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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. Gland: ovaries
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

2. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Chylomicrons are much bigger
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Smooth ER

3. spermatogonia arise from
Epithelial tissue near semniferous tubules
HCl; secreted by parietal cells under stim by gastrin
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
It targets liver conc of prothrombin - fibrinogen etc

4. Sensory - motor neurons are part of which nervous system
In gastric pits; secretions combine into gastric juice
Peripheral nervous sys
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
Peptides

5. Gastrin from G cells stims parietal cells...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Outermost layer of blood vessel
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

6. In IBS - What is defective

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7. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
- 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
Direction of differentiation
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)

8. Sensory neuron cell bodies vs. somatic motor cell bodies
Eukaryotes
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
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

9. lysosome pH
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
In gastric pits; secretions combine into gastric juice
5

10. Aldosterone (sodium uptake - potassium secretion)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
- 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
RBCs - large proteins; What does enter is called the filtrate
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)

11. How does blood sugar move into tissues?
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
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
Facilitated diffusion from hi to lo conc
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc

12. fat digestion is time - intensive
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Needs time for bile - lipase - micelle migration - enterocyte uptake

13. The esophageal sphincter is...
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Normally contracted

14. What do lipases do
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
The renal corpuscle
Break down TAGs to monoglycerides and free fatty acids
Many modern drugs are ligands for GPCRs

15. After meiosis II - Male

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16. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
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... ...
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

17. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

18. 80% of end product of carbohydrate metabolism is...
Glucose = aldose fructose = ketose
Glucose
RBCs - large proteins; What does enter is called the filtrate
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

19. energy source of neurons
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.
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Glucose and ketone bodies (not from glycogen stores)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

20. Embryology
Zygotes are diploid
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
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

21. Cell bodies of SYMP postganglionic neurons lie far from effector...
About 7.2
Within the paravertebral ganglion - running parallel to spinal cord
Processes: axons - dendrites
Vitamin K - b12 - thiamin - riboflavin

22. only monosaccharides are absorbed
Creates one ovum (23 N) and three polar bodies
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Inner lining of blood vessels

23. food in duod stims release of gastrointestinal hormones
'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
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

24. sensory (afferent) neurons
Ventrally (picture skeletal vertebrae)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Direction of differentiation

25. What is the net effect of the distal tubule
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
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Increases solute conc and osmotic pressure of the ***medulla
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

26. bundles of collecting ducts are called
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

27. What determines number of chromosomes?
Salivary amylase; both hydrolyze glycosidic linkages
Glucose = aldose fructose = ketose
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

28. Alpha - amylase found where
In mouth - breakdown of starch into polysaccharides
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons

29. FLAT PG: TSH aka thyrotropin
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
Beta cells
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.
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

30. What is main difference is signal transmission in nicotinic vs muscarinic?
Eukaryotes
***nicotinic is ionotropic; muscarinic is GPCR
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

31. Where does fertilization occur
Fallopian tubes
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
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Neurons may perform one of three functions....

32. Fructose relates how structurally to glucose
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
Peripheral nervous sys
Fructose is a structural isomer of glucose

33. liver and blood glucose...
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

34. golgi body
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Primitive streak - which consists of cells of the MESODERM ****
Abdominal cavity - which is coated in serous fluid
Sorts - modifies - concentrates proteins from the ER

35. SYMP neurons originate in= PARA neurons originate in=
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
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
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
Increases blood Calcium

36. How is the follicle developed during oogenesis
Glands w/ducts: Exocrine glands
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

37. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

38. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Gastrulation occurs: formation of three primary germ layers = differentiation

39. cytosol pH
Sorts - modifies - concentrates proteins from the ER
About 7.2
Most absorption occurs in sm intestine
Nitrogen

40. What is a plasmalogen?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

41. therefore - How does plasma leave capillary at the renal corpuscle

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42. interneurons
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Transfer signals from neuron - neuron; 90% of neurons are interneurons
HCl; secreted by parietal cells under stim by gastrin

43. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
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
Fovea (highest amount of cones)
1) by integral ion channels 2) transmitted by second messenger system

44. peroxisome is derived from this
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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
ER
5

45. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Lumen (ie continuous w/body cavity) and cytosol
Testosterone and estradiol

46. What else do parietals do?
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Contain capillary network - lymph vessels (lacteals)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

47. Anterior eye vs. posterior eye
Determined by whether in front of or behind the lens
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)
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

48. Meiosis I Anaphase I
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
Glucose
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Homologous chromosomes separate - migrate towards opposite poles/centrioles

49. when cells hit their limit for prot storage...
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
AAs can be burned for energy or converted to fat for storage
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

50. How do parietal cells work ** (involves CO2)
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
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach