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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.
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. lysosome main function and derivation
Form barrier to extracellular fluid
Peripheral nervous sys
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

2. bile + fat forms
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
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
Creates one ovum (23 N) and three polar bodies
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

3. How does reabsorption force nutrients across apical membrane of proximal tubule
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
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
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

4. 3 phases of menstrual cycle
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
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
Somatic nervous sys - autonomic nervous sys
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)

5. in the presence of ADH what happens to movement of water across nephron membr
Water flows from the tubule - concentrating the filtrate - raising BP
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
An endogenous morphine

6. fat digestion is time - intensive
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Needs time for bile - lipase - micelle migration - enterocyte uptake
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
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

7. Local vs long - distance mediators
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Paracrine (local) - endocrine (longer distance)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
The renal corpuscle

8. Some epithelial cells are... others...
5
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Increases solute conc and osmotic pressure of the ***medulla
- 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

9. Liver Functions
Fallopian tubes
Inner lining of circulatory system
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

10. What is the net effect of the loop of Henle
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)
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Most absorption occurs in sm intestine

11. What are the memb - bound enzymes of the brush border?
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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

12. calcitonin

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13. PNS is broken down into
Epithelial tissue near semniferous tubules
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
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
Somatic nervous sys - autonomic nervous sys

14. Luteal surge
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Below hypothalamus
Salivary amylase; both hydrolyze glycosidic linkages
Carry signals to musc OR Gland

15. A group of cell bodies in CNS is nucleus - outside CNS is...
Sympathetic: dilates pupil (for night hunting)
Fovea (highest amount of cones)
Ganglion
Uncontracted: parasymp (eg opoid use)

16. thyroid hormones: Not All One Kind of HORM
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
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Interstitial fluid (eg prostaglandins - cytokines)

17. Most important nutrients absorbed by large intestine
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
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

18. Gastrin from G cells stims parietal cells...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

19. PNS review: SAME DAVE
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

20. Neuronal cell bodies have extensions ie
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Processes: axons - dendrites
Within the paravertebral ganglion - running parallel to spinal cord
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

21. Meiosis I Telophase I
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
The renal corpuscle

22. What is feces composed of...
Glycosaminoglycans - prots - AAs - lipids
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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
Glucose and ketone bodies (not from glycogen stores)

23. How do parietal cells work ** (involves CO2)
Water flows from the tubule - concentrating the filtrate - raising BP
5
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Sensory (afferent - dorsal) - motor (efferent - ventral)

24. remaining secondary follicle becomes
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Homologous chromosomes separate - migrate towards opposite poles/centrioles

25. euk cell has two principal sides
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Creates one ovum (23 N) and three polar bodies
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Lumen (ie continuous w/body cavity) and cytosol

26. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Paracrine (local) - endocrine (longer distance)
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

27. Gastrulation: ectoderm/mesoderm/endoderm
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
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

28. protein absorption at enterocyte
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
5
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
Thru tight junctions by favorable osmotic gradient

29. What does peptic refer to in general
Peripheral nervous sys
Digestion
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

30. important pancreatic enzymes
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Peptides
Determined by whether in front of or behind the lens

31. In general - parietal=
Meiosis creates germ cells
The wall of the body or of a body cavity or hollow structure
ER
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

32. chylomicron concentration in blood after meal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
In mouth - breakdown of starch into polysaccharides
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

33. gametic life cycle
Form barrier to extracellular fluid
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
In gastric pits; secretions combine into gastric juice
Glucose

34. Where else does ADH act
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Carry signals to musc OR Gland
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
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

35. Aldosterone (sodium uptake - potassium secretion)
Sorts - modifies - concentrates proteins from the ER
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)
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

36. interneurons
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

37. FLAT PG: prolactin
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Low because AAs are immediately used in translation
Abdominal cavity - which is coated in serous fluid
Oxytocin and ADH (aka vasopressin)

38. What is a toxic byproduct of gluconeogenesis from proteins
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Ammonia; must be converted to urea by liver and excreted in urine by kidney

39. portal vein physiology...

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40. From that point...
Somatic nervous sys - autonomic nervous sys
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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.
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

41. Some PNS nerves are found in brain - spinal cord
Glycosaminoglycans - prots - AAs - lipids
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
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

42. Think of spinal cord injury
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
An endogenous morphine

43. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
In mouth - breakdown of starch into polysaccharides
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
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

44. Different tissues working together
'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.'
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Lysosome
Organs

45. lining of abdominal cavity=
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Homologous chromosomes separate - migrate towards opposite poles/centrioles

46. 80-90% fat absorbed this way
Gastrulation occurs: formation of three primary germ layers = differentiation
Eukaryotes
The wall of the body or of a body cavity or hollow structure
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

47. Different organs working together
Smooth ER
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Glucose
Systems (eg digestive system consists of many organs)

48. What are phagosomes
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)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Within the paravertebral ganglion - running parallel to spinal cord
Membrane - bound - endocytosed bodies

49. 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
Nitrogen
Interstitial fluid (eg prostaglandins - cytokines)
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
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

50. 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
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
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)