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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. 80-90% fat absorbed this way
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Membrane - bound - endocytosed bodies
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

2. mucus cells line the stomach...
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Alpha 1-4 and 1-6 (branching) glycosidic linkages
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
Corpus luteum degrades into corpus albicans

3. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
Adrenal gland -- AC: steroids (cortisol - aldosterone); AM: catecholamines (epi - norepi); Islets of langerhans: peptides (insulin/glucagon) ANTAGONISTS: calcitonin (thyroid - peptide lowers Ca in blood); parathyroid hormone - peptide - vitamin D pat
Salivary amylase; both hydrolyze glycosidic linkages
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
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

4. micelles vs liposomes
Sorts - modifies - concentrates proteins from the ER
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Liposome has phospholipid bilayer
Increases blood Calcium

5. After meiosis II - Female

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6. pancreatic enzymes are zymogens
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

7. How does glycogen compare to starch
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

8. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

9. Gastrin from G cells stims parietal cells...
Peptides
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Ups bicarbonate secretion by pancreas; raises pH to 6.0

10. How does blood sugar move into tissues?
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
Amino acid monomers - di - tri absorbed by symport at enterocyte; each AA has slightly diff mechanism; from entero - AAs enter bloodstream where they are taken up by all cells of the body - esp the liver by active or facilitated transport (NEVER PASS
Facilitated diffusion from hi to lo conc
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

11. little by little chyme is squirted out thru pyloric sphincter
Regulated by gastrointestinal horms
Ventrally (picture skeletal vertebrae)
Corpus luteum degrades into corpus albicans
Somatic nervous sys - autonomic nervous sys

12. Exocrine GlandS: stomach
Vitamin K - b12 - thiamin - riboflavin
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
- 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
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

13. How do parietal cells work ** (involves CO2)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

14. How do nutrients move?
'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
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Form barrier to extracellular fluid
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

15. Kidney physiology...

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16. what happens when glycogen stores are saturated and blood sugar remains high?
Uncontracted: parasymp (eg opoid use)
Glucose and ketone bodies (not from glycogen stores)
Below hypothalamus
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

17. What does portal vein do
- 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
All carbs absorbed at enterocytes are carried to liver by portal vein
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
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

18. Three stages of the menstrual cycle
Prod of steroid hormones in testes - ovaries
Ventrally (picture skeletal vertebrae)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

19. Path of food entering body...
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Many modern drugs are ligands for GPCRs
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
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

20. 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
Glucose
- 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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

21. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Digestion
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
Fructose is a structural isomer of glucose
Moves down thru esophageal sphincter

22. amylase acts where on carbs
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Glucose = aldose fructose = ketose
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

23. 80% of end product of carbohydrate metabolism is...
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
Somatic nervous sys - autonomic nervous sys
Interstitial fluid (eg prostaglandins - cytokines)
Glucose

24. What is feces composed of...
Facilitated diffusion: no symport w/ secondary transport
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
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
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

25. Ovum development is halted At what stage until fertilization...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Membrane - bound - endocytosed bodies
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Direction of differentiation

26. position of AP...
Below hypothalamus
Alpha 1-4 and 1-6 (branching) glycosidic linkages
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
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

27. lysosome pH
Somatic nervous sys - autonomic nervous sys
5
Ganglion
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

28. STOMACH: no absorption
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Conjunction of cell body w/axon
Salivary amylase; both hydrolyze glycosidic linkages
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

29. Glycogenolysis/gluconeogenesis
Prod of steroid hormones in testes - ovaries
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
- 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
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti

30. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Systems (eg digestive system consists of many organs)
The renal corpuscle
Gastrulation occurs: formation of three primary germ layers = differentiation
Increases solute conc and osmotic pressure of the ***medulla

31. What if large intestine isn't working well
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc

32. What is the function of the loop of Henle
Glands w/ducts: Exocrine glands
Outermost layer of blood vessel
Increases solute conc and osmotic pressure of the ***medulla
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

33. What are phagosomes
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Salivary amylase; both hydrolyze glycosidic linkages
Membrane - bound - endocytosed bodies

34. How does water cross the apical membrane
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Thru tight junctions by favorable osmotic gradient

35. FLAT PG: prolactin
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Urine enters kidneys via artery - to arteriole - capillary bed - glomerulus - Bowman's capsule - proximal tubule - loop of henle (concentrates medulla) - distal tubule - collecting tubule - collecting duct (renal pyramids) - renal calyx - renal pelvi
It targets liver conc of prothrombin - fibrinogen etc

36. what else is located in the inner ear (not directly related to auditory)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
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)
Has memb - bound organelles - etc...
Two perpendicular semicircular canals involved in balance - equilibrium

37. cAMP - cGMP - calmodulin...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

38. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Testosterone upon stim by LH
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

39. interneurons
Corpus luteum degrades into corpus albicans
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Transfer signals from neuron - neuron; 90% of neurons are interneurons

40. Different tissues working together
RBCs - large proteins; What does enter is called the filtrate
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
Organs
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

41. insulin secreted by
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Increases solute conc and osmotic pressure of the ***medulla
Beta cells

42. Determination is different than differentiation
Glucose
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Fructose is a structural isomer of glucose

43. calcitonin

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44. bundles of collecting ducts are called
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)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
About 7.2

45. What are the memb - bound enzymes of the brush border?
Glucose
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine

46. PNS review: SAME DAVE
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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... ...
Systems (eg digestive system consists of many organs)
Glucose

47. The bolus (chewing) is digested to what in the stomach
RBCs - large proteins; What does enter is called the filtrate
Oxytocin and ADH (aka vasopressin)
Chyme (by combined activity of exocrine glands)
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

48. main point of fat transport...
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

49. What is a toxic byproduct of gluconeogenesis from proteins
Outermost layer of blood vessel
- 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
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Ammonia; must be converted to urea by liver and excreted in urine by kidney

50. Alpha - amylase found where
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
In mouth - breakdown of starch into polysaccharides
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Gonadotropin releasing hormone - GnRH