N301 Pathophysiology 1 & Genetics Quiz 1 Study Guide

A comprehensive set of practice flashcards covering key concepts from Cellular Function, Signal Transduction, Tissue Types, Cellular Adaptations, Cell Injury, Oxidative Stress, Senescence, Epigenetics, Gene Expression (Genetics), and Chromosomal/Genetic Disorders as outlined in the lecture notes. Each card presents a question and its succinct answer to aid quick recall and exam preparation.

What is the difference between active transport and passive transport, and what are the three types of passive transport?

Active transport requires energy to move substances against their gradient; passive transport does not require energy and includes osmosis, simple diffusion, and facilitated diffusion.

What is the role of second messengers in signal transduction?

Second messengers relay and amplify extracellular signals inside the cell, activating downstream enzymes and pathways (e.g., cAMP, IP3, DAG, Ca2+).

What are the four types of cell communication and how do they differ?

Autocrine: signals affect the secreting cell; Paracrine: signals affect nearby cells; Endocrine: hormones travel through the bloodstream to distant cells; Synaptic: neurotransmitters cross synapses to a target cell.

What are the two main types of cell receptors and how do they differ?

Cell surface receptors bind hydrophilic ligands at the membrane; intracellular receptors bind lipophilic ligands that cross the membrane (cytoplasmic or nuclear).

What are the four basic tissue types and their general characteristics?

Epithelial: covers surfaces and forms glands; Connective: supports and connects tissues with extracellular matrix; Muscle: contracts to produce movement; Nervous: transmits electrical signals and coordinates responses.

What are the cellular adaptations and examples of atrophy, hypertrophy, hyperplasia, metaplasia, and dysplasia?

Atrophy: decrease in cell size; Hypertrophy: increase in cell size; Hyperplasia: increase in cell number; Metaplasia: one cell type replaces another; Dysplasia: disordered cell growth. Physiologic examples include muscle disuse (atrophy), exercise-induced hypertrophy, breast/hiver hyperplasia during puberty, metaplasia from smoking, cervical dysplasia; pathologic examples occur with disease states.

What are the three mechanisms of cell injury?

ATP depletion (often from hypoxia); mitochondrial dysfunction and ROS production; calcium influx and membrane damage leading to cell swelling and potential necrosis.

What are the effects of hypoxia in reversible cellular injury?

ATP depletion leading to failure of Na+/K+ pumps, cellular swelling, ER stress, ribosome detachment, and reduced protein synthesis; these changes may be reversible if oxygenation is restored.

Define oxidative stress and reactive oxygen species (ROS) and their role in cellular injury.

Oxidative stress is an imbalance between ROS/oxidants and antioxidants causing damage. ROS (e.g., superoxide, hydrogen peroxide, hydroxyl radical) can damage lipids, proteins, and DNA and contribute to injury; at low levels they can serve signaling roles.

What are apoptosis and necrosis, and how do they differ?

Apoptosis is programmed, orderly cell death with energy dependence, cell shrinkage, DNA fragmentation, and no inflammation; Necrosis is uncontrolled cell death from severe injury, with cell swelling, membrane rupture, and inflammation.

What are the cellular theories of senescence?

Telomere shortening leading to replicative senescence; accumulation of cellular damage; stress-induced premature senescence; some cells activate telomerase to counteract shortening.

What is epigenetics and how do DNA methylation and histone modifications affect gene expression?

Epigenetics: heritable changes in gene expression without DNA sequence changes. Increased DNA methylation at promoters generally silences genes; histone methylation can either repress or activate transcription depending on the residue; histone acetylation typically activates transcription by opening chromatin.

What are the characteristics and functions of mRNA, and what is its role in protein synthesis?

mRNA carries genetic information from DNA to the ribosome, where it is translated into a polypeptide; it undergoes processing, has codons that determine amino acids, and its stability influences protein expression.

Define genotype and phenotype and explain their relationship.

Genotype is the genetic makeup of an individual; phenotype is the observable traits. The genotype largely determines the phenotype, with environment modulating expression.

What is the difference between being a “carrier” of a genetic disease and expressing the phenotype?

A carrier has one mutant allele (often autosomal recessive or X-linked) and is typically asymptomatic; expressing the phenotype means having the disease manifested, usually due to two mutant alleles (recessive) or a dominant allele.

Define and differentiate between expressivity and penetrance.

Penetrance is the proportion of individuals with a genotype who express the phenotype; expressivity is the range or severity of phenotype among those who express it.

How do you create or interpret a Punnett square for inherited traits?

Cross parental alleles in a grid to determine the probabilities of offspring genotypes and phenotypes; identifies carrier statuses and disease risk.

What are transcription and translation, and what do they accomplish?

Transcription copies DNA into mRNA in the nucleus; translation uses mRNA to synthesize a polypeptide at the ribosome.

How do DNA and RNA differ in structure and function?

DNA is double-stranded, deoxyribose, uses thymine, stores genetic information. RNA is single-stranded, ribose, uses uracil, functions in transcription and translation.

Explain polygenic and multifactorial inheritance.

Polygenic inheritance involves multiple genes contributing to a trait; multifactorial inheritance involves multiple genes plus environmental factors influencing the trait.

Describe the heritability patterns of autosomal dominant, autosomal recessive, and X-linked genetic disorders.

Autosomal dominant: affected individuals often have affected parents; ~50% risk to offspring. Autosomal recessive: affected individuals typically have carrier parents; ~25% risk to offspring. X-linked: more common in males; carrier females may transmit; father-to-son transmission is not typical.

Describe the inheritance and features of hemophilia A.

X-linked recessive; deficiency of factor VIII; prolonged bleeding; mostly affects males; carrier females may have mild symptoms.

Describe the causes and clinical manifestations of autosomal recessive disorders cystic fibrosis, phenylketonuria, and Tay-Sachs disease.

Cystic fibrosis: CFTR mutations; thick mucus in lungs and pancreas; recurrent infections. Phenylketonuria: phenylalanine hydroxylase deficiency; elevated phenylalanine; intellectual disability unless diet is managed. Tay-Sachs disease: HEXA gene deficiency; GM2 ganglioside accumulation; neurodegeneration with onset in infancy; cherry-red macula.

Describe the causes and clinical manifestations of the autosomal dominant disorder Marfan syndrome.

FBN1 gene mutation leading to defective fibrillin-1; tall stature, long limbs, pectus excavatum, scoliosis, lens dislocation, aortic root dilation/aneurysm.

Explain the causes of autosomal dominant disorders.

Mutations in a single autosomal gene; often vertical transmission with affected individuals in successive generations; may involve gain-of-function or haploinsufficiency.

Identify the types of chromosomal disorders.

Numerical disorders (aneuploidy such as trisomies) and structural disorders (deletions, duplications, translocations, inversions, ring chromosomes).

Discuss the causes, pathogenesis, and clinical manifestations of selected chromosomal disorders.

Nondisjunction or structural rearrangements causing aneuploidy (e.g., Down syndrome from trisomy 21) with symptoms like intellectual disability and congenital features; Turner syndrome (monosomy X) and Klinefelter syndrome (XXY) are examples with characteristic clinical findings.