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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. Creating gradients requires what?
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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

2. only monosaccharides are absorbed
Which is why lactase - maltase - dextrinase - sucrase are on brush border
All carbs absorbed at enterocytes are carried to liver by portal vein
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
Water flows from the tubule - concentrating the filtrate - raising BP

3. The path from blood plasma to urine

4. How do monoglycerides and ffas get to brush border?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
'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
Corpus luteum degrades into corpus albicans

5. The EYE
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Fovea (highest amount of cones)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

6. Different organs working together
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Systems (eg digestive system consists of many organs)
Digestion
Gastrulation occurs: formation of three primary germ layers = differentiation

7. cytosol pH
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
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
About 7.2

8. in the presence of ADH what happens to movement of water across nephron membr
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Water flows from the tubule - concentrating the filtrate - raising BP
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
1) by integral ion channels 2) transmitted by second messenger system

9. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
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
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
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Pancreatic duct (made of acinar cells?)

10. At post - two weeks ovulation
Corpus luteum degrades into corpus albicans
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Two perpendicular semicircular canals involved in balance - equilibrium
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

11. insulin secreted by
***nicotinic is ionotropic; muscarinic is GPCR
Beta cells
Testosterone upon stim by LH
It targets liver conc of prothrombin - fibrinogen etc

12. What is an endorphin?
An endogenous morphine
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

13. Important of villi (='shaggy hair') More fluid makes contact with the epithelial tissue: thus nutrients in solution have less distance to travel to diffuse into villi.

14. What do lipases do
Primitive streak - which consists of cells of the MESODERM ****
Break down TAGs to monoglycerides and free fatty acids
Peptides
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

15. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
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)
Glands w/ducts: Exocrine glands

16. Neuronal cell bodies have extensions ie
Processes: axons - dendrites
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Only musc and esp ** liver can store large amounts
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

17. What is secreted into filtrate by cells of the proximal tubule?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Ventrally (picture skeletal vertebrae)

18. what happens to bile secretions
Mostly reabsorbed to liver
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Glucose = aldose fructose = ketose
Needs time for bile - lipase - micelle migration - enterocyte uptake

19. Anterior eye vs. posterior eye
Determined by whether in front of or behind the lens
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Glucose = aldose fructose = ketose
'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

20. albumin has What affect on blood osmotic pressure
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Albumin increases osmolarity of blood; increases osmotic pressure

21. What is the function of the loop of Henle
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Contain capillary network - lymph vessels (lacteals)
Increases solute conc and osmotic pressure of the ***medulla
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

22. alpha - amylase in the mouth digests what kind of bond
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

23. Determination is different than differentiation
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Ups bicarbonate secretion by pancreas; raises pH to 6.0

24. In other words...
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
Fructose is a structural isomer of glucose
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Thru tight junctions by favorable osmotic gradient

25. Anatomy of the villi
Contain capillary network - lymph vessels (lacteals)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Night vision
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

26. from the loop of henle...
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)
Peripheral nervous sys
Chyme (by combined activity of exocrine glands)
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

27. Which fats are not absorbed like this
Lumen (ie continuous w/body cavity) and cytosol
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Sympathetic: dilates pupil (for night hunting)
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

28. gradual increase in FSH typical of primary follicle development;
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
***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
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

29. spermatogonia arise from
Testosterone and estradiol
Epithelial tissue near semniferous tubules
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

30. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
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
Creates one ovum (23 N) and three polar bodies
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

31. What is a dorsal root ganglion?
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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

32. protein absorption at enterocyte
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
Normally contracted
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

33. sensory (afferent)/interneurons/motor (efferent)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Somatic nervous sys - autonomic nervous sys
Neurons may perform one of three functions....
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

34. extracellular matrix formed mainly of...
Regulated by gastrointestinal horms
All carbs absorbed at enterocytes are carried to liver by portal vein
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

35. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

36. 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
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Lumen (ie continuous w/body cavity) and cytosol
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

37. review: parietals secrete intrinsic factor...
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Ventrally (picture skeletal vertebrae)
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

38. food in duod stims release of gastrointestinal hormones
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Lower blood pH

39. is intracellular AA conc hi or low?
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Low because AAs are immediately used in translation
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

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

41. Both divisions (somatic - autonomic) of PNS consist of...
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
Sensory (afferent - dorsal) - motor (efferent - ventral)
Outermost layer of blood vessel
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

42. What is gastric acid?
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
HCl; secreted by parietal cells under stim by gastrin
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

43. position of AP...
Sensory (afferent - dorsal) - motor (efferent - ventral)
Pancreatic duct (made of acinar cells?)
Below hypothalamus
Chylomicrons are much bigger

44. medium for paracrine hormones
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
Glucose = aldose fructose = ketose
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Interstitial fluid (eg prostaglandins - cytokines)

45. interneurons
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Prod of steroid hormones in testes - ovaries
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

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

47. Meiosis II: EQUATIONAL DIVISION
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Carry signals to musc OR Gland
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
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

48. What is the endothelium?
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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
Inner lining of circulatory system
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

49. liver receives blood from...
Stores blood: when expanded liver serves as blood reservoir for body - filters blood: Kupfer cells phagocytize bacteria picked up from intestines - destroys bad RBCs: also done by Kupfer cells - detoxifies blood: detoxified chemicals are excreted eit
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
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

50. examples of different cavities... (compartments for viscera)
Creates one ovum (23 N) and three polar bodies
Form barrier to extracellular fluid
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)