Test your basic knowledge |

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. What is the net effect of the loop of Henle
An endogenous morphine
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)
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

2. Alpha - amylase found where
In mouth - breakdown of starch into polysaccharides
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.
Carry signals to musc OR Gland
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. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Chylomicrons are much bigger
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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

4. when thinking of proteins - think
Eukaryotes
Gastrulation occurs: formation of three primary germ layers = differentiation
Nitrogen
Albumin increases osmolarity of blood; increases osmotic pressure

5. Some epithelial cells are... others...
Eukaryotes
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
- 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
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

6. serous membranes have a viscera - facing layer and a body wall - facing layer
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
Low because AAs are immediately used in translation
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

7. glucagon secreted by
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

8. Tight junctions
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
Form barrier to extracellular fluid
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Sympathetic: dilates pupil (for night hunting)

9. motor (efferent) neurons --> VENTRAL
Carry signals to musc OR Gland
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

10. Ovum development is halted At what stage until fertilization...
Estradiol
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

11. What is somatostatin
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Two perpendicular semicircular canals involved in balance - equilibrium
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Fovea (highest amount of cones)

12. gametes are haploid
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
Peptides
Facilitated diffusion from hi to lo conc
Zygotes are diploid

13. almost all exocytosed proteins pass through this
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Smooth ER
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

14. Kidney physiology...

15. Gland: ovaries
Zygotes are diploid
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
- 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
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

16. What controls release of LH - FSH from anterior pituitary
Fovea (highest amount of cones)
- 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
Gonadotropin releasing hormone - GnRH
Direction of differentiation

17. Adrenal medulla hormones (TYR- DERIVED)
Inner lining of circulatory system
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Peptide; responsible for luteal surge (driven in part by LH-->testosterone -->estradiol -->LH positive feedback); results in ovulation (follicle bursting) - releasing egg into fallopian tube/oviduct

18. Local vs long - distance mediators
Paracrine (local) - endocrine (longer distance)
Neurons may perform one of three functions....
'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
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

19. Interaction of corpus luteum/placenta
Break down TAGs to monoglycerides and free fatty acids
Low because AAs are immediately used in translation
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

20. pancreas secretes enzymes via
Peptides
Pancreatic duct (made of acinar cells?)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Prod of steroid hormones in testes - ovaries

21. What is a plasmalogen?
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Interstitial fluid (eg prostaglandins - cytokines)
In mouth - breakdown of starch into polysaccharides
Testosterone upon stim by LH

22. lysosome main function and derivation
Low because AAs are immediately used in translation
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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

23. Chewing does what?
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Increases surface area of food ball (bolus)
Prod of steroid hormones in testes - ovaries

24. What is endothelium?
Inner lining of blood vessels
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Neurons may perform one of three functions....
Primitive streak - which consists of cells of the MESODERM ****

25. spermatogonia arise from
The renal corpuscle
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.
Epithelial tissue near semniferous tubules
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

26. gradual increase in FSH typical of primary follicle development;
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Night vision

27. Where is bile produced
Facilitated diffusion: no symport w/ secondary transport
Estradiol
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**
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. During ejaculation - sperm...

29. Creating gradients requires what?
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
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
Only musc and esp ** liver can store large amounts
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

30. Bile salts and lipase
Outermost layer of blood vessel
***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
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
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

31. pancreatic amylase is much stronger than
Salivary amylase; both hydrolyze glycosidic linkages
Gastrulation occurs: formation of three primary germ layers = differentiation
Most absorption occurs in sm intestine
Paracrine (local) - endocrine (longer distance)

32. duodenum must have receptors for fat content - protein because
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
'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.'

33. E storage per unit mass
Regulated by gastrointestinal horms
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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

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

35. Stomach has no lacteals
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)
Most absorption occurs in sm intestine
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
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

36. Sensory neuron cell bodies vs. somatic motor cell bodies
Beta cells
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Interstitial fluid (eg prostaglandins - cytokines)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

37. What is gastric acid?
About 7.2
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.
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
HCl; secreted by parietal cells under stim by gastrin

38. chylomicron concentration in blood after meal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Sympathetic: dilates pupil (for night hunting)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

39. liver and blood glucose...
Processes: axons - dendrites
Gonadotropin releasing hormone - GnRH
Liver is the control center for blood glucose; is fed by portal vein from sm intest
The wall of the body or of a body cavity or hollow structure

40. What are phagosomes
Membrane - bound - endocytosed bodies
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Estradiol

41. Cell determination begins At what stage of development
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
Direction of differentiation
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
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

42. Four tissues
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Prod of steroid hormones in testes - ovaries
An endogenous morphine
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

43. When 'coumadin targets liver enzymes to act as anticoagulant'...
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
RBCs - large proteins; What does enter is called the filtrate
Peptide; responsible for luteal surge (driven in part by LH-->testosterone -->estradiol -->LH positive feedback); results in ovulation (follicle bursting) - releasing egg into fallopian tube/oviduct
It targets liver conc of prothrombin - fibrinogen etc

44. Which fats are not absorbed like this
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
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Abdominal cavity - which is coated in serous fluid
Direction of differentiation

45. Different organs working together
Lysosome
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Systems (eg digestive system consists of many organs)

46. What does peptic refer to in general
Digestion
Steroid; target tissue is distal convoluted tubule of nephron and collecting duct; increases blood mineral concentration; potassium - protons secreted (blood pH increases); sodium - chloride reabsorbed (BP increases)
Glucose = aldose fructose = ketose
Direction of differentiation

47. After meiosis II - Male

48. light detection via GPCRs
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
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
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

49. Blastocyst
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant
Fructose is a structural isomer of glucose

50. main point of fat transport...
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
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