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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. Most important nutrients absorbed by large intestine
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.
Night vision
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

2. Interaction of corpus luteum/placenta
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Carry signals to musc OR Gland
Ventrally (picture skeletal vertebrae)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

3. What determines number of chromosomes?
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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
Ganglion

4. Both divisions (somatic - autonomic) of PNS consist of...
Sensory (afferent - dorsal) - motor (efferent - ventral)
Nitrogen
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... ...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

5. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Corpus luteum degrades into corpus albicans
Glucose and ketone bodies (not from glycogen stores)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

6. The path from blood plasma to urine

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7. signal transduction occurs by 2 paths
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
1) by integral ion channels 2) transmitted by second messenger system
Inner lining of blood vessels

8. Does bile digest fat?
**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)
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... ...
Alpha 1-4 and 1-6 (branching) glycosidic linkages

9. Which fats are not absorbed like this
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

10. Liver Functions
Chyme (by combined activity of exocrine glands)
Albumin increases osmolarity of blood; increases osmotic pressure
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
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

11. After meiosis II - Female

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12. micelles also pick up
Glycosaminoglycans - prots - AAs - lipids
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

13. cAMP - cGMP - calmodulin...
Facilitated diffusion: no symport w/ secondary transport
Estradiol
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

14. The EYE
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Paracrine (local) - endocrine (longer distance)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Meiosis creates germ cells

15. Aldosterone (sodium uptake - potassium secretion)
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Interstitial fluid (eg prostaglandins - cytokines)
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)

16. What testosterone released by secondary follicle by LH stim is converted to...
Zygotes are diploid
- 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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

17. Four tissues
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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

18. when thinking of proteins - think
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
Nitrogen
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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

19. What does peroxisome do
Direction of differentiation
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**
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

20. 'Cell bodies of somatic motor neurons are located in....'
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Lysosome
Albumin increases osmolarity of blood; increases osmotic pressure

21. medium for paracrine hormones
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
Interstitial fluid (eg prostaglandins - cytokines)
vitreous humor - retina - fovea
Within the paravertebral ganglion - running parallel to spinal cord

22. what cannot cross the fenestrations of the renal corpuscle
- 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
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
Moves down thru esophageal sphincter
RBCs - large proteins; What does enter is called the filtrate

23. lysosome pH
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
5
Liver is the control center for blood glucose; is fed by portal vein from sm intest
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

24. Gland: ovaries
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Transfer signals from neuron - neuron; 90% of neurons are interneurons
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
Albumin increases osmolarity of blood; increases osmotic pressure

25. Contrast PNS- Somatic with PNS- Autonomic
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
HCl; secreted by parietal cells under stim by gastrin
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

26. review: parietals secrete intrinsic factor...
'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
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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Ventrally (picture skeletal vertebrae)

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

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28. Posterior pituitary hormones (Small Peptides)
- 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
Epithelial tissue near semniferous tubules
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
Oxytocin and ADH (aka vasopressin)

29. Neuronal cell bodies have extensions ie
Contain capillary network - lymph vessels (lacteals)
'Microvilli function as the **primary surface of nutrient absorption in the gastrointestinal tract**. Because of this vital function - the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compoun
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Processes: axons - dendrites

30. What is a toxic byproduct of gluconeogenesis from proteins
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
***nicotinic is ionotropic; muscarinic is GPCR
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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

31. How do monoglycerides and ffas get to brush border?
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Glucose and ketone bodies (not from glycogen stores)

32. euk cell has two principal sides
Beta cells
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Lumen (ie continuous w/body cavity) and cytosol
Glucose = aldose fructose = ketose

33. pancreas secretes enzymes via
Increases surface area of food ball (bolus)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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
Pancreatic duct (made of acinar cells?)

34. Where would materials slated for digestion go?
Lysosome
In gastric pits; secretions combine into gastric juice
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

35. What is feces composed of...
Faces the lumen
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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

36. 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)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Creates one ovum (23 N) and three polar bodies

37. Energy from fat - prot - gluc
Lower blood pH
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Ventrally (picture skeletal vertebrae)
Carry signals to musc OR Gland

38. What is endothelium?
Inner lining of blood vessels
ER
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

39. What is the function of the loop of Henle
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
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
Primitive streak - which consists of cells of the MESODERM ****
Increases solute conc and osmotic pressure of the ***medulla

40. How does water cross the apical membrane
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Thru tight junctions by favorable osmotic gradient
Conjunction of cell body w/axon
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)

41. overview of prot digestion
Water flows from the tubule - concentrating the filtrate - raising BP
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

42. 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
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
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
In gastric pits; secretions combine into gastric juice

43. How is glucose absorbed in sm intest
via symport - secondary transport (ie by pre - established - ATP- intensive) with Na gradient into enterocyte......with no Na gradient (ie without ATP) carbohydrate monomers could not be transported in
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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

44. main point of fat transport...
SYMP: spinal cord --->paravetebral ganglion PARA: spinal cord - brain; cell processes --->ganglion near effector organ (preganglionic neurons) extend outside of spinal cord to synapse at ganglia - go on along postganglionic neurons
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

45. in mammals - gastrulation involves formation of the
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Primitive streak - which consists of cells of the MESODERM ****
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

46. in the dark is rhodopsin active or inactive?
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
About 7.2
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

47. fructose enters enterocyte by
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Zygotes are diploid
Determined by whether in front of or behind the lens
Facilitated diffusion: no symport w/ secondary transport

48. when cells hit their limit for prot storage...
Increases blood Calcium
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Lumen (ie continuous w/body cavity) and cytosol
AAs can be burned for energy or converted to fat for storage

49. Mucus - digestive enzymes released thru
Glands w/ducts: Exocrine glands
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
'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
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

50. Anatomy of the villi
Contain capillary network - lymph vessels (lacteals)
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**
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest