Gropper - The Cell A Microcosm of Life Flashcards
Membrane lipid bilayers consist primarily of ____.
(A) phospholipids
(B) cholesterol
(C) proteins
(D) saturated fatty acids
(A) phospholipids
Membrane proteins do not serve as ____.
(A) pumps
(B) detoxifiers
(C) receptors
(D) enzymes
(B) detoxifiers
What is the role of cholesterol in plasma membrane structure?
(A) to produce bile
(B) to regulate fluidity and permeability
(C) to reduce stability
(D) to produce hormones
(B) to regulate fluidity and permeability
Signals generated at one part of a cell are transmitted quickly to other parts of the cell due to the interconnection of the cytosol and ____.
(A) glycoproteins
(B) filaments
(C) glycolipids
(D) integral proteins
(B) filaments
The carbohydrate moieties of the plasma membrane glycoproteins and glycolipids are oriented
____.
(A) outwardly, away from the cytoplasmic matrix
(B) inwardly, toward the lumen
(C) equally inwardly and outwardly to maintain symmetry
(D) between the bilayers of the membranes
(A) outwardly, away from the cytoplasmic matrix
Proteins attached to the membrane through hydrophobic interactions and embedded in the membrane are called ____.
(A) peripheral proteins
(B) rough endoplasmic reticula
(C) integral proteins
(D) Golgi apparatuses
(C) integral proteins
In the cell structure, the ____ provides support and controls the movement of cell organelles.
(A) endoplasmic reticulum
(B) mitochondrion
(C) cytoskeleton
(D) matrix space
(C) cytoskeleton
The fluid portion of the cytoplasmic matrix does not contain ____.
(A) amino acids
(B) glucose
(C) carbon dioxide
(D) urea
(D) urea
Enzymes of metabolic pathways within the cytoplasmic matrix are often oriented so that the product of one enzyme is released in close proximity to the next enzyme for which it is a substrate, to facilitate the velocity of the overall pathway. This arrangement includes enzymes of ____.
(A) beta-oxidation
(B) glycolysis
(C) ketone production
(D) the Krebs cycle
(B) glycolysis
The organelle responsible for production of most of the metabolic energy (ATP) is the ____.
(A) Golgi apparatus
(B) endoplasmic reticulum
(C) nucleus
(D) mitochondrion
(D) mitochondrion
All components of the electron transport chain are embedded in the ____.
(A) mitochondrial inner membrane
(B) mitochondrial outer membrane
(C) mitochondrial matrix
(D) cytoplasmic matrix
(A) mitochondrial inner membrane
In which organelle do the TCA cycle and fatty acid oxidation occur?
(A) Golgi apparatus
(B) nucleus
(C) microsomes
(D) mitochondrion
(D) mitochondrion
What is the major route for ATP production?
(A) oxidative phosphorylation
(B) hydrolysis
(C) peroxidation
(D) transformation
(A) oxidative phosphorylation
Which organelle is capable of performing both fission and fusion?
(A) Golgi apparatus
(B) mitochondria
(C) rough endoplasmic reticulum
(D) nucleus
(B) mitochondria
Genes contained in mitochondrial DNA are inherited only from the mother and code for ____.
(A) all proteins functioning within the mitochondrial matrix
(B) nonfunctional ancient proteins considered remnants of evolution
(C) proteins vital to the production of ATP
(D) antioxidant proteins
(C) proteins vital to the production of ATP
The cell organelle responsible for the initiation and regulation of most cellular activity is the ____.
(A) cytoplast
(B) nucleus
(C) mitochondrion
(D) nucleolus
(B) nucleus
In addition to the mitochondria, which organelle possesses an inner and outer membrane?
(A) lysosome
(B) lysosome
(C) Golgi apparatus
(D) nucleus
(D) nucleus
Microtubule organization centers (MTOCs) on the outer nuclear membrane are associated with which cellular process?
(A) oxidative phosphorylation
(B) electron transport
(C) mitosis
(D) protein synthesis
(C) mitosis
Encoded within the nuclear DNA of each cell is ____.
(A) the entire genome for that organism
(B) the genes coding for proteins needed by that particular cell in the organism
(C) chromatin
(D) a cell-specific histone
(A) the entire genome for that organism
DNA in the nucleus is wrapped around ____.
(A) proteins called histones
(B) the nucleolus
(C) the nuclear envelope
(D) ribosomal RNA
(A) proteins called histones
Which nitrogenous base is unique to RNA?
(A) guanine
(B) uracil
(C) thymine
(D) cytosine
(B) uracil
Which enzyme is responsible for linking together the incoming nucleotides during DNA replication?
(A) DNA ligase
(B) helicase
(C) DNA polymerase
(D) reverse transcriptase
(C) DNA polymerase
Transcription is the process by which ____.
(A) the genetic information in a single strand of DNA makes a specific sequence of bases in a messenger RNA (mRNA) chain
(B) genetic information in an mRNA molecule specifies the sequence of amino acids in the protein product
(C) amino acids are linked together to form the primary structure of a protein
(D) the primary structure of a protein is folded several times to become the quaternary structure
(A) the genetic information in a single strand of DNA makes a specific sequence of bases in a messenger RNA (mRNA) chain
Translation is the process by which ____.
(A) the genetic information (base sequence) in a single strand of DNA is used to specify a complementary sequence of bases in an mRNA chain
(B) a daughter duplex DNA molecule that is identical to the parental duplex DNA is synthesized
(C) the polypeptide chain of the protein product is extended
(D) genetic information in an mRNA molecule specifies the sequence of amino acids in the protein product
(D) genetic information in an mRNA molecule specifies the sequence of amino acids in the protein product
Elongation is the process by which ____.
(A) the mRNA strand is formed
(B) peptide bonds are formed between aligned amino acids after the amino acids are positioned
(C) amino acids are activated by ATP at their carboxyl end
(D) activated amino acids are transferred to their specific tRNAs that contain the anticodon complementary to each amino acid’s codon
(A) the mRNA strand is formed
Transcription-level control mechanisms ____.
(A) determine the path by which mRNA can be translated into a polypeptide
(B) determine whether a particular mRNA is actually translated
(C) determine if a particular gene can be transcribed
(D) are driven by the interaction of tRNA and mRNA
(C) determine if a particular gene can be transcribed
MicroRNAs are small noncoding RNAs that ____.
(A) enhance gene expression by activating mRNA expression
(B) silence gene expression by binding to mRNA to inhibit translation
(C) modify gene expression by replacing specific nucleotides in mRNA
(D) mediate DNA production in a reverse direction
(B) silence gene expression by binding to mRNA to inhibit translation
Which organelle is composed of an extensive network of membranous channels that connects the nuclear membrane, the Golgi apparatus, and the plasma membrane?
(A) the lysosome
(B) the nucleolus
(C) the centrioles
(D) the endoplasmic reticulum
(D) the endoplasmic reticulum
The smooth endoplasmic reticulum (SER) is associated with ____.
(A) lipid synthesis
(B) protein synthesis
(C) the calcium ion pump necessary for the contractile process
(D) ribosomes and cytochrome P450 enzymes
(A) lipid synthesis
Which enzyme complex, used in metabolizing many drugs, is located on the rough endoplasmic reticulum in liver cells?
(A) chromatins
(B) lysozymes
(C) cytochromes
(D) polymerases
(C) cytochromes
What structural body is made up of flattened cisternae flanked by tubular networks and thought to be an extension of the endoplasmic reticulum?
(A) nucleus
(B) cytoplasm
(C) lysosome
(D) Golgi apparatus
(D) Golgi apparatus
The Golgi apparatus is prominent in neurons and secretory cells and functions ____.
(A) to stop the synthesis of proteins that may need carbohydrate additions
(B) to add polysaccharide or lipid moieties to polypeptides
(C) only for constitutive secretion of proteins
(D) only for regulated secretion of proteins
(B) to add polysaccharide or lipid moieties to polypeptides
Which organelle prevents proteins that have not reached their normal tertiary or quaternary structure from reaching the cell surface?
(A) the endoplasmic reticulum
(B) the Golgi apparatus
(C) the nucleus
(D) the mitochondrion
(A) the endoplasmic reticulum
The organelle that serves as the digestive system for the cell is the ____.
(A) polysome
(B) endosome
(C) lysosome
(D) ribosome
(C) lysosome
The organelle that detoxifies by oxidizing molecules such as hydrogen peroxide and ethanol is the ____.
(A) peroxisome
(B) endosome
(C) lysosome
(D) ribosome
(A) peroxisome
Destruction of which organelle(s) would cause the cell to cease to function due to a total loss of energy?
(A) the nucleus
(B) the Golgi apparatus
(C) the ribosomes
(D) the mitochondria
(D) the mitochondria
Digestive enzymes delivered to the small intestine from cells in the pancreas are able to leave those cells because of the functioning of the ____.
(A) endoplasmic reticulum
(B) ribosomes
(C) Golgi apparatus
(D) lysosomes
(A) endoplasmic reticulum
Damage to MTOCs will interfere with which cellular process?
(A) oxidative phosphorylation
(B) mitosis
(C) electron transport
(D) creation of an mRNA molecule
(B) mitosis
Molecular stimuli that bind specifically to receptors are known as ____.
(A) ligands
(B) enzymes
(C) allosteric enzymes
(D) hydrolases
(A) ligands
Which are highly specialized membrane proteins that modify the cell’s response to its environment?
(A) transport proteins
(B) enzymes
(C) receptors
(D) peroxisomes
(A) transport proteins
Most receptor proteins are most likely which type?
(A) peripheral proteins
(B) internal proteins
(C) integral proteins
(D) glycoproteins
(C) integral proteins
Cyclic AMP activates which enzymes?
(A) protein kinases
(B) restriction endonucleases
(C) allosteric enzymes
(D) adenyl (adenylyl) cyclases
(A) protein kinases
Constitutive enzymes are ____.
(A) uninfluenced by external stimuli
(B) influenced by external stimuli
(C) synthesized at variable rates
(D) unaffected by induction
(A) uninfluenced by external stimuli
Substances that bind with allosteric sites and alter the activity of regulatory enzymes are called ____.
(A) transport proteins
(B) modulators
(C) Na pumps
(D) sarcoplasmic reticula
(B) modulators
Diagnostic enzymology focuses on ____.
(A) enzymes that are widely distributed among many tissues
(B) intracellular enzymes that express their activity in the blood abnormally due to a disease process
(C) secreted enzymes such as clotting proteins in blood
(D) nuclear enzymes
(B) intracellular enzymes that express their activity in the blood abnormally due to a disease process
One trigger of apoptosis is ____.
(A) overexpression of Bcl-2
(B) inactivation of Casp-9
(C) swelling of the cell
(D) release of mitochondrial cytochrome c
(D) release of mitochondrial cytochrome c
Malformed Apaf-1 molecules in a cell might ____.
(A) cause rapid apoptosis of the cell
(B) inactivate cytochrome c
(C) lead to the development of a tumor
(D) have no effect on apoptosis
(C) lead to the development of a tumor
What is released when nutrient molecules are oxidized?
(A) oxygen
(B) potential (or free) energy
(C) kinetic energy
(D) hydrogen
(B) potential (or free) energy
In muscle cells, creatine phosphate is used to replenish which substance?
(A) glucose
(B) pyruvic acid
(C) ATP
(D) calcium
(C) ATP
Phosphorylation of a molecule is generally accomplished by transferring the terminal phosphate group from which substance?
(A) GTP
(B) pyruvic acid
(C) G6PD
(D) ATP
(D) ATP
The plasma membrane is a sheet-like structure composed solely of lipids.
(A) True
(B) False
(B) False
The lipid bilayer determines the function of the plasma membrane, while the proteins are primarily responsible for the structure of the membrane.
(A) True
(B) False
(B) False
The various components within a cell (e.g., mitochondria) are not “free-floating” in the cytosol, but rather, are held in place by the cytoskeleton.
(A) True
(B) False
(A) True
Peripheral proteins are involved in cell-cell recognition, whereas integral proteins function primarily as receptors/transporters.
(A) True
(B) False
(A) True
Different cells express different proteins because they contain different sequences of DNA in the nucleus.
(A) True
(B) False
(B) False
Polysomes function to transcribe mRNA into proteins.
(A) True
(B) False
(B) False
When discussing enzyme kinetics, Km refers to the substrate concentration at which the enzyme is saturated and functioning at maximal velocity.
(A) True
(B) False
(B) False
If two enzymes (e.g., pyruvate dehydrogenase and pyruvate carboxylase) compete for the same substrate (pyruvate), the one with the higher Km has less affinity and will be more active when pyruvate concentrations are high.
(A) True
(B) False
(A) True
Most cellular reactions are irreversible because the same enzyme that catalyzes the conversion cannot catalyze the reverse reaction.
(A) True
(B) False
(B) False
Allosteric regulation of enzymes is carried out by modulators, other proteins that bind to the enzyme to inhibit its activity.
(A) True
(B) False
(B) False
Most of the metabolic energy produced in cells is made in the mitochondria.
(A) True
(B) False
(A) True
The nuclear envelope is a single membrane structure that helps to isolate the nucleus from the rest of the cell.
(A) True
(B) False
(B) False
Transcription of DNA cannot be altered.
(A) True
(B) False
(B) False
An increase in the concentration of a substrate will increase the rate of the enzyme-catalyzed reaction.
(A) True
(B) False
(A) True
Oncosis results from cell injury and is associated with cellular swelling and swelling of the mitochondrial nucleus.
(A) True
(B) False
(A) True
A researcher in the field of nutritional genomics is least likely to study ____.
(A) the interactions among genes and bioactive components in food that change gene expression without changing the DNA nucleotide sequence (nutritional epigenetics)
(B) inborn changes in DNA nucleotide sequences or gene variants (nutrigenetics)
(C) genetic alterations that can be compensated for by increasing or decreasing specific nutrients
(nutrigenomics)
(D) the interaction between genetically engineered enzymes and their substrates
(D) the interaction between genetically engineered enzymes and their substrates
A common mutation in the 5,10-methylenetetrahydrofolate reductase enzyme (MTHFR) ____.
(A) prevents the individual from activating the B vitamin folate
(B) has no effect on the activity of the enzyme
(C) increases the activity of the enzyme
(D) modifies the folate molecule directly
(A) prevents the individual from activating the B vitamin folate
The primary mechanism by which gene expression is modified by bioactive factors in food appears to be ____.
(A) mutations causing cancer
(B) interactions with transcription factors
(C) production of SNPs
(D) downregulation of translation
(B) interactions with transcription factors
What lifestyle change would be most important to individuals with a common variant in the GST gene that impairs protection against toxins?
(A) increasing levels of daily exercise
(B) eating a low-fat diet
(C) increasing ingestion of cruciferous vegetables
(D) increasing intake of omega-3 fats
(C) increasing ingestion of cruciferous vegetables
Which class of bioactive food components has the ability to get into the nucleus of cells and bind to DNA to influence gene expression?
(A) lipophilic, small-molecular-weight molecules
(B) glycoproteins
(C) phospholipids
(D) water-soluble vitamins
(A) lipophilic, small-molecular-weight molecules