Chapter 2 Flashcards
(212 cards)
1
Q
Definition of Energy:
A
capacity to do work, or to put matter into motion.
2
Q
What are four types of energy used by the body?
A
(1) Chemical – Food energy is captured temporarily in the bonds of ATP
(2) Electrical – ions move across cell membranes, nervous system, electrical currents stimulate the heart to contract and pump blood.
(3) Mechanical Energy
(4) Radiant – vision, UV causes sunburn, but also generates vitamin D.
3
Q
What percent of the body by weight is CHON?
A
96%
4
Q
What is the Orbital Model of an Atom?
A
Electrons re represented as a cloud of negative charge.
5
Q
What is the planetary model of an atom?
A
shows electrons as small spheres on a circle around the nucleus.
6
Q
What is oxygen used for in the body?
A
Found in organic and inorganic molecules in the body.
As a gas, it is needed in cellular respiration: energy (ATP)
7
Q
What is Carbon used for in the human body?
A
Component of all organic molecules: carbohydrates, lipids (fats & oils), proteins, and nucleic acids.
8
Q
What is hydrogen used for in the human body?
A
Component of all organic molecules. As an ion (proton), it influences the pH of body fluids.
9
Q
What is nitrogen used for in the human body?
A
proteins and nucleic acids
10
Q
What is calcium used for in the human body?
A
Found as a salt in bones and teeth. Its ionic Ca+ form is required for muscle contraction, conduction of nerve impulses, and blood clotting.
11
Q
What is phosphorus used for in the human body?
A
Part of calcium phosphate salts in bones and teeth. Also present in nucleic acids, and as part of ATP phospholipids.
12
Q
What is potassium used for in the human body?
A
Its ion K+ is a major cation in cells. Necessary for conduction of nerve impulses and muscle contraction.
13
Q
What is sulfur used for in the human body?
A
Component of proteins, particularly muscle proteins
14
Q
What is sodium used for in the human body?
A
As an ion Na+, sodium is a cation found in extracellular fluids. Important for water balance, conduction of nerve impulses, and muscle contraction.
15
Q
What is chlorine used for in the human body?
A
Its ion Cl- is the most abundant negative ion (anion) in extracellular fluids.
16
Q
What is magnesium used for in the human body?
A
Present in bone. Also an important cofactor in a number of metabolic reactions.
17
Q
What is iodine used for in the human body?
A
Needed to make functional thyroid hormones.
18
Q
What is iron used for in the human body?
A
Component of hemoglobin and some enzymes.
19
Q
What are Trace Elements used for in the human body?
A
Many are found as part of enzymes or enzyme activation.
20
Q
What are radioisotopes?
A
Heavier isotopes of elements that are unstable and decompose spontaneously into more stable forms.
21
Q
How are radioisotopes used in medicine?
A
Radioactive isotopes share the same chemistry as their more stable isotopes and can be detected using scanners. Most radioisotopes are used for diagnosis and illuminate damaged or cancerous tissues. PET scans use radioisotopes.
22
Q
What are the three types of Mixtures?
A
(1) Solutions, (2) Colloids, & (3) Suspensions
23
Q
There are three types of mixtures. What is a solution? What are some examples?
A
Homogeneous mixtures of tiny solute particles that do not settle out or scatter light. Ex. mineral water, air we breathe, seawater.
24
Q
What does homogeneous mean?
A
Mixture that has exactly the same composition throughout. Solutions are homogenous mixtures.
25
How do we measure the concentration of a solution?
(1) percent (parts per 100)
(2) mg/dl
(3) Molarity: moles per liter.
26
What is a mole?
A mole of any element or compound is equal to its atomic mass in grams. Example: glucose has an atomic weight of (6 x 12.011) + (12 x 1.008) + (6 x 15.999) = 180.156. To make a one-molar solution of glucose, you would weigh out 180.156g of glucose and add enough water to make 1 L of solution.
27
What is Avogadro's Number?
6.02 x 10^23. Whether you have 1 mole of glucose or 1 mole of methane, in each case you will have 6.02 x 10^23 molecules of that substance.
28
What is a colloid? What is an example?
Heterogenous mixtures containing large solute particles that scatter light, but do not settle out. Ex. jell-o and cytosol.
29
What is an emulsion?
Colloids are also called emulsions.
30
What is a heterogeneous mixture?
the composition of the mixture is dissimilar in different areas of the mixture.
31
In this mixture, they often appear as translucent or milky. Although the solute particles are larger than those in true solutions, they still do not settle out.
Colloids.
32
What type of mixture can undergo sol-gel transformations?
Colloids.
33
What is a suspension? What is an example?
Heterogenous mixture with large solute particles that settle out and may scatter light. Ex. Blood settles out into plasma and red blood cells.
34
Describe the energy of electrons farthest away from the nucleus:
(1) have the greatest potential energy.
| (2) most likely to interact chemically with other atoms.
35
What is the octet rule?
atoms attempt to fill their outermost energy shell; typically eight electrons.
36
What are the three types of chemical bonds?
(1) Covalent Bonds.
(2) Ionic Bonds
(3) Hydrogen Bonds
37
What are ionic bonds?
An ionic bond forms when two ions are attracted to one another.
38
What is an electron acceptor called?
Anion -- gains electrons
39
What is an electron donor called?
Cation -- donates electrons.
40
Ionic bonds commonly form between atoms with how many valence electrons?
First Atom: 1 or 2 valence shell electrons
| Second Atom: 7 valence shell electrons.
41
Most ionic compounds fall into the chemical category called....
Salts
42
Large arrays of cations and anions held together by ionic bonds are called....
salt crystals.
43
What is a covalent bond?
sharing a pair of electrons
44
Covalent Bonds result in molecules that are electrically balanced or NOT electrically balanced. What do we call these two types of molecules?
Polar and NonPolar Molecules
45
When the covalent bonds result in molecules that are electrically balanced, we call them....
Non-polar Molecules.
46
When the covalent bonds result in molecules with unequal electron pair sharing (non symmetrical molecules containing atoms with different electron-attracting abilities), we call these...
Polar Molecules
47
What kinds of elements are electron-hungry and attract electrons very strongly (high electronegativity)?
Atoms with 6 or 7 valence electrons.
Examples: NOC
48
What kinds of elements tend to be electropositive?
Atoms with only one or two valence shell electrons. They usually lose their valence shell electrons to other atoms.
Ex. K+, Na+
49
Is Carbon Dioxide Polar or Non-Polar?
Non-Polar
50
Is water Polar or Non-Polar?
Polar
51
Which type of bond is the weakest of the three main types?
Hydrogen bonds are weaker than the ionic and covalent bonds.
52
What are hydrogen bonds?
already covalently linked to one electronegative atom (N or O), it is also attracted to another electron-hungry atom from a different molecule. Hydrogen bonds are common between dipoles because the slightly negative oxygen atoms of one molecule attract the slightly positive hydrogen atoms of another molecule.
53
What are the three types of chemical reactions?
(1) Synthesis
(2) Decomposition
(3) Exchange Reactions (Displacement)
54
What is a Synthesis (Combination) Reaction?
A + B → AB
Anabolic activities in body cells, such as joining small molecules called amino acids into large protein molecules.
55
What does Anabolic mean?
joining smaller molecules into larger ones.
56
Is a synthesis reaction anabolic or catabolic?
Anabolic
57
What is a Decomposition Reaction?
breaking down molecules into smaller pieces:
AB → A + B
Catabolic
58
Is Decomposition Anabolic or Catabolic?
Catabolic
59
What is a catabolic reaction?
involve breaking larger molecules into smaller ones.
60
What are exchange reactions?
Displacement Reactions: involves synthesis and decomposition. Bonds are made and broken. Parts of the reactant molecules change partners, producing different product molecules:
AB + C → AC + B and AB + CD → AD + CB
61
What type of chemical reaction does this describe: Occurs when ATP reacts with glucose and transfers its end phosphate group to glucose, forming glucose-phosphate. At the same time, ATP becomes ADP. This important reaction occurs whenever glucose enters a body cell, and it effectively traps the glucose fuel molecule inside the cell.
Exchange Reactions (displacement)
62
What is an oxidation-reduction reaction (redox reactions)?
Decomposition Reaction AND Exchange Reaction.
the Reactant losing electrons is oxidized. The reactant taking up the electrons is reduced.
63
In an Oxidation-Reduction reaction, the reactant losing electrons is said to be....
oxidized
64
In an Oxidation-Reduction reaction, the reactant accepting electrons is said to be....
reduced
65
How is cellular respiration an example of an oxidation-reduction reaction? : glucose + oxygen → carbon dioxide + water + ATP.
Glucose is oxidized to Carbon Dioxide. Oxygen is reduced to Water when it accepts the hydrogen atoms.
66
Chemical Reactions can either be exergonic or endergonic. What is the difference?
Exergonic: reactions that release energy.
Endergonic: energy absorbing reactions.
67
Reactions that release energy are called....
Exergonic Reactions
68
Reactions that absorb energy are.....
Endergonic Reactions.
69
Exergonic Reactions yield products with ______ energy than the initial reactants.
less
70
Are most Catabolic Reactions exergonic or endergonic?
exergonic.
71
Are most oxidative reactions endergonic or exergonic?
exergonic
72
Endergonic Reactions result in products that contain ____ potential energy in their chemical bonds than the reactants.
more
73
The energy released when fuel molecules are broken down (oxidized) is captured in ATP molecules and then used to synthesize the complex biological molecules the body needs to sustain life. In the body, endergonic reactions are usually ________ to exergonic reactions.
coupled
74
When neither the forward or reverse reaction is dominant, we say we have reached _________.
Chemical Equilibrium.
75
What four factors can influence the rate of chemical reactions?
(1) Temperature
(2) Concentration
(3) Particle Size: smaller particles move faster so collide more frequently and forcefully.
(4) Catalysts: substances that increase the rate of chemical reactions without themselves becoming chemically changed or part of the product. Biological catalysts are called enzymes.
76
What are the two major classes of chemicals in the body?
(1) Organic Compounds and (2) Inorganic Compounds
77
What class of Chemicals in the Body does this describe: Contain carbon and made by living things. Covalently bonded and most are large.
Organic Compounds
78
What class of Chemicals in the Body does this describe: water, salts, and many acids and bases. Compounds that generally lack carbon, with exceptions: Carbon Dioxide and Carbon Monoxide.
Inorganic Compounds
79
What do inorganic compounds include?
(1) Water
(2) Salts
(3) Acids & Bases
80
What percent of cells is water?
60 - 80%
81
What makes water so vital for life?
(1) High Heat Capacity
(2) High Heat of Vaporization
(3) Polar Solvent Properties:
(4) Reactivity
(5) Cushioning
82
What makes water vital for life? Describe the utility of water's high heat capacity?
(1) High Heat Capacity: absorbs and releases large amounts of heat before changing appreciably in temperature itself.
(2) High Heat of Vaporization
(3) Polar Solvent Properties
(4) Reactivity
(5) Cushioning
83
What makes water vital for life? Describe the utility of water's high heat of vaporization?
(1) High Heat Capacity
(2) High Heat of Vaporization: A large amount of heat is needed to break the hydrogen bonds that hold water together when it evaporates. This provides efficient cooling.
(3) Polar Solvent Properties
(4) Reactivity
(5) Cushioning
84
What makes water vital for life? Describe water's polar solvent properties.
(1) High Heat Capacity
(2) High Heat of Vaporization
(3) Polar Solvent Properties: biological molecules do not react chemically unless they are in solution; orients molecules (polar and non-polar ends), ionic compounds dissociate in water; charged proteins are shielded and do not settle out due to hydration layers (colloids), allow for transport of materials, and used in lubricants.
(4) Reactivity
(5) Cushioning
85
What makes water vital for life? Describe water's reactivity.
(1) High Heat Capacity
(2) High Heat of Vaporization
(3) Polar Solvent Properties
(4) Reactivity: Used in chemical reactions, such as hydrolysis.
(5) Cushioning
86
What makes water vital for life? Describe water's cushioning role.
(1) High Heat Capacity
(2) High Heat of Vaporization
(3) Polar Solvent Properties
(4) Reactivity
(5) Cushioning: resilient cushions around body organs, protecting them from physical trauma. Ex. cerebrospinal fluid.
87
What are salts?
Ionic Compounds containing cations other than H+ and anions other than OH-
88
--OH is called....
Hydroxyl ion
89
What are electrolytes?
All ions are electrolytes, substances that conduct an electrical current in solution.
90
When salts are dissolved in water, they _________ into their component ions.
dissociate
91
What are polyatomic ions?
groups of atoms that bear an overall charge, such as sulfate.
92
What salts are commonly found in the body?
NaCl, KCl, and CaCO3
93
Electrolyte properties of sodium and potassium ions are essential for....
Electrolyte properties of sodium and potassium ions are essential for nerve impulse transmission and muscle contraction.
94
Ionic _______ forms part of the hemoglobin molecules that transport oxygen within red blood cells.
Iron
95
How are Acids and Bases similar to salts?
Similar to salts, acids and bases are electrolytes. They ionize and dissociate in water and can conduct an electrical current.
96
Properties of Acids:
Sour Taste, react with and dissolve metals, burn.
Proton Donors
Ex. HCl. (Hydrogen is written first in the molecular formula of acids)
97
Properties of Bases:
Bitter taste, slippery, proton acceptors.
Similar to acids, hydroxides dissociate when dissolved in water, but in this case hydroxyl ions and cations are liberated.
Ex. hydroxides.
98
What is the pH scale?
The pH scale is based on the concentration of hydrogen ions in a solution, expressed in terms of moles per liter, or molarity. Runs from 0 to 14 and is logarithmic. pH is the -log[H+].
99
What is neutralization?
Acids and bases react with each other in displacement reactions to form water and a salt. HCl + NaOH → NaCl + H2O.
100
What are buffers?
Consist of a weak acid and base and play a role in homeostasis.
101
Homeostasis of acid-base balance is regulated by.....
Homeostasis of acid-base balance is regulated by the kidneys and lungs and by chemical systems (ex. proteins) called buffers.
102
What are strong acids?
acids that dissociate completely and irreversibly in water. HCl and sulfuric acid.
103
What are weak acids?
Acids that do not dissocate completely, like carbonic acid and acetic acid are weak acids.
HAc ←→ H+ + Ac-
Equilibrium will shift left if an acid is added to the solution and equilibrium will shift right if a base is added to the solution.
104
What are strong bases?
dissociate easily in water and quickly tie up H+
105
What are weak bases?
It accepts relatively few protons
106
What is the bicarbonate buffer system?
major one used in blood pH. A weak acid (carbonic acid: H2CO3) dissociates into bicarbonate ions and protons (H+). The chemical equilibrium shifts right or left as H+ ions are added to or removed from the blood.
107
How is carbon versatile?
Can form four covalent bonds: can form chains (fats), ring structures (carbohydrates and steroids), and many other structures.
108
Most Macromolecules are polymers. What are polymers?
Polymers are chainlike molecules made of many smaller, identical or similar subunits (monomers).
109
What is dehydration synthesis?
Hydrogen atom is removed from one monomer and a hydroxyl group is removed from the other that it is being joined to.
110
What is hydrolysis?
Water molecules break the bonds between monomers.
111
What elements are carbohydrates made of?
CHO
112
Sugars and Starches are what kind of biomolecule?
Carbohydrates
113
There are three main sizes of carbohydrates. What are they?
Monosaccharides, Disaccharides, and Polysaccharides.
114
What is a monosaccharide?
simple sugars composed of three to seven carbon atoms.
| CH2O ratio.
115
What are some examples of monosaccharides?
Glucose (6 carbons), Ribose (5 carbons), Galactose & Fructose isomers of glucose.
116
What is an isomer?
same chemical formula, but different arrangement of atoms; different chemical properties because of this.
117
Galactose & Fructose are ______ of glucose.
isomers
118
What is a disaccharide?
two monosaccharides joined by dehydration synthesis.
119
What are some examples of disaccharides?
Sucrose (glucose + fructose), Lactose (glucose + galactose), maltose (glucose + glucose).
120
Disaccharides are too large to transport through....
Cell membranes. they must be hydrolyzed to monosaccharides before the digestive tract can absorb them.
121
What is a polysaccharide?
polymers of simple sugars linked by dehydration synthesis.
122
What are two examples of polysaccharides?
Two Major Examples: Starch and Glycogen. Both are polymers of glucose.
Starch: storage carbohydrates in plants.
Glycogen: storage carbohydrate of animal tissues; stored in skeletal muscle and liver cells. Liver cells use their stored glycogen to maintain blood sugar levels.
123
What are the functions of carbohydrates?
provide ready, easily used sources of cellular fuel. Glucose is broken down and oxidized within cells. Electrons are transferred, releasing the bond energy stored in glucose. This energy is used to synthesize ATP. When ATP supplies are efficient, dietary carbohydrates are converted to glycogen or fat and stored. Only a small amount of carbohydrates are used for structural purposes.
124
What is the purpose of lipids?
insulate body organs, build cell membranes, and provide stored energy.
125
Lipids contain what elements?
CHO; proportion of oxygen is much lower than in carbohydrates. Phosphorus is found in complex lipids.
126
What are three examples of lipids?
(1) Triglycerides
(2) Phospholipids
(3) Steroids
127
What do triglycerides look like?
Triglycerides consist of one glycerol and three fatty acids.
Fatty Acids: linear chains of C and H with an organic acid group (COOH) at one end.
Glycerol: modified simple sugar (sugar alcohol).
The glycerol backbone is the same in all triglycerides, but the fatty acid chains vary, resulting in different kinds of fats and oils.
128
When triglycerides are solid, we call them ______. When triglycerides are liquid, we call them _____.
When triglycerides are solid, we call them FATS. When triglycerides are liquid, we call them OILS.
129
What is the purpose of triglycerides?
Provide the body with efficient and compact stored energy; when they are oxidized, they release a large amount of energy.
Triglycerides are found mainly beneath the skin, where they insulate the deeper body tissues from heat loss and protect them from mechanical trauma.
130
Are triglycerides polar or non-polar?
Hydrocarbon chains make triglycerides non-polar molecules.
131
Triglycerides can be saturated or unsaturated. What is the difference?
Saturated: straight fatty acid chains with single covalent bonds. Molecules of a saturated fat are packed closely together, forming a solid.
Unsaturated: contain one or more double bonds. Kinks occur. Oils. Unsaturated variety is said to be more heart healthy.
132
What are trans fats?
Trans Fats: common in many margarines and baked products, are oils that have been solidified by addition of H atoms at sites of carbon double bonds. They increase the risk of heart disease even more than solid animal fats.
133
Lipids include triglycerides, phospholipids, and steroids. What are phospholipids?
Large component of cell membranes: Have two instead of three fatty acid chains. The third chain is replaced by a phosphate group (PO4) with an attached nitrogen containing group. The phosphate group is hydrophilic and the fatty acid tails are hydrophobic.
134
What are steroids?
flat molecules made of four interlocking hydrocarbon rings. Like triglycerides, steroids are fat soluble and contain little oxygen.
135
What is an example of a steroid used to synthesize vitamin D, steroid hormones, and bile salts?
Cholesterol is found in cell membranes and is the material for synthesis of vitamin D, steroid hormones, and bile salts. Without sex hormones, reproduction would be impossible, and a lack of corticosteroids produced by the adrenal glands is fatal.
136
Proteins are the body's basic structural material and carry out other functions. What are some examples of proteins?
Enzymes, Hemoglobin of the blood, contractile proteins of muscle.
137
What are structural proteins?
provide mechanical support. Ex. collagen is found in connective tissue and is responsible for the tensile strength of bones, tendons, and ligaments.
138
What are enzyme proteins?
Catalysis. Protein enzymes are required in biochemical reactions in the body. Ex. Disaccharidases hydrolyze disaccharides.
139
What are transport proteins?
Moving substances (in blood or across plasma membranes). Ex. Hemoglobin transports oxygen in blood. Some plasma membrane proteins transport ions across the plasma membrane.
140
What are contractile proteins?
Movement. Ex. Actin and myosin cause muscle cell contraction and function in cell division in all cell types.
141
What are communication proteins?
Transmitting signals between cells. Can act as chemical messengers (hormones) or as receptors in the plasma membrane. Ex. insulin (protein) acts at its receptor to regulate blood sugar levels.
142
What are defensive proteins?
protect against disease. Ex. antibodies released by certain immune cells are specialized proteins that bind and inactivate foreign substances (bacteria, toxins, viruses).
143
What are the monomers of proteins?
Amino Acids
144
What are the two functional groups of amino acids?
basic Amine Group (--NH2) and organic Acid Group (--COOH).
145
All amino acids are identical except for the.....
R group
146
What is a peptide bond?
Link acid and basic ends of amino acids to form proteins.
147
What is the difference between dipeptide, tripeptide, and polypeptide?
Dipeptide: two united amino acids.
Tripeptide: three unite amino acids.
Polypeptide: ten or more amino acids linked.
Proteins: more than 50 amino acids linked.
148
What are the structural levels of proteins?
Primary, Secondary, Tertiary, and Quaternary
149
There are four structural levels of proteins: primary, secondary, tertiary, and quaternary. Describe the primary level.
Primary: linear sequence of amino acids composing the polypeptide chain.
150
There are four structural levels of proteins: primary, secondary, tertiary, and quaternary. Describe the secondary level.
Secondary: linear chains bend and twist upon themselves to form a complex structure. Includes alpha (slinky or coiled spring shape stabilized by hydrogen bonds formed between NH and CO groups in the primary chain that are about four amino acids apart) AND beta sheets (polypeptide chains are linked side by side by hydrogen bonds to form a pleated ribbonlike structure).
151
There are four structural levels of proteins: primary, secondary, tertiary, and quaternary. Describe the tertiary level.
Tertiary Structure: Involves the R-groups. Tertiary structure occurs when alpha-helical and beta-pleated regions of the chain fold upon one another to produce a compact ball-like molecule (globular). Hydrophobic R groups are on the inside of the molecule while hydrophilic R groups are on the outside. Their interactions plus those of the covalent and hydrogen bonds help to maintain the unique tertiary shape.
152
There are four structural levels of proteins: primary, secondary, tertiary, and quaternary. Describe the quaternary level.
Quaternary: When two or more polypeptide chains aggregate in a regular manner to form a complex protein.
153
What is the difference between fibrous and globular proteins?
Fibrous Proteins: structural proteins -- long strands.
Globular Proteins: functional proteins: compact, spherical proteins that have at least tertiary structure and are water soluble, chemically active, and play a role in biological processes.
154
What are fibrous Proteins?
structural proteins – long strands. Ex. collagen. Insoluble in water, very stable. Provide mechanical support and tensile strength to the body’s tissues. Also includes contractile proteins.
155
What are globular proteins?
functional proteins: compact, spherical proteins that have at least tertiary structure. Water-soluble, chemically active molecules, and they play a role in all biological processes. Some provide immunity (antibodies), others regulate growth and development (hormones), and transport proteins, and catalysts (enzymes).
156
Which proteins (fibrous or globular) are more susceptible to denaturation?
Globular proteins are not stable like fibrous proteins. Hydrogen bonds are important in maintaining the structure of globular proteins. Acidity or Temperature can break hydrogen bonds.
157
Why are denatured proteins a bad thing?
Denatured proteins can no longer perform their physiological functions. For example, an enzyme’s function depends on its active sites. Disruption of intramolecular bonds separates them and destroys the active site.
158
What are enzymes?
Enzymes are globular proteins that act as biological catalysts.
159
What is a catalyst?
Catalysts: substances that regulate and accelerate the rate of biochemical reactions but are not used up or changes in those reactions.
160
What is a substrate?
the substance on which an enzyme acs.
161
How do we know we are talking about an enzyme?
-ase
162
How do enzymes change the activation energy?
Activation Energy – energy required to carry out a chemical reaction. Enzymes allow reactions to occur at a normal body temperature by decreasing the amount of activation energy required. An enzyme speeds up a reaction by lowering the barrier.
163
What are the three steps involved in enzyme action?
(1) Substrates bind to the Enzyme’s Active Site, temporarily forming an enzyme-substrate complex.
(2) The enzyme-substrate complex undergoes internal rearrangements that form the products.
(3) The enzyme releases the products of the reaction.
164
What elements are found in nucleic acids?
CHONP
165
What are the two major classes of Nucleic Acids?
DNA and RNA
166
What are the two roles of DNA?
replicates itself before a cell division & provides the basic instructions for building every protein in the body.
167
What does DNA look like?
Nucleotides are linked by hydrogen bonds between their complementary bases. DNA is a double helix.
The backbone is alternating sugar and phosphate units.
168
What is the role of RNA?
Located chiefly outside the nucleus.
RNA carries out the orders for protein synthesis issued by DNA.
Three types of RNA: messenger RNA, ribosomal RNA, and transfer RNA.
169
What are the three components of a nucleotide?
Nitrogen Containing Base
Pentose Sugar
Phosphate Group
170
What is ATP?
ATP is an adenine containing RNA nucleotide to which two additional phosphate groups have been added.
171
How does ATP store energy?
ATP stores energy because its three negatively charged phosphate groups are closely packed and repel each other. When its terminal high-energy phosphate bond is broken (hydrolyzed) the chemical spring relaxes and the molecule becomes more stable.
172
What is phosphorylation?
An enzyme transfers the terminal phosphate group from ATP to another molecule in a process called phosphorylation. These newly phosphorylated molecules temporarily become more energetic and capable of performing some type of cellular work. In the process of doing that work, they lose the phosphate group.
173
How are ATP supplies renewed?
ATP supplies are renewed as glucose and other fuel molecules are oxidized and their bond energy is released.
174
Definition of an Atom?
Smallest unit of matter; smallest particles of an element that retain the element's properties.
175
Mixtures: created when atoms ____________ react. In mixtures, the chemical properties of the atom ____________ changed.
Mixtures: created when atoms PHYSICALLY react. In mixtures, the chemical properties of the atom ARE NOT changed.
176
What is a suspension?
Composed of a heterogenous solid and liquid mixture, where the solid is typically visible/cloudy and settles out. Ex. Blood settles out into plasma and red blood cells.
177
What is a Colloid?
Composed of a heterogenous solid and liquid mixture, where the solids are not visible and they are too small to settle out. Ex. milk and jell-o.
178
What is a solution?
Homogenous solid, liquid, or gas mixed with a liquid. Ex. sugar water or mineral water. Consists of a solvent and solute.
179
What is the definition for solute?
Substance being dissolved in the solvent.
180
What is the definition of a Solvent?
Substance in which the solute is dissolved.
181
If the valence shell is complete, the atom won't interact and is called ____.
inert.
182
If the valence shell is not full, the atom is ______. It will interact with other atoms until the valence is full or complete.
unstable.
183
What are the two different types of covalent bonds based on whether they share electrons equally or unequally?
Polar and Nonpolar
184
Electronegative:
atom with a stronger pull on electrons.
185
Which atom is more electronegative atom in a water molecule?
Oxygen
186
Hydrophilic Molecules...
Water-loving molecules. These are molecules that can be dissolved in water.
187
What types of molecules are hydrophilic?
Polar and Ionic Molecules.
188
What types of molecules are hydrophobic?
Nonpolar molecules.
189
Define Dissociation. What kinds of molecules dissociate?
Molecules come apart to form ions. Ionic Molecules dissociate.
190
What is ATP composed of?
Adenosine and three phosphate groups.
191
ATP is produced when a 3rd phosphate groups is added to a molecule of _____.
adenosine diphosphate.
192
What is the chemical reaction that shows the synthesis and hydrolysis of ATP?
ATP ADP + P + energy
Water is used in the hydrolysis of ATP to ADP. Water is formed in the synthesis of ATP from ADP.
193
When water dissociates, 2 ions are produced. What are they?
H+ (hydrogen ion)
| OH- (hydroxide ion)
194
Write the chemical reaction for the dissociation of water.
H2O H+ + OH-
195
Define Acid:
Proton Donor; substances that release H+ when they dissociate in water.
196
Distinguish between a weak and strong acid.
Weak: do NOT completely dissociate in solution.
Strong: completely dissociate in solution; have a strong affect on pH.
197
What is an example of a strong and weak acid?
Strong Acid: HCl
Weak Acids: Acetic Acid, Carbonic Acid
198
Define Base
Substances that dissociate in water, releasing OH- or accept H+
199
Distinguish between weak and strong bases.
Weak: do NOT completely dissociate in solution.
Strong: readily bind free H+ in solution.
200
What is an example of a weak and strong base?
Strong Base: NaOH
Weak Base: NH3
NaOH --> Na+ + OH-
NH3 + H+ --> NH4+
201
What is the definition of a salt?
Ionic compound consisting of any cation (except H+) and any anion (except OH-).
202
Define Electrolyte:
inorganic compound that dissociates into ions when placed in a solution. these ions are able to conduct current.
203
Wrote the equation for pH.
pH = log 1/[H+]
pH = -log[H+]
204
A solution with a pH of 8 would have ________x H+ than a solution with a pH of 6
100x less
205
Define a buffer.
Composed of a weak acid and base and helps to minimize change in the pH of a solution acids or bases are added. Buffers resist change in pH.
206
Why is it important to keep the pH at a constant level in the body?
Most cells cannot survive and function normally outside a narrow range around pH of 7.4.
207
How does a buffer minimize a change in pH when the pH increases?
The acid of the buffer releases H+
208
If the pH of a solution decreases, how does the buffer minimize the change in pH?
the base of the buffer absorbs H+
209
What are the most important buffers in the body?
```
Bicarbonate Ions (HCO3-)
Carbonic Acid (H2CO3)
```
210
What is the chemical reaction that would occur if the pH of blood decreases in the body:
H+ + HCO3- --> H2CO3
Bicarbonate ion is an important buffer in the human body.
211
Write the chemical reaction showing the dissociation that would occur if the pH of blood increases in the body:
OH- + H2CO3 --> HCO3- + H2O
Carbonic Acid is an important buffer in the body.
212
What types of molecules are formed when an acid reacts with a base?
Acid + Base --> Salt + Water
