MCAT Bio Flashcards
0
Q
What is produced from the decarboxylation of pyruvate? When does this occur?
A
1 NADH is produced for the decarboxylation of each pyruvate. This happens as a preparatory step before the Kreb’s Cycle.
1
Q
How many ATP and NADH are generated from glycolysis?
A
2 ATP
2 NADH
2
Q
What is produced during the Kreb’s cycle?
A
Per each pyruvate:
6 NADH
2 FADH2
2 ATP
3
Q
What receives the electrons at the end of the electron transport chain?
A
Oxygen is the final e- recipient.
2H + 2e + 1/2O => H2O
4
Q
How many ATP does each NADH make? Each FADH2?
A
Each NADH makes 3 ATP.
Each FADH2 makes 2 ATP.
5
Q
Why does FADH2 make fewer ATP than NADH?
A
FADH2 starts later in the electron transport chain. It goes straight to Complex II and ubiquinone instead of starting at Complex I.
6
Q
How many ATP does NADH from the matrix make? From the cytoplasm? Why?
A
NADH from matrix makes 3 ATP.
NADH from cytoplasm makes 2 ATP. This is because some of the energy in the NADH is used for the transporters that bring the NADH into the mitochondria.
7
Q
Where does glycolysis happen? The TCA Cycle? Electron Transport Chain?
A
Glycolysis is in the cytoplasm. TCA Cycle is in the mitochondrial matrix. Electron chain transport is in the inner membrane of the mitochondria.
8
Q
How many ATP are invested during Glycolysis? What is the return?
A
2 ATP invested, 4 ATP and 2 NADH (which each lead to 2 ATP) produced in return. A net gain of 6 ATP.
9
Q
How many ATP are produced during pyruvate decarboxylation?
A
6 ATP
10
Q
How many ATP are produced during the Citric Acid Cycle?
A
24 ATP.
6 NADH x 3ATP each = 18
2 FADH2 x 2ATP each = 4
2 GTP x 1 ATP each = 2
11
Q
What anaerobic options are there for producing ATP? What is the net production of ATP?
A
Alcohol Fermentation and Lactic Acid Fermentation. The net ATP production is 2. In the absence of oxygen, the cell cannot go thru with electron transport chain and the TCA Cycle. Therefore, the only production of ATP comes from glycolysis.
12
Q
What is the metabolic pathway of carbohydrates?
A
- carbohydrates
- hydrolysis to glucose
- PGAL
- pyruvate
- acetyl-CoA
- TCA Cycle
13
Q
What is the metabolic pathway of proteins?
A
- hydrolysis to amino acids
- deamination to alpha-keto acids (goes to pyruvate and/or acetyl-CoA)
2’. transamination leads to keto acids (goes to TCA cycle or acetyl-CoA)
14
Q
What is the metabolic pathway of fats?
A
- hydrolysis to
A. glycerol: goes to PGAL and continues on carbohydrate pathway
B. fatty acids: beta-oxidation to acetyl-CoA, then joins TCA cycle
15
Q
Compare prokaryotic vs. eukaryotic cells.
A
Prokaryotes: no membrane bound organelles (no nucleus, ER, mitochondria, etc.), they have plasmids, can be spherical or have a flagellum, have smaller ribosomes, unicellular organism, no cell specification
Eukaryotes: has nucleus and EMS, nucleus and nucleolus, can be multi- or uni-cellular organisms, cells can specify
16
Q
What is the difference between vesicles and vacuoles?
A
They are equivalent, but vacuoles are larger and tend to be found in plant cells.
17
Q
What are chloroplasts?
A
They are solar power plants. They contain their own DNA, much like mitochondria, and are the power plants for photosynthesis. They contain chlorophyl and create energy using sunlight, CO2 and water.
18
Q
What are the three components of the cytoskeleton?
A
- microfilaments: made of actin, used in muscles,
- intermediate filaments
- microtubules: made of tubulin proteins, hollow, provide big roads for transport, help separate chromosomes during mitosis and meiosis, structural basis for cilia and flagella
19
Q
What is the stomach primarily a site for?
A
Digestion, not absorption.
20
Q
What are the three sections of the small intestine?
A
duodenum, jejunum, and ileum.
21
Q
Where does most digestion occur in the small intestine?
A
most Digestion in Duodenum.
22
Q
What is the function of chewing?
A
Increase surface area of food so that it is more easily and readily digestible.
23
Q
Where does most of the absorption of digestion occur?
A
In the jejunum and ileum.
24
What are the fat soluble vitamins?
Vitamin A, D, E, and K.
25
What is the primary function of the large intestine? How does it compare in size to the small intestine?
The large intestine's primary function is the reabsorption of water. It has a larger diameter than the smaller intestine, but it is shorter (1.5m vs. 3m) in length.
26
What are the two processes of digestion?
1. Mechanical: breaks food into smaller bits.
| 2. Chemical: breaks chemical bonds in food molecules.
27
What is total lung capacity in humans?
About 6-7 liters
28
# Define the following lung capacities:
1. Total Lung Capacity
2. Vital Capacity
3. Residual Volume
4. Tidal Volume
5. Expiratory Reserve Volume
6. Inspiratory Reserve Volume
1. TLC: breath in as much as possible, total possible volume
2. VC: total amount we can force out (different then total volume bc expelling all air would collapse lung)
3. RV: amount left over after forcing out all we can
4. TV: normal amount exchanged on inhale/exhale (approx. 1L)
5. ERV: extra bit we can force out after normal tidal breath
6. IRV: extra bit we can force in after normal tidal breath
(TV + ERV + IRV = VC)
29
How does gas exchange occur at alveoli? What happens at higher altitudes to compensate for less oxygen?
CO2 and O2 passively run down their gradient in the alveoli, O2 into blood and CO2 into alveoli. At higher altitude people breath faster and also make more RBCs to compensate for the decreased concentration of O2.
30
Where does the Right Ventricle pump blood to? The Left Ventricle?
Right Ventricle: pumps blood into lungs.
Left Ventricle: pumps blood into body.
31
What is the order, by diameter, of the arteries and veins?
aorta, artery, arteriole, capillary, venule, vein, vena cava
32
What is the blood pathway in the entire body, starting from left ventricle?
left ventricle, aorta, arteries, arterioles, capillaries, venules, veins, vena cavas (inferior and superior), right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle.
33
What do portal systems in the cardiovascular system do?
They transport blood between organ systems without going back to the heart first. For example, the hepatic portal vein connects digestive system and liver.
34
Where is cardiac muscle found?
Only in the heart. Only in the heart.
35
What are the atrioventricular valves? What are their colloquial names?
The valves between the atria and ventricles of the heart.
On the right: tricuspid
On the left: bicuspid of mitral
36
What is the difference between sympathetic and parasympathetic nervous systems?
Sympathetic: What you need to run from a bear (breath faster, contract muscles, not pee, etc.)
Parasympathetic: When you're relaxing, digesting (respiration decreases,
37
What nervous system regulates heart beat?
Autonomic, which can be broken into sympathetic and parasympathetic.
38
What are the four electrically excitable structures in the heart?
1. Sinoatrial Node (SA)
2. Atrioventricular Node (AV)
3. Bundle of His (AV bundle)
4. Purkinje Fibers
SA begins in the action potential and contracts the atria simultaneously. The AP travels to the Purkinje Fibers via AV node, which causes the ventricles to contract.
39
What are the cells found in blood? What is their function?
1. Erythrocytes: transport oxygen, contain hemoglobin proteins to bind 4 oxygen molecules each, no organelles
2. Leukocytes:
- granular: Neutrophils, Basophils, Eosinophils (the PHILS!), help with inflammatory response, pus, allergies
- agranular: lymphocytes and monocytes that make B and T cells and macrophages
3. Platelets: cell fragments from broken up megakaryocytes
40
What does it mean that the alleles for blood are codominant?
It means that having one allele for either A or B blood type is enough for it to be expressed. That is why we can end up with type AB blood .
41
What is cooperative binding, and where does it occur?
It occurs with hemoglobin. Once one molecule of oxygen binds, the hemoglobin goes thru an allosteric conformation change that increases its affinity for more oxygen molecules. Thus, the hemoglobin becomes fully loaded before it starts to travel. But once the hemoglobin is full, the loss of one molecule of oxygen will cause another conformational change that will result in losing all of the oxygen.
42
How is CO2 transported in the body.
It is transported as HCO3-. Carbonic anhydrase facilitates this change.
CO2 + H2O => H+ and HCO3-
43
What is embryonic cleavage? Does the embryo change in size?
Cleavage is the cell division of the zygote. After the first cleavage, the zygote officially becomes an embryo.
44
When do the first, second, and third cleavage events happen?
They happen at 32, 60 and 72 hours respectively, after which point the fertilized egg has made it to the uterus.
45
What stage comes after the morula? What are the characteristics of this stage?
Blastula is the stage after morula. A mammalian blastula is a blastocyst and contains a fluid filled cavity and two cell groups:
1. trophoblast which becomes the placenta, and
2. ICM which becomes the person
46
What do the ectoderm, mesoderm and endoderm give rise to?
1. Ectoderm: brain stem, eyes, ears, skin
2. Mesoderm: muscle, skeleton, heart, kidney
3. Endoderm: epithelia, lungs, pancreas, liver, urogenital tract, thyroid, reproductive tracts
47
What are the stages of fetal development?
1. zygote
2. morula
3. blastula (blastocyst contains trophoblast and ICM)
4. gastrulation (formation endo-, meso- and ectoderm)
5. neurulation (development of nervous system begins)
48
Which has a greater oxygen affinity, maternal or fetal hemoglobin?
Fetal hemoglobin, this helps pull oxygen out of the maternal blood.
49
What are the two structures present in fetal circulation that are absent in people?
1. Foramen Ovale: allows blood to go from right atrium to left atrium
2. Ductus Arteriosus: sends blood from pulmonary artery to aorta
50
do fetal arteries carry oxygenated of deoxygenated blood?
Fetal arteries carry deoxygenated blood because it is carrying blood away from the fetus. Fetal veins carry oxygenated blood.
51
What is the difference between the "lock and key" and the "induced fit" theory?
Lock and Key: enzyme has an active site that is specific is size and shape for the substrate.
Induced Fit: substrate attaches to enzyme and forces a conformational change that is a perfect fit for the necessary enzymatic activity. Kind of like squeezing a stress ball.
52
What are 7 key features of enzymes?
1. lower activation energy
2. increase rate of reaction
3. do not alter equilibrium constant
4. are not consumed
5. are pH and temperature sensitive
6. do not affect overall delta G of reaction
7. specific for a particular reaction or class of reactions
53
What is the Michaelis-Menten equation?
E + S <=>* ES <=>** E + P
* rate K1 is forward, rate K2 is backwards
* * rate K3
54
What is the measure of an enzymes affinity for substrate? What does a low and high value mean?
Km is the measure of an enzyme's affinity for substrate. A low Km means there is a high affinity, a high Km means there is a low affinity.
55
at half Vmax, what is the value of Km equal to?
@ 1/2 Vmax, Km = [S]
56
At what temperature and pH do most biological enzymes work best?
37 celsius, and pH = 7.4
*some exceptions occur, such as enzymes in the stomach (pH 2) or in the small intestine (pH 8.5)
57
How can allosteric effects affect an enzyme?
They can be either inhibiting or activating.
58
Explain feedback inhibition.
A => B => C => D => E... and then E goes back and stops the chain between A and B.
59
What are the three types of reversible inhibition?
Competitive: Occupancy of the active site, can be overcome by increasing substrate (using statistics)
Noncompetitive: Binds to a non active site, but causes an allosteric change which deactivates the enzyme
Uncompetitive: Inhibitor binds to SE complex, removing it from the equation. Le Chatelier's pulls more S and E into complex because of this. The net effect is a lower Km and also a lower Vmax.
60
What happens during S stage in the cell cycle?
The genetic information is doubled. >... ><
61
What are the four phases of mitosis? What happens at each?
1. Prophase: chromosomes condense
2. Metaphase: chromosomes line up
3. Anaphase: sister chromatids separate
4. Telophase: new nuclear membranes form
62
What are centrioles? What do they do?
Centrioles are organelles that migrate to opposite poles of the cell and produce spindles. They pull apart the chromatids during anaphase.
63
When does the nucleus dissolve during mitosis? When does it begin to reform?
Dissolves at prophase.
Reforms at telophase.
64
What are four methods of asexual reproduction?
1. Binary Fission: cell doubles in size and genetic information and then cytokinesis (invagination occurs, and then the cells separate).
2. Budding: DNA replicates, but cytokinesis is unequal; less cytoplasm goes to the daughter cell.
3. Regeneration: lizards that grow back their tales, sea stars that reproduce from just one leg, etc.
4. Parthenogenesis: adult organisms develop from unfertilized eggs,- ie bees.
65
Which cells undergo meiosis? Mitosis?
Meiosis: gametocytes
Mitosis: somatic cells
66
Meiosis results in how many cells? What is there n?
4 cells. Haploid (n=1).
67
What does crossing over (recombination) occur in meiosis?
Prophase I
68
Compare meiosis and mitosis.
Meiosis: 2n => n, crossing over, sex cells only
Mitosis: 2n => 2n, no crossing over, occurs in all dividing cells.
69
Where is testosterone produced?
Leydig cells.
70
Where are sperm produced?
In the seminiferous tubules and they are nourished by the sertoli cells.
71
What does the hepatic portal vein do?
It delivers nutrients absorbed during digestion to the liver.
72
What are some major functions of the liver?
1. store/release glucose
2. store vitamins
3. make bile
4. interconversion of fats, amino acids and carbohydrates
73
What hormones does the posterior pituitary produce? The anterior?
posterior: ADH, oxytocin
anterior: FSH, LH, ACTH, TSH, Prolactin, Endorphins, GH
* mnemonic: FLAT PEG
74
How many Na and K are exchanged at the Na/K pumps?
3 Na out
| 2 K in
75
What is the function of the oligoendrocyte?
It wraps the nervous axon in myelin.
76
What happens to neurotransmitters after they have served their function in the synaptic cleft?
3 things:
1. reuptake (eg, dopamine and serotonin)
2. diffuse away (eg, nitric oxide)
3. broken down (acetylcholinesterase)
77
What is the breakdown of the nervous system?
```
I. Central
a. brain
b. spinal cord
II. Peripheral
a. somatic- muscles
b. autonomic
1. sympathetic- fight or flight
2. parasympathetic- rest and digest
```
78
Which nerves carry information to the brain? Away?
Afferent takes info to brain.
Efferent sends information from brain to body.
79
How do the hemispheres of the brain communicate?
Corpus Collosum.
80
What is an example of a monosynaptic reflex arc?
The patellar knee jerk. A stretch receptor is fired that directly fires an AP to contract the quadricep.
81
What is a polysynaptic reflex arc?
Involves more than one neuron. For example, stepping on a tack inspires lifting one leg while placing the other leg on the ground to maintain balance.
82
How many neurons does the SNS use to get to the muscle?
1
83
How many neurons does the ANS use to transmit its message?
2.
84
What NTs does the SNS use?
Preganglionic uses acetylcholine.
Postganglionic uses norepinephrine.
85
What NTs does the PNS use?
Uses acetylcholine in both pre- and postganglionic synapses.
86
What are the three types of sensory neurons? What do they sense?
1. Exteroceptors: external environment, light, sound, taste, touch, pain, etc.
2. Interoceptors: internal environment, pH, temperature, blood volume, CO2 in blood
3. Proprioceptors: position sense, spacial awareness
87
What is an allele?
Alternative forms of a gene.
88
What is the difference between genotype and phenotype?
Genotype is the actual allelic distribution of genes in an organism.
Phenotype is the outward appearance of an organism and is dependent on genotype.
89
What is homozygous? Heterozygous?
Homo: both copies of the allele are the same, AA or aa.
Hetero: the copies of the allele are different, Aa.
90
T = tall, t = short, P = purple, p = white
What is the F1 of TTPP x ttpp?
What is the F2 ratio of a cross of the F1 offspring?
F1: All are TtPp.
F2: 9:3:3:1 (tall/purple: tall/white: short/purple: short white)
91
What is the range of recombination frequencies?
0-50%
0% if the genes are close and tightly linked.
50% if the genes are far apart and expected to recombine from independent assortment.
92
How do you make a genetic map? What is one map unit?
Use the recombination frequencies to determine how close two genes are. 1 map unit = 1% chance of recombination
93
Describe incomplete dominance. What is an example?
Neither allele is dominant and will give a mixture of phenotype. Example is the snapdragon flower (red:pink:white, 1:2:1)
94
What is codominance? Give an example.
Codominance is when there are two different dominant alleles, and they are both expressed. An example is blood type, A and B are both dominant to O.
95
What does a sex linked trait refer to?
A trait that is carried on the X chromosome. Only mothers can pass this disease, and if it is dominant, all sons who inherit this allele will be phenotypically positive.
96
What are the conventions of a pedigree? Males/Females, Carriers, and Recessive?
Male=squares
Females=circles
Shaded=affected
Half-Shaded=carrier (not all carriers are identified)
97
What is a human (46 chromosomes) aneuploid?
In humans, an aneuploid is one who varies from the number of 46 chromosomes. The source of this is commonly found in nondisjunction.
98
What are the pyramidines and purines?
Pyrimidines: Adenine and Guanine (have extra 5-membered ring)
Purines: Thymine and Cytosine
99
What direction does DNA replication and transcription go?
Always made 5' to 3'.
100
Compare DNA and RNA.
DNA: double stranded, uses thymine, deoxyribose, A/T and G/C, found only in nucleus
RNA: single stranded, uses uracil, oxyribose, A/U and G/C, rRNA, tRNA, mRNA and hnRNA*, found in nucleus and cytoplasm
*hnRNA- heteronuclearRNA, the immediate precursor to mRNA.
101
What is the antisense strand?
Antisense is the coded strand of the DNA, and it contains the compliment to the genetic information that is required.
102
What are promoters?
Special DNA sequence that signal where to start transcription.
103
What is a termination sequence?
It is what tells the RNA polymerase to stop transcribing.
104
What post-transcriptional processing must happen before the hnRNA becomes mRNA?
1. add a 5' guanysol cap to stabilize
2. add a poly-A tail to protect 3' end
3. remove introns
105
What is a codon?
The triplet sequence of peptides in the RNA that codes for a protein.
106
Why is the genetic code degenerate?
There are redundancies in the genetic "language" which means that one protein, Proline for example, can be coded for by multiple triplets: CCU, CCC, CCA, and CCG.
107
Where is the anti-codon?
on the tRNA, it uses the complement to the codon to recognize where to deposit the amino acid.
108
What are transformation, conjugation and transduction?
1. Transformation- integrating a plasmid, or DNA from a plasmid, into a bacteria's genome.
2. Conjugation- bacteria's "sexual" reproduction. A cytoplasmic bridge is formed, called a sex pili, and the plasmid is copied and sent thru the bridge. Both bacteria leave with a copy of the plasmid.
3. Transduction- sometimes genetic information can be picked up by viruses and relayed to other bacteria.
109
What is the difference between inducible and repressible systems?
Inducible- default is off, it requires an inducer to activate the operon.
Repressible- system is always on unless a repressor attaches and inhibits transcription.
110
What is Lamarck's theory of evolution, and why was it wrong?
He proposed "use and disuse" suggesting that organs that were used a lot would develop, and those that weren't would atrophy. These would become "acquired characteristics".
We know this is wrong because characteristics are inherited, not acquired.
111
What are some of Darwin's tenents?
1. Organisms produce offspring, few of which reproduce.
2. Chance genetic variations are inheritable, and if they provide an advantage they are favorable.
3. Organisms with more favorable variations are more likely to reproduce which will result in an increase in these traits; this is known as natural selection.
112
What are the 5 criteria for Hardy-Weinberg equilibrium?
1. Very large population
2. No mutations that affect the gene pool
3. Random mating
4. No net migration of people into or out of the population
5. Genes are equally successful at reproducing
113
What are the Hardy-Weinberg equations?
1. p + q = 1
2. p^2 + 2pq + q^2 = 1
```
p^2 = TT (dominant homozygotes)
2pq = Tt (heterozygotes)
q^2 = tt (recessive homozygotes)
```
Equation 1 gives the frequency of alleles. Equation 2 gives the phenotype of the population.
Hardy-Weinberg will be true if evolution does not occur... which is impossible.
114
What are 5 forms of microevolution?
1. Natural Selection- selecting favorable genotypes,- ie a bird with more efficient wings can spend more time humping.
2. Mutation- gene mutations occur naturally
3. Assortive Mating- mates are not randomly chosen
4. Genetic Drift- founder's effect,- ie Gilligan's Island Babies
5. Gene Flow- migration of individuals between populations,- ie me and HJ
115
What is stabilizing, directional and disruptive selection?
1. Stabilizing- birth weight is a narrow range.
2. Directional- bacteria on a petri dish that are ampicillin resistant, they become the only surviving species.
3. Disruptive- nuts on Galapagos are either big or small, so finch beaks are either big or small, not medium.
116
How does Neo-Darwinism account for altruistic behavior,- ie bees that don't produce?
It's the idea of the whole gene pool, and organisms will be altruistic if they are closely related to those that can reproduce.
117
What are three patterns of evolution?
1. Divergent: cats and seals
2. Parallel
3. Convergent: fish and dolphins
118
What hormones does the posterior pituitary release?
ADH: increases water re-uptake in kidneys, has osmoreceptors in the hypothalamus.
Oxytocin: helps with uterine contractions and expressing milk.
119
What two hormones regulate calcium levelsin the blood?
Calcitonin: decreases calcium in blood by excreting more in urine, storing more in the bones, and decreasing absorption in the gut.
Parathyroid Hormone (PTH): increases calcium in blood by decreasing loss of Ca in urine, reabsorbs Ca from bone, and increases absorption in the gut.
120
What hormones does the adrenal cortex secrete?
Corticosteroids.
They are all derived from cholesterol and include glucocorticoids, mineralocorticoids, and cortical sex hormones (sugar, salt and sex).
121
What do cortisol and cortisone do?
They are glucocorticoids. They increase gluconeogensis and decrease protein synthesis.
122
Give an example of a mineralcorticoid.
Aldosterone. It increases salt reabsorption and increases excretion of potassium and hydrogen.
123
What system regulates release of aldosterone, what other things have to be released before aldosterone is released? Where is the sensor that triggers this?
It is under the regulation of the renin-angiotensin system. The sensor is at the glomerulus.
124
What is secreted in the medulla of the adrenal gland? What is the larger classification of molecules that these hormones fall under? What type of hormones are they?
epi and norepi.
Part of molecules known as catecholamines.
Peptide hormones.
125
What two important hormones are secreted by the pancrease... how are they antagonists of each other?
Glucagon and Insulin.
Insulin causes muscle and liver to take up glucose and store it as glycogen. Glucagon causes the muscles and liver to release glucose.
126
What do FSH and LH do and where do they act?
FSH: stimulate sertoli cells and is necessary for mature sperm.
LH: causes the interstitial cells to make testosterone.
127
What are the four phases of menstruation? What happens at each?
1. Follicular Phase: begins with menstrual flow
2. Ovulation: peak in LH induces release of egg
3. Luteal Phase: high progesterone (maintains uterine lining for implantation) and estrogen levels (regenerates uterine lining), causes negative feedback on GRH, FSH, and LSH to prevent release of another egg
4. Menstruation: progesterone levels decline and uterine lining released
128
What does the pineal gland do?
secretes melatonin which is believed to be involved in the circadian rhythm.
129
What are the three classifications of hormones?
1. Peptide
2. Steroid
3. Amino Acid-Derived
130
How do peptide hormones travel? What type of messenger are they?
Peptide hormones are water soluble. They are exocytosed and travel in the blood and bind to external cell receptors. They are first messengers that cause second messengers,- ie cAMP, to bind to intracellular targets and complete the hormone's ultimate task.
131
Does cAMP work in a 1:1 ratio? What terminates the actions of cAMP?
cAMP creates a signal cascade and amplifies.
Phosphodiesterase stops cAMP.
132
How do steroids travela and where are steroid receptors?
Steroids are lipid soluble and travel freely. Steroid receptors are intracellular.
133
What works faster, peptide or steroid hormones?
Peptide hormones... amplification, signal cascade.
| steroids usually affect transcription and cause the production of proteins which takes more time
134
What are some amino acid derived hormones?
Epi, norepi and thyroxine.
135
What is the order of the taxonomic rankings?
```
Domain
Kingdom
Phylum (zoology) or Division (botany)
Class
Order
Family
Genus
Species
```
136
Are steroid hormones water or lipid soluble?
Lipid.
137
Where are the receptors for steroid hormones? What are some examples of steroid hormones?
Receptors are in the cell.
Examples: estrogen, progesterone, testosterone, glucocorticoids
138
hypertonic vs. hypotonic
hypertonic: lots of solute in the fluid
hypotonic: very little solute in the fluid
(hypo-osmotic = hypotonic)
139
What are the three important fetal shunts?
1. Ductus Venosus
2. Foramen Ovale
3. Ductus Arteriosus.
140
What is a telomere?
Region of repeated nucleotide sequences at both ends of a chromatid to prevent DNA degredation.
141
What is a Schwann cell?
The type of cell that is myelin.
142
What is ontogeny?
Study of the development of an organism from fertilization of an egg to a mature adult.
143
What is phylogeny?
The study of evolutionary relationships among groups of organisms (eg- species, populations).
144
What is the difference between nonsense and missense?
Nonsense = premature stop codon
Missense = exchanging one nucleotide for another
145
Define "Ceolom"
The ceolom turns into the body cavity in a developing fetus. Found in arthropods and other species.
146
What is an obligate parasite?
An organism that cannot complete its life cycle without exploiting a host.
