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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. A pinpoint iris is contracted or uncontracted
Uncontracted: parasymp (eg opoid use)
RBCs - large proteins; What does enter is called the filtrate
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

2. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Gastrulation occurs: formation of three primary germ layers = differentiation
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
The wall of the body or of a body cavity or hollow structure
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

3. is intracellular AA conc hi or low?
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Fructose is a structural isomer of glucose
Low because AAs are immediately used in translation

4. Chewing does what?
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Increases surface area of food ball (bolus)
Prod of steroid hormones in testes - ovaries
Organs

5. insulin secreted by
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Systems (eg digestive system consists of many organs)
Digestion
Beta cells

6. What happens when rod cell is depolarized
Inner lining of circulatory system
Night vision
Chyme (by combined activity of exocrine glands)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

7. What is endothelium?
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Inner lining of blood vessels
Ventrally (picture skeletal vertebrae)

8. Glycogenolysis/gluconeogenesis
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
Direction of differentiation
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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

9. euk cell has two principal sides
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Lumen (ie continuous w/body cavity) and cytosol
Neurons may perform one of three functions....
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

10. How does duod deal with hi HCl from stom
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

11. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

12. Where would materials slated for digestion go?
Digestion
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Lysosome
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

13. What controls release of LH - FSH from anterior pituitary
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Gonadotropin releasing hormone - GnRH
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

14. gradual increase in FSH typical of primary follicle development;
Ganglion
Peripheral nervous sys
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

15. What is the function of the loop of Henle
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
Increases solute conc and osmotic pressure of the ***medulla
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum
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

16. FSH - LH - HCG - inhibin are...
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Peptides
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)
Determined by whether in front of or behind the lens

17. small intestine=
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Raises BP; causes collecting ducts at end of nephron (kidney) to become permeable to water - which concentrates urine; coffee - beer block ADH and increase urine volume
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Glucose = aldose fructose = ketose

18. Thus inhibiting parietal cells could do What to blood pH
5
Lower blood pH
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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

19. What do lipases do
Sympathetic: dilates pupil (for night hunting)
Chylomicrons are much bigger
Break down TAGs to monoglycerides and free fatty acids
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

20. Between meals most fats appear in blood as
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
90-140 mg/dl
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

21. amylase acts where on carbs
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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

22. light detection via GPCRs
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
***starting with adipose tiss: FFAs are transported in the blood by albumin (major component of blood plasma); one albumin typically carries three fatty acid molecules but can hold up to 30 FAs
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Sensory (afferent - dorsal) - motor (efferent - ventral)

23. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

24. Thus - central nervous sys is...
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Organs

25. Seen in lysosomal storage diseases
Needs time for bile - lipase - micelle migration - enterocyte uptake
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

26. A contracted iris occurs with what kind of stimulation
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
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Sympathetic: dilates pupil (for night hunting)
5

27. What force is acting upon chyme to move it forward down sm intestine
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Sensory (afferent - dorsal) - motor (efferent - ventral)

28. little by little chyme is squirted out thru pyloric sphincter
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum
Regulated by gastrointestinal horms
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

29. Where does blood to be filtered by kidney enter the nephron?

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30. main point of fat transport...
Thru tight junctions by favorable osmotic gradient
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Facilitated diffusion from hi to lo conc
Inner lining of circulatory system

31. 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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
- 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
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

32. Path of food entering body...
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
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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

33. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Eukaryotes
Testosterone and estradiol
Lower blood pH
5

34. inhibin secreted by
Peptides
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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

35. Meiosis I Metaphase I
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
Somatic nervous sys - autonomic nervous sys
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Contain capillary network - lymph vessels (lacteals)

36. How does birth control work?
Water flows from the tubule - concentrating the filtrate - raising BP
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
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
Outermost layer of blood vessel

37. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

38. almost all cells can store Some glycogen - but...
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
It targets liver conc of prothrombin - fibrinogen etc
Only musc and esp ** liver can store large amounts

39. What is a dorsal root ganglion?
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
All carbs absorbed at enterocytes are carried to liver by portal vein
Beta cells
Fructose is a structural isomer of glucose

40. physiology of gall bladder - liver and pancreatic secretions
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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
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)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

41. The esophageal sphincter is...
Normally contracted
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang
Chylomicrons are much bigger
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

42. trypsin is secreted by
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

43. How long are peptides when absorbed at brush border
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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
Faces the lumen

44. What is gastric acid?
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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
HCl; secreted by parietal cells under stim by gastrin
Sympathetic: dilates pupil (for night hunting)

45. What is the pH at the entrance to the duodenum
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

46. SYMP neurons originate in= PARA neurons originate in=
In mouth - breakdown of starch into polysaccharides
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
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
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

47. What is the adventitia?
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Inner lining of blood vessels
Outermost layer of blood vessel
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

48. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Faces the lumen
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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

49. mitosis creates somatic cells
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Meiosis creates germ cells
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Albumin increases osmolarity of blood; increases osmotic pressure

50. Where is bile produced
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Facilitated diffusion from hi to lo conc
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**
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