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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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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. After meiosis II - Male

2. What controls release of LH - FSH from anterior pituitary
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Gonadotropin releasing hormone - GnRH
Albumin increases osmolarity of blood; increases osmotic pressure
vitreous humor - retina - fovea

3. energy source of neurons
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Glucose and ketone bodies (not from glycogen stores)
Peptides
5

4. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Peptide; stims growth of nearly all cell of body; all other anterior pituitary horms have specific targets; upregulates anabolic pathways; use of fat for energy goes up (fat - burning); increases AA transport across cell membrane (nutrient uptake)
Adrenal gland -- AC: steroids (cortisol - aldosterone); AM: catecholamines (epi - norepi); Islets of langerhans: peptides (insulin/glucagon) ANTAGONISTS: calcitonin (thyroid - peptide lowers Ca in blood); parathyroid hormone - peptide - vitamin D pat
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

5. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Creates one ovum (23 N) and three polar bodies
In mouth - breakdown of starch into polysaccharides
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

6. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Abdominal cavity - which is coated in serous fluid
Testosterone and estradiol
Glucose
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

7. fat digestion is time - intensive
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Carry signals to musc OR Gland
Needs time for bile - lipase - micelle migration - enterocyte uptake

8. What does lipase attack exactly
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Ventrally (picture skeletal vertebrae)
All carbs absorbed at enterocytes are carried to liver by portal vein
Break down TAGs to monoglycerides and free fatty acids

9. In general - parietal=
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
The wall of the body or of a body cavity or hollow structure
Most absorption occurs in sm intestine

10. Difference between euk and prok flagella
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Prod of steroid hormones in testes - ovaries
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

11. FLAT PG: TSH aka thyrotropin
RBCs - large proteins; What does enter is called the filtrate
AAs can be burned for energy or converted to fat for storage
Lumen (ie continuous w/body cavity) and cytosol
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

12. Kidney
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Processes: axons - dendrites
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

13. small intestine=
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Regulated by gastrointestinal horms
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
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)

14. How does reabsorption force nutrients across apical membrane of proximal tubule
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
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
Determined by whether in front of or behind the lens
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

15. pancreatic amylase is much stronger than
Beta cells
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
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.
Salivary amylase; both hydrolyze glycosidic linkages

16. Creating gradients requires what?
Neurons may perform one of three functions....
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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
Fallopian tubes

17. peroxisome is derived from this
ER
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Peptides
Gonadotropin releasing hormone - GnRH

18. mitosis creates somatic cells
Ventrally (picture skeletal vertebrae)
Meiosis creates germ cells
Salivary amylase; both hydrolyze glycosidic linkages
Uncontracted: parasymp (eg opoid use)

19. Kidney physiology...

20. is intracellular AA conc hi or low?
Low because AAs are immediately used in translation
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 (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

21. Local vs long - distance mediators
Paracrine (local) - endocrine (longer distance)
AAs can be burned for energy or converted to fat for storage
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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

22. A contracted iris occurs with what kind of stimulation
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Sympathetic: dilates pupil (for night hunting)
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

23. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
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
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... ...
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

24. Induction affects...
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Direction of differentiation
***nicotinic is ionotropic; muscarinic is GPCR

25. overview of prot digestion
Vitamin K - b12 - thiamin - riboflavin
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

26. 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
- 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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Thru tight junctions by favorable osmotic gradient
Ups bicarbonate secretion by pancreas; raises pH to 6.0

27. important because in meiosis germ - line cells begin as 46 2N w/ 23 pairs of homologous chromosomes which are replicated in S phase of interphase to 23 pairs of sister chromatids = still 46 2N
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
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
Epithelial tissue near semniferous tubules
Fallopian tubes

28. Where would materials slated for digestion go?
Lysosome
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
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

29. Think of spinal cord injury
Zygotes are diploid
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

30. liver and blood glucose...
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
Gonadotropin releasing hormone - GnRH
Liver is the control center for blood glucose; is fed by portal vein from sm intest
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

31. How does the body mobilize fat stores
***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
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
Liposome has phospholipid bilayer
Glands w/ducts: Exocrine glands

32. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Normally contracted
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Mostly reabsorbed to liver
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

33. Gland: ovaries
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

34. what else is located in the inner ear (not directly related to auditory)
Secondary oocyte (stim'd by LH stimulation of theca cells causing release of testosterone - converted to estradiol; eventually brings about luteal surge -->EQUATIONAL DIVISION-->ovum released during ovulation into fallopian tube; burst follicle becom
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Two perpendicular semicircular canals involved in balance - equilibrium
Lysosome

35. Adrenal cortex hormones (STEROIDS)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Gastrulation occurs: formation of three primary germ layers = differentiation
Pancreatic duct (made of acinar cells?)
Facilitated diffusion from hi to lo conc

36. What surrounds the hydrophilic heads of the new TAGs
Epithelial tissue near semniferous tubules
Beta cells
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
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

37. After meiosis II...
Faces the lumen
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

38. gametic life cycle
Increases blood Calcium
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Albumin increases osmolarity of blood; increases osmotic pressure
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

39. sensory (afferent)/interneurons/motor (efferent)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Neurons may perform one of three functions....
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

40. Different organs working together
Systems (eg digestive system consists of many organs)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Neurons may perform one of three functions....
About 7.2

41. what cannot cross the fenestrations of the renal corpuscle
Sympathetic: dilates pupil (for night hunting)
Lumen (ie continuous w/body cavity) and cytosol
RBCs - large proteins; What does enter is called the filtrate
Normally contracted

42. Contrast PNS- Somatic with PNS- Autonomic
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Neurons may perform one of three functions....
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Needs time for bile - lipase - micelle migration - enterocyte uptake

43. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
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

44. Interaction of corpus luteum/placenta
About 7.2
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
Below hypothalamus
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

45. PNS nerve signal
Mostly reabsorbed to liver
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
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
ER

46. only monosaccharides are absorbed
Many modern drugs are ligands for GPCRs
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Interstitial fluid (eg prostaglandins - cytokines)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

47. Some epithelial cells are... others...
In mouth - breakdown of starch into polysaccharides
Carry signals to musc OR Gland
- 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
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

48. Gastrulation: ectoderm/mesoderm/endoderm
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Glands w/ducts: Exocrine glands
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

49. Failure of apoptosis can result in
Sensory (afferent - dorsal) - motor (efferent - ventral)
Moves down thru esophageal sphincter
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Cancer; apop can be programmed cell death; mitochon can play important role in apop

50. The esophageal sphincter is...
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Normally contracted
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion