Genetics Study, DNA, and Chromosomes Mutations

Explore genetics anticipation through alpha thalassemia and Huntington's syndrome, showing how defective genomes lead to inherited disease with earlier onset and increasing severity across generations.

Explore autosomal dominant, autosomal recessive, and X-linked inheritance patterns, highlighting carriers and diseased individuals across generations. Observe no skipping in dominant and X-linked patterns, and note skipping in recessive graphs.

Huntington's disease arises from CAG repeat expansion causing NMDA excitotoxicity and caudate-putamen atrophy, with anticipation, decreased GABA and acetylcholine, increased dopamine, chorea, and haloperidol or tetrabenazine as treatments.

The polymerase chain reaction amplifies small amounts of DNA by denaturing the strands with heat, annealing primers, and elongating to produce new DNA, enabling tests like HIV screening.

Learn how blotting tests detect DNA, RNA, and proteins using southern, northern, western, and southwestern blots, with primers and antibodies revealing HIV DNA, gene expression, and DNA-bound proteins.

Flow cytometry uses antibodies and a laser to detect a protein as cells pass through a narrow tube, revealing hemoglobin pathologies, maternal fetal blood mixing, and CD4 counts in HIV.

Transcribes DNA to RNA and processes mRNA by capping with methylguanosine, splicing introns, and adding a poly(A) tail. Export mRNA to the cytoplasm for translation by ribosomes.

Summarizes oncogenes and their cancer associations, including ALK with lung adenocarcinoma, KIT with GI cancers, BCR-ABL with myeloid and lymphoid leukemias, and BRAF with melanoma.

Explore tumor suppressor genes such as APC, DCC, Smad, CDK, PTEN, NF1, NF2, RB, TSC, and Tp53, and their links to colon, pancreatic, renal, and breast cancers.

Identify key tumor markers used in cancer screening and diagnosis, including alkaline phosphatase, CA 19-9, AFP, beta hCG, CA 125, and CA 15/27.

Explore central nervous system development from neural plate formation to neural tube and crest, detailing forebrain, midbrain, and hindbrain vesicles and their derivatives telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon, and ventricles.

Cover renal embryology in three stages: pronephros, mesonephros, and metanephros, including ureteric bud–blastema interaction and mesonephros' role in male reproductive organs and garter duct formation.

Compare oogenesis and spermatogenesis, noting diploid primary oocytes arrest prophase I and haploid secondary oocytes arrest metaphase II, with six-phase spermatogenesis producing mature sperm after fertilization.

Explore how DNA forms chromosomes and a karyotype, and how mutations on chromosomes drive diseases such as von Hippel-Lindau on chromosome 3 and polycystic kidney disease on chromosome 4.

Explain how absence of dystrophin disrupts linking of muscle fibers to the cell membrane, causing fiber degeneration and early weakness in boys with X-linked frameshift mutations leading to dilated cardiomyopathy.

Ehlers-Danlos syndrome is an inherited disorder with dominant or recessive inheritance caused by defects in procollagen peptidase or lysyl oxidase, leading to defective collagen, hyperextensible skin, hypermobile joints, and aneurysms.

men1 involves parathyroid adenomas, pituitary adenomas, and gi tumors on chromosome 11; men2a and men2b involve ret-associated cancers including parathyroid hyperplasia, thyroid cancer, pheochromocytoma, neuromas, and marfan syndrome.

Shy-drager syndrome and Riley Day syndrome both cause autonomic dysfunction and orthostatic hypertension; Shy-drager is a late, parkinsonism-related disorder, while Riley Day is autosomal recessive and presents at birth.

Explain Wilson disease from copper transport defects in ATP7A and ATP7B, causing low copper and ceruloplasmin, with cornea ring, arthritis, parkinsonism, liver cirrhosis, and options like trientine, zinc, penicillamine.

Explain how autosomal recessive cftr defect on chromosome 7 disrupts an atp-gated chloride channel. Show the resulting thick lung mucus, pancreatic duct blockage, meconium ileus, high sweat chloride, and infertility.

Identify Marfan syndrome features: tall stature, mitral valve prolapse, spontaneous pneumothorax, scoliosis, myopia with lens subluxation, long fingers, and a Phibron one gene mutation on chromosome 15.

Explore the complications of Down syndrome, including congenital heart defects, gastrointestinal issues, immunological disorders, sleep apnea, obesity, leukemia, dementia, and atlantoaxial instability, with emphasis on early management and routine care.

Explore prenatal screening for down syndrome, including quad test with alpha fetoprotein, estriol, hcg and inhibin a, ultrasound markers like nuchal translucency, followed by chorionic villus sampling and amniocentesis.

Explore Down syndrome through nondisjunction meiosis causing trisomy 21. Key features include hypotonia, single palmar crease, epicanthic folds, and low nasal bridge.

Edwards' syndrome, a trisomy 18, features hypotonia with overlapping fingers, rocker-bottom feet, abnormal intellect, horseshoe kidney or kidney absence, and quad test showing decreased afp, hcg, estriol, and inhibin a.

Patau syndrome (trisomy 13) features cleft lip/palate, renal anomalies, aplasia cutis, and polydactyly, with quad screen markers inhibin, estriol, fetoprotein, and hCG guiding detection and high first-year mortality.

Turner syndrome arises from loss of one sex chromosome, leaving 46 with a single X; it causes webbed neck, lymphedema, heart and kidney abnormalities, and streak ovaries.

A defect in iron sensing increases intestinal iron absorption and macrophage iron release. Lab findings show elevated iron, transferrin, ferritin, and decreased TIBC, with symptoms after age four.

Kallmann syndrome, caused by a Kal gene mutation, disrupts olfactory bulb migration and GnRH release, causing absent LH/FSH and androgens, infertility in males and amenorrhea in females; renal agenesis; testosterone.

Explain how an extra X chromosome causes Klinefelter syndrome in males, with defective testicular cells, tall stature, testicular atrophy, FSH/LH, low testosterone, higher estrogen, and gynecomastia; treat with testosterone replacement.

Describe autosomal recessive phenylketonuria caused by defective phenylalanine hydroxylase, with phenylalanine buildup, tyrosine deficiency, musty odor, hyperpigmentation, and neural damage; newborn screening and tyrosine supplementation prevent symptoms.

Jacques mutation drives polycythemia vera to overproduce red blood cells, causing hyper viscosity and hypertension, aquagenic pruritus, decreased EPO, and myelofibrosis or leukemia; treat with hydroxyurea or phlebotomy.

explains how a bacterium isolates an antibiotic resistance gene by transposition and transfers it via the sex palace mating bridge from an f-positive donor to an f-negative recipient during conjugation.

Explore how bacteriophages infect bacteria, inject genomes, and drive genetic change through generalized and specialized transduction, including lytic and lysogenic pathways and traits like exotoxin production and antibiotic resistance.

Discover how bacteria extract DNA to form plasmids, enabling efficient, repetitive use, and how transposition reinserts plasmid DNA into the chromosome for sharing among bacteria.

Explain antigenic shift via reassortment when two viruses in one cell produce progeny that can infect both cell types; note the four reassortment groups and compare to drift.

Explore virulence factors: protein A of Staphylococcus aureus blocks phagocytosis; protein M mediates mimicry; IgA protease; injectisome type three secretion; serpentine cord factor with granuloma; sulfatides; K capsule.

Identify acute lymphoblastic leukemia in children aged 2–5, with b-cell predominance (80%) or t-cell predominance, thymus enlargement with superior vena cava syndrome, and cd10, cd19, cd20 markers, plus t(12;21) translocation.

Understand basal cell carcinoma, the most common skin cancer, often arising from sun exposure and presenting with an ulcerated center, rolled borders, and telangiectasias.

Learn how tumor grading assesses cellular differentiation to guide prognosis, and how TNM staging evaluates tumor size, nodular involvement, and metastasis, with clinical, pathological, or symptom-based modifiers.

Explore cancer treatment terminology: adjuvant therapy adds cyclophosphamide to doxorubicin, neoadjuvant therapy precedes standard therapy, and induction, consolidation, maintenance, and salvage therapies describe dosing sequences.

Explore carcinogens such as aflatoxin, vinyl chloride, and benzene, and their links to liver, bladder, thyroid, and lung cancers, including smoking and alcohol effects.

Explore how the diaphysis hosts Ewing sarcoma and osteoid osteoma, the metaphysis osteosarcoma, and the epiphysis giant cell tumors, with onion skin patterns and biopsy-based diagnosis, plus resection, chemo, radiotherapy.

Learn how melanoma is a skin cancer with metastasis risk from sun exposure and tanning beds. Recognize ABCD criteria, BRAF mutations, and vertical depth guiding prognosis and vemurafenib therapy.

Multiple myeloma drives hyperactive bone marrow plasma cells that overproduce nonfunctional IgG and IgA, causing infections, renal Bence Jones proteins, rouleaux formation, anemia, and lytic bone lesions.

Cover oncogenic microbes and their cancer links, including Hepatitis B and C, Helicobacter pylori, Clonorchis, HIV, herpes, Schistosoma, Epstein-Barr virus, HPV, and genital warts.

Pheochromocytoma is an adrenal medullary tumor from chromaffin cells that secretes epinephrine and dopamine; diagnose with urinary metanephrines and chromogranin, treat with alpha blockade, then beta blockade, then removal.

Identify squamous cell carcinoma as the second most common skin cancer. Link it to sun exposure, immunosuppressive drugs, trauma, burns, and arson exposure.

Explore adrenergic receptors and their catecholamine triggers, and how alpha and beta blockers modulate vascular tone, respiration, and metabolic responses in hypertension, asthma, and impotence.

Examine how diverse autoantibodies target desmosomes, hemidesmosomes, basement membrane, and endocrine and neural targets, driving diseases such as pemphigus vulgaris, Hashimoto, Graves, myasthenia gravis, Goodpasture, and antiphospholipid syndrome.

Identify key biochemistry terms such as kinase, phosphorylase, phosphatase, dehydrogenase, hydroxylase, mutase, and carboxylase, and explain their roles in phosphate addition and removal, ATP use, NADH/FAD, biotin, and rate-limiting enzymes.

Examine how epithelial cell junctions connect skin cells to the basement membrane. Learn about tight, adherence, desmosomes, and gap junctions, and related diseases like pemphigus vulgaris and bullous pemphigoid.

Examine the four hypersensitivity types, from type I IgE-mediated anaphylaxis with histamine release to type IV T cell–mediated delayed responses, with examples like contact dermatitis and serum sickness.

Explain how lead binds sulfur hydrate groups to inhibit ferrochelatase and ala dehydratase, causing basophilic stippling and microcytic hypochromic anemia in red blood cells.

Explore how active and passive immunity divide into natural and artificial forms, including natural infection–driven antibody development, gestational maternal antibodies, vaccines, and monoclonal antibodies.

Explore red blood cell morphologies such as acanthocytes, macrocytes, bite cells, basophilic stippling, echinocytes, elliptocytosis, target cells, spherocytes, sickle cells, schistocytes, and sideroblasts, and their disease associations.

Analyze a case where a virus transitions from an RNA genome to double-stranded DNA and back to RNA, mirroring HIV's replication with reverse transcriptase.

analyze a lead poisoning case in a six-year-old, noting irritable behavior, abdominal pain, weight loss, white metaphyseal lines, and microcytic hypochromic anemia, with inhibition of ferrochelatase and ala dehydratase.

This case demonstrates bacterial transformation, where E. coli takes environmental DNA to acquire vancomycin resistance, blocked by a DNA lysing agent that prevents uptake.