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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. In IBS - What is defective

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2. What are phagosomes
Membrane - bound - endocytosed bodies
visual (rhodopsin is receptor - derived from Vit A; conformation change occurs with photon to hyperpolarize rod cells; cone cells use photopsin for receptor) - olfactory - mood (NTs targeted by antidepressants - antipsychotics - etc; GABA is inhibit
Peptide; responsible for luteal surge (driven in part by LH-->testosterone -->estradiol -->LH positive feedback); results in ovulation (follicle bursting) - releasing egg into fallopian tube/oviduct
Hormones --->stimulate exocrine glands - acetylcholine (increases all secretion of gastric pits) - gastrin (from G cells) - histamine (increases HCl secretion of parietals) ...Ach increases all secretions; gastrin increases gastric acid (parietal cel

3. components of interstitial fluid
Regulated by gastrointestinal horms
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Stores blood: when expanded liver serves as blood reservoir for body - filters blood: Kupfer cells phagocytize bacteria picked up from intestines - destroys bad RBCs: also done by Kupfer cells - detoxifies blood: detoxified chemicals are excreted eit
Glycosaminoglycans - prots - AAs - lipids

4. What does peptic refer to in general
Digestion
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

5. Different tissues working together
Organs
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

6. Some epithelial cells are... others...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Nitrogen
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
- enterocytes w/ *microvilli brush border*: membrane - bound digestive enzymes for carbs - fats - nucleic acids - goblet cells: secrete mucous - Deep between villi are the intestinal exocrine glands - the crypts of Lieberkuhn - which secrete pH 7.6 i

7. What controls release of LH - FSH from anterior pituitary
Inner lining of circulatory system
Gonadotropin releasing hormone - GnRH
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

8. mucus cells line the stomach...
Below hypothalamus
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

9. Where would materials slated for digestion go?
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Lysosome
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

10. Aldosterone (sodium uptake - potassium secretion)
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Steroid; target tissue is distal convoluted tubule of nephron and collecting duct; increases blood mineral concentration; potassium - protons secreted (blood pH increases); sodium - chloride reabsorbed (BP increases)
Thru tight junctions by favorable osmotic gradient
'Microvilli function as the **primary surface of nutrient absorption in the gastrointestinal tract**. Because of this vital function - the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compoun

11. lining of abdominal cavity=
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Moves down thru esophageal sphincter
Estradiol

12. How is the follicle developed during oogenesis
Gastrulation occurs: formation of three primary germ layers = differentiation
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Follicular phase: primary - secondary - ovulation (1 week) luteal phase: ovulation - thickening of uterine lining w/corpus luteum secretion - corpus luteum degrades (2 weeks) flow: shedding of uterine lining (4 days)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

13. Human chorionic gonadotropin...
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
vitreous humor - retina - fovea
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

14. large intestine E. coli aid absorption of...
Estradiol
Stomach - sm intest - spleen - pancreas from the hepatic portal vein...all blood that passes thru liver go thru flattened spaces called the ***hepatic sinusoids -->hepatic vein --->vena cava
Many modern drugs are ligands for GPCRs
Vitamin K - b12 - thiamin - riboflavin

15. what else is located in the inner ear (not directly related to auditory)
Two perpendicular semicircular canals involved in balance - equilibrium
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Salivary amylase; both hydrolyze glycosidic linkages

16. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
Smooth ER
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Carbohydrates are highly hydrated: one water mol per carbon mol - fats are anhydrous: contain more reduced carbons per unit mass - altogether fats contain 6X energy per unit mass

17. What if large intestine isn't working well
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Salivary amylase; both hydrolyze glycosidic linkages
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

18. What is feces composed of...
Homologous chromosomes line up w/ attachment of spindle fibers/microtubule polymers to centromeres via kinetochores; identical in appearance under light microscope to metaphase of mitosis
75% water/ 25% solid mass: of that solid mass: 10-20% fat = phospholipid bilayer of bacteria - slough - off enterocytes ie stomach lining (must be constantly rebuilt) 10-20% inorganic material 30% roughage = fiber = cellulose (indigestible) 2-3% prot
Collection of cell bodies; cell processes project out from both ends of ganglion; synapses with interneuron in spinal cord on one end and sensory receptor on other
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

19. What is secreted into filtrate by cells of the proximal tubule?
Testosterone upon stim by LH
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Increases solute conc and osmotic pressure of the ***medulla
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

20. Path of food entering body...
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Glands w/ducts: Exocrine glands

21. insulin secreted by
Low because AAs are immediately used in translation
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Beta cells

22. What is the net effect of the loop of Henle
Increases blood Calcium
REABSORPTION: draws off water and ions - increases osmolarity of the medulla while slightly lowering osmolarity of the filtrate -->medulla must have hi osmolarity in order to concentrate urine at collecting duct (final step in nephron)
Only musc and esp ** liver can store large amounts
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

23. What is main difference is signal transmission in nicotinic vs muscarinic?
Glands w/ducts: Exocrine glands
Transfer signals from neuron - neuron; 90% of neurons are interneurons
***nicotinic is ionotropic; muscarinic is GPCR
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

24. gametic life cycle
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Ganglion
Chyme (by combined activity of exocrine glands)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

25. The esophageal sphincter is...
Stomach - sm intest - spleen - pancreas from the hepatic portal vein...all blood that passes thru liver go thru flattened spaces called the ***hepatic sinusoids -->hepatic vein --->vena cava
Peptide; responsible for luteal surge (driven in part by LH-->testosterone -->estradiol -->LH positive feedback); results in ovulation (follicle bursting) - releasing egg into fallopian tube/oviduct
Normally contracted
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

26. Difference between euk and prok flagella
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Monitors filtrate pressure in the distal tubule; has specialized cells (granular cells) that secrete an enzyme (**renin); renin initiates regulatory cascade that produces angiotensin I - II - III that stim adrenal cortex to secrete aldosterone... ...

27. spermatogonia arise from
Epithelial tissue near semniferous tubules
- enterocytes w/ *microvilli brush border*: membrane - bound digestive enzymes for carbs - fats - nucleic acids - goblet cells: secrete mucous - Deep between villi are the intestinal exocrine glands - the crypts of Lieberkuhn - which secrete pH 7.6 i
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Determined by whether in front of or behind the lens

28. parathyroid hormones
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Liposome has phospholipid bilayer
Digestion

29. Blastocyst
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach
The wall of the body or of a body cavity or hollow structure

30. What does lipase attack exactly
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

31. medium for paracrine hormones
Facilitated diffusion: no symport w/ secondary transport
Interstitial fluid (eg prostaglandins - cytokines)
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

32. Sensory - motor neurons are part of which nervous system
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Normally contracted
Peripheral nervous sys

33. On what surface of the retina is the eye most sensitive
Processes: axons - dendrites
Raises BP; causes collecting ducts at end of nephron (kidney) to become permeable to water - which concentrates urine; coffee - beer block ADH and increase urine volume
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu
Fovea (highest amount of cones)

34. Meiosis II: EQUATIONAL DIVISION
Prophase II: no crossing over b/c there are no homologous chromosomes; nuclear envelope dissolves Metaphase II: chromosomes line up at metaphase plate Anaphase II: sister chromatids separate - migrate to opp poles Telophase II: nuclear envelope reap
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Smooth ER
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

35. Meiosis I Anaphase I
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Homologous chromosomes separate - migrate towards opposite poles/centrioles
An endogenous morphine
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

36. Seen in lysosomal storage diseases
Many modern drugs are ligands for GPCRs
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

37. Meiosis I Telophase I
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Creates one ovum (23 N) and three polar bodies

38. Adrenal cortex hormones (STEROIDS)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant
Peripheral nervous sys

39. How is glucose absorbed in sm intest
via symport - secondary transport (ie by pre - established - ATP- intensive) with Na gradient into enterocyte......with no Na gradient (ie without ATP) carbohydrate monomers could not be transported in
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

40. A contracted iris occurs with what kind of stimulation
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
Sympathetic: dilates pupil (for night hunting)
Form barrier to extracellular fluid

41. position of AP...
Conjunction of cell body w/axon
Below hypothalamus
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

42. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Gastrulation occurs: formation of three primary germ layers = differentiation
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
Work together to emulsify fats: bile works as a detergent to increase SA of the fat; increased SA gives more substrate to lipase for digestion
- parietal cells (**oxyntic= hi oxygen consumption - hi E??): have hi conc mito; need lots of energy to create proton gradient; thus - responsible for extremely harsh pH conditions in stom; denaturing conditions - chief cells (peptic): synthesize pep

43. Anatomy of the villi
Gastrulation occurs: formation of three primary germ layers = differentiation
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
via symport - secondary transport (ie by pre - established - ATP- intensive) with Na gradient into enterocyte......with no Na gradient (ie without ATP) carbohydrate monomers could not be transported in
Contain capillary network - lymph vessels (lacteals)

44. when thinking of proteins - think
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Nitrogen
AAs enter bloodstream for uptake by all cells (esp liver). If intracellular prot conc is at max AAs can be converted to fats or glucose via gluconeogenesis. Byproduct of gluconeo is ammonia --->urea.
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

45. extracellular matrix formed mainly of...
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve
Glands w/ducts: Exocrine glands
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

46. ligands are the messenger compounds that target secondary messenger systems on effectors
Regulated by gastrointestinal horms
Gastrulation occurs: formation of three primary germ layers = differentiation
Many modern drugs are ligands for GPCRs
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

47. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Systems (eg digestive system consists of many organs)
Glands w/ducts: Exocrine glands
Gastrulation occurs: formation of three primary germ layers = differentiation
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

48. Sensory neuron cell bodies vs. somatic motor cell bodies
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Inner lining of circulatory system
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Ventrally (picture skeletal vertebrae)

49. thyroid hormones: Not All One Kind of HORM
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Secondary oocyte (stim'd by LH stimulation of theca cells causing release of testosterone - converted to estradiol; eventually brings about luteal surge -->EQUATIONAL DIVISION-->ovum released during ovulation into fallopian tube; burst follicle becom
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
REABSORPTION: draws off water and ions - increases osmolarity of the medulla while slightly lowering osmolarity of the filtrate -->medulla must have hi osmolarity in order to concentrate urine at collecting duct (final step in nephron)

50. bundles of collecting ducts are called
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Zygote (fertilization in fallopian tubes); morula (up to 8 cells - undifferentiated ie totipotent); blastocyst (4+ days - implants into uterus; HCG secretion stims corpus luteum; gradually placenta replaces HCG as estrogen/progest source; cells not t
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
via symport - secondary transport (ie by pre - established - ATP- intensive) with Na gradient into enterocyte......with no Na gradient (ie without ATP) carbohydrate monomers could not be transported in