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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. ADH
Determined by whether in front of or behind the lens
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

2. smooth ER main function
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
90-140 mg/dl
Neurons may perform one of three functions....

3. fructose enters enterocyte by
Facilitated diffusion: no symport w/ secondary transport
Thru tight junctions by favorable osmotic gradient
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS 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

4. lining of abdominal cavity=
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

5. Kidney
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Excretes waste products: urea - uric acid - ammonia - phosphate - maintains homeostasis: including body fluid volume (water reabsorption) and solute composition (mineral balance - nutrient reabsorption) - controls *plasma* pH: antiport of Na/K and pr
Night vision

6. How does glycogen compare to starch
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Urine enters kidneys via artery - to arteriole - capillary bed - glomerulus - Bowman's capsule - proximal tubule - loop of henle (concentrates medulla) - distal tubule - collecting tubule - collecting duct (renal pyramids) - renal calyx - renal pelvi
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

7. 3 phases of menstrual cycle
Salivary amylase; both hydrolyze glycosidic linkages
The wall of the body or of a body cavity or hollow structure
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
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)

8. Which fats are not absorbed like this
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Ventrally (picture skeletal vertebrae)
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

9. cAMP - cGMP - calmodulin...
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Only musc and esp ** liver can store large amounts
Digestion

10. The apical side of the villi...
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Faces the lumen
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

11. Meiosis I Telophase I
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

12. 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)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Has memb - bound organelles - etc...
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

13. FLAT PG: FSH
Chyme (by combined activity of exocrine glands)
Oxytocin and ADH (aka vasopressin)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Sympathetic: dilates pupil (for night hunting)

14. What determines number of chromosomes?
Facilitated diffusion: no symport w/ secondary transport
Break down TAGs to monoglycerides and free fatty acids
In mouth - breakdown of starch into polysaccharides
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

15. Sensory - motor neurons are part of which nervous system
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Form barrier to extracellular fluid
Peripheral nervous sys
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

16. gametes are haploid
Zygotes are diploid
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Abdominal cavity - which is coated in serous fluid
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

17. Chewing does what?
Increases surface area of food ball (bolus)
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Most absorption occurs in sm intestine

18. From that point...
Lumen (ie continuous w/body cavity) and cytosol
ER
It targets liver conc of prothrombin - fibrinogen etc
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.

19. What is a plasmalogen?
Night vision
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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Neurons may perform one of three functions....

20. Stomach has no lacteals
In gastric pits; secretions combine into gastric juice
Inner lining of blood vessels
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
Most absorption occurs in sm intestine

21. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
About 7.2
Increases blood Calcium
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

22. duodenum must have receptors for fat content - protein because
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
All carbs absorbed at enterocytes are carried to liver by portal vein
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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. On what surface of the retina is the eye most sensitive
Fovea (highest amount of cones)
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Albumin increases osmolarity of blood; increases osmotic pressure
Vitamin K - b12 - thiamin - riboflavin

24. Mucus - digestive enzymes released thru
5
Glands w/ducts: Exocrine glands
Fructose is a structural isomer of glucose
In mouth - breakdown of starch into polysaccharides

25. PNS nerve signal
***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
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Sorts - modifies - concentrates proteins from the ER
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

26. What kind of cells make up epithel tiss of stom - then sm intest?
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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
Thru tight junctions by favorable osmotic gradient

27. Adrenal medulla hormones (TYR- DERIVED)
Processes: axons - dendrites
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
Epithelial tissue near semniferous tubules
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

28. medium for paracrine hormones
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Beta cells
Systems (eg digestive system consists of many organs)
Interstitial fluid (eg prostaglandins - cytokines)

29. spermatogonia arise from
Testosterone upon stim by LH
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.
Epithelial tissue near semniferous tubules
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste

30. insulin secreted by
Beta cells
Salivary amylase; both hydrolyze glycosidic linkages
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

31. 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
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
- 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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

32. in the dark is rhodopsin active or inactive?
Sorts - modifies - concentrates proteins from the ER
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Ganglion
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

33. signal transduction occurs by 2 paths
1) by integral ion channels 2) transmitted by second messenger system
Facilitated diffusion from hi to lo conc
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

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

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35. signal transduction occurs only in
Eukaryotes
Prod of steroid hormones in testes - ovaries
Processes: axons - dendrites
Glycosaminoglycans - prots - AAs - lipids

36. energy source of neurons
Peptides
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
In gastric pits; secretions combine into gastric juice
Glucose and ketone bodies (not from glycogen stores)

37. important pancreatic enzymes
Neurons may perform one of three functions....
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

38. What is the endothelium?
Inner lining of circulatory system
HCl; secreted by parietal cells under stim by gastrin
Oxytocin and ADH (aka vasopressin)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

39. Polypeptides are formed with what kind of reaction?
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

40. Cell bodies of SYMP postganglionic neurons lie far from effector...
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
ER
Smooth ER
Within the paravertebral ganglion - running parallel to spinal cord

41. Both divisions (somatic - autonomic) of PNS consist of...
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Liposome has phospholipid bilayer
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Sensory (afferent - dorsal) - motor (efferent - ventral)

42. Energy from fat - prot - gluc
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Chylomicrons are much bigger
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

43. from the loop of henle...
Gastrulation occurs: formation of three primary germ layers = differentiation
Increases blood Calcium
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

44. ligands are the messenger compounds that target secondary messenger systems on effectors
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Many modern drugs are ligands for GPCRs
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
- 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

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

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46. What is secreted into filtrate by cells of the proximal tubule?
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
In gastric pits; secretions combine into gastric juice
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

47. motor (efferent) neurons --> VENTRAL
Corpus luteum degrades into corpus albicans
Carry signals to musc OR Gland
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

48. Luteal surge
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Meiosis creates germ cells
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

49. Interaction of corpus luteum/placenta
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
In mouth - breakdown of starch into polysaccharides
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

50. What are phagosomes
Ganglion
Membrane - bound - endocytosed bodies
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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