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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
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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. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Lysosome
Creates one ovum (23 N) and three polar bodies

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

3. Four tissues
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Form barrier to extracellular fluid
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

4. cytosol pH
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
About 7.2
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

5. What are the memb - bound enzymes of the brush border?
Carry signals to musc OR Gland
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Testosterone and estradiol
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

6. What is the function of the loop of Henle
Peptides
Increases solute conc and osmotic pressure of the ***medulla
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Faces the lumen

7. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Chylomicrons are much bigger
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)
Two perpendicular semicircular canals involved in balance - equilibrium
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

8. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Two perpendicular semicircular canals involved in balance - equilibrium
1) by integral ion channels 2) transmitted by second messenger system
The renal corpuscle
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

9. what happens when glycogen stores are saturated and blood sugar remains high?
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Liposome has phospholipid bilayer
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

10. Bile salts and lipase
Peptides
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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

11. lining of abdominal cavity=
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

12. Does bile digest fat?
Direction of differentiation
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

13. Local vs long - distance mediators
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Paracrine (local) - endocrine (longer distance)

14. gametes are haploid
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Epithelial tissue near semniferous tubules
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Zygotes are diploid

15. ADH
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
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
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Creates one ovum (23 N) and three polar bodies

16. peroxisome is derived from this
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
ER
Increases solute conc and osmotic pressure of the ***medulla

17. What do lipases do
Break down TAGs to monoglycerides and free fatty acids
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
Beta cells
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

18. Contrast PNS- Somatic with PNS- Autonomic
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

19. only monosaccharides are absorbed
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Fovea (highest amount of cones)
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Gonadotropin releasing hormone - GnRH

20. FLAT PG: prolactin
Ventrally (picture skeletal vertebrae)
Sorts - modifies - concentrates proteins from the ER
Prod of steroid hormones in testes - ovaries
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

21. FSH - LH - HCG - inhibin are...
RBCs - large proteins; What does enter is called the filtrate
Peptides
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

22. How is glucose absorbed in sm intest
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Peptides
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
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

23. sensory (afferent) neurons
Organs
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Pancreatic duct (made of acinar cells?)

24. How does the body mobilize fat stores
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
***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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

25. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
vitreous humor - retina - fovea
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Increases solute conc and osmotic pressure of the ***medulla

26. In other words...
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
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
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

27. Sensory - motor neurons are part of which nervous system
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Peripheral nervous sys
Sorts - modifies - concentrates proteins from the ER
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

28. From that point...
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
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.
***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
Albumin increases osmolarity of blood; increases osmotic pressure

29. 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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
'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
Membrane - bound - endocytosed bodies

30. almost all exocytosed proteins pass through this
Smooth ER
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

31. What is endothelium?
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
'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
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
Inner lining of blood vessels

32. 'Cell bodies of somatic motor neurons are located in....'
Neurons may perform one of three functions....
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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
90-140 mg/dl

33. FLAT PG: LH
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)
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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

34. Alpha - amylase found where
'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
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
In mouth - breakdown of starch into polysaccharides

35. What does peroxisome do
Primitive streak - which consists of cells of the MESODERM ****
Organs
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

36. Adrenal medulla hormones (TYR- DERIVED)
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Water flows from the tubule - concentrating the filtrate - raising BP
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
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

37. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
- 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
Two perpendicular semicircular canals involved in balance - equilibrium
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
All carbs absorbed at enterocytes are carried to liver by portal vein

38. sporic life cycle
Pancreatic duct (made of acinar cells?)
Direction of differentiation
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

39. A pinpoint iris is contracted or uncontracted
Form barrier to extracellular fluid
Liver is the control center for blood glucose; is fed by portal vein from sm intest
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.
Uncontracted: parasymp (eg opoid use)

40. Think of spinal cord injury
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Beta cells
The wall of the body or of a body cavity or hollow structure
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

41. overall - fatty - prot - rich food in duod causes
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
Sympathetic: dilates pupil (for night hunting)
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
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

42. Leydig cells produce
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
Testosterone upon stim by LH
Low because AAs are immediately used in translation
Has memb - bound organelles - etc...

43. liver and blood glucose...
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Liver is the control center for blood glucose; is fed by portal vein from 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
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

44. Aldosterone (sodium uptake - potassium secretion)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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)
Gonadotropin releasing hormone - GnRH
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

45. smooth ER main function
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)
Glands w/ducts: Exocrine glands
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Peripheral nervous sys

46. How does reabsorption force nutrients across apical membrane of proximal tubule
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Abdominal cavity - which is coated in serous fluid
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

47. STOMACH: no absorption
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
All carbs absorbed at enterocytes are carried to liver by portal vein
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc

48. important pancreatic enzymes
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Liposome has phospholipid bilayer

49. Path of urine

50. SYMP neurons originate in= PARA neurons originate in=
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
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
Night vision