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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. Where are these exocrine glands located
Regulated by gastrointestinal horms
In gastric pits; secretions combine into gastric juice
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Below hypothalamus

2. bundles of collecting ducts are called
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Oxytocin and ADH (aka vasopressin)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

3. mucus cells line the stomach...
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

4. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Glands w/ducts: Exocrine glands
Conjunction of cell body w/axon
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

5. The apical side of the villi...
Increases blood Calcium
Albumin increases osmolarity of blood; increases osmotic pressure
Facilitated diffusion: no symport w/ secondary transport
Faces the lumen

6. Where would materials slated for digestion go?
Many modern drugs are ligands for GPCRs
Lysosome
Low because AAs are immediately used in translation
Liver is the control center for blood glucose; is fed by portal vein from sm intest

7. Three stages of the menstrual cycle
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

8. How does water cross the apical 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
Thru tight junctions by favorable osmotic gradient
Digestion
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

9. medium for paracrine hormones
Interstitial fluid (eg prostaglandins - cytokines)
Many modern drugs are ligands for GPCRs
Fovea (highest amount of cones)
Glycosaminoglycans - prots - AAs - lipids

10. golgi body
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Sorts - modifies - concentrates proteins from the ER
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
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

11. What hormones affect the stomach?
AAs can be burned for energy or converted to fat for storage
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
Increases surface area of food ball (bolus)
Facilitated diffusion from hi to lo conc

12. How do parietal cells work ** (involves CO2)
About 7.2
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

13. What testosterone released by secondary follicle by LH stim is converted to...
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Break down TAGs to monoglycerides and free fatty acids
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

14. 3 phases of menstrual cycle
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)
AAs can be burned for energy or converted to fat for storage
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
Increases blood Calcium

15. 80% of end product of carbohydrate metabolism is...
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Gastrulation occurs: formation of three primary germ layers = differentiation
Glucose

16. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Carry signals to musc OR Gland
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

17. Where does the bolus go after mouth chews food
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Moves down thru esophageal sphincter
Cancer; apop can be programmed cell death; mitochon can play important role in apop

18. mitosis creates somatic cells
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Systems (eg digestive system consists of many organs)
Meiosis creates germ cells
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

19. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
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
Vitamin K - b12 - thiamin - riboflavin
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Chylomicrons are much bigger

20. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Glands w/ducts: Exocrine glands
***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

21. zygotic life cycle
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Pancreatic duct (made of acinar cells?)
Zygotes are diploid
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

22. chylomicron concentration in blood after meal
Glucose
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

23. when thinking of proteins - think
In mouth - breakdown of starch into polysaccharides
The renal corpuscle
Nitrogen
Water flows from the tubule - concentrating the filtrate - raising BP

24. From that point...
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
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.
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

25. E storage per unit mass
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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
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
Carbohydrates are highly hydrated: one water mol per carbon mol - fats are anhydrous: contain more reduced carbons per unit mass - altogether fats contain 6X energy per unit mass

26. Kidney physiology...

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27. axon hillock physiology
Lower blood pH
Conjunction of cell body w/axon
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)
'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

28. Exocrine GlandS: stomach
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
- 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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

29. The bolus (chewing) is digested to what in the stomach
- 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
Chyme (by combined activity of exocrine glands)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

30. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
visual (rhodopsin is receptor - derived from Vit A; conformation change occurs with photon to hyperpolarize rod cells; cone cells use photopsin for receptor) - olfactory - mood (NTs targeted by antidepressants - antipsychotics - etc; GABA is inhibit
Chylomicrons are much bigger
Estradiol
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

31. overview of prot digestion
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Peripheral nervous sys
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
Beta cells

32. After meiosis II - Female

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33. ADH
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Within the paravertebral ganglion - running parallel to spinal cord
Sorts - modifies - concentrates proteins from the ER
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

34. In other words...
Facilitated diffusion from hi to lo conc
Determined by whether in front of or behind the lens
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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

35. What else do parietals do?
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

36. these transport proteins - when concs are high enough...
It targets liver conc of prothrombin - fibrinogen etc
Salivary amylase; both hydrolyze glycosidic linkages
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

37. FSH - LH - HCG - inhibin are...
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)
Peptides
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

38. food in duod stims release of gastrointestinal hormones
Gastrulation occurs: formation of three primary germ layers = differentiation
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

39. Thus inhibiting parietal cells could do What to blood pH
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
The wall of the body or of a body cavity or hollow structure
Lower blood pH
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

40. serous membranes have a viscera - facing layer and a body wall - facing layer
Estradiol
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

41. Where does fertilization occur
Fallopian tubes
Peripheral nervous sys
Increases surface area of food ball (bolus)
Glands w/ducts: Exocrine glands

42. What controls release of LH - FSH from anterior pituitary
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Gonadotropin releasing hormone - GnRH
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

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

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44. peroxisome is derived from this
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
ER
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Increases blood Calcium

45. What do lipases do
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Break down TAGs to monoglycerides and free fatty acids
'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.'
Needs time for bile - lipase - micelle migration - enterocyte uptake

46. What is a toxic byproduct of gluconeogenesis from proteins
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Paracrine (local) - endocrine (longer distance)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Ammonia; must be converted to urea by liver and excreted in urine by kidney

47. Where do absorbed fats go in the enterocyte
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Interstitial fluid (eg prostaglandins - cytokines)

48. What does peroxisome do
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
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
Increases solute conc and osmotic pressure of the ***medulla

49. What is a dorsal root ganglion?
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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

50. What does portal vein do
Fallopian tubes
Organs
Pancreatic duct (made of acinar cells?)
All carbs absorbed at enterocytes are carried to liver by portal vein