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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. During ejaculation - sperm...

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2. How does glycogen compare to starch
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

3. in the dark is rhodopsin active or inactive?
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Water flows from the tubule - concentrating the filtrate - raising BP
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

4. What is the path of a sound wave that enters the ear?
Organs
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
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
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)

5. Four tissues
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
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

6. oxytocin
Low because AAs are immediately used in translation
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Form barrier to extracellular fluid

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

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8. albumin has What affect on blood osmotic pressure
Albumin increases osmolarity of blood; increases osmotic pressure
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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**
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

9. How long are peptides when absorbed at brush border
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
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
Prod of steroid hormones in testes - ovaries
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

10. Contrast PNS- Somatic with PNS- Autonomic
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Micelles; micelles (made of bile) go back and forth between brush border and chyme

11. How does duod deal with hi HCl from stom
Neurons may perform one of three functions....
Ups bicarbonate secretion by pancreas; raises pH to 6.0
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

12. Peritoneal refers to...
Abdominal cavity - which is coated in serous fluid
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
- 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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

13. What testosterone released by secondary follicle by LH stim is converted to...
Paracrine (local) - endocrine (longer distance)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Chylomicrons are much bigger
Glands w/ducts: Exocrine glands

14. Where does fertilization occur
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Gastrulation occurs: formation of three primary germ layers = differentiation
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
Fallopian tubes

15. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
In mouth - breakdown of starch into polysaccharides
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
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

16. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

17. main point of fat transport...
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Needs time for bile - lipase - micelle migration - enterocyte uptake
Facilitated diffusion: no symport w/ secondary transport
Sensory (afferent - dorsal) - motor (efferent - ventral)

18. What does peroxisome do
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
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

19. trypsin is secreted by
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

20. At post - two weeks ovulation
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Corpus luteum degrades into corpus albicans
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

21. What is a toxic byproduct of gluconeogenesis from proteins
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Sensory (afferent - dorsal) - motor (efferent - ventral)
Increases surface area of food ball (bolus)
All carbs absorbed at enterocytes are carried to liver by portal vein

22. amylase acts where on carbs
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
In mouth - breakdown of starch into polysaccharides
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Faces the lumen

23. Where does the bolus go after mouth chews food
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
Glands w/ducts: Exocrine glands
Direction of differentiation
Moves down thru esophageal sphincter

24. What is the endothelium?
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Inner lining of circulatory system
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Creates one ovum (23 N) and three polar bodies

25. Embryology
Glucose
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
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
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

26. Meiosis II: EQUATIONAL DIVISION
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Lower blood pH

27. What is a nerve? (PNS)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Night vision
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
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

28. Kidney physiology...

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29. Creating gradients requires what?
Chylomicrons are much bigger
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
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
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

30. What is somatostatin
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
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. ADH
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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
1) by integral ion channels 2) transmitted by second messenger system
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

32. gradual increase in FSH typical of primary follicle development;
***nicotinic is ionotropic; muscarinic is GPCR
Pancreatic duct (made of acinar cells?)
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

33. axon hillock physiology
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Conjunction of cell body w/axon
Fructose is a structural isomer of glucose
Testosterone upon stim by LH

34. For focal point that is nearby - what will the lens look like
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Beta cells
***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
ER

35. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Low because AAs are immediately used in translation
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

36. euk cell has two principal sides
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Lumen (ie continuous w/body cavity) and cytosol

37. How does water cross the apical membrane
Lysosome
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
Thru tight junctions by favorable osmotic gradient
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

38. pancreatic amylase is much stronger than
Liposome has phospholipid bilayer
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi 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
Salivary amylase; both hydrolyze glycosidic linkages

39. Anatomy of the villi
Contain capillary network - lymph vessels (lacteals)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Smooth ER
Direction of differentiation

40. Meiosis I Anaphase I
Needs time for bile - lipase - micelle migration - enterocyte uptake
Smooth ER
Homologous chromosomes separate - migrate towards opposite poles/centrioles
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

41. Aldosterone (sodium uptake - potassium secretion)
1) by integral ion channels 2) transmitted by second messenger system
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
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)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

42. What are the memb - bound enzymes of the brush border?
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Salivary amylase; both hydrolyze glycosidic linkages

43. Leydig cells produce
Testosterone upon stim by LH
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Most absorption occurs in sm intestine
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

44. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Testosterone and estradiol
'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
Lower blood pH
Fallopian tubes

45. motor (efferent) neurons --> VENTRAL
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Carry signals to musc OR Gland
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Contain capillary network - lymph vessels (lacteals)

46. Where does blood to be filtered by kidney enter the nephron?

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47. Sensory - motor neurons are part of which nervous system
Peripheral nervous sys
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti
Peptides
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

48. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Creates one ovum (23 N) and three polar bodies
Systems (eg digestive system consists of many organs)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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

49. In effect LH - FSH stimulate
- 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
Prod of steroid hormones in testes - ovaries
All carbs absorbed at enterocytes are carried to liver by portal vein
Two perpendicular semicircular canals involved in balance - equilibrium

50. inhibin secreted by
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Conjunction of cell body w/axon
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
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