chapter two: energy and chemical reactions + organic compounds Flashcards
1
Q
What is energy?
A
the capacity to do work
2
Q
What is work?
A
the action of moving something
3
Q
How can energy be classified?
A
potential or kinetic energy
4
Q
What is potential energy?
A
energy an object contains because of its position; not doing work at the time
5
Q
What is kinetic energy?
A
the energy of motion; energy that is doing work
6
Q
Do ions in greater concentration on one side of a membrane have potential or kinetic energy?
A
potential energy
7
Q
Ions that flow through to the other side have kinetic energy, what is their kinetic energy used to create?
A
used to create an electrical signal
8
Q
What is chemical energy?
A
potential energy stored in the bonds of molecules
9
Q
What is heat?
A
the kinetic energy of molecular motion
10
Q
What is electromagnetic energy?
A
the kinetic energy of photons
11
Q
What does adding heat to a substance do?
A
increases molecular motion
12
Q
What is electrical energy?
A
the electrical current produced from the kinetic energy of particles that begin to move around
13
Q
What is free energy?
A
the potential energy available in a system to do work
14
Q
In human physiology, where is the most relevant free energy stored?
A
chemical bonds
15
Q
What is a chemical reaction?
A
a process in which a covalent or ionic bond is formed or broken
16
Q
What are decomposition reactions?
A
a large molecule breaks down into two or more smaller ones
17
Q
What are synthesis reactions?
A
two or more small molecules combine to form a larger one
18
Q
What are exchange reactions?
A
two molecules exchange atoms or groups of atoms
19
Q
What are reversible reactions?
A
reactions can go in either direction under different circumstances
20
Q
What is the law of mass action?
A
the rate of a chemical reaction is directly proportional to the product of the reactant concentration values
21
Q
What state do reversible reactions exist in?
A
equilibrium; the ratio of products to reactants is stable
22
Q
What 3 things increases the rate of a reaction?
A
- increases when the reactants are more concentrated, so they collide more
- increases when temperature rises so molecules collide with greater force and frequency
- increased by catalyst
23
Q
What are catalysts?
A
substances that increases the rate of a chemical reaction
24
Q
What is metabolism?
A
all the chemical reactions that take place in the body
25
What can metabolism be sub classified as?
catabolism and anabolism
26
What is catabolism?
metabolic reactions that release energy and break complex molecules
27
What is anabolism?
metabolic reactions that consume energy and construct more complex molecules
28
What are exergonic reactions?
energy-releasing
29
Is catabolism or anabolism an exergonic reaction?
catabolism
30
What are endergonic reactions?
require energy input
31
Is catabolism or anabolism an endergonic reaction?
anabolism
32
What is oxidation?
any reaction in which a molecule gives up electrons and releases energy
33
What is an oxidized molecule?
molecule that gives up electrons
34
What is an oxidizing agent?
the molecule that takes electrons (electron acceptor)
35
What is reduction?
a chemical reaction in which a molecule gains electrons and energy
36
What is a reduced molecule?
a molecule that accepts electrons
37
What is a reducing agent?
the molecule that donates electrons (electron donor)
38
What is organic chemistry?
the study of compounds of carbon
39
What are organic molecules classified as?
carbohydrates
lipids
proteins
nucleic acids
40
What determines the properties of an organic molecule?
functional groups
41
What is a monomer?
one of the smaller subunits of a larger molecule
42
What is a polymer?
a molecule consisting of a long chain made up of monomers
43
What is polymerization?
the joining of monomers as a polymer
44
How is polymerization achieved?
dehydration synthesis
45
What byproduct is produced from a dehydration synthesis reaction?
water
46
What is hydrolysis?
splitting a polymer in monomers by the addition of water
47
In hydrolysis, what is water ionized into?
H+ and OH-
48
Is a carbohydrate a hydrophobic or hydrophilic organic molecule?
hydrophilic
49
What does the root sacchar- and suffix -ose mean?
sugar
50
What are monosaccharides?
the simplest carbohydrates including glucose, fructose, and galactose
51
What is glucose?
the "blood sugar" that provides energy to cells
52
What are disaccharides?
sugars composed of two monosaccharides such as sucrose, lactose, and maltose
53
What are polysaccharides?
long chains of glucose
54
What is glycogen?
energy-storage polysaccharide produced by cells of the liver, muscles, brain, uterus, and vagina
55
What is starch?
energy-storage polysaccharide made by plants
56
What is the only digestible polysaccharide in the human diet?
starch
57
What is cellulose?
a structural polysaccharide made by plants; cannot be broken down by the body
58
What are carbohydrates the source of?
source of energy that can be quickly mobilized
59
What are carbohydrates converted to?
glucose
60
What are glycolipids?
a phospholipid molecule and carbohydrate
61
What are glycoproteins?
protein molecule with a smaller carbohydrate
62
What is a major component of mucus that is a protective substance?
glycoproteins
63
What are proteoglycans?
a conjugated molecule where the carbohydrate is dominant and the protein forms a smaller component
64
What is a moiety in conjugated molecules?
each type of component in the molecule
65
What are lipids?
hydrophobic molecules composed of carbon, hydrogen, and oxygen
66
What is the structure of a fatty acid?
a chain of 4-24 carbon atoms with a carboxyl group at one end and a methyl group at another
67
What is a saturated fatty acid?
carbon atoms linked by a single covalent bond; has as much hydrogen as it can carry; it is "saturated" with hydrogen
68
What is an unsaturated fatty acid?
has some carbons joined by double covalent bonds; thus not "saturated" with hydrogen
69
What do polyunsaturated fatty acids have?
many double bonds
70
What is the structure of triglycerides?
a molecule consisting of three fatty acids bonded to glycerol
71
What is the primary function of fat?
energy storage; it also insulates and cushions organs
72
What is the structure of phospholipids?
a molecule with a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids
73
What is the most important function of phospholipids?
they are a structural component of cell membranes
74
What is the structure of a steroid?
a lipid molecule with 17 of its carbon atoms arranged in four rings
75
What is the "parent" steroid from which all others are synthesized?
cholesterol
76
What is a protein?
a polymer of amino acids; a polypeptide
77
What are amino acids?
the monomers of which proteins are composed
78
What is a peptide?
any molecule composed of two or more amino acids joined by peptide bonds
79
What are oligopeptides?
chains of fewer than 10-15 amino acids
80
What is a polypeptide?
50 or more amino acids
81
What can changes in protein conformation do?
destroy their function
82
What is the primary structure of proteins?
the protein's amino acid sequence
83
What is the secondary structure of protein?
a coiled or folded shape held together by hydrogen bonds
84
What are the two common secondary structures?
alpha helix and beta pleated sheet
85
What is the tertiary structure of protein?
formed by further bending and folding resulting from the association of hydrophobic R groups with each other to avoid water
86
What are two types of proteins with tertiary structure?
globular proteins and fibrous proteins
87
What are globular proteins?
enzymes and antibodies that are suited for proteins embedded in cell membranes and proteins that must move freely in body fluids
88
What are fibrous proteins?
provide strength to skin, hair, and tendons better suited for muscle contractions
89
What are disulfide bridges?
two sulfur-containing amino acids form a bond between their sulfur groups
90
What is the quaternary structure of protein?
the association of two or more polypeptide chains by noncovalent forces
91
What is one of the most important properties of proteins?
proteins can change conformation reversibly, important to processes such as muscle contraction and enzyme function
92
What is denaturation?
a change in the 3D conformation of a protein that destroys enzymatic or other functional properties
93
What usually causes denaturation?
extreme changes in temperature or pH
94
What are 7 functions of proteins?
1. structure
2. communication
3. membrane transport
4. catalysis
5. recognition and protection
6. movement
7. cell adhesion
95
What are enzymes?
proteins that function as a biological catalyst, permitting biochemical reactions to occur rapidly at body temperatures
96
What is a substrate?
a chemical that is acted upon and changed by an enzyme
97
What is activation energy and what do enzymes do to it?
activation energy is the energy needed to start a reaction; enzymes lower activation energy by releasing energy in small steps
98
What is the active site of an enzyme?
the region of an enzyme that is the substrate-binding site
99
What is the enzyme-substrate complex?
the bound substrate and enzyme; enzymes are selective, only one enzyme binds to one substrate
100
What are cofactors?
a nonprotein needed for an enzyme to function
101
How do cofactors work?
bind to enzymes and induce it to fold into a shape that activates its active site
102
What are coenzymes?
organic cofactors
103
What is a metabolic pathway?
a chain of reactions with each step catalyzed by a different enzyme
104
What are nucleotides?
organic compounds consisting of nitrogenous base, a monosaccharide, and a phosphate group; basic structure of nucleic acids
105
What is one of the best-known nucleotides?
ATP; the body's energy-transfer molecule
106
What is phosphorylation?
addition of an inorganic phosphate group to an organic molecule
107
What is phosphorylation carried out by?
kinases
108
Where does the energy for ATP synthesis come from?
glucose oxidation
109
What is glycolysis?
the splitting of glucose into pyruvic acid
110
What is anaerobic fermentation?
pyruvic acid is converted into lactic acid when oxygen is not available
111
What is aerobic respiration?
pyruvic acid is broken down into CO2 and water if oxygen is available
112
What is GTP?
involved in energy transfers; donates phosphate groups to other molecules
113
What is cyclic adenosine monophosphate (cAMP)?
serves as a "second messenger" in many hormone and neurotransmitter actions
114
What are the polymers of nucleotides?
nucleic acids
115
What does nucleic acids function in?
heredity and protein synthesis
116
What is the largest nucleic acid?
DNA
117
What is the function cholesterol?
component of cell membranes for structure integrity and is important for nervous system function
118
What is the function of fatty acids?
source of energy and a precursor to triglycerides
119
What is the function of triglycerides?
energy storage
thermal insulation
binding and cushioning organs
120
What are the 5 primary lipids?
```
fatty acids
triglycerides
phospholipids
steroids
eicosanoids
```
121
What are eicosanoids?
chemical messengers between cells; "hormone like" function
