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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. Three stages of the menstrual cycle
Sorts - modifies - concentrates proteins from the ER
Glucose and ketone bodies (not from glycogen stores)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
'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

2. Mucus - digestive enzymes released thru
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
'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
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Glands w/ducts: Exocrine glands

3. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
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)
Testosterone and estradiol
'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.'
Increases solute conc and osmotic pressure of the ***medulla

4. How does glycogen compare to starch
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

5. What is the net effect of the loop of Henle
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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Testosterone upon stim by LH
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)

6. position of AP...
Creates one ovum (23 N) and three polar bodies
Below hypothalamus
- 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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

7. Think of spinal cord injury
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Glucose and ketone bodies (not from glycogen stores)
Fovea (highest amount of cones)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

8. Cell bodies of SYMP postganglionic neurons lie far from effector...
Within the paravertebral ganglion - running parallel to spinal cord
'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
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

9. What are the memb - bound enzymes of the brush border?
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Glucose
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

10. Path of urine

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11. How does the body mobilize fat stores
***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
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
In gastric pits; secretions combine into gastric juice

12. What does peptic refer to in general
Digestion
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Uncontracted: parasymp (eg opoid use)
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

13. What is the path of a sound wave that enters the ear?
'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
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
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
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

14. 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
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)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Transfer signals from neuron - neuron; 90% of neurons are interneurons

15. Meiosis II: EQUATIONAL DIVISION
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Organs
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
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

16. Meiosis I Telophase I
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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
Somatic nervous sys - autonomic nervous sys

17. calcitonin

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18. In other words...
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
In mouth - breakdown of starch into polysaccharides
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
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

19. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
The renal corpuscle
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Creates one ovum (23 N) and three polar bodies
Liver is the control center for blood glucose; is fed by portal vein from sm intest

20. Local vs long - distance mediators
An endogenous morphine
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Paracrine (local) - endocrine (longer distance)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

21. Where does the bolus go after mouth chews food
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Moves down thru esophageal sphincter
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

22. duodenum must have receptors for fat content - protein because
Gonadotropin releasing hormone - GnRH
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
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
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

23. Blastocyst
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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
Sorts - modifies - concentrates proteins from the ER
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

24. ADH
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

25. FLAT PG: FSH
Many modern drugs are ligands for GPCRs
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
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)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

26. Adrenal cortex hormones (STEROIDS)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
In mouth - breakdown of starch into polysaccharides
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Oxytocin and ADH (aka vasopressin)

27. energy source of neurons
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Somatic nervous sys - autonomic nervous sys
Glucose and ketone bodies (not from glycogen stores)

28. sporic life cycle
Only musc and esp ** liver can store large amounts
Mostly reabsorbed to liver
Direction of differentiation
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

29. euk cell has two principal sides
Lumen (ie continuous w/body cavity) and cytosol
Ganglion
Corpus luteum degrades into corpus albicans
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

30. FLAT PG: prolactin
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

31. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Sympathetic: dilates pupil (for night hunting)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Conjunction of cell body w/axon

32. serous membranes have a viscera - facing layer and a body wall - facing layer
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Which is why lactase - maltase - dextrinase - sucrase are on brush border

33. Energy from fat - prot - gluc
Membrane - bound - endocytosed bodies
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Neurons may perform one of three functions....
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

34. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Meiosis creates germ cells
HCl; secreted by parietal cells under stim by gastrin
5
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

35. lining of abdominal cavity=
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
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
***nicotinic is ionotropic; muscarinic is GPCR

36. Four tissues
Most absorption occurs in sm intestine
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
- 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

37. What is the endothelium?
Inner lining of circulatory system
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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Lower blood pH

38. parathyroid hormones
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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**
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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

39. Posterior eye
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
vitreous humor - retina - fovea
Two perpendicular semicircular canals involved in balance - equilibrium
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

40. Peritoneal refers to...
Abdominal cavity - which is coated in serous fluid
About 7.2
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
AAs can be burned for energy or converted to fat for storage

41. 80-90% fat absorbed this way
Chylomicrons are much bigger
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

42. Failure of apoptosis can result in
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Glycosaminoglycans - prots - AAs - lipids
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

43. golgi body
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
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Sorts - modifies - concentrates proteins from the ER
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

44. Where else does ADH act
Pancreatic duct (made of acinar cells?)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
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

45. What testosterone released by secondary follicle by LH stim is converted to...
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Sensory (afferent - dorsal) - motor (efferent - ventral)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

46. What does lipase attack exactly
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
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)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

47. E storage per unit mass
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Abdominal cavity - which is coated in serous fluid

48. A pinpoint iris is contracted or uncontracted
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Inner lining of blood vessels
Uncontracted: parasymp (eg opoid use)

49. What is the net effect of the distal tubule
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

50. Glucose is a .... sugar; fructose is a .... sugar
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Corpus luteum degrades into corpus albicans
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Glucose = aldose fructose = ketose