Biochemistry Proteins and Cell Structures
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Questions and Answers

What is the half-life of ornithine decarboxylase?

  • 4 months
  • 30 minutes
  • 1 hour
  • 11 minutes (correct)

    • Which amino acid is considered stabilizing according to the N-end rule for protein half-lives?

  • Acetylated alanine
  • Lysine
  • Arginine
  • Serine (correct)

    • Which of the following diseases is associated with the failure of degradation of misfolded proteins?

  • Multiple sclerosis
  • Huntington's disease
  • Alzheimer’s disease (correct)
  • Parkinson’s disease

    • What is a primary function of peroxisomes in cells?

    <p>Fatty acid catabolism</p> Signup and view all the answers

    What type of structures are inclusions within a cell?

    <p>Non-living and not metabolically active</p> Signup and view all the answers

    What primarily causes the bulging muscles seen in bodybuilders?

    <p>Enlargement of individual skeletal muscle fibers</p> Signup and view all the answers

    What type of hypertrophy occurs in the heart due to pressure overload?

    <p>Concentric left ventricular hypertrophy</p> Signup and view all the answers

    Which of the following is characteristic of hyperplasia?

    <p>Increase in the number of cells capable of division</p> Signup and view all the answers

    Which scenario best describes compensatory hyperplasia?

    <p>Liver regeneration after donation of a lobe</p> Signup and view all the answers

    What is the main trigger for hormonal hyperplasia?

    <p>Hormonal stimuli, such as increased estrogen</p> Signup and view all the answers

    What is a common cause of pathologic hyperplasia in the endometrium?

    <p>Excessive estrogen production or intake</p> Signup and view all the answers

    Which condition does NOT exemplify hyperplasia?

    <p>Enlargement of muscle fibers from weightlifting</p> Signup and view all the answers

    What is a primary characteristic feature of necrosis compared to apoptosis?

    <p>Cell death is due to progressive depletion of ATP.</p> Signup and view all the answers

    Which of the following is a primary cause of steatosis?

    <p>Chronic alcohol abuse.</p> Signup and view all the answers

    What microscopic feature is typically associated with cell injury?

    <p>Accumulation of clear fat vacuoles.</p> Signup and view all the answers

    Which organ is primarily affected in fatty change due to its role in fat metabolism?

    <p>Liver.</p> Signup and view all the answers

    What cellular structure is associated with mitochondrial densities during cell injury?

    <p>Cytosol.</p> Signup and view all the answers

    In which of the following conditions would you expect to find a pale, turgid organ upon gross inspection?

    <p>Cellular necrosis.</p> Signup and view all the answers

    What histological feature is considered a hallmark of severe cellular injury?

    <p>Formation of myelin figures.</p> Signup and view all the answers

    What is a significant consequence of autophagy in the context of cell death?

    <p>Targets dysfunctional organelles for degradation.</p> Signup and view all the answers

    What morphological change indicates a cell is undergoing apoptosis rather than necrosis?

    <p>Cell shrinkage and chromatin condensation.</p> Signup and view all the answers

    What is the role of cyclin D in the cell cycle?

    <p>It binds to CDK4 and CDK6 to facilitate progression into S phase.</p> Signup and view all the answers

    What happens to cyclins after they fulfill their functions?

    <p>They are degraded by the ubiquitin-proteasome pathway.</p> Signup and view all the answers

    Which complex is formed when cyclin A binds to CDK2?

    <p>It permits the cell to leave the S phase and enter G2 phase.</p> Signup and view all the answers

    What is the primary function of checkpoints in the cell cycle?

    <p>To ensure proper DNA synthesis and chromosome segregation.</p> Signup and view all the answers

    How does cyclin E contribute to the cell cycle?

    <p>It facilitates the cell's progression into the S phase.</p> Signup and view all the answers

    What do focal points refer to in cellular structures?

    <p>Points of interaction between the cell and the extracellular matrix.</p> Signup and view all the answers

    Which cyclin is responsible for allowing the cell to enter the M phase?

    <p>Cyclin B.</p> Signup and view all the answers

    Which phase of the cell cycle does cyclin A primarily influence?

    <p>G2 phase.</p> Signup and view all the answers

    What constitutes the gel-like networks in the cell?

    <p>They provide structural support for the cell cortex.</p> Signup and view all the answers

    During which phase is cyclin D synthesized?

    <p>G1 phase.</p> Signup and view all the answers

    What is required for the binding of aminoacyl t-RNA to the A site?

    <p>Activation of aminoacyl tRNA by eEF-1 and GTP</p> Signup and view all the answers

    What does the anticodon of a tRNA molecule pair with?

    <p>A specific codon on the mRNA</p> Signup and view all the answers

    Which enzyme is responsible for the peptide bond formation during translation?

    <p>Peptidyl transferase</p> Signup and view all the answers

    Which events happen during translocation within the ribosome?

    <p>Peptidyl-tRNA moves from A site to P site</p> Signup and view all the answers

    What signals the termination of translation?

    <p>Recognition of stop codons in the A site</p> Signup and view all the answers

    What is the total energy expenditure for the formation of one peptide bond?

    <p>Four high energy phosphate bonds</p> Signup and view all the answers

    What happens to the GTP during the process of elongation?

    <p>It is hydrolyzed to GDP during aminoacyl-tRNA binding.</p> Signup and view all the answers

    Which factors are involved in the hydrolysis of the bond between the peptide chain and t-RNA during termination?

    <p>Peptidyl transferase and eRFs</p> Signup and view all the answers

    What is the first amino acid encoded by the starting codon on mRNA?

    <p>Methionine</p> Signup and view all the answers

    Which of the following statements about eEF-2 is correct?

    <p>It is involved in the translocation of t-RNA</p> Signup and view all the answers

    What is the consequence of mutations in proto-oncogenes?

    <p>They are responsible for many cancers.</p> Signup and view all the answers

    Which of the following factors is NOT a trigger for a cell to enter the cell cycle?

    <p>Nutrient absorption.</p> Signup and view all the answers

    What structural feature is common to chromosomes during mitosis?

    <p>Two sister chromatids at the centromere.</p> Signup and view all the answers

    How do signaling cells in the tissue affect cell proliferation?

    <p>By releasing ligands that act as growth factors.</p> Signup and view all the answers

    What defines the diploid number of chromosomes in somatic cells?

    <p>They have 46 chromosomes representing 23 homologous pairs.</p> Signup and view all the answers

    What happens to proto-oncogenes when their expression is not properly regulated?

    <p>They can cause unwanted cell proliferation.</p> Signup and view all the answers

    What is a significant result of gene amplification in oncogenes?

    <p>Elevated production of proteins that promote tumor formation.</p> Signup and view all the answers

    During which phase of the cell cycle does extensive chromatin condensation occur?

    <p>M phase.</p> Signup and view all the answers

    What role does the centromere play in chromosome structure?

    <p>It holds sister chromatids together.</p> Signup and view all the answers

    What is the difference between drug potentiation and drug synergism?

    <p>Synergism involves the drugs increasing each other's effects without changing their individual potencies.</p> Signup and view all the answers

    How is the therapeutic index (TI) defined?

    <p>TI = TD50 / ED50, indicating relative safety of a drug.</p> Signup and view all the answers

    What does the Quantal Dose-Response Curve primarily evaluate?

    <p>The relationship between drug dosage and the proportion of individuals exhibiting an all-or-none response.</p> Signup and view all the answers

    What is indicated by a low therapeutic index (TI) for a drug?

    <p>There is a risk of toxicity at therapeutic doses.</p> Signup and view all the answers

    What is the primary characteristic of liquefactive necrosis?

    <p>Release of hydrolytic enzymes that digest dead cells into a liquid</p> Signup and view all the answers

    What does the Median-Effective-Dose (ED50) represent in drug therapy?

    <p>The drug dose that produces a specific therapeutic response in half of the patients.</p> Signup and view all the answers

    Which clinical condition is a typical example of gangrenous necrosis?

    <p>Dry gangrene of the foot due to diabetes mellitus</p> Signup and view all the answers

    What unique morphological feature characterizes caseous necrosis?

    <p>Soft, granular, and yellow appearance resembling dry cheese</p> Signup and view all the answers

    Which form of fat necrosis occurs due to enzyme activity following acute pancreatitis?

    <p>Enzymatic mesenteric fat necrosis</p> Signup and view all the answers

    In liquefactive necrosis, what primarily contributes to the accumulation of pus?

    <p>Accumulation of leukocytes and release of digestive enzymes</p> Signup and view all the answers

    Which statement accurately describes the fate of necrotic cells within a living patient?

    <p>Most are removed through enzymatic digestion and phagocytosis</p> Signup and view all the answers

    What distinguishes traumatic fat necrosis from enzymatic fat necrosis?

    <p>Traumatic fat necrosis is linked to injury in fat-rich tissues</p> Signup and view all the answers

    Which toxin inhibits tRNA binding through action on the 60S subunit?

    <p>Shiga toxin</p> Signup and view all the answers

    What is the primary mechanism by which lysosomes receive materials for degradation?

    <p>Fusion with phagosomes, pinocytotic vesicles, or autophagosomes</p> Signup and view all the answers

    Which statement accurately describes the function of lysosomal enzymes?

    <p>They are involved in degrading cells and organelles.</p> Signup and view all the answers

    What is a potential consequence of lysosomal dysfunction on cellular health?

    <p>Accumulation of cellular debris</p> Signup and view all the answers

    Which of the following is a key function of diphtheria toxin?

    <p>Inhibiting translocation by binding to Eukaryotic-EF-2</p> Signup and view all the answers

    What type of enzymes are found in lysosomes?

    <p>Acid hydrolases</p> Signup and view all the answers

    Which process is NOT a method by which substances can be transported into lysosomes?

    <p>Exocytosis</p> Signup and view all the answers

    How do substrates enter lysosomes?

    <p>Via late endosomes</p> Signup and view all the answers

    Which of the following statements about lysosomes' acidic environment is true?

    <p>The pH is maintained by proton pumps in the lysosomal membrane.</p> Signup and view all the answers

    What is the primary role of enzymes in glycogenolysis?

    <p>To degrade glycogen into glucose molecules</p> Signup and view all the answers

    Which condition is characterized by excessive triglyceride accumulation in parenchymal cells?

    <p>Steatosis</p> Signup and view all the answers

    What might heavy exposure to carbon dust lead to in individuals?

    <p>Anthracosis</p> Signup and view all the answers

    What type of pigment is lipofuscin, and where is it typically found?

    <p>An endogenous pigment in long-lived cells</p> Signup and view all the answers

    What impact does excessive sun exposure have on melanin production?

    <p>Results in generalized hyperpigmentation</p> Signup and view all the answers

    What is a common consequence of glycogen storage diseases?

    <p>Abnormal accumulation of glycogen</p> Signup and view all the answers

    Which cellular structure is directly involved in lipid storage?

    <p>Adipocytes</p> Signup and view all the answers

    What condition could lead to hyperpigmentation localized to specific skin tumors?

    <p>Nevus</p> Signup and view all the answers

    What factor primarily leads to the pathological accumulation of cholesterol in the body?

    <p>Increased dietary fat intake</p> Signup and view all the answers

    What is a significant consequence of protein accumulation in cells, as seen in Alzheimer's disease?

    <p>Formation of intracellular inclusions</p> Signup and view all the answers

    What is the primary characteristic feature of steatosis in liver tissue?

    <p>Intracellular accumulation of triglycerides</p> Signup and view all the answers

    Which of the following mechanisms primarily distinguishes necrosis from apoptosis?

    <p>Rupture of lysosomal membranes</p> Signup and view all the answers

    What microscopic feature is typically associated with early cellular injury?

    <p>Clear cytoplasmic vacuoles</p> Signup and view all the answers

    Which of the following substances accumulates in cytosol and organelles during severe cellular injury?

    <p>Myeline figures</p> Signup and view all the answers

    In which type of cell death is mitochondrial damage and ATP depletion predominantly involved?

    <p>Necrosis</p> Signup and view all the answers

    What is the gross appearance of an organ affected by steatosis?

    <p>Yellow and greasy</p> Signup and view all the answers

    Which cellular structure is particularly affected by swelling and dilation in response to injury?

    <p>Endoplasmic reticulum</p> Signup and view all the answers

    Which statement best describes the fate of lipids within a phagosome?

    <p>Lipids remain undigested and contribute to residual bodies.</p> Signup and view all the answers

    What is the primary regulatory function of autophagy-related genes (Atgs)?

    <p>They control the formation of autophagosomes from organelles.</p> Signup and view all the answers

    Which condition is NOT known to activate the process of autophagy?

    <p>Nutrient excess</p> Signup and view all the answers

    Which of the following statements accurately describes the role of autophagy in cells?

    <p>It facilitates the removal of damaged organelles and proteins.</p> Signup and view all the answers

    What is the primary role of autophagosomes in the autophagy process?

    <p>They encapsulate organelles and cytoplasm for degradation.</p> Signup and view all the answers

    What is the primary reason for apoptosis in embryogenesis?

    <p>To allow for the formation of digits by eliminating interdigital tissue</p> Signup and view all the answers

    Which of the following statements is true regarding the role of apoptosis in normal physiological conditions?

    <p>Apoptosis helps maintain cell turnover in proliferating cell populations</p> Signup and view all the answers

    How are caspases involved in the process of apoptosis?

    <p>They activate enzymes that lead to cell death</p> Signup and view all the answers

    What primarily triggers the apoptosis process in autoreactive T cells?

    <p>Activation of p53 gene due to DNA damage</p> Signup and view all the answers

    What is the consequence of failure to clear necrotic cells in tissues?

    <p>Calcification due to dystrophic changes</p> Signup and view all the answers

    Which scenario describes the primary effect of apoptosis in pathological conditions?

    <p>Eliminates irreparably damaged cells without triggering inflammation</p> Signup and view all the answers

    Which of the following is a physiological condition that normally utilizes apoptosis?

    <p>Withdrawal of ovarian hormones during the menstrual cycle</p> Signup and view all the answers

    What role does the extracellular matrix play in apoptosis?

    <p>It prevents apoptosis by providing survival signals</p> Signup and view all the answers

    What initiates the 'execution phase' of apoptosis?

    <p>Activation of intrinsic enzymes</p> Signup and view all the answers

    What role do microtubules play during cell division?

    <p>They facilitate the separation of chromatids by forming the mitotic spindle.</p> Signup and view all the answers

    Which structural feature of microtubules explains their dynamic nature?

    <p>They consist of multiple subunits that can be assembled or disassembled.</p> Signup and view all the answers

    Which drug specifically inhibits microtubule polymerization by binding to tubulin?

    <p>Colchicine</p> Signup and view all the answers

    What is one of the primary functions of microtubules within a cell?

    <p>Regulating the intracellular movement of organelles and vesicles</p> Signup and view all the answers

    Which structural components primarily make up a microtubule?

    <p>Protofilaments composed of α- and β-tubulin heterodimers</p> Signup and view all the answers

    What happens to the average half-life of a microtubule during rapid polymerization?

    <p>It decreases significantly.</p> Signup and view all the answers

    Which of the following statements characterizes the contribution of microtubules to cell shape?

    <p>They offer rigidity and maintain cell shape.</p> Signup and view all the answers

    What is the function of the centrosome related to microtubules?

    <p>It serves as a nucleation site for microtubule formation.</p> Signup and view all the answers

    How do microtubules contribute to ciliary and flagellar motion?

    <p>By enabling the sliding of adjacent microtubules against each other.</p> Signup and view all the answers

    What primary component do microtubules rely on for their dynamic behavior?

    <p>Reversible polymerization of tubulin subunits</p> Signup and view all the answers

    Which of the following accurately describes the role of tRNA in the translation process?

    <p>tRNA carries amino acids and serves as a bridge between mRNA and the ribosome.</p> Signup and view all the answers

    What is the significance of the start codon AUG in the genetic code?

    <p>It is the only codon that codes for Methionine, initiating the translation process.</p> Signup and view all the answers

    Which characteristic of the genetic code allows multiple codons to specify the same amino acid?

    <p>The genetic code is degenerate.</p> Signup and view all the answers

    Which of the following components is essential for the formation of peptide bonds during translation?

    <p>Ribosomes</p> Signup and view all the answers

    What role do stop codons (UAA, UAG, UGA) play in the translation process?

    <p>They terminate the translation process.</p> Signup and view all the answers

    Which of the following statements accurately reflects the flow of genetic information during translation?

    <p>The information flows from mRNA to polypeptide chains.</p> Signup and view all the answers

    Which feature of genetic code implies that it is read in a specific direction?

    <p>The genetic code is read from 5’ to 3’ direction.</p> Signup and view all the answers

    What is one reason vincristine and colchicine are utilized in cancer chemotherapy?

    <p>They disrupt the formation of the mitotic spindle.</p> Signup and view all the answers

    How does the genetic code encode information from nucleic acids to proteins?

    <p>By converting nucleotide sequences into amino acid sequences.</p> Signup and view all the answers

    What is the main difference between hypertrophy and hyperplasia in response to stress?

    <p>Hypertrophy leads to an increase in organ size through larger cells, whereas hyperplasia increases organ size through additional cell proliferation.</p> Signup and view all the answers

    Which statement accurately describes the physiological and pathological forms of hypertrophy?

    <p>Physiological hypertrophy is associated with increased functional demand, while pathological hypertrophy is a result of excess hormones or growth factors.</p> Signup and view all the answers

    What are common triggers for hypertrophy in skeletal and cardiac muscle?

    <p>Increased workload and muscle fiber damage.</p> Signup and view all the answers

    In which scenario would hypertrophy and hyperplasia coexist?

    <p>During pregnancy, as the uterus enlarges to support fetal growth.</p> Signup and view all the answers

    What condition arises if the limits of adaptive responses are exceeded?

    <p>Cell injury, which may be reversible or irreversible.</p> Signup and view all the answers

    What is a primary characteristic of the hypertrophied organ?

    <p>It has no new cells, only larger cells.</p> Signup and view all the answers

    What is a consequence of sustained hypertrophy in muscle cells?

    <p>Enhanced force generation and work capacity of the muscle.</p> Signup and view all the answers

    What is the primary function of autophagy during starvation?

    <p>To degrade proteins and organelles for macromolecular precursors</p> Signup and view all the answers

    How does the ubiquitination process influence protein degradation in cells?

    <p>It marks proteins for degradation by attaching multiple ubiquitin molecules</p> Signup and view all the answers

    In which scenario does autophagy function as a potential survival mechanism for tumor cells?

    <p>In conditions of limited angiogenesis leading to cell starvation</p> Signup and view all the answers

    What role does proteasomal activity play in the cellular regulation of proteins?

    <p>It is responsible for breaking down malformed and ubiquitin-tagged proteins</p> Signup and view all the answers

    What is one effect of pharmacological stimulation of autophagy on body weight?

    <p>It can reduce weight gain and associated obesity alterations</p> Signup and view all the answers

    What is a key characteristic of the sex chromatin found in females compared to males?

    <p>It remains tightly coiled in one of the X chromosomes in females.</p> Signup and view all the answers

    What is the main function of the nucleolus within the nucleus?

    <p>Synthesis of ribosomal subunits.</p> Signup and view all the answers

    During which phase of the cell cycle does DNA replication occur?

    <p>S phase.</p> Signup and view all the answers

    What type of cells are typically used to study sex chromatin?

    <p>Epithelial cells lining the cheek.</p> Signup and view all the answers

    What is the role of heterochromatin in relation to the nucleolus?

    <p>It is frequently found attached to the nucleolus.</p> Signup and view all the answers

    Which ribonucleoproteins are synthesized in the nucleolus?

    <p>Ribosomal subunits.</p> Signup and view all the answers

    What is the primary component of nucleoplasm?

    <p>Fluid and proteinaceous matrix.</p> Signup and view all the answers

    What happens during the G1 phase of the cell cycle?

    <p>Macromolecule synthesis begins.</p> Signup and view all the answers

    How is rRNA associated with ribosomal proteins within the nucleolus?

    <p>They associate to form ribosomal subunits.</p> Signup and view all the answers

    What is the primary structural component of microtubules?

    <p>Heterodimers of globular α- and β-tubulin</p> Signup and view all the answers

    How do microtubules contribute to cellular motion?

    <p>They act as pathways for the movement of organelles and vesicles</p> Signup and view all the answers

    What is the average lifespan of a microtubule in a cell?

    <p>10 minutes</p> Signup and view all the answers

    What is the role of the centrosome in relation to microtubules?

    <p>It houses the centrioles and γ-tubulin ring complexes for microtubule nucleation</p> Signup and view all the answers

    What clinical effect does colchicine have on microtubules?

    <p>It prevents the polymerization of tubulin molecules into microtubules</p> Signup and view all the answers

    Which of the following is NOT a function of microtubules?

    <p>Regulating protein synthesis in the cytoplasm</p> Signup and view all the answers

    Which statement accurately reflects the dynamic nature of microtubules?

    <p>They constantly grow and shrink at their plus ends.</p> Signup and view all the answers

    Which component is part of the structure of microtubules?

    <p>Heterodimeric α- and β-tubulin proteins</p> Signup and view all the answers

    During which process do microtubules undergo rapid polymerization?

    <p>Cell division</p> Signup and view all the answers

    What structural arrangement do microtubules consist of?

    <p>13 parallel protofilaments</p> Signup and view all the answers

    What do proto-oncogenes primarily control within the cell?

    <p>Cell proliferation pathways</p> Signup and view all the answers

    Which of the following is NOT a factor that stimulates a cell to enter the cell cycle?

    <p>Aging of the cell</p> Signup and view all the answers

    How can alterations in proto-oncogenes lead to cancer development?

    <p>By promoting uncontrolled cell division</p> Signup and view all the answers

    What is the result of a mutation in proto-oncogenes?

    <p>Formation of oncogenes</p> Signup and view all the answers

    Which structure connects the two sister chromatids in a chromosome?

    <p>Centromere</p> Signup and view all the answers

    What happens to chromatin fibers as a cell prepares for mitotic or meiotic activity?

    <p>They undergo extensive condensation</p> Signup and view all the answers

    What is the chromosomal configuration in somatic cells of humans?

    <p>Diploid with 46 chromosomes</p> Signup and view all the answers

    Which mechanism does NOT alter oncogene activity?

    <p>Gene silencing</p> Signup and view all the answers

    Which of these statements best describes the effect of growth factors in cell signaling?

    <p>They induce the expression of proto-oncogenes.</p> Signup and view all the answers

    What critical function do cyclins perform in the cell cycle?

    <p>Activate cyclin-dependent kinases (CDKs)</p> Signup and view all the answers

    What is primarily synthesized during the G1 phase of the cell cycle?

    <p>RNA and regulatory proteins</p> Signup and view all the answers

    Which process occurs during the S phase of the cell cycle?

    <p>DNA replication occurs</p> Signup and view all the answers

    What key event occurs in the G2 phase prior to mitosis?

    <p>Microtubule formation</p> Signup and view all the answers

    What characterizes the G0 phase of the cell cycle?

    <p>Permanent cessation of division</p> Signup and view all the answers

    Why do highly differentiated cells, like neurons, exit the cell cycle?

    <p>To maintain their specialized functions</p> Signup and view all the answers

    What happens to the centrioles during the cell cycle?

    <p>They begin to duplicate in G1 and finish in G2</p> Signup and view all the answers

    How does the cell ensure the integrity of DNA before mitosis?

    <p>By analyzing and correcting any errors</p> Signup and view all the answers

    Which statement best describes what happens during mitosis?

    <p>The cell divides both its nucleus and cytoplasm into two daughter cells</p> Signup and view all the answers

    What indicates a cell has completed mitosis and re-entered the interphase?

    <p>Cellular growth and synthesis activities</p> Signup and view all the answers

    Which drug type is used to decrease the synthesis of Angiotensin-II to manage high blood pressure?

    <p>Angiotensin Converting Enzyme Inhibitors</p> Signup and view all the answers

    What effect do receptor antagonists like Valsartan have on Angiotensin-II?

    <p>They block the action of Angiotensin-II.</p> Signup and view all the answers

    In which communication mode do mediators like neurotransmitters primarily operate between neurons?

    <p>Synaptic signaling</p> Signup and view all the answers

    What is NOT a method of suppressing disease-related mediators?

    <p>Increasing their receptor density</p> Signup and view all the answers

    What systemic communication happens when a signal is released into the bloodstream?

    <p>Hormonal signaling</p> Signup and view all the answers

    What is the primary mechanism behind hyperplasia in tissue?

    <p>Proliferation of cells capable of division</p> Signup and view all the answers

    Which type of hyperplasia occurs as a response to hormonal stimulation during puberty?

    <p>Hormonal hyperplasia</p> Signup and view all the answers

    Which condition is most likely to result in concentric left ventricular hypertrophy?

    <p>Aortic valve disease</p> Signup and view all the answers

    What distinguishes pathologic hyperplasia from physiologic hyperplasia?

    <p>It results from inappropriate hormonal stimulation</p> Signup and view all the answers

    What is a common physiological response of the liver following donation of one lobe?

    <p>Compensatory hyperplasia</p> Signup and view all the answers

    What is a risk associated with pathologic hyperplasia of the endometrium?

    <p>Malignant transformation</p> Signup and view all the answers

    Which factor is primarily responsible for stimulating compensatory hyperplasia in response to liver damage?

    <p>Release of signaling pathways from stem cells</p> Signup and view all the answers

    Which cyclin binds to CDK4 and CDK6 during the early G1 phase?

    <p>Cyclin D</p> Signup and view all the answers

    What is the role of the ubiquitin-proteasome pathway for cyclins?

    <p>To degrade cyclins into their component molecules</p> Signup and view all the answers

    Which checkpoint is responsible for ensuring proper chromosome segregation before the cell leaves its current phase?

    <p>M checkpoint</p> Signup and view all the answers

    During which phase of the cell cycle does cyclin B facilitate the transition to the M phase?

    <p>G2 phase</p> Signup and view all the answers

    What type of cellular activities are supported by gel-like networks in the cell cortex?

    <p>Cell migration and vesicle transport</p> Signup and view all the answers

    Which cyclin is involved in permitting the cell to enter the G2 phase and induces cyclin B formation?

    <p>Cyclin A</p> Signup and view all the answers

    What cellular structure do focal points refer to in relation to cell activities?

    <p>Contact points with the extracellular matrix</p> Signup and view all the answers

    What process initiates the degradation of cyclins after they fulfill their function in the cell cycle?

    <p>Ubiquitin-proteasome pathway</p> Signup and view all the answers

    Which cyclin is synthesized in the late G1 phase and binds to CDK2 to help the cell progress to the S phase?

    <p>Cyclin E</p> Signup and view all the answers

    What is the primary role of the checkpoints in the cell cycle?

    <p>To delay progression for DNA repair and growth</p> Signup and view all the answers

    What mechanism do Shiga toxin and ricin both utilize to inhibit eukaryotic translation?

    <p>Preventing tRNA binding</p> Signup and view all the answers

    Which condition is associated with diphtheria toxin's mechanism of action?

    <p>Inhibition of ribosomal translocation</p> Signup and view all the answers

    Which type of cellular process is NOT facilitated by lysosomes?

    <p>Protein synthesis</p> Signup and view all the answers

    What is the primary function of hydrolytic enzymes found in lysosomes?

    <p>Breaking down macromolecules</p> Signup and view all the answers

    What environment is required for lysosomal enzymes to function optimally?

    <p>Acidic pH</p> Signup and view all the answers

    Which of the following pathways do substances destined for lysosomal degradation NOT use?

    <p>Secretory vesicles</p> Signup and view all the answers

    How are lysosomal enzymes initially processed within the cell?

    <p>Manufactured in rough endoplasmic reticulum</p> Signup and view all the answers

    Which of the following correctly describes a role of autophagy?

    <p>Removing damaged organelles</p> Signup and view all the answers

    What type of cellular structure do lysosomes primarily digest?

    <p>Macromolecules and cellular debris</p> Signup and view all the answers

    In the context of cell health, what consequence could result from lysosomal dysfunction?

    <p>Accumulation of waste materials</p> Signup and view all the answers

    What is the primary function of the nucleolus in a cell?

    <p>Synthesis of ribosomal subunits</p> Signup and view all the answers

    Which phase of the cell cycle involves the duplication of DNA?

    <p>S phase</p> Signup and view all the answers

    In which type of cells is sex chromatin most commonly studied?

    <p>Epithelial cells</p> Signup and view all the answers

    What characteristic describes the visible sex chromatin in females?

    <p>It remains tightly coiled and genetically inactive.</p> Signup and view all the answers

    Which components are found in the nucleoplasm?

    <p>Histones and ribonucleoproteins</p> Signup and view all the answers

    What is the significance of heterochromatin's association with the nucleolus?

    <p>Its functional significance is unknown.</p> Signup and view all the answers

    Which of the following correctly describes the G1 phase of the cell cycle?

    <p>Cell growth and macromolecule synthesis begin.</p> Signup and view all the answers

    What chromosomal configuration is present in human males?

    <p>XY</p> Signup and view all the answers

    Which of the following stages does NOT occur during mitosis?

    <p>Synthesis</p> Signup and view all the answers

    During which phase of mitosis do the chromosomes first condense and become visible under a microscope?

    <p>Prophase</p> Signup and view all the answers

    What is the primary role of spindle fibers during mitosis?

    <p>To ensure proper chromosome alignment and separation</p> Signup and view all the answers

    Which component is involved in organizing the microtubules during mitosis?

    <p>Centrosome</p> Signup and view all the answers

    How many total chromosomes are found in human somatic cells?

    <p>46</p> Signup and view all the answers

    What primarily differentiates germ cells from somatic cells?

    <p>Germ cells are haploid</p> Signup and view all the answers

    What is the process called where the inactive X chromosome in female somatic cells is randomly determined?

    <p>X-inactivation</p> Signup and view all the answers

    Which of the following statements is true regarding the inactive X chromosome in females?

    <p>It remains inactive throughout the individual's life.</p> Signup and view all the answers

    Which of the following proteins is likely to have an extended half-life?

    <p>Crystallins in the lens of the eye</p> Signup and view all the answers

    What effect do destabilizing N-terminal amino acids have on proteins?

    <p>They lead to rapid turnover and degradation</p> Signup and view all the answers

    In the context of protein degradation, what triggers the process of poly-ubiquination?

    <p>Addition of free ubiquitin to already bound proteins</p> Signup and view all the answers

    Which of the following enzymes is NOT commonly found in peroxisomes?

    <p>Acetyl CoA carboxylase</p> Signup and view all the answers

    What is a primary function of inclusions within a cell?

    <p>To store non-living components like pigments and crystals</p> Signup and view all the answers

    What role does hydrogen peroxide (H2O2) play in peroxisomes?

    <p>It is a byproduct of fatty acid catabolism</p> Signup and view all the answers

    Which of the following statements about glycogen is accurate?

    <p>It is abundant in muscle and liver cells</p> Signup and view all the answers

    What can result from the failure to degrade misfolded proteins in the cell?

    <p>Development of neurodegenerative diseases</p> Signup and view all the answers

    What characterizes PEST sequences within proteins?

    <p>They promote rapid ubiquination and degradation</p> Signup and view all the answers

    Which structural feature distinguishes peroxisomes from mitochondria?

    <p>Self-replicating ability</p> Signup and view all the answers

    What is the primary result of meiosis that ensures genetic variability in gametes?

    <p>Crossing over during prophase I</p> Signup and view all the answers

    Which phase of meiosis is characterized by the lining up of homologous pairs of chromosomes on the equatorial plate?

    <p>Metaphase I</p> Signup and view all the answers

    During which phase of meiosis do homologous chromosomes migrate away from each other?

    <p>Anaphase I</p> Signup and view all the answers

    How does meiosis contribute to the reduction of chromosome number in gametes?

    <p>By separating homologous chromosomes in Meiosis I</p> Signup and view all the answers

    What critical event occurs during prophase I of meiosis that is pivotal for genetic diversity?

    <p>Crossing over between homologous chromosomes</p> Signup and view all the answers

    What occurs to the chromosomes during telophase after mitosis?

    <p>They uncoil into chromatin.</p> Signup and view all the answers

    Which structure is crucial for spindle fibers to attach during metaphase?

    <p>Kinetochore</p> Signup and view all the answers

    What indicates the initiation of cytokinesis during anaphase?

    <p>Formation of the cleavage furrow</p> Signup and view all the answers

    In the absence of centrioles, what impact does it have on mitosis?

    <p>Mitosis proceeds improperly.</p> Signup and view all the answers

    What is the primary function of spindle fibers during mitosis?

    <p>To bind to the kinetochore and separate chromatids.</p> Signup and view all the answers

    What is the key feature of the chromosomes during metaphase?

    <p>Chromosomes align along the equator of the spindle.</p> Signup and view all the answers

    What happens to sister chromatids during anaphase?

    <p>They separate and migrate to opposite poles.</p> Signup and view all the answers

    What role does the contractile ring play during cytokinesis?

    <p>It helps separate the two daughter cells.</p> Signup and view all the answers

    What is the result of the separation of chromatids during mitosis?

    <p>Creation of two identical daughter cells.</p> Signup and view all the answers

    What occurs to the spindle apparatus during telophase?

    <p>It disappears.</p> Signup and view all the answers

    Which category of intermediate filaments is primarily found in epithelial cells?

    <p>Keratins</p> Signup and view all the answers

    What is the functional purpose of occluding junctions?

    <p>To create an impermeable barrier</p> Signup and view all the answers

    Which type of junction is described as resembling spot welds on the cell surface?

    <p>Macula junctions</p> Signup and view all the answers

    Which type of cell has desmin intermediate filaments within its structure?

    <p>Muscle cells</p> Signup and view all the answers

    Which intermediate filament type is associated with astrocytes?

    <p>Glial fibrillary acidic proteins</p> Signup and view all the answers

    What primarily causes increased hypertrophy in skeletal muscle fibers during strength training?

    <p>Increase in cellular demand and workload</p> Signup and view all the answers

    How does pathologic hyperplasia differ from physiologic hyperplasia?

    <p>Pathologic hyperplasia is initiated by hormonal imbalances</p> Signup and view all the answers

    Which example best illustrates compensatory hyperplasia?

    <p>Liver regrowth after lobe donation</p> Signup and view all the answers

    What is a significant consequence of excessive estrogen on target tissues?

    <p>Can lead to endometrial and breast hyperplasia</p> Signup and view all the answers

    Which statement accurately describes the cellular mechanism behind hyperplasia?

    <p>It is driven by stem cell activation and growth factor influence</p> Signup and view all the answers

    In what scenario would you expect to see bone marrow hyperplasia?

    <p>Following acute blood loss</p> Signup and view all the answers

    What characterizes concentric left ventricular hypertrophy?

    <p>Thickening of the heart wall in response to increased pressure</p> Signup and view all the answers

    What is the primary aim of protein maturation?

    <p>To activate proteins to their functional form and localize them</p> Signup and view all the answers

    Which of the following is a key role of molecular chaperones during protein folding?

    <p>They help proteins to fold into their proper 3D structures</p> Signup and view all the answers

    What process involves the removal of signal peptides from proteins after they have reached their final destination?

    <p>Proteolysis</p> Signup and view all the answers

    Which post-translational modification is critical for blood clotting and bone ossification?

    <p>γ-carboxylation of glutamic acid</p> Signup and view all the answers

    Which modification helps stabilize glycoproteins against degradation?

    <p>Glycosylation</p> Signup and view all the answers

    How does acylation primarily affect proteins?

    <p>It helps anchor proteins to cellular membranes</p> Signup and view all the answers

    What is a potential consequence of errors in translation?

    <p>Production of dysfunctional or misfolded proteins</p> Signup and view all the answers

    What clinical application is attributed to tetracyclines and macrolides like erythromycin?

    <p>Altering bacterial translation</p> Signup and view all the answers

    Which type of amino acid modification is essential for collagen synthesis?

    <p>Hydroxylation</p> Signup and view all the answers

    What is the purpose of glycosylation in protein maturation?

    <p>To help stabilize proteins and provide proper conformation</p> Signup and view all the answers

    What is the primary role of microtubule-associated proteins (MAPs) in the cell?

    <p>To prevent depolymerization of microtubules and assist organelle transport.</p> Signup and view all the answers

    Which statement accurately describes the movement of dynein and kinesin along microtubules?

    <p>Dynein moves vesicles toward the minus end, while kinesin moves them toward the plus end.</p> Signup and view all the answers

    What structural configuration do centrioles exhibit?

    <p>Nine microtubule triplets arranged in a cylindrical structure.</p> Signup and view all the answers

    During which cellular process do centrioles participate in forming the spindle apparatus?

    <p>Mitosis.</p> Signup and view all the answers

    What defines the structure of actin filaments in a contractile bundle?

    <p>Actin filaments are loosely arranged and alternate direction at their ends.</p> Signup and view all the answers

    What is the significance of actin's plus and minus ends in cellular dynamics?

    <p>The plus end grows faster, allowing for rapid filament elongation and cell movement.</p> Signup and view all the answers

    What specifically triggers the formation of cilia and flagella in cells?

    <p>Centrioles acting as basal bodies in the cytoplasm.</p> Signup and view all the answers

    Which property of microtubules allows for bidirectional movement of organelles?

    <p>Their dynamic instability and polarity facilitate movement in both directions.</p> Signup and view all the answers

    What condition is characterized by excessive, abnormal accumulations of triglycerides within parenchymal cells?

    <p>Steatosis</p> Signup and view all the answers

    Which type of pigment is a yellow-to-brown pigment found in long-lived cells such as neurons and cardiac muscle?

    <p>Lipofuscin</p> Signup and view all the answers

    What is the primary implication of abnormal lipid accumulation in tissues?

    <p>Steatosis</p> Signup and view all the answers

    In the context of cellular inclusions, which of the following statements is true regarding exogenous pigments?

    <p>They originate from external sources.</p> Signup and view all the answers

    What condition may result from excessive sun exposure leading to increased melanin production?

    <p>Hyperpigmentation</p> Signup and view all the answers

    What is the role of lipids within cells aside from storage?

    <p>Serve as a potential source of energy</p> Signup and view all the answers

    Which of the following conditions does not directly relate to the accumulation of endogenous pigments?

    <p>Carbon deposits in lungs</p> Signup and view all the answers

    What type of cells primarily store triglycerides in their cytoplasm?

    <p>Adipocytes</p> Signup and view all the answers

    What condition describes the accumulation of carbon pigment in the lungs and lymph nodes due to heavy smoking or coal exposure?

    <p>Anthracosis</p> Signup and view all the answers

    What is one of the main adverse effects of macrophages phagocytosing tattoo ink?

    <p>Permanent pigment retention</p> Signup and view all the answers

    What is the primary role of cadherins in cell adhesion?

    <p>To reinforce tight junctions formed by claudins and occludins.</p> Signup and view all the answers

    What characterizes desmosomes in epithelial cells?

    <p>They are 'spot weld'-like structures composed of attachment plaques.</p> Signup and view all the answers

    How do gap junctions facilitate intercellular communication?

    <p>Through connexons that form aqueous pores between adjacent cells.</p> Signup and view all the answers

    What is the typical width of the intercellular space at zonula adherens?

    <p>15 to 20 nm</p> Signup and view all the answers

    What type of protein accumulates at the cytoplasmic aspect of desmosome attachment plaques?

    <p>Intermediate filaments of cytokeratin</p> Signup and view all the answers

    What best describes reversible cell injury?

    <p>Characterized by mild functional and structural alterations</p> Signup and view all the answers

    Which of the following is NOT a feature consistently seen in reversibly injured cells?

    <p>Formation of extensive necrotic tissue</p> Signup and view all the answers

    What triggers fatty change in cells?

    <p>Rapid accumulation of triglycerides in cytoplasm</p> Signup and view all the answers

    What is the primary cause of hydropic change in cells under mild to moderate injury?

    <p>Failure of ATP-dependent Na+-K+ plasma membrane pump</p> Signup and view all the answers

    How does squamous metaplasia occur in response to chronic irritation?

    <p>Stem cells are stimulated and reprogrammed</p> Signup and view all the answers

    Which condition is associated with columnar cell intestinal metaplasia?

    <p>Chronic exposure to acidic gastric juice</p> Signup and view all the answers

    What is a common consequence of ATP depletion in cells?

    <p>Failure of cellular ion pumps leading to swelling</p> Signup and view all the answers

    What characterizes the disappearance of the nuclear envelope during mitosis?

    <p>It happens early in the metaphase phase.</p> Signup and view all the answers

    Which process is primarily responsible for the separation of sister chromatids during mitosis?

    <p>Karyokinesis</p> Signup and view all the answers

    Which of the following occurs during telophase?

    <p>Nuclear envelope reconstitution</p> Signup and view all the answers

    What role does the kinetochore play in mitosis?

    <p>It helps in the migration of chromatids.</p> Signup and view all the answers

    Which statement about the cleavage furrow is correct?

    <p>It appears during anaphase and indicates cytokinesis.</p> Signup and view all the answers

    What is the outcome for daughter cells after mitosis?

    <p>They are genetically identical to each other.</p> Signup and view all the answers

    During which phase does the contractile ring begin to form?

    <p>Anaphase</p> Signup and view all the answers

    Which of the following best describes the organization of chromosomes after mitosis?

    <p>They remain highly condensed and organized.</p> Signup and view all the answers

    What leads to improper formation of spindle fibers in the absence of centrioles?

    <p>Dispersed microtubule-nucleating material</p> Signup and view all the answers

    What is a key distinction between metaphase and anaphase?

    <p>Sister chromatids separate in anaphase.</p> Signup and view all the answers

    Which cellular structures are primarily involved in exocytosis and endocytosis?

    <p>Gel-like networks and actin filaments</p> Signup and view all the answers

    During which phase of the cell cycle does the assembly of the cyclin D-CDK4 complex occur?

    <p>G1 phase</p> Signup and view all the answers

    What quality control mechanism does the cell utilize before progressing to the next phase of the cell cycle?

    <p>Cellular checkpoints</p> Signup and view all the answers

    What is the primary mechanism for the degradation of cyclins after their functions are completed?

    <p>Ubiquitin-proteasome pathway</p> Signup and view all the answers

    Which cyclin is synthesized during the late G1 phase that allows the cell to enter the S phase?

    <p>Cyclin E</p> Signup and view all the answers

    What facilitates the proper segregation of chromosomes during mitosis?

    <p>Cyclin A-CDK2 complex</p> Signup and view all the answers

    Which types of cell structures serve as points of contact for the cell with the extracellular matrix?

    <p>Focal points</p> Signup and view all the answers

    What is the outcome of unchecked progression through the cell cycle?

    <p>Tumor formation</p> Signup and view all the answers

    Which amino acids are coded by only one codon in genetic coding?

    <p>Tryptophan and Methionine</p> Signup and view all the answers

    What does the wobble theory suggest about codons?

    <p>The third nucleotide is often less important for amino acid specificity.</p> Signup and view all the answers

    Which characteristic of the genetic code states that each codon specifies only one amino acid?

    <p>Unambiguous Code</p> Signup and view all the answers

    During the initiation stage of protein biosynthesis, which component is NOT required?

    <p>DNA</p> Signup and view all the answers

    Which of the following describes the reading mechanism of the genetic code?

    <p>Read continuously without punctuation</p> Signup and view all the answers

    What is the role of GTP during the initiation of protein biosynthesis?

    <p>To stabilize the formation of the initiation complex</p> Signup and view all the answers

    In the context of translation elongation, what does the A site of the ribosome do?

    <p>Provides access for new aminoacyl-tRNA binding</p> Signup and view all the answers

    What is the effect of hydrolysis of ATP to ADP + Pi during the initiation stage?

    <p>It facilitates the binding of mRNA to the ribosome.</p> Signup and view all the answers

    Which statement correctly describes the components of the initiation complex?

    <p>Comprises eIFs, mRNA, and initiator tRNA</p> Signup and view all the answers

    Which description best identifies tRNA charging?

    <p>Recognition and attachment of amino acids to tRNA</p> Signup and view all the answers

    What primarily drives the process of hyperplasia?

    <p>Growth factor-driven proliferation</p> Signup and view all the answers

    What is a common physiological trigger for hormonal hyperplasia?

    <p>Increased estrogen during pregnancy</p> Signup and view all the answers

    Which condition exemplifies pathologic hyperplasia?

    <p>Increased breast tissue due to hormonal changes</p> Signup and view all the answers

    Under what circumstances does compensatory hyperplasia typically occur?

    <p>Following the removal of a damaged organ</p> Signup and view all the answers

    What defines concentric left ventricular hypertrophy?

    <p>Enlargement of individual cardiac muscle fibers from pressure overload</p> Signup and view all the answers

    Which of the following best illustrates a situation that cannot lead to hyperplasia?

    <p>Inadequate oxygen supply to tissues</p> Signup and view all the answers

    What role do growth factors play in hyperplasia?

    <p>They stimulate the activation of signaling pathways for proliferation</p> Signup and view all the answers

    Which of the following accurately describes the role of cadherins in cell adhesion?

    <p>They connect the cytoplasmic aspect of the cell membrane to actin filaments.</p> Signup and view all the answers

    What is the primary function of gap junctions in cellular communication?

    <p>They allow the direct exchange of small molecules and ions.</p> Signup and view all the answers

    What distinguishes desmosomes from other types of cell junctions?

    <p>They provide mechanical strength through intermediate filaments.</p> Signup and view all the answers

    Which statement best describes the process of intercellular fusion at focal points?

    <p>It entails a selective merging of cell membranes at specific sites.</p> Signup and view all the answers

    Which characteristic is unique to the composition of zonula adherens compared to tight junctions?

    <p>Presence of cadherins as extracellular components.</p> Signup and view all the answers

    What is the role of eEF-1 in the binding of aminoacyl t-RNA to the A site?

    <p>It binds GTP to activate aminoacyl t-RNA.</p> Signup and view all the answers

    What initiates the hydrolysis of the bond between the peptide chain and t-RNA during termination?

    <p>The recognition of a stop codon by releasing factors.</p> Signup and view all the answers

    Which factor is responsible for the translocation of the newly formed peptidyl-tRNA from the A site to the P site?

    <p>eEF-2.</p> Signup and view all the answers

    What is the role of the anticodon in tRNA during translation?

    <p>It pairs with a codon on the mRNA.</p> Signup and view all the answers

    How many high energy phosphate bonds are consumed for the formation of one peptide bond?

    <p>4 bonds.</p> Signup and view all the answers

    What type of enzyme is peptidyl transferase during the peptide bond formation?

    <p>A ribozyme.</p> Signup and view all the answers

    What primarily happens to the discharged t-RNA after translocation?

    <p>It quickly dissociates.</p> Signup and view all the answers

    What is the mechanism by which termination occurs during protein synthesis?

    <p>Recognition of stop codons by releasing factors.</p> Signup and view all the answers

    Which of the following codons is recognized as a start codon during translation?

    <p>AUG.</p> Signup and view all the answers

    What happens to the 80S ribosome subunit after termination of translation?

    <p>It dissociates into its subunits.</p> Signup and view all the answers

    Which amino acid is coded by only one codon?

    <p>Tryptophan</p> Signup and view all the answers

    What is the primary importance of the first two nucleotides in a codon according to the wobble theory?

    <p>They dictate the specific amino acid that is incorporated.</p> Signup and view all the answers

    Which statement correctly describes the genetic code?

    <p>It is non-overlapping and read in fixed triplet sequences.</p> Signup and view all the answers

    What is NOT a component required for the initiation complex in protein biosynthesis?

    <p>DNA polymerase</p> Signup and view all the answers

    During elongation, where does the binding of aminoacyl-tRNA occur?

    <p>A site</p> Signup and view all the answers

    What role does eIF-3 play in the initiation stage of protein biosynthesis?

    <p>Prevents the reassociation of ribosomal subunits.</p> Signup and view all the answers

    Which of the following accurately describes tRNA charging?

    <p>It involves the attachment of amino acids to the 3' hydroxyl terminus.</p> Signup and view all the answers

    What happens to GTP during the process of protein elongation?

    <p>It is hydrolyzed, providing energy for translocation.</p> Signup and view all the answers

    Which of the following statements about the universal nature of the genetic code is true?

    <p>The same codons code for amino acids in nearly all organisms.</p> Signup and view all the answers

    Which mechanism is primarily used by lysosomes to obtain substances for degradation?

    <p>Phagosomes, pinocytotic vesicles, or autophagosomes</p> Signup and view all the answers

    What type of toxin inhibits tRNA binding by acting on the ribosome's 60S subunit?

    <p>Shiga toxin</p> Signup and view all the answers

    Which of the following statements regarding lysosomal enzymes is incorrect?

    <p>They are active at neutral pH.</p> Signup and view all the answers

    What is a primary role of autophagy in a cell?

    <p>Serving as a cellular sink for excess materials</p> Signup and view all the answers

    Which mechanism does diphtheria toxin utilize to impede cellular functions?

    <p>Interference with translocation</p> Signup and view all the answers

    What type of organelles receive digestive contents from late endosomes?

    <p>Lysosomes</p> Signup and view all the answers

    Which statement accurately describes the composition of lysosomes?

    <p>They have at least 40 different types of acid hydrolases.</p> Signup and view all the answers

    Which process best describes how lysosomal enzymes are manufactured?

    <p>Synthesized in the rough endoplasmic reticulum and packaged in Golgi</p> Signup and view all the answers

    What is the main consequence of improper lysosomal function?

    <p>Accumulation of undigested substances</p> Signup and view all the answers

    What role does the proteasome play in cellular function?

    <p>Degrading misfolded or damaged proteins</p> Signup and view all the answers

    What characterizes reversible cell injury?

    <p>Functional and structural alterations that can revert</p> Signup and view all the answers

    Which of the following accurately describes hydropic change in reversibly injured cells?

    <p>Generalized swelling of the cell and its organelles</p> Signup and view all the answers

    What leads to the occurrence of fatty change in the liver?

    <p>Disruption of mitochondrial metabolic pathways</p> Signup and view all the answers

    Which mechanism primarily causes cell swelling in reversible injury?

    <p>Failure of the Na+-K+ pump due to ATP depletion</p> Signup and view all the answers

    Which condition is associated with squamous metaplasia due to chronic irritation?

    <p>Long-term smoking or stones</p> Signup and view all the answers

    What is the primary feature observed in cells undergoing hydropic change?

    <p>Blebbing of plasma membrane</p> Signup and view all the answers

    Which cyclin is responsible for the transition from the G2 phase to the M phase?

    <p>Cyclin B</p> Signup and view all the answers

    Which of these is a common cause for the occurrence of columnar cell intestinal metaplasia?

    <p>Irritation by acidic gastric juice</p> Signup and view all the answers

    What happens to cyclins after they have performed their functions in the cell cycle?

    <p>They enter the ubiquitin-proteasome pathway for degradation.</p> Signup and view all the answers

    During which phase is cyclin E synthesized, and which CDK does it bind to?

    <p>Late G1 phase, binds to CDK2.</p> Signup and view all the answers

    Which structural feature refers to the points of contact between the cell and the extracellular matrix?

    <p>Focal points</p> Signup and view all the answers

    What primary mechanism leads to the breakdown of cellular components during necrosis?

    <p>Release of lysosomal enzymes</p> Signup and view all the answers

    What morphological change characterizes necrotic cells under electron microscopy?

    <p>Dilation of mitochondria and amorphous densities</p> Signup and view all the answers

    What effect does the leakage of ATP from damaged cells have on the immune response?

    <p>It triggers phagocytosis and cytokine production.</p> Signup and view all the answers

    Which of the following nuclear changes is associated with significant DNA breakdown in necrotic cells?

    <p>Karyolysis</p> Signup and view all the answers

    Which pathological process is NOT commonly linked to the initiation of necrosis?

    <p>Hormonal signaling</p> Signup and view all the answers

    What histological characteristic is used to identify necrotic cellular changes in tissue samples?

    <p>Glassy homogeneous appearance</p> Signup and view all the answers

    What is the role of reactive oxygen species in the pathogenesis of necrosis?

    <p>They cause damage to mitochondria and phospholipids.</p> Signup and view all the answers

    Which type of cellular protein change occurs due to denaturation during necrosis?

    <p>Loss of protein function and structural integrity</p> Signup and view all the answers

    Which cellular event is likely to occur after lysosomal enzyme leakage during necrosis?

    <p>Enzymatic digestion of cellular structures</p> Signup and view all the answers

    What is the primary function of the nuclear pores?

    <p>To provide controlled pathways for substance exchange between the nucleus and cytoplasm.</p> Signup and view all the answers

    Which component of the nucleus is primarily responsible for the synthesis of RNA?

    <p>Nucleolus</p> Signup and view all the answers

    What feature distinguishes the nuclear envelope from the cytoplasmic membrane?

    <p>It has two parallel membranes separated by a space.</p> Signup and view all the answers

    How are molecules larger than 9 nm transported into the nucleus?

    <p>By receptor-mediated active transport requiring ATP.</p> Signup and view all the answers

    What is the basic structural unit of chromatin?

    <p>Nucleosome</p> Signup and view all the answers

    What is a key characteristic of the nuclear envelope?

    <p>It is continuous with the endoplasmic reticulum.</p> Signup and view all the answers

    What distinguishes chromatin from other nuclear components?

    <p>It is composed of DNA and proteins like histones.</p> Signup and view all the answers

    Why do nuclei appear dark blue or black in hematoxylin and eosin-stained preparations?

    <p>Because of the staining affinity for the DNA and associated proteins.</p> Signup and view all the answers

    What role does ATP play in the nuclear transport of larger molecules?

    <p>It is required for the active transport of these molecules through nuclear pores.</p> Signup and view all the answers

    What defines the continuity between the nuclear envelope and the endoplasmic reticulum?

    <p>The fusion points where the membranes join.</p> Signup and view all the answers

    Which type of necrosis preserves the architecture of dead tissue for several days?

    <p>Coagulative necrosis</p> Signup and view all the answers

    What primarily causes coagulative necrosis in organs such as the heart and kidneys?

    <p>Ischemia or impaired blood supply</p> Signup and view all the answers

    Which cellular change is associated with the process of necrosis?

    <p>Membrane integrity disturbance</p> Signup and view all the answers

    Which biochemical marker is typically elevated in cases of myocardial infarction?

    <p>Creatine kinase-MB</p> Signup and view all the answers

    What distinguishes necrosis from apoptosis in cells?

    <p>Necrosis leads to an inflammatory response</p> Signup and view all the answers

    Which of the following conditions is most likely to exhibit caseous necrosis?

    <p>Tuberculosis</p> Signup and view all the answers

    What is a common feature observed in fatty necrosis?

    <p>Death of adipose tissue</p> Signup and view all the answers

    What is a key feature of liquefactive necrosis?

    <p>Transformation of tissue into a viscous liquid</p> Signup and view all the answers

    Which of the following findings would be most helpful in diagnosing necrosis early?

    <p>Elevated intracellular proteins in circulation</p> Signup and view all the answers

    Which plasma marker is associated with liver cell damage?

    <p>Alanine transaminase (ALT)</p> Signup and view all the answers

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    Test your knowledge on the half-life of proteins, the N-end rule, and the roles of various cellular structures. This quiz covers important biochemistry concepts, including protein degradation and the functions of organelles. Perfect for those studying cellular biology or biochemistry!

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