MCAT biology review flashcards
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- lactic acid
- what pyruvate is converted to under anaerobic conditions, uses up 1 NADH and produces water and heat by-products. Reverse process occurs in the liver.
- alcoholic fermentation
- pyruvate converts to ethanol under anaerobic conditions, uses 1 NADH and produces CO2 as a by-product
- digestion of peptides
- protein --> stomach (gastrin stimulates the release of HCl and pepsin(ogen))- peptides --> small intestine (enterokinase, aminopeptidase, dipeptidase)- amino acids/dipeptides --> (active transport) bloodstream and epithelial cells --> ammonia/build new proteins --> ammonia enters urea cycle
- 3 types of hormones
-
1) amino acid based (catecholamines)- act via 2nd messengers/direct regulation of gene expression
2) peptide (ADH, insulin)- 1st messgeners, act via receptors and 2nd messengers
3) steroid (cholesterol derived, sex hormones)- bind to DNA --> transcription of specific genes - erythropoeitin
- secreted by the kidney in response to decreased renal O2 levels --> stimulates bone marrow to produce more RBCs
- estrogen
- stimulates development of female reproductive structures, thickening of endometrium. Secreted by ovarian follicles and corpus luteum.
- progesterone
- secreted by the corpus luteum, stimulates development and maintenance of endometrium.
- intestinal secretions
- maltase, sucrase, lactase, aminopeptidase, dipeptidase, enterokinase (activates trypsinogen), CCK (stimulates release of bile)
- vitamins
-
A, D, E, K = lipid soluble
B, C = water soluble - Bohr Effect
- shift of the Hb binding curve to the right due to increased temperatures, H+ concentration, CO2 (HCO3-) concentration-- in systemic tissues
- blood clotting mechanism
- cut --> thrombopoeitin release + Ca2+ and Vitamin K --> converts prothrombin --> thrombin --> converts fibrinogen --> fibrin --> forms clot
- humoral immunity
-
B lymphocytes, originate in Bone marrow.
1) plasma cells, primary response: produce antibodies /immunoglobulins (IgM, IgA, IgD, IgG, IgE)
2) memory cells: secondary response
Active immunity achieved via antibody production following vaccination.
Passive immunity achieved following natural infection. - point mutation
- one base switched for another
- frame shift
- addition/deletion of one base
- transposon
- mobile piece of DNA, if inserted can cause mutation
- missense
- substitute one amino acid for another
- nonsense
- premature stop codon. Think NO = STOP!
- helicase
- unwinds dsDNA
- SSB proteins
- single strand binding proteins, stabilize ssDNA
- topoisomerase
- prevents "supercoiling of DNA" by breaking and reattaching strands
- blood type
-
codominant system:
1) A has A antigens and anti-B antibodies
2) B has B antigens and anti-A antibodies
3) AB (universal recipient) has A and B antigens, no antibodies
4) O (universal donor) has no antigens but A and B antibodies
Rh+ = has Rh factor: during pregnancy, an Rh- mother can develop anti-Rh antibodies = bad for a 2nd Rh+ baby.
Alleles: IA, IB, i - recombination frequency
- =genetic mapping units. The closer two alleles are, the less likely they are to recombine
- oligodendrocyte
- a type of glial cell that produces myelin in the CNS
- Schwann cells
- a type of glial cell that produces myelin in the PNS
- cell-mediated immunity
-
T cells, produced in the thymus.
1) cytotoxic T cells- direct attack
2) helper T cells- regulate other T and B cells - interferon
- protein produced by cells under viral attack-- diffuse to other cells and prevent spread of virus
- lymphatic system
-
transports excess interstitial fluid (lymph) to keep fluid levels in body constant.
Lymph nodes = swellings along lymph vessels, contain phagocytic cells (leukocytes) that filter lymph and remove/destroy foreign particles - functions of the liver
- regulate blood glucose levels (insulin/glucagon), process nitrogenous wastes (amino acids --> hepatic portal vein --> deamination --> ammonia --> urea), detoxification, store iron and Vitamin B12, destroy old RBCs, make bile and other blood proteins, defense, and beta-oxidation of fatty acids to ketones
- ADH/vasopressin
- produced in the hypothalamus and stored in the posterior pituitary, increases water absorption, inhibited by alcohol/caffeine
- adrenal cortex
- produces aldosterone (increases Na+ absorption and water absorption by osmosis), regulated by renin-angiotensin system.