Formative

• Alcohol affects the body’s glucose metabolism by blocking synthesis of glucose through gluconeogenesis, causing hypoglycemia.
• Alcohol dehydrogenase produces NADH when alcohol is broken down, giving the body a false sense of energy and blocking gluconeogenesis.
• Oligopotent cells are progenitor cells that can differentiate into a few cell types.
• Lineage restricted cell types are a type of tissue specific or restricted cell.
• Tissue specific or restricted cell is a multipotent cell that gives rise to a limited number of lineages.
• Unipotent cells are precursor cells that are committed to forming a single cell type.
• Alcohol increases the body’s sensitivity to insulin, causing a quick “crash” in blood sugar as too much glucose is taken in by cells leading to hypoglycemia.
• Alcohol delays glycogenolysis, leading to longer periods of hypoglycemia with no glycogen breakdown.
• Chronic alcohol ingestion can lead to deficiency in vitamin B1 and other B vitamins, which are required for the enzymatic activity of enzymes involved in glucose metabolism.
• Vitamin B1 is a coenzyme for the pyruvate and alpha keto-glutarate dehydrogenase enzyme complexes in the form of thiamine pyrophosphate.
• Pantothenic acid (vitamin B5) is also a component of coenzyme A, which is used to synthesize acetyl CoA and succinyl CoA.
• Vitamin B2 is a coenzyme for the succinate and alpha keto-glutarate dehydrogenase enzyme complexes in the form of FAD.
• Vitamin B3 is a coenzyme for the malate, isocitrate and alpha keto-glutarate dehydrogenase enzyme complexes in the form of NAD.
• Dietary thiamin is used for the synthesis of its coenzyme thiamine pyrophosphate.
• Acetoacetate is used as a ketone body but also broken down spontaneously into acetone and hydroxybutyrate using the enzyme hydroxybutyrate dehydrogenase.
• By inhibiting CPT-1, malonyl-CoA prevents the entry of fatty acids into the mitochondrial matrix, where they would undergo beta-oxidation to generate acetyl-CoA for energy production.
• Cholesterol is important in the body for plasma membrane, steroid hormone synthesis, bile acid synthesis, and vitamin D3 production.
• The synctiotrophoblast is a multinucleated protoplasmic mass that secretes hydrolytic enzymes which break down the maternal uterine tissue at the implantation site.
• Glucose + Fructose -> sucrose + H2O is a thermodynamically unfavourable reaction that is coupled with ATP hydrolysis, making it negative and thermodynamically favourable.
• Malonyl co-A signals to cells that fatty acids are being synthesized and inhibits Carnitine Acyl Transferase I, an enzyme involved in the transport of fatty acids into the mitochondria for oxidation.
• The phases of fertilization include the passage of sperm through the corona radiata, sperm penetration into the zona pellucida, fusion of plasma membranes, completion of the second meiotic division, formation of the male pronucleus, pronuclei fusion, and formation of the zygote.
• If the concentration of Malonyl-CoA is high in the cytosol, the pathway for fatty acid synthesis is activated and beta oxidation of fatty acids is inactivared.
• TPP is required for the metabolism of glucose and branched-chain amino acids.
• TPP is involved in the decarboxylation of alpha keto-acids.
• TPP is a cofactor for pyruvate dehydrogenase and a-ketoglutarate dehydrogenase in the TCA cycle.
• TPP is also the cofactor for transketolase in the Pentose Phosphate Pathway.
• Many major catabolic, energy producing pathways are dependant on TPP, causing muscle weakness.
• The formation of the primitive streak is marked by the appearance of a thickened band on the epiblast as a result of proliferation and accumulation of epiblast cells on the posterior part of the embryonic disc – cranial end proliferates into the primitive node.
• Cells in this basal layer are pluripotent and give rise to various cell types within the epidermis, including keratinocytes.
• The endoderm of the yolk sac is where the primordial germ cells are formed.
• The yolk sac membrane facilitates the transport of nutrients into the embryo.
• The basal layer cells undergo rapid proliferation and then migrate upward, forming layers of cells.
• Cells migrate from the deep surface of the primitive streak and form a loose network of tissue called the mesenchyme – embryonic connective tissue.
• These later migrate to the gonadal ridges and mature into primary oocytes or spermatogonia.
• The mesoderm extends cranially from the primitive node towards the prochordal plate forming the notochordal process and notochordal canal.
• A narrow primitive groove and a primitive pit appear during the formation of the primitive streak.
• The ectoderm also gives rise to other structures such as the nervous system.
• The basal layer of the epidermis originates from a specialized region of the ectoderm.
• By the middle of the third week, the intraembryonic mesoderm separates the ectoderm and endoderm except at the coacal and oropharyngeal membrane.
• The synctiotrophoblast facilitates the invasion of the blastocyst into the endometrium and secretes human chorionic gonadotrophin (hCG) which stimulates the hormonal activity of the corpus luteum during pregnancy to secrete estrogen and progesterone.