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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. calcitonin

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2. Meiosis I Anaphase I
Processes: axons - dendrites
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

3. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
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
Testosterone and estradiol
Lumen (ie continuous w/body cavity) and cytosol
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

4. A contracted iris occurs with what kind of stimulation
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Sympathetic: dilates pupil (for night hunting)
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

5. During ejaculation - sperm...

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6. insulin secreted by
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
Estradiol
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
Beta cells

7. What is a plasmalogen?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

8. Four tissues
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
***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
Nitrogen
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

9. What if large intestine isn't working well
Digestion
Increases surface area of food ball (bolus)
Membrane - bound - endocytosed bodies
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

10. Determination is different than differentiation
Night vision
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Creates one ovum (23 N) and three polar bodies

11. signal transduction occurs only in
Sympathetic: dilates pupil (for night hunting)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Eukaryotes

12. zygotic life cycle
The wall of the body or of a body cavity or hollow structure
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Mostly reabsorbed to liver
Low because AAs are immediately used in translation

13. Beta - oxidation in liver produces...
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Sympathetic: dilates pupil (for night hunting)
It targets liver conc of prothrombin - fibrinogen etc

14. keep in mind that enterocyte is like a regular euk cell
Increases blood Calcium
Has memb - bound organelles - etc...
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Needs time for bile - lipase - micelle migration - enterocyte uptake

15. Thus - central nervous sys is...
***nicotinic is ionotropic; muscarinic is GPCR
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

16. Where does the bolus go after mouth chews food
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Moves down thru esophageal sphincter
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
- 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

17. Morula (...totipotent)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Salivary amylase; both hydrolyze glycosidic linkages

18. Stomach has no lacteals
ER
Vitamin K - b12 - thiamin - riboflavin
Most absorption occurs in sm intestine
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

19. Failure of apoptosis can result in
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Facilitated diffusion from hi to lo conc
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

20. How does birth control work?
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Processes: axons - dendrites
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

21. chylomicron concentration in blood after meal
Sorts - modifies - concentrates proteins from the ER
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Increases surface area of food ball (bolus)

22. Where do pancreatic secretions take effect
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
RBCs - large proteins; What does enter is called the filtrate

23. Fructose relates how structurally to glucose
Inner lining of circulatory system
Liposome has phospholipid bilayer
Fructose is a structural isomer of glucose
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

24. golgi body
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
'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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Sorts - modifies - concentrates proteins from the ER

25. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve
HCl; secreted by parietal cells under stim by gastrin
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
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... ...

26. Exocrine GlandS: stomach
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
- 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
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

27. glucagon secreted by
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Chylomicrons are much bigger
'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.'

28. The path from blood plasma to urine

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29. what happens to bile secretions
In mouth - breakdown of starch into polysaccharides
Mostly reabsorbed to liver
Primitive streak - which consists of cells of the MESODERM ****
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

30. examples of different cavities... (compartments for viscera)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Paracrine (local) - endocrine (longer distance)
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**
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.

31. What does peptic refer to in general
Somatic nervous sys - autonomic nervous sys
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Digestion
Inner lining of blood vessels

32. Seen in lysosomal storage diseases
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Sorts - modifies - concentrates proteins from the ER
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

33. 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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
- 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
Peptides
Outermost layer of blood vessel

34. review: parietals secrete intrinsic factor...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
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
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
Peripheral nervous sys

35. when thinking of proteins - think
Mostly reabsorbed to liver
Nitrogen
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Ventrally (picture skeletal vertebrae)

36. The esophageal sphincter is...
Normally contracted
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Growth 1 (G1) phase: STRUCTURAL ProteinS - ENZYMES; This is a very active period - where the cell synthesizes its vast array of proteins - including the enzymes and structural proteins it will need for growth. In G1 stage each of the chromosomes cons

37. Kidney
Moves down thru esophageal sphincter
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
In mouth - breakdown of starch into polysaccharides
Meiosis creates germ cells

38. Induction affects...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Direction of differentiation
Vitamin K - b12 - thiamin - riboflavin
Below hypothalamus

39. Meiosis I Telophase I
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
Many modern drugs are ligands for GPCRs
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

40. What testosterone released by secondary follicle by LH stim is converted to...
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Mostly reabsorbed to liver
It targets liver conc of prothrombin - fibrinogen etc
Sympathetic: dilates pupil (for night hunting)

41. What surrounds the hydrophilic heads of the new TAGs
Apoproteins attach to outside of globules; these move to Golgi and are released into interstitial fluid via exocytosis as chylomicrons --->most go to lacteal system
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
In gastric pits; secretions combine into gastric juice
Zygotes are diploid

42. serous membranes have a viscera - facing layer and a body wall - facing layer
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
In gastric pits; secretions combine into gastric juice
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

43. Gland: ovaries
Regulated by gastrointestinal horms
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

44. almost all cells can store Some glycogen - but...
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Only musc and esp ** liver can store large amounts
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Sympathetic: dilates pupil (for night hunting)

45. exocrine types
Membrane - bound - endocytosed bodies
Digestion
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

46. After meiosis II - Male

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47. little by little chyme is squirted out thru pyloric sphincter
- 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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Regulated by gastrointestinal horms
Interstitial fluid (eg prostaglandins - cytokines)

48. pancreatic enzymes are zymogens
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Sympathetic: dilates pupil (for night hunting)
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

49. What are the memb - bound enzymes of the brush border?
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

50. Sensory - motor neurons are part of which nervous system
Gonadotropin releasing hormone - GnRH
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Peripheral nervous sys