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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. gametes are haploid
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Increases surface area of food ball (bolus)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Zygotes are diploid

2. Local vs long - distance mediators
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
'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
Paracrine (local) - endocrine (longer distance)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

3. Gastrin from G cells stims parietal cells...
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
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

4. The esophageal sphincter is...
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Normally contracted
- 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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

5. PNS nerve signal
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Interstitial fluid (eg prostaglandins - cytokines)

6. In other words...
Pancreatic duct (made of acinar cells?)
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
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
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

7. Beta - oxidation in liver produces...
Primitive streak - which consists of cells of the MESODERM ****
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
vitreous humor - retina - fovea

8. position of AP...
Ganglion
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
Below hypothalamus
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

9. What kind of cells make up epithel tiss of stom - then sm intest?
Below hypothalamus
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

10. What is a nerve? (PNS)
Systems (eg digestive system consists of many organs)
HCl; secreted by parietal cells under stim by gastrin
Moves down thru esophageal sphincter
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

11. What is the endothelium?
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Inner lining of circulatory system

12. What is somatostatin
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
'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
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Increases surface area of food ball (bolus)

13. How do nutrients move?
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
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
Has memb - bound organelles - etc...
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

14. main point of fat transport...
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
An endogenous morphine
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

15. cytosol pH
About 7.2
Prod of steroid hormones in testes - ovaries
Inner lining of circulatory system
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

16. Glucose is a .... sugar; fructose is a .... sugar
Glucose = aldose fructose = ketose
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

17. What is a toxic byproduct of gluconeogenesis from proteins
Beta cells
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
An endogenous morphine
Ammonia; must be converted to urea by liver and excreted in urine by kidney

18. only monosaccharides are absorbed
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Conjunction of cell body w/axon
Sympathetic: dilates pupil (for night hunting)
RBCs - large proteins; What does enter is called the filtrate

19. 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
SYMP: spinal cord --->paravetebral ganglion PARA: spinal cord - brain; cell processes --->ganglion near effector organ (preganglionic neurons) extend outside of spinal cord to synapse at ganglia - go on along postganglionic neurons
Excretes waste products: urea - uric acid - ammonia - phosphate - maintains homeostasis: including body fluid volume (water reabsorption) and solute composition (mineral balance - nutrient reabsorption) - controls *plasma* pH: antiport of Na/K and pr
- 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
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

20. Where does fertilization occur
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**
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
The wall of the body or of a body cavity or hollow structure
Fallopian tubes

21. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Gastrulation occurs: formation of three primary germ layers = differentiation
Glycosaminoglycans - prots - AAs - lipids
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

22. what cannot cross the fenestrations of the renal corpuscle
RBCs - large proteins; What does enter is called the filtrate
Within the paravertebral ganglion - running parallel to spinal cord
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

23. Seen in lysosomal storage diseases
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
***nicotinic is ionotropic; muscarinic is GPCR
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

24. How does water cross the apical membrane
Membrane - bound - endocytosed bodies
Thru tight junctions by favorable osmotic gradient
Nitrogen
SYMP: spinal cord --->paravetebral ganglion PARA: spinal cord - brain; cell processes --->ganglion near effector organ (preganglionic neurons) extend outside of spinal cord to synapse at ganglia - go on along postganglionic neurons

25. Anterior eye
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
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
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

26. Embryology
- 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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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
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

27. Gastrulation: ectoderm/mesoderm/endoderm
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
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
Lumen (ie continuous w/body cavity) and cytosol
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

28. 80-90% fat absorbed this way
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Below hypothalamus
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

29. Failure of apoptosis can result in
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Night vision
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Cancer; apop can be programmed cell death; mitochon can play important role in apop

30. protein absorption at enterocyte
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
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

31. How does glycogen compare to starch
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

32. almost all cells can store Some glycogen - but...
Has memb - bound organelles - etc...
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Only musc and esp ** liver can store large amounts

33. How does reabsorption force nutrients across apical membrane of proximal tubule
Contain capillary network - lymph vessels (lacteals)
Water flows from the tubule - concentrating the filtrate - raising BP
Carry signals to musc OR Gland
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

34. Induction affects...
Ammonia; must be converted to urea by liver and excreted in urine by kidney
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Direction of differentiation

35. pancreas secretes enzymes via
Inner lining of blood vessels
Facilitated diffusion from hi to lo conc
Pancreatic duct (made of acinar cells?)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

36. During ejaculation - sperm...

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37. Ovum development is halted At what stage until fertilization...
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Chylomicrons are much bigger
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

38. Neuronal cell bodies have extensions ie
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Peptide; stims growth of nearly all cell of body; all other anterior pituitary horms have specific targets; upregulates anabolic pathways; use of fat for energy goes up (fat - burning); increases AA transport across cell membrane (nutrient uptake)
Processes: axons - dendrites
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

39. Sensory neuron cell bodies vs. somatic motor cell bodies
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

40. lysosome pH
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
5
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

41. 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)
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
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
The renal corpuscle
Sympathetic: dilates pupil (for night hunting)

42. Adrenal cortex hormones (STEROIDS)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

43. Between meals most fats appear in blood as
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Membrane - bound - endocytosed bodies
Abdominal cavity - which is coated in serous fluid
Glands w/ducts: Exocrine glands

44. In IBS - What is defective

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45. overall - fatty - prot - rich food in duod causes
Beta cells
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
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
Estradiol

46. Polypeptides are formed with what kind of reaction?
Peptide; stims growth of nearly all cell of body; all other anterior pituitary horms have specific targets; upregulates anabolic pathways; use of fat for energy goes up (fat - burning); increases AA transport across cell membrane (nutrient uptake)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
***nicotinic is ionotropic; muscarinic is GPCR
Apoproteins attach to outside of globules; these move to Golgi and are released into interstitial fluid via exocytosis as chylomicrons --->most go to lacteal system

47. PNS review: SAME DAVE
Has memb - bound organelles - etc...
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

48. Where does the bolus go after mouth chews food
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Cancer; apop can be programmed cell death; mitochon can play important role in apop
The renal corpuscle
Moves down thru esophageal sphincter

49. Meiosis I Anaphase I
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Homologous chromosomes separate - migrate towards opposite poles/centrioles
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

50. 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)
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
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Facilitated diffusion: no symport w/ secondary transport