CH.4 Flashcards
Synthesis is a term, which could be used synonymously with _______.
anabolism
Synthesis refers to the process of building up larger molecules from smaller ones, commonly associated with anabolism.
Which of the following is an example of catabolism?
hydrolysis
Catabolism involves breaking down complex molecules into simpler ones, and hydrolysis is a reaction that exemplifies this process.
Penicillin acts to render bacterial cells nonviable because it damages their _______.
cell walls
Penicillin inhibits the synthesis of peptidoglycan in bacterial cell walls, leading to cell lysis.
Which of these is an enzyme name?
lipase
Lipase is an enzyme that catalyzes the breakdown of fats.
Most reactions that produce energy in a cell utilize _______ as the main reaction type.
oxidation
Oxidation reactions are critical in cellular respiration for energy production.
Of the following, the molecule with the greatest amount of usable cell energy is _______.
ATP
ATP (adenosine triphosphate) is the primary energy carrier in cells.
How many net ATP molecules result from glycolysis?
2
Glycolysis produces a net gain of 2 ATP molecules.
The most significant function of proteins is to produce _______.
cell structures
Proteins play a crucial role in forming cellular structures and performing various functions.
A gene instructs an organism to produce a/an _______.
protein
Genes encode the information necessary to synthesize proteins.
The fundamental units found in DNA, RNA and ATP are _______.
nucleotides
Nucleotides are the basic building blocks of nucleic acids.
The following belong together except which one?
thymine
Thymine is a DNA base, while uracil is found in RNA.
The amino acids are transported to the place where they will be assembled into proteins by _______.
tRNA
Transfer RNA (tRNA) carries amino acids to ribosomes for protein synthesis.
Enzymes function in chemical reactions to _______.
lower the energy of activation needed to start the reaction
Enzymes catalyze reactions by reducing the activation energy required.
Most of the readily-available energy stored in ATP is stored during the _______.
decomposition of ATP to ADP
The hydrolysis of ATP releases energy used by the cell.
The first several steps of glycolysis are considered the energy-investment steps because _______.
energy within glucose is expended to start the pathway
These steps require energy input to initiate the glycolytic pathway.
The acetyl group is transported to the citric acid cycle (Krebs cycle) by what carrier?
coenzyme A
Coenzyme A is essential for transporting acetyl groups into the Krebs cycle.
What occurs during the citric acid cycle?
Carbon dioxide and hydrogen atoms are released, and two molecules of ATP form.
The Krebs cycle generates ATP and releases CO2 as a waste product.
Which molecule represents the storage form of glucose in the liver?
glycogen
Glycogen is the stored form of glucose in animals.
A _______ bond is formed when an amino group of one amino acid joins the acid group of another.
peptide
Peptide bonds link amino acids together in proteins.
A protein with many amino acids is called a _______.
polypeptide
Polypeptides are long chains of amino acids that fold into functional proteins.
The chemical process of _______ is involved in the digestion of a compound such as a disaccharide.
hydrolysis
Hydrolysis breaks down larger molecules by adding water.
The molecule that is acted upon by an enzyme is a _______.
substrate
Substrates are the reactants that enzymes act upon.
The _______ will decompose hydrogen peroxide.
enzyme catalase
Catalase catalyzes the breakdown of hydrogen peroxide into water and oxygen.
Which of the following will catalyze the breakdown of starches?
amylase
Amylase is the enzyme responsible for starch digestion.
The substrate for lipase would be _______.
fats
Lipase specifically targets lipid substrates for hydrolysis.
The following terms belong together except which one?
mineral
Minerals are inorganic elements, while enzymes and vitamins are organic compounds.
What are the most common coenzyme molecules used to activate an enzyme?
vitamins
Many coenzymes are derived from vitamins.
The following factors will decrease the function of most enzymes except which one?
pH of 7.4
A neutral pH of 7.4 is typically optimal for enzyme activity.
Energy metabolism is an expression that can be used to mean the same as _______.
cellular respiration
Cellular respiration encompasses all metabolic processes that produce energy.
Respiration yields _______ as a gaseous waste product.
carbon dioxide
CO2 is produced during aerobic respiration as a byproduct.
Which part of ATP contains the most energy?
third phosphate bond
The high-energy bond between the last two phosphates is where most energy is stored.
Carbohydrates in the diet are changed into glucose by a process of _______.
hydrolysis
Hydrolysis breaks down carbohydrates into simpler sugars like glucose.
The following are true of glycolysis except which statement?
requires oxygen
Glycolysis is an anaerobic process and does not require oxygen.
Before entering the Kreb cycle, pyruvic acid must be converted to a/an _______ molecule.
acetyl coenzyme A
Pyruvic acid is converted to acetyl CoA to enter the Krebs cycle.
The following are end products of the Kreb cycle except which one?
citric acid
Citric acid is a reactant in the Krebs cycle, not an end product.
Which of these is the last to be produced in glycolysis?
phosphoenolpyruvic acid
Phosphoenolpyruvic acid is one of the final intermediates produced before pyruvic acid.
In the Kreb cycle, the acetyl coenzyme A combines with _______ to form citric acid.
oxaloacetic acid
Acetyl CoA reacts with oxaloacetic acid to form citric acid.
Which vitamin is essential to the formation of acetyl coenzyme A?
pantothenic acid
Pantothenic acid is a precursor for the synthesis of coenzyme A.
The following are true of NAD and FAD except which statement?
are in the Kreb cycle
While NAD and FAD are involved in cellular respiration, they are not enzymes specific to the Krebs cycle.
In the cytochrome oxidase system, the final acceptor of a pair of electrons is _______.
oxygen
Oxygen serves as the final electron acceptor in aerobic respiration.
What is oxidized during oxidative phosphorylation?
glucose
Glucose is oxidized to produce ATP during oxidative phosphorylation.
Excess glucose or its end products can be stored as _______ if they are not completely oxidized.
glycogen
Glycogen serves as a storage form of glucose in the liver and muscles.
The presence of _______ is an indication that glucose has been completely oxidized.
carbon dioxide
CO2 is a byproduct of complete glucose oxidation.
The most common form of a lipid that is used or burned for energy is called a _______.
triglyceride
Triglycerides are the primary form of stored fats in the body.
The most heat generating organ in the body probably is the _______.
liver
The liver is metabolically active and generates significant heat during various biochemical processes.
Glycerol can enter the Kreb cycle if it is converted to _______.
acetyl coenzyme A
Glycerol can be converted to acetyl CoA to enter the Krebs cycle for energy production.
The potentially harmful chemicals resulting from lipid metabolism are the _______.
ketones
Ketones can accumulate in the blood during excessive fat metabolism, leading to ketoacidosis.
Ketones are molecules that result from _______ metabolism.
fat
Ketones are produced during the metabolism of fats, particularly when glucose is scarce.
Which molecule contains the genetic code?
DNA
DNA carries the genetic blueprint for an organism.
The double helix structure is part of the _______ molecule.
DNA
The double helix is a characteristic feature of DNA structure.
One strand of DNA is connected to the other by the _______.
nitrogen bases
Nitrogenous bases pair through hydrogen bonds between the two strands of DNA.
The following are DNA bases except which one?
uracil
Uracil is a base found in RNA, not DNA.
The base thymine can pair with the base _______.
adenine
Thymine pairs with adenine in DNA through complementary base pairing.
The genetic code is transferred from DNA to _______.
mRNA
Messenger RNA (mRNA) is synthesized from DNA during transcription.
What is a complimentary mRNA sequence for DNA A,T,C,C,G?
UAGGC
The mRNA sequence is complementary to the DNA template during transcription.
A genetic code is a sequence of _______.
three bases
Codons are sequences of three nucleotides that specify an amino acid.
A set of nucleotides called the _______ in RNA recognizes the nucleotide genetic codes of DNA.
anti-codon
Anti-codons are on tRNA and pair with codons on mRNA during translation.
What is the anticodon for DNA base sequence ATG?
UAC
The anticodon UAC pairs with the mRNA codon AUG during translation.
Which statement is NOT true about catabolic processes?
Dehydration synthesis is involved in catabolic processes.
Catabolic processes involve breaking down molecules, while dehydration synthesis builds them.
Metabolic pathways are regulated by a(n) _______ enzyme, which is also often the first enzyme in a series.
rate-limiting
Rate-limiting enzymes control the speed of metabolic pathways.
A genetic mutation refers to _______.
a missing or altered nucleotide base or a missing gene
Mutations can result from various factors and can affect gene function.
Which of the following is an example of a catabolic reaction?
hydrolysis of proteins
Hydrolysis breaks down proteins into amino acids, exemplifying catabolism.
If sufficient oxygen within a cell were available, what would be the end product of glycolysis?
pyruvic acid
With oxygen, glycolysis produces pyruvic acid, which can enter the Krebs cycle.
What are the direct end products of the Citric Acid Cycle?
carbon dioxide and ATP
The Krebs cycle produces ATP and releases CO2 as waste.
What are the final end products of the electron transport chain?
ATP and water
The electron transport chain produces ATP and water as final products.
The first step in the utilization of amino acids for energy is _______ which occurs in the liver.
deamination
Deamination removes the amino group from amino acids for energy metabolism.
Genes are functional regions found within molecules of _______.
deoxyribonucleic acid
DNA contains the genes that direct cellular functions.
The production of mRNA from a DNA template is termed _______.
transcription
Transcription is the process of synthesizing mRNA from a DNA strand.
The base sequence termed the anticodon is found on molecules of _______.
tRNA
Anticodons on tRNA help translate mRNA codons into amino acids.
Most enzymes are derived from some type of protein.
True
Enzymes are typically proteins that catalyze biochemical reactions.
Enzymes are catalysts that alter chemical reaction rates by chemically combining with the substrate.
True
Enzymes bind to substrates to lower activation energy and speed up reactions.
During the formation of an enzyme-substrate complex, the enzyme combines with what are termed the specific active sites on the substrate.
True
The active site of an enzyme is where substrate binding occurs.
Humans normally synthesize the proteins and vitamins that are the essential components of enzymes.
False
While proteins are synthesized, vitamins must be obtained from the diet.
All biochemical reactions must have some source of energy.
True
Energy is required to drive all biochemical processes in living organisms.
Most of the energy in human cells is derived from reactions that require oxygen.
True
Aerobic respiration is the primary source of energy in human cells.
Oxygen will increase the rate of glycolysis.
False
Glycolysis can occur without oxygen; its rate is not directly increased by oxygen.
Carbohydrates could travel down catabolic pathways and result in energy, or anabolic pathways and be stored as glycogen or lipid.
True
Carbohydrates can be metabolized for energy or stored as glycogen or fat.
Some of the reactions within a mitochondrion do not require oxygen in order to proceed.
True
Certain reactions, like those in the Krebs cycle, can occur without oxygen.
During glycolysis, glucose becomes bound to phosphate in a process called phosphorylation.
True
Phosphorylation is a key step in glycolysis that activates glucose.
Glucose is converted to fructose in the beginning of glycolysis.
False
Glycolysis begins with glucose and does not convert it to fructose.
Cytochrome oxidase refers to a group of Kreb cycle enzymes.
False
Cytochrome oxidase is part of the electron transport chain, not the Krebs cycle.
It is possible that one could produce body fat from eating excess carbohydrates.
True
Excess carbohydrates can be converted to fat for storage.
There are about 20 amino acids that are considered to be essential and must be obtained from the diet.
True
Essential amino acids cannot be synthesized by the body and must be ingested.
The direction that metabolic pathways take is directly controlled by the amount of substrate available.
True
Substrate availability influences the flow of metabolic pathways.
The synthesis of mRNA from DNA is called transcription.
True
Transcription is the process of creating mRNA from a DNA template.
The synthesis of proteins occurs during the transcription stage of RNA.
False
Protein synthesis occurs during translation, not transcription.
The addition of oxygen to a cell during glycolysis will increase the amount of ATP produced by this metabolic pathway.
False
Glycolysis itself does not increase ATP production in the presence of oxygen.
Most of the ATP energy in the metabolism of glucose is derived from the Kreb’s cycle (TCA; Citric Acid Cycle.)
False
Most ATP is generated during oxidative phosphorylation, not directly from the Krebs cycle.
A metabolic pathway consists of enzyme-controlled reactions leading to the formation of a product.
True
Metabolic pathways are sequences of reactions catalyzed by enzymes to produce specific products.
The nucleus contains the genes necessary for most of the cell functions.
True
The nucleus houses DNA, which contains the genetic instructions for cellular activities.
Any change in a DNA sequence is called a mutation and may happen for a number of reasons.
True
Mutations can occur spontaneously or due to environmental factors.
Glycolysis occurs in the cytosol and does not require oxygen.
True
Glycolysis is an anaerobic process that occurs in the cytoplasm.
An ATP molecule consists of an adenine, a ribose, and five phosphates.
False
An ATP molecule consists of one adenine, one ribose, and three phosphates.
