going to depend on the enzyme.
164
What is the regulatory molecule?
You get a snake bite and the poison might be the inhibitor.
| The inhibitor might be something that's already in your body that's blocking the active site.
165
Is it necessary to regulate all the enzymes of a pathway?
Lets say we have a pathway with 5 enzymes...if we want to shut this pathway off, must we inactivate all 5 enzymes? How could we do this in a more efficient way?
There's a mechanism to shut off a pathway. An entire pathway...using the final product of the pathway. Shut off a pathway using the final product. This is referred to as *FEEDBACK INHIBITION.*
166
Isoleucine is made from threonine in __ steps.
5
167
It takes 5 steps to make isoleucine.
Enzyme #1 has an ________ site. The allosteric site is complementary to the shape of isoleucine. So isoleucine can bind to that enzyme, and inhibit it. What's the effect on that binding inhibition?
allosteric. You turn off the enzyme.
168
What happens if you shut off enzyme one?
You no longer make your product.
169
So we've shut off an entire pathway through the _______ of that pathway, which ______ back either the first enzyme or a very early enzyme in the pathway. This is called _______ inhibition.
product, feeds, feedback
170
By turning off key enzymes, you can shut down entire _______.
pathways
171
Where an enzyme is ________ can affect the rate of an enzyme catalyzed reaction
located
172
Describe three ways that cells localize their enzymes for more efficient functioning in metabolic pathways
1) In organelles
2) As membrane proteins
3) In multi-enzyme complexes
173
ATP hydrolysis can be COUPLED to an endergonic reaction to make that reaction happen. For example, an unfavorable reaction with a delta G of ____ could be driven (or fueled) by a mole of ATP.
a) +5.5 kcal/mole
b) +8.0 kcal/mole
c) -14.6kcal/mole
d) -7.3 kcal/mole
e) 0 kcal/mole
+5.5 kcal/mole. The delta g of ATP hydrolysis - an exergonic reaction - is -7.3 kcal/mole. ATP hydrolysis can be used to fuel an endergonic reaction - one with a positive delta G - that requires LESS THAN 7.3 kcal/mole
174
During coupling, HOW is ATP actually used to make a reaction happen?
A phosphate is transferred from ATP to a reactant.
175
_________ is the basic mechanism by which ATP is used to do work.
Phosphorylation
176
Either a _______ or a ______ may be phosphorylated.
reactant or a protein
177
In steps _ and _ of glycolysis, phosphorylation is used to boost the energy of metabolic intermediates.
1 and 3
178
How exactly does ATP drive the sodium-potassium pump?
A phosphate is transferred from ATP to the pump
179
Does allosteric regulation STIUMULATE or INHIBIT an enzyme's activity?
Either stimulates or inhibits
180
Isoleucine biosynthesis is regulated by FEEDBACK INHIBITION; an early step of its metabolic pathway is blocked at high concentrations of _________.
isoleucine
181
If the activity of threonine deaminase is completely inhibited, would you expect greater concentrations of threonine to increase activity?
No, greater concentrations of threonine would not be able to out-compete the inhibitor, so inhibition would continue. Competition between the substrate and the regulatory molecule occurs when both molecules are capable of binding to the active site; this is known as competitive inhibition
182
Threonine deaminase binds threonine through _____ interactions.
weak
183
How are lysosomal hydrolyses localized in a cell?
They are confined together within an organelle
