Life on This Rock: Section 3 Flashcards
(134 cards)
1
Q
What is the main thing that drives biological processes?
A
Energy.
2
Q
What is the scientific definition of energy?
A
The capacity to carry out work.
3
Q
What is kinetic energy?
A
Energy that is currently performing work.
4
Q
What is potential energy?
A
Energy that is being stored for later use.
5
Q
Is the energy contained within the chemical bonds of molecules potential or kinetic energy?
A
Potential.
6
Q
How does the potential energy stored inside the chemical bonds of molecules become kinetic energy?
A
It becomes kinetic energy when the bonds are broken.
7
Q
True or false? It takes work to build up potential energy.
A
True.
8
Q
We fight constantly to take in enough energy to _______.
A
Keep ourselves alive.
9
Q
What are the laws of thermodynamics?
A
Physical principles that describe energy and its properties.
10
Q
What is the first law of thermodynamics?
A
Energy is cannot be created nor destroyed, but changes form.
11
Q
What is the second law of thermodynamics?
A
Energy cannot be changed from one form to another without a loss of usable energy. Also, systems become more disorganized over time.
12
Q
Every engine loses some of its power as ____.
A
Heat.
13
Q
What happens when we burn/metabolize a glucose molecule?
A
We capture some energy to do work and lose some as heat.
14
Q
What is entropy?
A
A way to measure how disorganized a piece of energy is.
15
Q
What do we use to measure energy?
A
Calories.
16
Q
What is a calorie?
A
The amount of energy needed to raise the temperature of one gram of water 1 degree celcius.
17
Q
What does “Calorie” (with a capital c) refer to?
A
A kilocalorie (1000 calories)
18
Q
Molecules _____ until they are evenly spread out in a solution.
A
Diffuse.
19
Q
Why do cells need to use energy?
A
To prevent themselves from diffusing.
20
Q
When an organism consumes another organism, what is much of the energy lost as?
A
Heat and waste.
21
Q
Where does the earth receive all of its energy from?
A
The sun.
22
Q
What is the third law of thermodynamics?
A
The entropy of a system approaches a constant value as the temperature approaches absolute zero.
23
Q
What is the Zeroth law of thermodynamics?
A
If two systems are in thermal equilibrium with a third system, they must be in equilibrium with each other.
24
Q
What is thermal equilibrium?
A
A state in which heat is not transferred between systems that are connected by a path that is permeable by heat.
25
How do cells fight entropy?
They eject H+ ions through transmembrane proteins until they reach an equivalent concentration inside and outside the cell.
26
True or false? Most of the rays that the sun sends to the earth remain there.
False. Most of them bounce off.
27
Does entropy increase or decrease as light travels from the sun to us?
It increases.
28
Does it take energy to break down molecules?
Yes.
29
True or false? Since it takes energy to break down molecules, we always need to reserve a little bit of energy.
True.
30
Why do we always need to keep a little energy on reserve?
So that we can take advantage of any incoming food.
31
Where do organisms get the energy they have in their reserves?
From the previous metabolic activity.
32
What do animals use energy for?
Surviving, growing, reproducing, and starting the next reaction.
33
What is the term for reactions that release energy?
Exergonic reactions.
34
What is the term for reactions that assemble molecules?
Endergonic reactions.
35
What happens when a molecule like glycogen is broken down?
Energy is released.
36
What two things will happen to the energy from broken bonds?
Some of it will be used to create new bonds, some of it will be lost as heat.
37
What is the molecule that captures energy for reactions?
ATP
38
What is ATP short for?
Adenosine Tri-Phosphate
39
How is ATP made?
By adding a phosphate group to ADP using a standard dehydration reaction.
40
Is a dehydration reaction an exergonic or endergonic reaction?
Endergonic.
41
What are endergonic reactions powered by?
The energy released from exergonic reactions.
42
Why does it take energy to assemble a molecule of ATP?
The three phosphate groups are all negatively charged, so it takes energy to push them together.
43
Is ATP used immediately or saved for later?
Saved for later.
44
Which phosphate group in ATP holds the most energy?
The third one.
45
Why does the third phosphate group carry enough energy for a single reaction?
So that when some energy is lost as heat, there is not a lot of wasted energy.
46
What is meant when we say that cells "Couple reactions"?
They use the energy released from breaking down molecules to make ATP.
47
What is muscle contraction?
A process that converts chemical energy {stored in ATP} into physical energy.
48
What does muscle contraction rely on?
The hydrolysis of ATP (Removing the third phosphate group by adding a water molecule.
49
What are the cytoseleton fibers of a muscle cell made of?
Actin.
50
What do muscle cells organize their cytoskeleton fibers into?
A superstructure.
51
What kind of motor protein is found along our muscle's actin fibers?
Myosin.
52
True or false? Myosin has head and tail ends.
True.
53
What does the tail end of myosin do?
Bind to some of the actin fibers.
54
What does the head of myosin do?
It waits for a signal from the brain and then binds to ATP.
55
What happens when ATP binds to the head of myosin?
The ATP deposits its third phosphate group on the myosin head.
56
By getting the phosphate group from ATP, what is the head of myosin able to do?
Stretch out and bind to another actin filament.
57
What happens when the head of myosin binds to another actin filament using the phosphate group?
The phosphate group gets pushed off the head and contracts to its original shape, pulling the second filament along with it.
58
Why does rigor mortis occur?
There is no more ATP to break and make myosin connections.
59
True or false? Adenine is a simple base.
False. It is a nitrogenous base.
60
True or false? Nitrogenous bases make up the rungs of the DNA ladder.
True.
61
What three things is ATP made up of?
Adenine, ribose, and three phosphate groups.
62
What are nitrogenous bases?
Bases made from carbon and nitrogen.
63
What is a phosphate?
Phosphorous surrounded by oxygen.
64
What is the combination of adenine and ribose called?
Adenosine.
65
What part of the cell helps to assemble ATP?
The mitochondria.
66
Where do we get the energy to assemble ATP?
From breaking down molecules.
67
What assembles ATP in a plant cell?
The thylocoid membrane inside the chloroplast.
68
What do plants use to make ATP?
Light energy and using their mitochondria to break down sugars.
69
What do plants use ATP for?
Building sugars.
70
What is LUCA?
The last universal common ancestor. The ancestor of all cells on our planet.
71
What did LUCA have?
It used ATP, had DNA, had RNA, had ribosomes, and had membranes.
72
Why do scientists believe LUCA had these things?
These things are found in all cells on our planet.
73
True or false? ATP is a base for RNA and is similar in structure to DNA.
True.
74
What do we do when we have excess glucose in our system?
Store some of it as glycogen.
75
Is glycogen a short or long term storage form?
Short term.
76
What does short-term energy storage do?
Give us a quick burst of energy when we need it.
77
What is the rush we feel during a fight or flight response?
Our system hydrolyzing glycogen reserves into glucose for quick action.
78
True or false? Glycogen is an unstable molecule and easy to break apart.
False.
79
What makes glycogen break apart?
A hydrolysis reaction.
80
What kinds of proteins are hydrolysis reactions mediated by?
Enzymes.
81
True or false? The enzyme is not consumed or changed during a hydrolysis reaction.
True.
82
What does an enzyme do in a hydrolysis reaction?
It gets the reaction started.
83
What is activation energy?
The initial push by which reactions begin and lead to a chain of events.
84
How do enzymes get reactions started?
They lower the activation barrier that prevents reactions from happening by themselves.
85
What is a good metaphor for activation energy?
Getting out of bed being the hardest part of the day.
86
True or false? There are specific enzymes for each reaction.
True.
87
What are substrates in the context of enzymes?
The things enzymes use to work.
88
How do reactions with enzymes work?
The substrates fit into pockets within the enzyme, and then the enzyme breaks down molecules or twists them to weaken the chemical bonds.
89
What do enzymes that form polymers do?
They grab a pair of monomers and push their functional groups together so that they can easily grab onto each other.
90
What is trypsin?
An enzyme secreted into our stomach that breaks down proteins.
91
Amino acids are _____ of proteins.
Monomers.
92
How do some enzymes build copies of our DNA?
They read the sequence of the existing copy.
93
What do "supervisor" enzymes do?
They check replicated DNA to see if it is correct.
94
What is feedback inhibition?
When an enzyme senses that the products of its activities are accumulating too much and it stops working. It allows enzymes to regulate their own activity.
95
How do enzymes accomplish feedback inhibition?
They have an extra pocket into which the products fit. If the product goes into this extra pocket, it twists the shape of the enzyme so that the catalytic site is blocked from binding a substrate.
96
What happens to an enzyme when its products build up?
It slows down or stops working.
97
True or false? Fighting the diffusion process takes energy from a cell.
True.
98
What do cells need to collect?
Food particles and necessary molecules.
99
What do cells need to exude?
Waste.
100
What do cells need to do first and foremost?
Separate themselves from the outside environment.
101
What part of a cell restricts what gets in and out?
The cell membrane.
102
What is created when a cell is sealed off from the outside?
An environment for biological reactions to occur.
103
What two things do cells use to regulate movement of things in and out of the cell?
Transmembrane proteins and vesicle fusion or splitting.
104
True or false? Atoms, ions, and molecules in solution tend to flow from an area of high concentration to an adjacent area of low concentration until they are evenly distributed.
True.
105
What is passive transport?
When things flow freely in and out of the cell via transmembrane proteins.
106
What is active transport?
When a cell tries to actively collect needed ions and molecules .
107
True or false? Active transport requires energy.
True.
108
Why can't cells rely on donut-shaped proteins to perform active transport?
It would be impossible to accumulate any more than what is already in the blood.
109
What kinds of transmembrane proteins does active transport utilize?
Gateway proteins.
110
True or false? Transport can occur at any time through gateway proteins.
False. It is only possible when the "gate" is open.
111
What does each opening and closing of a gateway protein's gate use?
A molecule of ATP.
112
How do gateway proteins work?
There is a pocket in the protein into which the necessary molecule can bind. It then triggers the ATP into action, which flips the molecule's gate and deposits the molecule inside the cell.
113
What can cells do using specialized transport proteins?
They can collect ions or other molecules from the blood.
114
What is photosynthesis?
Forming sugars using the sun's energy.
115
What is respiration?
Harvesting energy by breaking down sugars.
116
How do cells gain power to make ATP?
They allow a large amount of H+ ions to build up outside. Then, they let them crash through the transmembrane proteins. The force and speed generated by this makes energy.
117
True or false? Cells do not need to regulate their water content?
False.
118
What happens when dissolved ions or other molecules cannot flow freely to achieve a balance between two connected regions of water?
The water will flow into the area of higher concentration in an attempt to balance the two regions.
119
Why does water attempt to strike a balance between regions often?
It is also a molecule.
120
What will happen if a cell has a much higher concentration of certain dissolved ions than are present in the surrounding blood?
Water will be drawn out of the blood and flow into the cell.
121
What will happen if too much water gets into a cell?
It will swell and burst.
122
What will happen if there is too little water in a cell?
It will dry to the point that it can no longer function.
123
What are aquaporins?
Small channels within the cell membrane through which water passes through.
124
What is osmosis?
The process by which water moves across a membrane.
125
What is usually the purpose of osmosis?
To correct a difference in dissolved substances.
126
How do cells keep themselves from swelling or drying up?
They maintain their total concentration of dissolved substances (TCDS) at a similar concentration as the total concentration of dissolved substances in blood.
127
Is the cell membrane permeable, non-permeable, or semi-permeable?
Semi-permeable.
128
What is diffusion in regards to the movement of molecules across a cell membrane?
The passive transport of molecules across a membrane.
129
True or false? Drinking seawater dehydrates you.
True.
130
How many grams of salt are in each cup of seawater?
Five.
131
What is phagocytosis?
When a cell takes a big gulp of the surrounding fluid.
132
What is pinocytosis?
When cells take small sips of the fluid around them.
133
What is endocytosis?
When cells pull in a vesicle.
134
What is it called when a cell ejects waste?
Exocytosis.
