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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. Thus inhibiting parietal cells could do What to blood pH
Nitrogen
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
Membrane - bound - endocytosed bodies
Lower blood pH

2. signal transduction occurs only in
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Glucose
Eukaryotes
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

3. What testosterone released by secondary follicle by LH stim is converted to...
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste
Contain capillary network - lymph vessels (lacteals)
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.

4. microvilli: increase SA of enterocyte; have hi conc of digestive enzymes

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5. How is the follicle developed during oogenesis
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Salivary amylase; both hydrolyze glycosidic linkages
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

6. 80-90% fat absorbed this way
Corpus luteum degrades into corpus albicans
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
In gastric pits; secretions combine into gastric juice
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

7. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
Smooth ER
- filtration occurs at the fenestrations of the renal corpuscle - most reabsorption and secretion occur in the proximal tubule - medulla is concentrated in the loop of henle - sodium and calcium are reabsorbed in the distal tubule -->collecting tubul
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Combined via conjunction of pancreatic duct and common bile duct; common bile duct originates at **cystic duct where gall bladder and liver secretions combine ..cystic duct+common bile duct+pancreatic duct --->into duodenum

8. What is the endothelium?
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Inner lining of circulatory system
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

9. FLAT PG: ACTH
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Fovea (highest amount of cones)
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

10. Think of spinal cord injury
Fovea (highest amount of cones)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Paracrine (local) - endocrine (longer distance)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

11. Which fats are not absorbed like this
Interstitial fluid (eg prostaglandins - cytokines)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Homologous chromosomes separate - migrate towards opposite poles/centrioles

12. remaining secondary follicle becomes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
5
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
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)

13. What is the net effect of the distal tubule
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Lowers osmolarity of the filtrate (IONS - Water Are Taken Back Up By The Kidney)--->at the end of the distal tubule (the collecting tubule) is where aldosterone acts - along with the JGA
Sorts - modifies - concentrates proteins from the ER

14. Peritoneal refers to...
Inner lining of circulatory system
Fovea (highest amount of cones)
Abdominal cavity - which is coated in serous fluid
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

15. medium for paracrine hormones
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Interstitial fluid (eg prostaglandins - cytokines)

16. Leydig cells produce
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Testosterone upon stim by LH
Stims release of tyrosine - derived horms T3/T4 (increase basal metabolic rate); TSH increases thyroid cell size - number - rate of T3/T4 synth -----> thus - iodine deficiency causes swollen thyroid due to lack of neg feedback onto TSH in anterior pi

17. Between meals most fats appear in blood as
Signal picked up by sensory cell - goes thru dorsal root ganglion to SC - may continue to interneurons in brain or simple reflex arc in SC - brain integrates info and decides (voluntary) response - travels back down SC to appropriate ventral root gan
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Sympathetic: dilates pupil (for night hunting)

18. albumin has What affect on blood osmotic pressure
Interstitial fluid (eg prostaglandins - cytokines)
90-140 mg/dl
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
Albumin increases osmolarity of blood; increases osmotic pressure

19. Creating gradients requires what?
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Lots of energy; eg neurons have hi glucose need for 3Na out 2K in ATPase; stomach epithel tiss needs E for parietal cells to pump protons into lumen and bicarbonate into blood
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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

20. After meiosis II - Female

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21. What is the pH at the entrance to the duodenum
Presence of fat - prot in duodenum causes release of **gastric inhibitory peptide**; result is slower stomach contraction; slower emptying into duod thru pyloric sphincter (slower chyme secretion); more time to properly digest - absorb nutrients
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

22. What is somatostatin
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
In mouth - breakdown of starch into polysaccharides
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Facilitated diffusion: no symport w/ secondary transport

23. Some epithelial cells are... others...
Membrane - bound - endocytosed bodies
- 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
Facilitated diffusion from hi to lo conc
Homologous chromosomes separate - migrate towards opposite poles/centrioles

24. physiology of gall bladder - liver and pancreatic secretions
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Combined via conjunction of pancreatic duct and common bile duct; common bile duct originates at **cystic duct where gall bladder and liver secretions combine ..cystic duct+common bile duct+pancreatic duct --->into duodenum
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

25. Embryology
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
Food is digested from mouth to stomach (denaturation by gastric acid - digested by pepsin) to duodenum (more digestion); then absorption occurs in jejunum and ileum
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

26. What is a plasmalogen?
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

27. Where are these exocrine glands located
In gastric pits; secretions combine into gastric juice
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt
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

28. in the presence of ADH what happens to movement of water across nephron membr
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
AAs can be burned for energy or converted to fat for storage
Water flows from the tubule - concentrating the filtrate - raising BP
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

29. Difference between euk and prok flagella
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Processes: axons - dendrites
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Thru tight junctions by favorable osmotic gradient

30. therefore - How does plasma leave capillary at the renal corpuscle

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31. Both divisions (somatic - autonomic) of PNS consist of...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Sensory (afferent - dorsal) - motor (efferent - ventral)
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

32. Stomach has no lacteals
Most absorption occurs in sm intestine
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

33. Meiosis I Telophase I
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Alpha 1-4 and 1-6 (branching) glycosidic linkages

34. Different organs working together
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Systems (eg digestive system consists of many organs)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

35. at lo blood sugar...
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

36. smooth ER main function
Moves down thru esophageal sphincter
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

37. Gastrulation: ectoderm/mesoderm/endoderm
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

38. How does duod deal with hi HCl from stom
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt
Beta cells
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Glucose and ketone bodies (not from glycogen stores)

39. keep in mind that enterocyte is like a regular euk cell
Has memb - bound organelles - etc...
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Glucose and ketone bodies (not from glycogen stores)
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

40. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
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.
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

41. chylomicron concentration in blood after meal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
AAs can be burned for energy or converted to fat for storage
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
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

42. energy source of neurons
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)
Glucose and ketone bodies (not from glycogen stores)
5
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

43. Induction affects...
Chyme (by combined activity of exocrine glands)
Direction of differentiation
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
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

44. What is the mesentery?
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... ...
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Signal picked up by sensory cell - goes thru dorsal root ganglion to SC - may continue to interneurons in brain or simple reflex arc in SC - brain integrates info and decides (voluntary) response - travels back down SC to appropriate ventral root gan

45. when cells hit their limit for prot storage...
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Meiosis creates germ cells
AAs can be burned for energy or converted to fat for storage

46. Adrenal cortex hormones (STEROIDS)
Water flows from the tubule - concentrating the filtrate - raising BP
Form barrier to extracellular fluid
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Faces the lumen

47. Gastrin from G cells stims parietal cells...
Vitamin K - b12 - thiamin - riboflavin
Sensory (afferent - dorsal) - motor (efferent - ventral)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
About 7.2

48. Interaction of corpus luteum/placenta
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Many modern drugs are ligands for GPCRs
Glucose = aldose fructose = ketose
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

49. interneurons
Moves down thru esophageal sphincter
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
'Increased absorptive area is useful because digested nutrients (including sugars and amino acids) pass into the villi through diffusion - which is effective only at short distances. In other words - **increased surface area (in contact with the flui
Transfer signals from neuron - neuron; 90% of neurons are interneurons

50. Liver Functions
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Meiosis creates germ cells
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
Oxytocin and ADH (aka vasopressin)