Test your basic knowledge |

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. what happens when glycogen stores are saturated and blood sugar remains high?
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
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**

2. What is the mesentery?
Lysosome
Zygotes are diploid
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

3. sensory (afferent) neurons
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Corpus luteum degrades into corpus albicans
Conjunction of cell body w/axon
Faces the lumen

4. Meiosis I Anaphase I
Somatic nervous sys - autonomic nervous sys
Within the paravertebral ganglion - running parallel to spinal cord
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Liposome has phospholipid bilayer

5. testosterone can be aromatized to...
Estradiol
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Glucose and ketone bodies (not from glycogen stores)
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

6. The bolus (chewing) is digested to what in the stomach
Chyme (by combined activity of exocrine glands)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Inner lining of blood vessels
Membrane - bound - endocytosed bodies

7. When 'coumadin targets liver enzymes to act as anticoagulant'...
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
It targets liver conc of prothrombin - fibrinogen etc
Lysosome

8. alpha - amylase in the mouth digests what kind of bond
Only musc and esp ** liver can store large amounts
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Eukaryotes
Form barrier to extracellular fluid

9. Where would materials slated for digestion go?
Lysosome
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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
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)

10. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Peptides
Corpus luteum degrades into corpus albicans
Gastrulation occurs: formation of three primary germ layers = differentiation

11. Meiosis I Metaphase I
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

12. inhibin secreted by
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Sorts - modifies - concentrates proteins from the ER
Processes: axons - dendrites
Micelles; micelles (made of bile) go back and forth between brush border and chyme

13. How does reabsorption force nutrients across apical membrane of proximal tubule
Digestion
Facilitated diffusion: no symport w/ secondary transport
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

14. What else do parietals do?
- 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
An endogenous morphine
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

15. parathyroid hormones
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Zygote (fertilization in fallopian tubes); morula (up to 8 cells - undifferentiated ie totipotent); blastocyst (4+ days - implants into uterus; HCG secretion stims corpus luteum; gradually placenta replaces HCG as estrogen/progest source; cells not t
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

16. fructose enters enterocyte by
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Facilitated diffusion: no symport w/ secondary transport
Estradiol

17. pancreatic amylase is much stronger than
Beta cells
Salivary amylase; both hydrolyze glycosidic linkages
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

18. E storage per unit mass
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
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Nitrogen
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

19. 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
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Outermost layer of blood vessel

20. After meiosis II...
1) by integral ion channels 2) transmitted by second messenger system
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.
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

21. review: parietals secrete intrinsic factor...
- 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
AAs can be burned for energy or converted to fat for storage
Salivary amylase; both hydrolyze glycosidic linkages
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

22. micelles vs liposomes
Liposome has phospholipid bilayer
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

23. In other words...
Creates one ovum (23 N) and three polar bodies
Smooth ER
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
Below hypothalamus

24. 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
Below hypothalamus
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

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

26. almost all exocytosed proteins pass through this
Eukaryotes
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Increases solute conc and osmotic pressure of the ***medulla
Smooth ER

27. Adrenal cortex hormones (STEROIDS)
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Organs
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Transfer signals from neuron - neuron; 90% of neurons are interneurons

28. Chewing does what?
Increases surface area of food ball (bolus)
Inner lining of circulatory system
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
Fovea (highest amount of cones)

29. Adrenal medulla hormones (TYR- DERIVED)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Facilitated diffusion from hi to lo conc
- 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
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

30. gradual increase in FSH typical of primary follicle development;
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)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
All carbs absorbed at enterocytes are carried to liver by portal vein
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

31. at lo blood sugar...
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
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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... ...
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

32. What controls release of LH - FSH from anterior pituitary
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Direction of differentiation
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang
Gonadotropin releasing hormone - GnRH

33. from the loop of henle...
All carbs absorbed at enterocytes are carried to liver by portal vein
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
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

34. 3 phases of menstrual cycle
About 7.2
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)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

35. 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
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Faces the lumen
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

36. important pancreatic enzymes
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
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

37. lysosome pH
5
Lower blood pH
Interstitial fluid (eg prostaglandins - cytokines)
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

38. Important of villi (='shaggy hair') More fluid makes contact with the epithelial tissue: thus nutrients in solution have less distance to travel to diffuse into villi.

39. in mammals - gastrulation involves formation of the
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Primitive streak - which consists of cells of the MESODERM ****
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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)

40. What is the endothelium?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Inner lining of circulatory system
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

41. Does bile digest fat?
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Glycosaminoglycans - prots - AAs - lipids
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

42. Energy from fat - prot - gluc
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Testosterone upon stim by LH
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Mostly reabsorbed to liver

43. mucus cells line the stomach...
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Nitrogen
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

44. Four tissues
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
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

45. food in duod stims release of gastrointestinal hormones
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
***nicotinic is ionotropic; muscarinic is GPCR

46. What is a dorsal root ganglion?
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
In gastric pits; secretions combine into gastric juice
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
***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

47. Embryology
Estradiol
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Zygote (fertilization in fallopian tubes); morula (up to 8 cells - undifferentiated ie totipotent); blastocyst (4+ days - implants into uterus; HCG secretion stims corpus luteum; gradually placenta replaces HCG as estrogen/progest source; cells not t
Transfer signals from neuron - neuron; 90% of neurons are interneurons

48. What is somatostatin
Interstitial fluid (eg prostaglandins - cytokines)
'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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

49. 80-90% fat absorbed this way
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Vitamin K - b12 - thiamin - riboflavin

50. Leydig cells produce
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Fructose is a structural isomer of glucose
Testosterone upon stim by LH