Biochemistry Final Exam – Flashcards
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What is a monosaccharide?
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The most basic units of carbohydrates. Made of 1 aldehyde and 1 ketone. They are the simplest form of sugar and are usually colorless, water-soluble, crystalline solids. Some monosaccharides have a sweet taste. Examples of monosaccharides include glucose (dextrose), fructose (levulose) and galactose
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Nature uses the D or L form of carbohydrates
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D
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The two kinds of monosaccharides are
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Aldoses, Ketoses
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The bonds between carbohydrate monomers are called
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Glycosidic
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Starches are polymers made exclusively from
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Glucose
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The difference between amylose and amylopectin are
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The structure (branched vs linear)
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Dietary fiber is
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Complex Carbohydrates Cellulose Divided into soluble and insoluble
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In the 2-compartment model for water in the body, water partitions into
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Intracellular and extracellular
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In the 3 compartment model for water in the body, the__________ compartment is further divided into interstitial and plasma compartments
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extracellular
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Fluid in the blood is classified specifically as _________ fluid
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extracellular
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In an ideally balanced human system water inputs would equal
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Water outputs
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An electrolyte is a) sugar b. fat c. charged molecule d water
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charged molecule
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______________ ions account for nearly 90% of the positively charged ions found in extracellular fluid
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Sodium
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The hormone aldosterone regulates the concentrations of _______ and ________ in the body.
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Potassium ions and sodium ions
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_______ is the most common extracelluar cation, while _________ is the most abundant intracellular cation.
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Sodium, potassium
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The three most important buffer systems in body fluids include the bicarbonate buffer system, the ____ buffer system and the protein buffer system.
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Phosphate
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How is it possible for the rate and depth of breathing to affect hydrogen ion concentrations in body fluids?
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The rate and depth of breathing does not alter hydrogen ion concentration in body fluids.
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What is the normal pH of the blood?
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7.35-7.45
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What is the most significant plasma buffer?
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bicarbonate
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Which of these is not a consequence of vomiting? a. dehydration b. metabolic acidosis c. respiratory alkalosis d. metabolic alkalosis
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c. respiratory alkalosis
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What is the most common intracellular buffer?
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phosphate
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Which of the following is the product of trans-deaminiatio reactions a. urea b. NH3 c. NH4 d. Carbonic acid
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c. NH4
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Which of the following terms is the total of all the breakdown processes in the body?
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catabolism
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Amino acids that must be consumed in the diet are called
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essential amino acids
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The amino acid pool is
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all the amino acids within the tissue and body fluids
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Select the best definition of an enzyme a. an enzyme is an amino acid that speeds up chemical reactions. b. an enzyme is a protein that is consumed in the diet and aids in chemical reactions. c. enzymes are proteins that speed up metabolic reactions and are destroyed in the process. d. enzymes are proteins that speed up metabolic reactions and are not destroyed in the process.
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d. enzymes are proteins that speed up metabolic reactions and are not destroyed in the process.
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The bond that links to amino acids together is called
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a peptide bond
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There are a total of __ amino acids and _______ are considered essential
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20;9
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The side chain on an amino acid may include which element?
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Sulfur
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A small chain of amino acids is called a
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peptide
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Each amino acid contains
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an amine group and a carboxyl group
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Proteins are necessary for which of the following? a. Muscle structure b. Immune system function c. Neurotransmitter production d. All of the above
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d. All of the above
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Which of these food groups is not considered a good source of protein? a. meat b. beans. c. milk d. fruit
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d. fruit
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What determines the three-dimensional shape of a protein molecule?
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The order and chemical properties of the amino acids
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The necessary coenzyme for the transamination reaction is
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Pyridoxal Phosphate (PLP)
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Which of the following statements about protein synthesis is false? a. limiting amino acids can halt protein synthesis b. nonessential amino acids can be made through transamination c. amino acids needed for protein synthesis come from the amino acid pool d. Essential amino acids can be made through transamination
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d. Essential amino acids can be made through transamination
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In transamination an amine group is transferred to ________ to form a nonessential amino acid.
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a. Alpha keto acid
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The NH3 produced in muscle degradation of amino acids and other nitrogenated compounds is transported through blood to the liver using ______ as a carrier
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alanine
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The 3 carbon alpha ketoacid formed from the oxidative deamination of alanine is
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Pyruvate
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In oxidative deamination, an amine group is removed from an amino acid (usually glutamic acid) leaving ammonia and keto acid. In this process _________ is formed which can enter the electron transport chain.
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NADH
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Which of the following processes is involved in using proteins as a source of energy?
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Keogenesis
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What biomolecule is formed at very high levels in the blood of PKU patients?
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phenylalanine
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T/F Protein complementation combines foods containing proteins with different limiting amino acids in order to improve the protein quality of the diet.
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True
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T/F Proteins help keep fluids an pH balanced in the body
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True
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T/F Methionine is the only amino acid that contains sulfur.
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False- cysteine also does
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T/f Alanine exists as a zwitterion at a pH7
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True
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T/F Amino acid catabolism is increased during starvation
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True
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T/F The Urea cycle is regulated by an enzyme called CPS-1
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True
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T/F All amino acids are essential amino acids
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False
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T/F The major excretory product of amino acid catabolism is ammonia
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False
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T/F Protein synthesis is decreased during periods of growth.
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False- increased during periods of growth
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Ammonia is detoxified to urea via the urea cycle in the liver
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True
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Explain the major role of glutamate and alpha ketoglutarate in amino acid biosynthesis and degradation
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They lose or gain an amine group to generate energy and create NH4 or NADH
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An abnormal accumulation of interstitial fluid is called
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edema
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What do we call the amino acids that human beings can synthesize?
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nonessential
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How do humans obtain the amino acids that cannot be synthesized by the body?
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we eat them
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Name two classes of protein in the body
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structural enzymes
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How many common amino acids are there?
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20
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Which amino acid is not chiral?
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Glycine
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Name the two classification of secondary structures found in proteins
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alpha helix beta sheet
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The most common monomer of carbohydrate is
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Glucose
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Monosaccharides are
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Aldoses and ketoses
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A disaccharide is _____ monosaccharides joined together covalently by a
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2; Glycosidic bond
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Sucrose is a disaccharide made up of
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Glucose and fructose
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Glucose, lactose and galactose are all _____ each other, in that they all have the molecular formula C6H12O6
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isomers of
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Glucose is used for a. Structure b. Energy storage c. Quick energy d. All of the above
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d. All of the above
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Which carbohydrate is not digestible and provides fiber or "roughage" in humans?
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cellulose
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Which carbohydrate does not come from plant sources
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Lactose
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Complex carbohydrates a. include glycogen, cellulose, and starch b. consist of many glucose molecules bound together in long chains. c. can be energy storage molecules d. are polysaccharides. e.all of these
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e. all of these
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The brain relies almost entirely on _______ for energy production
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glucose
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For long-term storage, glucose is converted to _________ while for short-term storage glucose is converted to
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Fat, glycogen
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Skeletal muscle cells derive most of their energy from
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Glycogen
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Which carbohydrate is formed from 2 glucose molecules?
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Maltose
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Before the payoff phase of glycolysis can begin, the cell needs to invest _____ ATP
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2
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The energy currency of the cell is
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ATP
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Given these phases of aerobic respiration list the phases in order 1. Acetyl-coenzyme A formation 2. citric acid cycle 3. Electron-transport chain 4. Glycolysis
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4 Glycolysis 1 acetyl-coenzyme A formation 3 Citric Acid cycle 2 Electron transport chain
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During glycolysis, fructose and galactose enter the liver and are phosphorylated at carbon number
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1
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Anaerobic respiration produces _____________ ATPs and _____________ as a waste product
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2, lactic acid
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Aerobic respiration _____________ ATPs and _____ require oxygen
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38 does
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Which major metabolic product is produced under anaerobic conditions by muscle cells during intense exercise
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Lactate
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The electron-carrier molecules that are used in electron-transport chain to generate additional ATP are
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NADH and FADH2
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NADH is produced
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from the reduction of NAD
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Besides ATP the end products of aerobic respiration are
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carbon dioxide water
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At the end of aerobic respiration all six carbon atoms from the glucose molecule are
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found in carbon dioxide molecules
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Excess glucose in the body following a meal can be stored in the liver as this is for use in the near future:
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Glycogen
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These events occur during the reactions of the citric acid cycle except: a. ATP production b. NADH and FADH2 production c. Carbon dioxide formation d. Water molecule formation
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d water molecule formation
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This energy-requiring process forms larger molecules by joining together smaller molecules
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Anabolism
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During vigorous exercise, pyruvate produced by glycolysis is converted to
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lactate
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The process by which amino acids and glycerol can be converted to glucose is called
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Gluconeogenesis
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The energy released by oxidation of glucose is stored as
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ADP
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How many total ATP are made from the complete oxidation of 1 glucose molecule to CO2 and H2O
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38
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The 6-carbon molecule that is formed by the addition of acytyl CoA to ocaloacetate is
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Citrate
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Amino acid carbon skeletons can be used to synthesize ________ or ________
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Ketones or Glucose
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The main site for gluconeogenesis is
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The liver
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Gluconeogenesis is the
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Synthesis of glucose from non-carbohydrate precursors
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The carbohydrate storage polysaccharide made by animals is
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Glycogen
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What are the storage polymers
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Starch, cellulose, glycogen
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A person who is lactose intolerant is deficient in which enzyme's activity?
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Lactase
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what do amylose, amylopectin, glycogen, and cellulose all have in common?
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starches
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What condition is required in the cell for pyruvate to be converted to acetyl CoA
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aerobic
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How many CO2 molecules are released during one round of the Citric Acid Cycle?
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2
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Which metabolic step is irreversible? What consequence does that have for gluconeogenesis?
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Conversion of pyruvate to Acetyl CoA - less efficient
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Where in the cell does glycolysis occur?
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cytoplasm
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Where in the cell does the TCA cycle occur?
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matrix of the mitochondria
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What are Eicosanoids
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signaling molecules made by oxidation of 20-carbon fatty acids. They exert complex control over many bodily systems, mainly in inflammation or immunity, and as messengers in the central nervous system. They are derived from either Omega 6 or 3 Fatty acids.
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What is a buffer?
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A buffer is an aqueous solution that has a highly stable pH. If you add acid or base to a buffered solution, its pH will not change significantly. Similarly, adding water to a buffer or allowing water to evaporate will not change the pH of a buffer.
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What are the phases of detoxification? What enzymes are used?
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PhaseI:Functionalization • Hepatic enzymes are responsible for the metabolism of xenobiotics by first activating them • Oxidation • Reduction • Hydrolysis • Hydration • PhaseII:Conjugation • active secondary metabolite with • Glucuronic acid • Sulphuric acid • Glutathione • Followed by excretion in bile or urine.
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What is the primary organ site for detoxification?
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Liver
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Central principle/dogma of molecular biology:
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genetic information flows from DNA to RNA to protein Amino acids can't do anything without template from DNA DNA replicates its information (via many enzymes): REPLICATION DNA codes for mRNA during transcription : TRANSCRIPTION mRNA processed into proteins : TRANSLATION
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RNA can turn back into
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DNA via Reverse Transcription
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Difference between RNA and DNA
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The hydroxy group on 2 prime carbon indicates RNA.