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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. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
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)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
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... ...
Smooth ER

2. What does lipase attack exactly
Estradiol
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
- 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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

3. Luteal surge
ER
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

4. 'Cell bodies of somatic motor neurons are located in....'
Peripheral nervous sys
Glucose = aldose fructose = ketose
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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

5. medium for paracrine hormones
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Interstitial fluid (eg prostaglandins - cytokines)
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Only musc and esp ** liver can store large amounts

6. ADH
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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
Corpus luteum degrades into corpus albicans
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

7. In IBS - What is defective

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8. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Membrane - bound - endocytosed bodies
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

9. The bolus (chewing) is digested to what in the stomach
Chyme (by combined activity of exocrine glands)
Paracrine (local) - endocrine (longer distance)
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
An endogenous morphine

10. Posterior pituitary hormones (Small Peptides)
Oxytocin and ADH (aka vasopressin)
Increases surface area of food ball (bolus)
'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
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

11. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
'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
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

12. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
Moves down thru esophageal sphincter
Within the paravertebral ganglion - running parallel to spinal cord
Ups bicarbonate secretion by pancreas; raises pH to 6.0

13. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Gonadotropin releasing hormone - GnRH
Creates one ovum (23 N) and three polar bodies
In gastric pits; secretions combine into gastric juice

14. 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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

15. is intracellular AA conc hi or low?
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Low because AAs are immediately used in translation
Fovea (highest amount of cones)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

16. What are the memb - bound enzymes of the brush border?
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt
Two perpendicular semicircular canals involved in balance - equilibrium
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

17. cAMP - cGMP - calmodulin...
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Paracrine (local) - endocrine (longer distance)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Sensory (afferent - dorsal) - motor (efferent - ventral)

18. Mucus - digestive enzymes released thru
Oxytocin and ADH (aka vasopressin)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Hormones --->stimulate exocrine glands - acetylcholine (increases all secretion of gastric pits) - gastrin (from G cells) - histamine (increases HCl secretion of parietals) ...Ach increases all secretions; gastrin increases gastric acid (parietal cel
Glands w/ducts: Exocrine glands

19. Which fats are not absorbed like this
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Prod of steroid hormones in testes - ovaries
Lysosome

20. liver receives blood from...
Inner lining of circulatory system
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Liposome has phospholipid bilayer

21. Chewing does what?
Increases surface area of food ball (bolus)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
In gastric pits; secretions combine into gastric juice
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

22. What controls release of LH - FSH from anterior pituitary
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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
Glucose and ketone bodies (not from glycogen stores)
Gonadotropin releasing hormone - GnRH

23. Between meals most fats appear in blood as
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

24. The apical side of the villi...
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
Sorts - modifies - concentrates proteins from the ER
Faces the lumen
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

25. Leydig cells produce
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 (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Testosterone upon stim by LH
Primitive streak - which consists of cells of the MESODERM ****

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

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27. micelles also pick up
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

28. motor (efferent) neurons --> VENTRAL
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
'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.'
Carry signals to musc OR Gland
Mostly reabsorbed to liver

29. position of AP...
Faces the lumen
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Below hypothalamus

30. duodenum must have receptors for fat content - protein because
Fovea (highest amount of cones)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Epithelial tissue near semniferous tubules
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

31. testosterone can be aromatized to...
Facilitated diffusion: no symport w/ secondary transport
Estradiol
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

32. Posterior eye
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
vitreous humor - retina - fovea
Fructose is a structural isomer of glucose

33. PNS nerve signal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

34. What is the net effect of 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)
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
About 7.2
Two perpendicular semicircular canals involved in balance - equilibrium

35. Both divisions (somatic - autonomic) of PNS consist of...
Sensory (afferent - dorsal) - motor (efferent - ventral)
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Nitrogen
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

36. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
Has memb - bound organelles - etc...
- 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
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

37. Glycogenolysis/gluconeogenesis
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
Sensory (afferent - dorsal) - motor (efferent - ventral)
'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
Pancreatic duct (made of acinar cells?)

38. remaining secondary follicle becomes
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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

39. What is somatostatin
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

40. examples of different cavities... (compartments for viscera)
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Sympathetic: dilates pupil (for night hunting)
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... ...
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

41. What does peroxisome do
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Albumin increases osmolarity of blood; increases osmotic pressure
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

42. Path of food entering body...
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt

43. Induction affects...
Direction of differentiation
Meiosis creates germ cells
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

44. Interaction of corpus luteum/placenta
In mouth - breakdown of starch into polysaccharides
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
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

45. gametes are haploid
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.
Form barrier to extracellular fluid
Zygotes are diploid
Below hypothalamus

46. quote on cavities/viscera

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47. zygotic life cycle
Water flows from the tubule - concentrating the filtrate - raising BP
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Oxytocin and ADH (aka vasopressin)

48. thyroid hormones: Not All One Kind of HORM
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

49. lining of abdominal cavity=
It targets liver conc of prothrombin - fibrinogen etc
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Night vision
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

50. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Primitive streak - which consists of cells of the MESODERM ****