Tag: physician

Anemia Study Guide Notes: Vocabulary, Types of Anemia, Heme Breakdown, and Anemia of Chronic Disease [Biology, MCAT, USMLE]

In this study guide, we review anemia, types of anemia, formulas, vocabulary, heme breakdown, and anemia of chronic diseases.

Immunology 101: Stages of B-cell Development [Biology, MCAT, USMLE Medicine]

B-Cell Development Stages. stem cell –> early pro-B cell –> late pro-B cell –> large pre-B cell –> [1st checkpoint – selects for functional heavy chains] –> small pre-B cell –> [2nd checkpoint – select for functional light chains] –> Immature B cell (has surface IgM, no surface IgD). Somatic recombination is the process in which different individual gene segments of the H (heavy) chain combine with rearranged gene segments of the L (light) chain. The enzymes responsible for somatic recombination are the recombinase enzymes (RAG-1 and RAG-2) that recognize specific sequences (RSS) or recombination signal sequences. RAG-1 and RAG-2 are only expressed in B or T lymphocytes. These specific sequences recognized by the RAG-1 or RAG-2 enzymes are either a 1) heptamer or 2) nonamer. The heptamer literally contains 7 nucleotides, and the nonamer literally contains 9 nucleotides. There are typically 12 or 23 nucleotides in between the heptamer and nonamer to separate them.

Gastrointestinal System: Pathophysiology of Diseases and Cancers [Biology, MCAT, USMLE]

In this quick and easy guide, learn about Gastrointestinal System: Pathophysiology of Diseases and Cancers [Biology, MCAT, USMLE]. Topics include heptobiliary disease, understanding liver functions and cirrhosis, liver function tests, causes of liver injury, alcoholic hepatitis, NAFLD, NASH, viral hepatitis, autoimmune hepatitis, durg-induced liver injury, hereditary hemochromatosis, Wilson’s disease, Alpha-1 Antitrypsin Deficiency, PSC, PBC, cholelithiasis, cholecystitis, cholangitis, hepatocellular carcinoma, and more.

Biology 101: Gel Electrophoresis

In this educational lesson, we learn about the purpose of gel electrophoresis and how gel electrophoresis works. Gel electrophoresis in a method of separating DNA. It can be used to separate the size of DNA, RNA, and protein. You first start with a variety of different fragments of DNA all mixed together. The gel is a porous matrix like a sponge and separates the DNA based on two main things: 1) size and 2) charge. The charge on DNA is what makes it move through the gel. DNA is a negatively charged molecule, so it will move towards a positive charge.