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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. Local vs long - distance mediators
Paracrine (local) - endocrine (longer distance)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
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... ...
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

2. Meiosis I Metaphase I
Faces the lumen
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
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Homologous chromosomes line up w/ attachment of spindle fibers/microtubule polymers to centromeres via kinetochores; identical in appearance under light microscope to metaphase of mitosis

3. After meiosis I - daughter cells are...

4. Liver Functions
Form barrier to extracellular fluid
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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
Most absorption occurs in sm intestine

5. FLAT PG: TSH aka thyrotropin
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
Systems (eg digestive system consists of many organs)
Sorts - modifies - concentrates proteins from the ER
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

6. Posterior eye
vitreous humor - retina - fovea
Conjunction of cell body w/axon
Sorts - modifies - concentrates proteins from the ER
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

7. What is secreted into filtrate by cells of the proximal tubule?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Low because AAs are immediately used in translation
Organs

8. Which fats are not absorbed like this
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Fovea (highest amount of cones)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Beta cells

9. light detection via GPCRs
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
Increases solute conc and osmotic pressure of the ***medulla
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

10. PNS review: SAME DAVE
Peptides
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
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Cancer; apop can be programmed cell death; mitochon can play important role in apop

11. inhibin secreted by
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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
Increases surface area of food ball (bolus)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

12. pancreatic enzymes are zymogens
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)
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
- 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

13. what happens to bile secretions
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
Mostly reabsorbed to liver
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

14. FLAT PG: ACTH
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
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)

15. On what surface of the retina is the eye most sensitive
Fovea (highest amount of cones)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Primitive streak - which consists of cells of the MESODERM ****
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

16. A group of cell bodies in CNS is nucleus - outside CNS is...
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Night vision
Ganglion
Creates one ovum (23 N) and three polar bodies

17. What is endothelium?
Inner lining of blood vessels
Glucose
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
RBCs - large proteins; What does enter is called the filtrate

18. in the presence of ADH what happens to movement of water across nephron membr
Two perpendicular semicircular canals involved in balance - equilibrium
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Water flows from the tubule - concentrating the filtrate - raising BP
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

19. What is the function of the loop of Henle
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Vitamin K - b12 - thiamin - riboflavin
Increases solute conc and osmotic pressure of the ***medulla
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... ...

20. How long are peptides when absorbed at brush border
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

21. energy source of neurons
Glucose and ketone bodies (not from glycogen stores)
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
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.
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

22. almost all exocytosed proteins pass through this
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Smooth ER
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

23. Meiosis I Telophase I
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Zygotes are diploid
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

24. albumin has What affect on blood osmotic pressure
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Albumin increases osmolarity of blood; increases osmotic pressure
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

25. from the loop of henle...
Increases solute conc and osmotic pressure of the ***medulla
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Water flows from the tubule - concentrating the filtrate - raising BP
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

26. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Sympathetic: dilates pupil (for night hunting)
Ganglion
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Glands w/ducts: Exocrine glands

27. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Faces the lumen
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Low because AAs are immediately used in translation
Gastrulation occurs: formation of three primary germ layers = differentiation

28. Exocrine GlandS: stomach
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
- 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
- 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

29. What is an endorphin?
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
Lower blood pH
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
An endogenous morphine

30. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Creates one ovum (23 N) and three polar bodies
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Testosterone and estradiol

31. gradual increase in FSH typical of primary follicle development;
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Ups bicarbonate secretion by pancreas; raises pH to 6.0

32. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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
Contain capillary network - lymph vessels (lacteals)

33. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Estradiol
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

34. Anatomy of the villi
Outermost layer of blood vessel
***nicotinic is ionotropic; muscarinic is GPCR
Contain capillary network - lymph vessels (lacteals)
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

35. What is a plasmalogen?
5
Only musc and esp ** liver can store large amounts
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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

36. sensory (afferent)/interneurons/motor (efferent)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Neurons may perform one of three functions....
Increases blood Calcium

37. quote on cavities/viscera

38. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Testosterone and estradiol
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Sorts - modifies - concentrates proteins from the ER

39. The path from blood plasma to urine

40. only monosaccharides are absorbed
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Water flows from the tubule - concentrating the filtrate - raising BP

41. physiology of gall bladder - liver and pancreatic secretions
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
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
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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

42. Failure of apoptosis can result in
- 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
Below hypothalamus
***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
Cancer; apop can be programmed cell death; mitochon can play important role in apop

43. medium for paracrine hormones
Processes: axons - dendrites
Interstitial fluid (eg prostaglandins - cytokines)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

44. How does reabsorption force nutrients across apical membrane of proximal tubule
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

45. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
Glucose and ketone bodies (not from glycogen stores)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Salivary amylase; both hydrolyze glycosidic linkages

46. micelles also pick up
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Lower blood pH
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

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

48. small intestine=
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Break down TAGs to monoglycerides and free fatty acids

49. Leydig cells produce
Testosterone upon stim by LH
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
***nicotinic is ionotropic; muscarinic is GPCR
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

50. smooth ER main function
Fructose is a structural isomer of glucose
Determined by whether in front of or behind the lens
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5