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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. Where are these exocrine glands located
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Lower blood pH
In gastric pits; secretions combine into gastric juice
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

2. keep in mind that enterocyte is like a regular euk cell
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Has memb - bound organelles - etc...
Peripheral nervous sys

3. Exocrine GlandS: stomach
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
- 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
In mouth - breakdown of starch into polysaccharides
Glycosaminoglycans - prots - AAs - lipids

4. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Smooth ER
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

5. insulin secreted by
Beta cells
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

6. What is a dorsal root ganglion?
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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Abdominal cavity - which is coated in serous fluid
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

7. 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
Mostly reabsorbed to liver
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Systems (eg digestive system consists of many organs)

8. SYMP neurons originate in= PARA neurons originate in=
Water flows from the tubule - concentrating the filtrate - raising BP
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
Peptides
Gastrulation occurs: formation of three primary germ layers = differentiation

9. Anterior eye
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
***nicotinic is ionotropic; muscarinic is GPCR
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

10. pancreatic enzymes are zymogens
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Normally contracted
The renal corpuscle

11. FLAT PG: FSH
Organs
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

12. What else do parietals do?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

13. examples of different cavities... (compartments for viscera)
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
'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

14. ADH
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
Water flows from the tubule - concentrating the filtrate - raising BP
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
Carry signals to musc OR Gland

15. Cell determination begins At what stage of development
Estradiol
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

16. The esophageal sphincter is...
Sensory (afferent - dorsal) - motor (efferent - ventral)
Has memb - bound organelles - etc...
Normally contracted
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

17. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Form barrier to extracellular fluid
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
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
Paracrine (local) - endocrine (longer distance)

18. After meiosis II...
***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
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
In mouth - breakdown of starch into polysaccharides
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

19. almost all exocytosed proteins pass through this
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Smooth ER

20. 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
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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)
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

21. position of AP...
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Below hypothalamus
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

22. Beta - oxidation in liver produces...
Uncontracted: parasymp (eg opoid use)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Break down TAGs to monoglycerides and free fatty acids
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

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

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24. What is an endorphin?
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Water flows from the tubule - concentrating the filtrate - raising BP
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
An endogenous morphine

25. Four tissues
Thru tight junctions by favorable osmotic gradient
Many modern drugs are ligands for GPCRs
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

26. Where is bile produced
Nitrogen
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Regulated by gastrointestinal horms
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**

27. Contrast PNS- Somatic with PNS- Autonomic
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
It targets liver conc of prothrombin - fibrinogen etc

28. remaining secondary follicle becomes
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
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
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

29. What is secreted into filtrate by cells of the proximal tubule?
Smooth ER
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
AAs can be burned for energy or converted to fat for storage

30. What hormones affect the stomach?
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
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
HCl; secreted by parietal cells under stim by gastrin

31. gametes are haploid
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Determined by whether in front of or behind the lens
Zygotes are diploid
Glands w/ducts: Exocrine glands

32. What is main difference is signal transmission in nicotinic vs muscarinic?
***nicotinic is ionotropic; muscarinic is GPCR
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu
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
Increases solute conc and osmotic pressure of the ***medulla

33. Sensory - motor neurons are part of which nervous system
All carbs absorbed at enterocytes are carried to liver by portal vein
Peripheral nervous sys
Lower blood pH
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

34. cytosol pH
About 7.2
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**
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
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

35. 3 phases of menstrual cycle
Carry signals to musc OR Gland
In gastric pits; secretions combine into gastric juice
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
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)

36. physiology of gall bladder - liver and pancreatic secretions
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Combined via conjunction of pancreatic duct and common bile duct; common bile duct originates at **cystic duct where gall bladder and liver secretions combine ..cystic duct+common bile duct+pancreatic duct --->into duodenum
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Liver is the control center for blood glucose; is fed by portal vein from sm intest

37. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Moves down thru esophageal sphincter

38. After meiosis II - Female

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39. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Chylomicrons are much bigger
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Corpus luteum degrades into corpus albicans
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

40. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Gastrulation occurs: formation of three primary germ layers = differentiation
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
An endogenous morphine

41. bile + fat forms
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Break down TAGs to monoglycerides and free fatty acids
Regulated by gastrointestinal horms

42. The bolus (chewing) is digested to what in the stomach
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
Chyme (by combined activity of exocrine glands)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

43. Determination is different than differentiation
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
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
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Inner lining of circulatory system

44. Liver Functions
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Glucose
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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

45. How does glycogen compare to starch
ER
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

46. How does birth control work?
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Most absorption occurs in sm intestine

47. important pancreatic enzymes
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Night vision
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
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

48. Failure of apoptosis can result in
Peripheral nervous sys
Interstitial fluid (eg prostaglandins - cytokines)
Cancer; apop can be programmed cell death; mitochon can play important role in apop
'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

49. What is the path of a sound wave that enters the ear?
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
ER
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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

50. Adrenal cortex hormones (STEROIDS)
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Conjunction of cell body w/axon
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)