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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. these transport proteins - when concs are high enough...
Paracrine (local) - endocrine (longer distance)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Somatic nervous sys - autonomic nervous sys
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

2. Anterior eye
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... ...
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
'The hepatic portal vein is not a true vein - because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver.'
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

3. pancreatic amylase is much stronger than
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
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Salivary amylase; both hydrolyze glycosidic linkages

4. extracellular matrix formed mainly of...
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
The renal corpuscle
Meiosis creates germ cells
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

5. Posterior pituitary hormones (Small Peptides)
Glands w/ducts: Exocrine glands
Oxytocin and ADH (aka vasopressin)
Water flows from the tubule - concentrating the filtrate - raising BP
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

6. examples of different cavities... (compartments for viscera)
Micelles; micelles (made of bile) go back and forth between brush border and chyme
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Fallopian tubes
Growth 1 (G1) phase: STRUCTURAL ProteinS - ENZYMES; This is a very active period - where the cell synthesizes its vast array of proteins - including the enzymes and structural proteins it will need for growth. In G1 stage each of the chromosomes cons

7. Adrenal cortex hormones (STEROIDS)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Within the paravertebral ganglion - running parallel to spinal cord
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

8. pancreatic enzymes are zymogens
Regulated by gastrointestinal horms
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
'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

9. How does duod deal with hi HCl from stom
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Determined by whether in front of or behind the lens
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

10. Where does fertilization occur
Fallopian tubes
Glucose and ketone bodies (not from glycogen stores)
Systems (eg digestive system consists of many organs)
Paracrine (local) - endocrine (longer distance)

11. what cannot cross the fenestrations of the renal corpuscle
RBCs - large proteins; What does enter is called the filtrate
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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
Direction of differentiation

12. The bolus (chewing) is digested to what in the stomach
Chyme (by combined activity of exocrine glands)
It targets liver conc of prothrombin - fibrinogen etc
Which is why lactase - maltase - dextrinase - sucrase are on brush border
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

13. motor (efferent) neurons --> VENTRAL
Two perpendicular semicircular canals involved in balance - equilibrium
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Carry signals to musc OR Gland

14. Meiosis II: EQUATIONAL DIVISION
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
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
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

15. euk cell has two principal sides
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Zygotes are diploid
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Lumen (ie continuous w/body cavity) and cytosol

16. A contracted iris occurs with what kind of stimulation
Lumen (ie continuous w/body cavity) and cytosol
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Sympathetic: dilates pupil (for night hunting)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

17. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

18. How does birth control work?
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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

19. Tight junctions
Sympathetic: dilates pupil (for night hunting)
Contain capillary network - lymph vessels (lacteals)
Form barrier to extracellular fluid
Testosterone and estradiol

20. Failure of apoptosis can result in
Vitamin K - b12 - thiamin - riboflavin
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

21. fructose enters enterocyte by
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
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Facilitated diffusion: no symport w/ secondary transport

22. thyroid hormones: Not All One Kind of HORM
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Testosterone and estradiol
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

23. Aldosterone (sodium uptake - potassium secretion)
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)
Direction of differentiation
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

24. How do monoglycerides and ffas get to brush border?
The wall of the body or of a body cavity or hollow structure
Vitamin K - b12 - thiamin - riboflavin
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

25. oxytocin
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Most absorption occurs in sm intestine
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Ammonia; must be converted to urea by liver and excreted in urine by kidney

26. Different tissues working together
Lumen (ie continuous w/body cavity) and cytosol
Outermost layer of blood vessel
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Organs

27. alpha - amylase in the mouth digests what kind of bond
Peripheral nervous sys
Abdominal cavity - which is coated in serous fluid
Alpha 1-4 and 1-6 (branching) glycosidic linkages
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

28. 3 phases of menstrual cycle
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
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)
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

29. How is glucose absorbed in sm intest
Meiosis creates germ cells
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
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
Prod of steroid hormones in testes - ovaries

30. Think of spinal cord injury
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.
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
AAs can be burned for energy or converted to fat for storage
Glycosaminoglycans - prots - AAs - lipids

31. Which fats are not absorbed like this
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Albumin increases osmolarity of blood; increases osmotic pressure
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Corpus luteum degrades into corpus albicans

32. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
Chyme (by combined activity of exocrine glands)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

33. What is gastric acid?
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
HCl; secreted by parietal cells under stim by gastrin
Oxytocin and ADH (aka vasopressin)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

34. liver and blood glucose...
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
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Most absorption occurs in sm intestine

35. The apical side of the villi...
Chyme (by combined activity of exocrine glands)
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
Faces the lumen

36. bile + fat forms
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Ventrally (picture skeletal vertebrae)
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

37. Mucus - digestive enzymes released thru
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
Glands w/ducts: Exocrine glands
Beta cells
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

38. trypsin is secreted by
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Glucose
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

39. 'Cell bodies of somatic motor neurons are located in....'
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Carry signals to musc OR Gland
Glucose and ketone bodies (not from glycogen stores)
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

40. How does water cross the apical membrane
Regulated by gastrointestinal horms
Mostly reabsorbed to liver
Conjunction of cell body w/axon
Thru tight junctions by favorable osmotic gradient

41. E storage per unit mass
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
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Peptides

42. interneurons
Outermost layer of blood vessel
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
HCl; secreted by parietal cells under stim by gastrin
Transfer signals from neuron - neuron; 90% of neurons are interneurons

43. when cells hit their limit for prot storage...
AAs can be burned for energy or converted to fat for storage
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

44. At post - two weeks ovulation
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Corpus luteum degrades into corpus albicans
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

45. Exocrine GlandS: stomach
- 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
- 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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

46. What is the net effect of the distal tubule
Break down TAGs to monoglycerides and free fatty acids
Prod of steroid hormones in testes - ovaries
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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

47. Sensory neuron cell bodies vs. somatic motor cell bodies
Primitive streak - which consists of cells of the MESODERM ****
Has memb - bound organelles - etc...
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

48. Some PNS nerves are found in brain - spinal cord
Chyme (by combined activity of exocrine glands)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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)

49. serous membranes have a viscera - facing layer and a body wall - facing layer
Lower blood pH
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
The renal corpuscle
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**

50. glucagon secreted by
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi