First Exam Flashcards
(151 cards)
1
Q
Binding of the _______ _______ causes enzymatic activity on the intracellular side of enzyme linked receptors
A
Signaling molecule
2
Q
What is a transmembrane protein with a binding site for the signaling molecule outside the cell called?
A
An enzyme-linked receptor
3
Q
What is the active site of an enzymatic reaction?
A
A combination of binding and lowering activation energy
4
Q
Endocrine cell signaling is typically carried through ________
A
The bloodstream
5
Q
Are cofactors organic or inorganic?
A
Inorganic
6
Q
_____ change the receptor’s shape (and function) which sends a message throughout the membrane
A
Ligands
7
Q
What causes enzymatic activity on the intracellular side of enzyme linked receptors?
A
Binding of the signaling molecule
8
Q
Ion channels are __________
A
A type of surface receptor
9
Q
What’s the difference between cofactors and coenzymes?
A
Cofactors are inorganic, coenzymes are organic biomolecules
10
Q
Neural and synaptic signals are an example of ______ signaling
A
Paracrine
11
Q
What are examples of paracrine signaling?
A
Neural and synaptic signals
12
Q
What type of signaling targets far away cells?
A
Endocrine
13
Q
Where are ion channels found?
A
In the plasma membrane
14
Q
Describe the second domain of surface receptors
A
It extends through the plasma membrane
15
Q
What type of signaling often doesn’t have to go through the cell membrane?
A
Gap junctions
16
Q
_____ is a chemical substance that binds to a receptor
A
Ligands
17
Q
What are enzymes?
A
Protein catalysts that speed up reactions by lowering the required activation energy
18
Q
When is ATP considered free energy?
A
When the bond is broken
19
Q
What do noncompetitive inhibitors do?
A
They bind to the enzyme at a different location, causing a slower reaction rate
20
Q
What are gap junctions?
A
A connection between two cells where direct cytoplasm exchange can occur; a special type of paracrine signaling
21
Q
What does autocrine cell signaling affect?
A
Itself, and in some cases other nearby cells
22
Q
What is GDP diphosphate?
A
Used up energy
23
Q
What is a docking site for signaling molecules?
A
The external domain of surface receptors
24
Q
____ signaling can remind a cell to __________________
A
Autocrine signaling can remind a cell as to what to develop into
25
What's an example of a positive metabolic feedback loop?
Breastfeeding
26
What typically provides the energy for endergonic reactions?
ATP
27
What happens when substrates bind the active sites of an enzyme?
There is a small change in shape to maximize
28
Describe the external domain of surface receptors
It's a docking site for signaling molecules
29
Define surface receptors
Hydrophilic ligands bind on the surface of the cell
30
When are enzymes most effective?
When the temperature and pH are optimal
31
What is receptor up-regulation?
A regulation that increases the number of receptors synthesized and amplifies the signal molecule's effect
32
_____ receptors bind to hydrophilic ligands, _____ receptors bind to hydrophobic ligands
Surface receptors bind to hydrophilic ligands, intracellular receptors bind to hydrophobic ligands
33
What do enzyme-linked receptors have inside the cell?
An enzyme component
34
What is the type of cellular respiration that requires oxygen where nutrients are catabolized to CO2 from H2O called?
Aerobic respiration
35
What type of cell signaling targets itself?
Autocrine
36
What is aerobic respiration?
A type of cellular respiration that requires oxygen where nutrients are catabolized to CO2 from H2O
37
Gap junctions are also called ______ _____ _____
Direct connection signaling
38
What are the 4 steps of the cell signaling process?
Transmission, reception, transduction, response
39
What is the first step of the cell signaling process?
Transmission
40
Each component in a transduction pathway acts as a _______ _____
Molecular switch
41
What is an acronym for the 4 steps of the cell signaling process?
TRTR
42
What is an example of a direct connection?
Desmosomes
43
Cells extract energy from food to generate ATP in a processes called glucose catabolism, also known as _____ _______
Cellular respiration
44
What is a combination of binding and lowering activation energy called?
The active site
45
What domain of surface receptors extends through the cytoplasm and transmits the signal inside the cell?
The third domain/ the tail
46
Which is more common; positive or negative feedback loops?
Negative feedback loops
47
What are coenzymes?
Organic biomolecules
48
What is the second step of the cell signaling process?
Reception
49
What's an example of a receptor being activated and triggering the synthesis of a secondary messenger?
G-protein and cyclic AMP (cAMP)
50
What is necessary to maintain homeostasis?
Communication
51
What type of reaction is spontaneous, exergonic or endergonic?
Exergonic
52
What is disorder and chaos called?
Entropy (S)
53
Energy transfers aren't ______ ______
Completely efficient
54
Living systems are ______ systems
Open systems
55
What are the three classes of surface receptors?
Ion channels, enzyme linked receptors, and g-proteins
56
What converts chemical signals into electrical signals?
Ion channels
57
What is enthalpy?
The total energy in a system
58
What is the first law of thermodynamics?
The law of conservation of energy; that energy cannot be created nor destroyed
59
What does the end product of a metabolic pathway do?
It influences the rate or progression of the pathway itself
60
What is the third domain of surface receptors?
The tail
61
What binds to an enzyme at a different location, causing a slower reaction rate?
Noncompetitive inhibitors
62
Is endocrine signaling fast or slow?
Slow
63
What do molecular switches do?
They relay signals, and can also amplify them
64
What must happen in order to transmit a new signal?
Every activated molecule in a transduction/ signaling pathway must be inactivated in order to transmit a new signal
65
What do ligands change?
The receptor's shape/function
66
Are spontaneous reactions fast or slow?
Slow
67
What is glucose catabolism?
Cellular respiration
68
What is a characteristic of reception?
It's a highly specific process
69
What does an endergonic reaction look like regarding free energy?
🔺G < 0
70
What type of signaling is organism-wide systemic signaling?
Endocrine signaling
71
What type of cell signaling is important after differentiation?
Autocrine signaling
72
What are enzyme linked receptors?
A transmembrane protein with a binding site for the signaling molecule outside the cell
73
What does the third domain/tail of surface receptors do?
It extends through the cytoplasm and transmits the signal inside the cell
74
What two things do ion channels do?
They open or close in response to the binding of a ligand, and they convert chemical signals into electrical signals
75
What are examples of coenzymes?
Vitamins and electron carriers
76
Define cells
The smallest living unit of life
77
Free energy is gained in what type of reaction?
Endergonic
78
Some enzymes require one or more _____ or ______ to function
Cofactors or coenzymes
79
What is the total energy in a system?
Enthalpy (H)
80
What are redox reactions?
Coupled oxidation reduction reactions
81
What positions two substrates so they align perfectly for a reaction?
Enzymes
82
What is entropy?
Disorder and chaos (S)
83
Enzyme linked receptors are ___________
A type of surface receptor
84
What reminds a cell what to develop into?
Autocrine cell signaling
85
What are the three categories of responses?
Ion channels open or close, enzyme activity is altered, or specific gene activity is turned on or off
86
Where is the enzyme component of enzyme-linked receptors found?
Inside the cell
87
What type of cell signaling can work as a reminder?
Autocrine
88
What does an exergonic reaction look like regarding free energy?
🔺G > 0
89
What can change or be present at different times in the development of cells?
Receptor types
90
What contorts or stresses a substrate so it's less static and more likely to react?
Enzymes
91
Desmosomes are ______ _________
Direct connections
92
Activation of _______ can trigger the synthesis of small molecules called secondary messengers
receptors
93
Molecular switches are found in what?
Transduction
94
Name a type of specialized ligand
Hormones
95
What are competitive inhibitors?
Molecules that are a similar shape to the substrate, competing with the substrate for the active site
96
Gap junctions are a special type of _____ ______
Paracrine signaling
97
Why is reception a highly specific process?
Because only target cells have specific receptors to pick up those particular signals
98
What is free energy?
The amount of energy available to do work (G)
99
What do enzymes do?
They work as catalysts by lowering the activation energy of a reaction to speed it up
100
What is GTP triphosphate?
A molecule that has a lot of energy
101
What's a characteristic of receptor types?
They can change or be present at different times in the development of cells
102
________ is a connection between two cells where direct cytoplasm exchange can occur
Gap junctions
103
What is transduction?
When a signal is relayed through a sequence of molecules
104
What are secondary messengers?
Small molecules synthesized by the activation of receptors
105
What type of receptor has 3 domains?
Surface receptors
106
What is also known as ligand-gated channels?
Ion channels
107
What happens through the release of chemical signals?
Communication
108
What are the two types of metabolic feedback loops?
Positive and negative feedback
109
What type of cell signaling is slower and longer lasting?
Endocrine
110
What does cellular respiration do? (Basic explanation)
Convert food to ATP
111
How do cells drive endergonic reactions?
By coupling them with exergonic reactions
112
How does communication between cells happen?
Through the release of chemical signals
113
What is phosphorylation?
Adding phosphorus with changes protein shape and function
114
What is the smallest living unit of life?
Cells
115
What is important to remember when considering intracellular reception?
Phospholipid bilayer composition
116
Define intracellular receptors
Hydrophobic ligands can enter the cell and bind to intracellular receptors
117
What is the fourth step of the cell signaling process?
Reception
118
What are molecules that are a similar shape to the substrate and compete with the substrate for the active site called?
Competitive inhibitors
119
What is a special type of paracrine signaling?
Gap junctions
120
What are ligands?
A chemical substance that binds to a receptor
121
Free energy is released in what type of reaction?
In an exergonic reaction
122
What are chemical reactions where electrons are transferred from one molecule to another called?
Redox reactions
123
What uses gap junction signaling?
Cardiac muscle
124
What is the third step of the cell signaling process?
Transduction
125
What domain of surface receptors extends through the plasma membrane?
The second domain
126
What are the three domains of surface receptors?
External, second, and tail
127
What is required for enzymes?
Cofactors
128
How can the amount of activation energy be lowered?
By catalysts
129
What type of cell signaling is typically carried far across the body through the bloodstream?
Endocrine cell signaling
130
How do cells regulate enzymes/ what affects enzymatic activity?
By modifying temperature/pH, producing molecules that inhibit or promote enzyme function, or availability of coenzymes or cofactors
131
What type of signaling targets nearby cells?
Paracrine
132
What are the two main types of receptors?
Surface and intracellular
133
What do allosteric enzymes do?
They change their confirmation upon binding to an effector, which results in an apparent change in binding affinity at a different ligand binding site?
134
What is Gibbs free energy equation?
🔺G = (🔺H)-T🔺S
135
How can cells help control their environment and meet needs?
By regulating enzymatic activity, they can adjust temperature or pH
136
Energy is needed for what type of reaction?
Endergonic
137
What are coupled oxidation reduction reactions?
Redox reactions
138
G-proteins are __________
A type of surface receptor
139
Define activation energy
The energy required for a reaction to proceed
140
What do cofactors and coenzymes do?
They help enzymes do the job
141
What type of signaling is used by tumors? What does it cause?
Paracrine signaling is used by rumors to cause neighboring cells to have the same growth problem
142
What type of cell signaling is typically hormones?
Endocrine
143
How are molecular switches usually regulated?
By the addition or removal of phosphate groups
144
What is another name for cellular respiration?
Glucose catabolism
145
What are hormones?
Specialized ligands
146
What is something nearly all cells have?
Receptors
147
What is receptor down-regulation?
A regulation that involves transporting receptors to lysosomes that destroy them
148
Enzymes work as ______
Catalysts
149
What are ion channels also called?
Ligand-gated channels
150
How do enzymes lower activation energy?
By either: positioning the two substrates so they align perfectly, providing optimal pH, contorting or stressing the substrate so it's more likely to react, or temporarily reacting with the substrate
151
Any chemical diffusion is considered _____ signaling
Paracrine
