Bio 235 - Unit 6 Exam Questions and
Answers
define metabolism, catabolism, anabolism - Correct Answers -All the chemical
processes that occur within a living organism in order to maintain life.
2 types:
Catabolism: chemical reactions that break down complex organic molecules > simpler
ones
- exergonic: they produce more energy than they consume
- ex: simple molecules like glucose, amino acids, glycerol, and fatty acids
Anabolism: combine simple molecules and monomers to form the body's complex
structural
and functional components; endergonic: consume more energy than they produce
explain the role of ATP in anabolism and catabolism. - Correct Answers -the coupling of
energy-releasing and energy-requiring actions is achieved through ATP
- ATP is readily available to "buy" cellular activities, like money
- each ATP molecule only lasts for less than a minute, so it is not a long-term storage
form of currency; made up of an adenine molecule, ribose molecule, and 3 phosphate
groups
-When terminal phosphate group is split off ATP, ADP and a phosphate group (P) are
formed
- released energy is used to drive anabolic reactions (ex: formation of glycogen from
glucose)
- energy from complex molecules is used in catabolic reactions to combine ADP to ATP
- ADP + (P) + energy ATP
describe oxidation-reduction reactions. - Correct Answers -Oxidation-reduction
reactions: every time a substance is oxidized, another is simultaneously reduced
- ex: when lactic acid is reduced to pyruvic acid, the two hydrogen atoms that are
removed
are used to reduce NAD+
Oxidation: the removal of electrons from an atom or molecule resulting in a decrease in
the
potential energy of the atom or molecule
,Reduction: opposite of oxidation; addition of electrons to a molecule resulting in an
increase
in the potential energy
Mechanisms of ATP Generation:
-Substrate level phosphorylation
-Oxidative phosphorylation
-Photophosphorylation - Correct Answers -Organisms used three mechanisms of
phosphorylation to generate ATP:
1. Substrate-level phosphorylation: generates ATP by transferring high-energy
phosphate group from a substrate directly into ADP; in humans, this occurs in cytosol
2. Oxidative phosphorylation: removes electrons from organic compounds and passes
through a series of electron acceptors to molecules of oxygen; occurs in the inner
mitochondrial membrane of cells
3. Photophosphorylation: occurs only in chlorophyll-containing plant cells or bacteria
describe the fate and catabolism of carbohydrates. (Glucose) - Correct Answers -Both
polysaccharides and disaccharides are hydrolyzed into the monosaccharides glucose
(about 80%), fructose, and galactose during the digestion of carbohydrates
Glucose is a body's preferred source for synthesizing ATP and depends on:
-ATP production, Amino Acid Synthesis, Glycogen Synthesis, Triglyceride synthesis
Catabolism:
The oxidation of glucose to produce ATP is also known as cellular respiration, and it
involves four sets of reactions:
1. Glycolysis. A set of reactions in which one glucose molecule is oxidized and two
molecules of pyruvic acid are produced. The reactions also produce two molecules of
ATP and two energy- containing NADH + H+.
2. Formation of acetyl coenzyme A. A transition step that prepares pyruvic acid for
entrance into the Krebs cycle. This step also produces energy-containing NADH + H+
plus carbon dioxide (CO2).
3. Krebs cycle reactions. These reactions oxidize acetyl coenzyme A and produce CO2,
ATP, NADH + H+, and FADH2.
4. Electron transport chain reactions. These reactions oxidize NADH + H+ and FADH2
and transfer their electrons through a series of electron carriers.
When oxygen is plentiful, pyruvic acid enters mitochondria, is converted to acetyl
coenzyme A, and enters the Krebs cycle (aerobic pathway)
- when oxygen is scarce, most pyruvic acid is converted to lactic acid via an anaerobic
path
describe the lipoproteins that transport lipids in the blood.
-Chylomicrons, Very low density lipoproteins, low density lipoproteins, high density
lipoproteins - Correct Answers -1. Chylomicrons: transport dietary (ingested) lipids to
adipose tissue for storage; contain 1-2% of proteins, 85% triglycerides, 7%
phospholipids, and 6-7% cholesterol
, - its protein activates an enzyme that removes fatty acids from chylomicron triglycerides
2. Very-low-density lipoproteins (VDLs): form in hepatocytes and contain mostly
endogenous
lipids; 10% protein, 50% triglycerides, 20% phospholipids, 20% cholesterol
- transport triglycerides in that were synthesized in hepatocytes to adipocytes for
storage
3. Low-density-lipoproteins (LDLs): 25% proteins, 5% triglycerides, 20% phospholipids,
and
50% cholesterol; deliver 75% of total cholesterol in blood to cells throughout the body
- once a cell has reached sufficient cholesterol levels, a negative feedback system will
inhibit the cell's synthesis of new LDL receptors
- cholesterol in LDL can be known as bad due to increased risk of coronary artery
disease
4. High-density-lipoproteins (HDLs): 40-45% proteins, 5-10% triglycerides, 30%
phospholipids, and 20% cholesterol; remove excess cholesterol to liver for elimination
- this cholesterol known as good cholesterol due to decreased risk of coronary artery
disease
describe the fate and metabolism of lipids. - Correct Answers -Lipids may be oxidized to
produce ATP; if lipids are not used immediately, they will be stored in adipose tissue in
body and liver
-Two essential fatty acids that the body cannot synthesize are linoleic acid and linolenic
acid.
Lipid catabolism: lipolysis: triglycerides are split into glycerol and fatty acids
- this allows for muscle, liver, and adipose tissue to oxidize the fatty acids derive from
those triglycerides in order to produce ATP; catalyzed by enzymes called lipase
- this processed is enhanced by epinephrine, norepinephrine, and cortisol; inhibited by
insulin
Lipid anabolism: lipogenesis: liver cells and adipose cells can synthesize lipids from
glucose or amino acids through lipogenesis which is stimulated by insulin
- occurs when individuals consume more calories than needed to satisfy ATP needs
- resulting glycerol and fatty acids can become stored triglycerides or they can produce
other lipids such as lipoproteins, phospholipids, and cholesterol
describe the fate and metabolism of proteins. - Correct Answers -During digestion,
proteins are broken down into amino acids. amino acids are either oxidized to produce
ATP or used to synthesize new proteins for body growth and repair
-active transport of amino acids into body cells stimulated by IGFs (insulin growth
factors) and insulin;
Answers
define metabolism, catabolism, anabolism - Correct Answers -All the chemical
processes that occur within a living organism in order to maintain life.
2 types:
Catabolism: chemical reactions that break down complex organic molecules > simpler
ones
- exergonic: they produce more energy than they consume
- ex: simple molecules like glucose, amino acids, glycerol, and fatty acids
Anabolism: combine simple molecules and monomers to form the body's complex
structural
and functional components; endergonic: consume more energy than they produce
explain the role of ATP in anabolism and catabolism. - Correct Answers -the coupling of
energy-releasing and energy-requiring actions is achieved through ATP
- ATP is readily available to "buy" cellular activities, like money
- each ATP molecule only lasts for less than a minute, so it is not a long-term storage
form of currency; made up of an adenine molecule, ribose molecule, and 3 phosphate
groups
-When terminal phosphate group is split off ATP, ADP and a phosphate group (P) are
formed
- released energy is used to drive anabolic reactions (ex: formation of glycogen from
glucose)
- energy from complex molecules is used in catabolic reactions to combine ADP to ATP
- ADP + (P) + energy ATP
describe oxidation-reduction reactions. - Correct Answers -Oxidation-reduction
reactions: every time a substance is oxidized, another is simultaneously reduced
- ex: when lactic acid is reduced to pyruvic acid, the two hydrogen atoms that are
removed
are used to reduce NAD+
Oxidation: the removal of electrons from an atom or molecule resulting in a decrease in
the
potential energy of the atom or molecule
,Reduction: opposite of oxidation; addition of electrons to a molecule resulting in an
increase
in the potential energy
Mechanisms of ATP Generation:
-Substrate level phosphorylation
-Oxidative phosphorylation
-Photophosphorylation - Correct Answers -Organisms used three mechanisms of
phosphorylation to generate ATP:
1. Substrate-level phosphorylation: generates ATP by transferring high-energy
phosphate group from a substrate directly into ADP; in humans, this occurs in cytosol
2. Oxidative phosphorylation: removes electrons from organic compounds and passes
through a series of electron acceptors to molecules of oxygen; occurs in the inner
mitochondrial membrane of cells
3. Photophosphorylation: occurs only in chlorophyll-containing plant cells or bacteria
describe the fate and catabolism of carbohydrates. (Glucose) - Correct Answers -Both
polysaccharides and disaccharides are hydrolyzed into the monosaccharides glucose
(about 80%), fructose, and galactose during the digestion of carbohydrates
Glucose is a body's preferred source for synthesizing ATP and depends on:
-ATP production, Amino Acid Synthesis, Glycogen Synthesis, Triglyceride synthesis
Catabolism:
The oxidation of glucose to produce ATP is also known as cellular respiration, and it
involves four sets of reactions:
1. Glycolysis. A set of reactions in which one glucose molecule is oxidized and two
molecules of pyruvic acid are produced. The reactions also produce two molecules of
ATP and two energy- containing NADH + H+.
2. Formation of acetyl coenzyme A. A transition step that prepares pyruvic acid for
entrance into the Krebs cycle. This step also produces energy-containing NADH + H+
plus carbon dioxide (CO2).
3. Krebs cycle reactions. These reactions oxidize acetyl coenzyme A and produce CO2,
ATP, NADH + H+, and FADH2.
4. Electron transport chain reactions. These reactions oxidize NADH + H+ and FADH2
and transfer their electrons through a series of electron carriers.
When oxygen is plentiful, pyruvic acid enters mitochondria, is converted to acetyl
coenzyme A, and enters the Krebs cycle (aerobic pathway)
- when oxygen is scarce, most pyruvic acid is converted to lactic acid via an anaerobic
path
describe the lipoproteins that transport lipids in the blood.
-Chylomicrons, Very low density lipoproteins, low density lipoproteins, high density
lipoproteins - Correct Answers -1. Chylomicrons: transport dietary (ingested) lipids to
adipose tissue for storage; contain 1-2% of proteins, 85% triglycerides, 7%
phospholipids, and 6-7% cholesterol
, - its protein activates an enzyme that removes fatty acids from chylomicron triglycerides
2. Very-low-density lipoproteins (VDLs): form in hepatocytes and contain mostly
endogenous
lipids; 10% protein, 50% triglycerides, 20% phospholipids, 20% cholesterol
- transport triglycerides in that were synthesized in hepatocytes to adipocytes for
storage
3. Low-density-lipoproteins (LDLs): 25% proteins, 5% triglycerides, 20% phospholipids,
and
50% cholesterol; deliver 75% of total cholesterol in blood to cells throughout the body
- once a cell has reached sufficient cholesterol levels, a negative feedback system will
inhibit the cell's synthesis of new LDL receptors
- cholesterol in LDL can be known as bad due to increased risk of coronary artery
disease
4. High-density-lipoproteins (HDLs): 40-45% proteins, 5-10% triglycerides, 30%
phospholipids, and 20% cholesterol; remove excess cholesterol to liver for elimination
- this cholesterol known as good cholesterol due to decreased risk of coronary artery
disease
describe the fate and metabolism of lipids. - Correct Answers -Lipids may be oxidized to
produce ATP; if lipids are not used immediately, they will be stored in adipose tissue in
body and liver
-Two essential fatty acids that the body cannot synthesize are linoleic acid and linolenic
acid.
Lipid catabolism: lipolysis: triglycerides are split into glycerol and fatty acids
- this allows for muscle, liver, and adipose tissue to oxidize the fatty acids derive from
those triglycerides in order to produce ATP; catalyzed by enzymes called lipase
- this processed is enhanced by epinephrine, norepinephrine, and cortisol; inhibited by
insulin
Lipid anabolism: lipogenesis: liver cells and adipose cells can synthesize lipids from
glucose or amino acids through lipogenesis which is stimulated by insulin
- occurs when individuals consume more calories than needed to satisfy ATP needs
- resulting glycerol and fatty acids can become stored triglycerides or they can produce
other lipids such as lipoproteins, phospholipids, and cholesterol
describe the fate and metabolism of proteins. - Correct Answers -During digestion,
proteins are broken down into amino acids. amino acids are either oxidized to produce
ATP or used to synthesize new proteins for body growth and repair
-active transport of amino acids into body cells stimulated by IGFs (insulin growth
factors) and insulin;
