Biochemistry - MCAT Flashcards
(150 cards)
1
Q
Pinocytosis can also be called what due to the fact that it ingests dissolved electrolytes and solvents?
A
cell drinking
2
Q
Can urea diffuse across the membrane?
A
yes
3
Q
Can an ion moving through an ion channel down its concentration gradient also be moving against an osmotic gradient?
A
yes
4
Q
How many potassium (K) are pumped inside and sodium (Na) are pumped outside of the cell with NaK ATPase?
A
2, 3
5
Q
Does phagocytosis take up solids or liquids?
A
solids
6
Q
During the citric acid cycle, what form of energy is phosphorylated/is the energy product?
A
GTP
7
Q
What molecules are oxidized in the electron transport chain?
A
NADH, FADH2
8
Q
How many NET ATP are produced in glycolysis?
A
2
9
Q
How many ATP are produced per NADH oxidized?
A
2.5
10
Q
How many ATP are produced per FADH2 oxidized?
A
1.5
11
Q
Does higher salt content in your sweat mean higher or lower salt content in your blood?
A
lower
12
Q
If a molecule is reduced will it have more or fewer bonds to oxygen?
A
fewer
13
Q
If a molecule likes to be reduced, will it have a higher or lower reduction potential?
A
higher
14
Q
As you go across the ETC, each complex has a higher or lower reduction potential than the last?
A
higher
15
Q
What glucose transporter is in nearly *all* tissues and increases when blood glucose is low? hint: “baseline”
A
GLUT1
16
Q
What glucose transporter is on gluconeogenic cells, is bidirectional, and senses glucose on the pancreas?
A
GLUT2
17
Q
What glucose transporter has a high glucose affinity even during low conc.? note: in brain and placenta
A
GLUT3
18
Q
What glucose transporter is expressed at high glu conc because it stores glucose?
A
GLUT4
19
Q
Where does glycolysis take place in the cell?
A
cytosol
20
Q
Where does the citric acid cycle take place in eukaryotes?
A
mitochondrial matrix
21
Q
Draw the graphs for competitive inhibitors
A
Vmax doesn’t change Km increases (binding affinity decreases bc more than one molecule is competing for binding site)
22
Q
Draw the graphs for *noncompetitive* inhibitors
A
Binds allosterically and decreases the enzyme activity (Vmax) but binding affinity stays the same (no change to Km)
23
Q
Draw the graphs for *uncompetitive* inhibitors
A
Binds allosterically and won’t let enzyme release the substrate (increases binding affinity/decreases Km), Vmax decreases bc less enzyme is left to work
24
Q
What is the brain division for the forebrain called?
A
prosencephalon (personality and behavior)
25
What is the developing brain division for the area that carries the thalamus, hypothalamus, pineal gland, and posterior pituitary called?
diencephalon
26
What is the developing brain division for the area that carries the cerebrum, cerebral cortex, hippocampus, and basal ganglia called?
telencephalon
27
The limbic system controls what? hint: 3 m's
motion, motivation, memory
28
What are the functions of the frontal lobe?
higher-level cognition, executive functions
29
What are the functions of the temporal lobe?
sound and language processing memory consolidation
30
What are the functions of the occipital lobe?
primary visual cortex
31
What are the functions of the parietal lobe?
sensory processing (such as touch via the postcentral gyrus)
32
What is the function of the cerebrum?
coordination of motor control (contains basal ganglis, hippocampus, and pons)
33
What is the function of the medulla oblongata?
controls autonomic functions (breathing, HR, etc)
34
What are the functions of the pons?
sleep, respiration, swallowing, taste, bladder control, balance
35
What is the name for the developing division of the midbrain and what are its functions?
mesencephalon motor control, sleeping, homeostatic regulation + superior colliculus (visual reflex) +inferior colliculus (auditory reflex)
36
What is the developing brain division for the hindbrain?
rhombencephalon
37
What are the components of the brainstem?
midbrain, pons, medulla oblongata
38
What are the functions of the somatic nervous system?
voluntary movement, innervation of muscles
39
How long are sympathetic nerves (preganglionic axons) and where do they release neurotransmitter?
Short, onto ganglions near the spinal cord typically
40
What is the pre-ganglionic neurotransmitter for both the sympathetic and parasympathetic nervous systems?
ACh
41
What is the post-ganglionic neurotransmitter for the PSNS?
ACh
42
What neurotransmitter's loss is associated with loss of fine motor control?
Dopamine
43
What is the most prominent excitatory neurotransmitter?
glutamate
44
What is the most prominent inhibitory neurotransmitter?
GABA
45
What sensation does the medial geniculate body of the thalamus process?
Auditory along with the inferior colliculus
46
What areas of the brain help with voluntary motor control?
Precentral gyrus, cerebellum, basal ganglis (substantia nigria with Dopamine)
47
What cells provide nutrients, protection, and insulation for neurons?
glial cells
48
What type of glial cell coats the blood brain barrier?
Astrocytes (transport nutrients in and out)
49
What glial cells protect the central and peripheral nervous system respectively?
Oligodendrocytes and Schwann cells (form myelation)
50
What acts as macrophages in the CNS?
microglia
51
What cells secrete CSF?
ependymal
52
How long are pre-ganglionic and post-ganglionic parasympathetic fibers respectively?
long, short
53
Draw an action potential on a depolarization graph with sodium and potassium channels
ok - add a pic if you can get this to work
54
What sensation does the \*lateral\* geniculate body of the thalamus process?
vision along with the superior colliculus
55
What are the structures of the limbic system?
the amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus
56
Do endo and exo-cytosis require ATP?
yes!
57
What is the electrical potential difference across the plasma membrane?
negative because cytoplasm is negative in relation to the extracellular fluid
58
What direction do potassium leak channels and Na/K ATPase channels move potassium respectively?
out of cell, into cell
59
Na/K ATPase moves how many molecules of Na and K and in what direction?
3 Na out / 2 K in
60
Do axons with large or small diameters transmit signals faster?
large (greater conductance)
61
What molecules greatly contribute to the positive extracellular environment at rest?
Sodium, chloride, and Ca2+
62
What molecule is in great amounts in intracellular fluid at rest?
Potassium
63
What way does potassium travel through \*leak\* channels?
Out of the cell
64
What is the resting membrane potential of the cell?
-70 mV
65
What do baroreceptors respond to?
Changes in pressure
66
Which is harder to depolarized: small or large neurons?
large due to the more area to store charge along their membrane
67
What is membrane resistance?
The ability to keep charges separate
68
What is cytoplasmic resistance?
How much the cytoplasm itself impedes the flow of ions
69
The larger the neuron, the ____ the cytoplasmic resistance, the ___ the conductance
lower, greater
70
What is the effect of a higher membrane resistance on action potential?
It makes transmission more effective
71
What is the effect of myelination on membrane resistance and capacitance?
Increases resistance and decreases capacitance making signals travel faster
72
What type of fatty acid subclass is arachidonic acid (a fatty acid) a precursor for?
prostanoids
73
What biomolecule is the precursor for prostanoids / prostaglandins?
Arachidonic Acid
74
What is a nucleotide comprised of?
ribose (deoxy for DNA) + phosphate + nitrogenous base
75
What does RT-PCR analyze?
RNA
76
What does a nucleoSIDE consist of?
Nitrogenouse base + ribose sugar
77
Can proteins cross the blood brain barrier?
YES - proteins are needed for EVERY cell
78
What structure gives rise to the nervous system in development?
ectoderm
79
What structure gives rise to the bone, cartilage, 3 types of muscle, and tissues involved in the excretory and reproductive systems in developing fetuses?
Mesoderm
80
What is a positive control?
A control group that is NOT the same as the experimental but is KNOWN to elicit the expected effects
81
What is a negative control?
A control group that is not the experimental and does NOT elicit an effect
82
What is a thioether?
R-S-R'
83
What is an imine?
A double-bonded nitrogen and carbon (2R-C=N-R')
84
What is an imide?
A nitrogen bound to TWO carbonyl carbons
85
What is physiological pH in humans?
Around 7.4 (7.37-7.47)
86
What is the side chain pKa of Tyr?
10.1
87
88
When does an amine group have a neutral charge?
When pH \> its pKa (pKa=~9.7)
89
If pH = a side chain's pKa, what characteristics does the side chain hold?
Half is protonated and half is deprotonated
90
What is an amino acid's pI?
The pH in which its charge is zero (on a vertical slope of the titration curve)
91
92
To find the pI of an acidic or basic amino acid, how do you calculate?
average highest two pKa's for basic, average the lowest two pKa's for acidic
93
What are tropic hormones?
Hormones that act on endocrine glands (don't elicit effects explicitly)
94
What are the types of \*exocrine\* secretions onto epithelial surfaces?
apocrine, merocrine, holocrine
95
Do peptide hormones need transport proteins?
No (they are hydrophilic) but DO need membrane receptors for the same reason
96
Do steroid hormones need transport proteins in the blood?
Yes! (they are hydrophobic) but they can freely diffuse into the cell for the same reason!
97
Where are steroid hormones synthesized?
From cholesterol in the smooth ER and can freely diffuse into the blood from there
98
What is the process for protein hormone synthesis?
Transcription, translation (in ribosome) to form pre-prohormone, modification in rough ER to prohormone, travel to golgi apparatus and get cleaved to form active hormone
99
What type of hormones are T3 and T4?
amino-acid derived (from tyrosine) but hydrophobic
100
What type of hormones are epi and norepi?
catecholamines (amino acid derived) and they are hydrophilic
101
What type of hormone is melatonin?
amino acid-derived (from tryptophan) and is amphipathic (both hydrophobic and philic)
102
What type of hormone can affect gene expression in the target cell?
steroid hormones
103
Do steroid or peptide hormones have slow initiating, long-lasting effects?
steroid!
104
What hormones are secreted by the pancreas?
insulin, glucagon, somatostatin
105
What is the function of the thyroid hormone calcitonin?
to increase calcium storage in bone and increase secretion of calcium in urine
106
What are the effects of vasopressin (ADH)?
increase water reabsorption in kidney collecting duct, decrease blood osmolarity, increase blood pressure
107
What stimulates estrogen and follicle production respectively?
LH and FSH
108
What type of hormones are secreted from the anterior and posterior pituitary?
peptide hormones
109
What is the function of LH and FSH in males, respectively?
Stimulates Leydig cells, spermatogenesis
110
111
What is the function of parathyroid hormone?
increase calcium levels (promotes absorption in intestine, decreases storage in bone, and decreases excretion in urine)
112
What is the function of the glucocorticoid hormone aldosterone (stimulated by the renin-angiotensin pathway)?
Increase sodium reabsorption in distal convoluted tubule and collecting duct. Causes fluid retention via osmosis
113
What hormones are released from the adrenal cortex?
cortisol, androgens (estrogen and testosterone), and aldosterone
114
What is the function of somatostatin secreted by delta cells in the pancreas?
inhibit growth hormone, reduce stomach acid, block digestive hormones
115
What is vitamin d's (calcitriol's) effect on calcium?
increases serum calcium levels
116
What hormone functions to decrease sodium reabsorption and thus decrease blood pressure?
atrial natriuretic peptide (ANP) from cardiomyocytes of heart
117
How do analogs function?
As competitive inhibitors!
118
What hormones does the corpus luteum produce?
estrogen and progesterone
119
What causes the proliferation of the endometrium of the uterus?
estrogen
120
What are primary sex characteristics in males and females respectively?
testes development, ovary development
121
What creates myelin sheaths in the CNS and PNS respectively?
oligodendrocytes and Schwann cells
122
What strand of DNA is mRNA synthesized from?
The template strand is 3' to 5' -- DNA synthesized 5' to 3' (it is identical to the coding strand)
123
What are the stop codons of DNA?
UAA, UGA, UAG (do not get synthesized into a protein)
124
What type of lipid is shown?
phosphatide
125
What is the composition of sucrose?
glucose (6) + fructose (5)
126
What is the structure of lactose?
glucose (6) + galactose (6)
127
What is the difference between a pyranose and furanose sugar?
pyranose - 6 membered ring
furanose - 5 membered ring
128
How do you know if a glucose molecule is D-glucose?
Bottom-most hydroxyl is on the right
129
How do you determine if a glycosidic bond is alpha or beta?
By the hydroxyl position on the **anomeric carbon**
Alpha - hydroxyl down
Beta - hydroxyl up
130
What is maltose comprised of?
glucose + glucose
131
What enzyme catalyzes the reaction forming glycosidic linkages?
glycosyltransferase
132
What is the main structure of bacterial cell walls (not membranes)?
peptidoglycan
note: it can hide bacteria from immune system by hiding surface antigens
133
What are plant cell walls composed of?
cellulose
also dietary fiber for humans (can't digest)
134
What is a major component of fungal cell walls?
chitin
135
What are the two types of starch?
amylose (alpha-1,4 glucoses) and amylopectin (alpha-1,6 glucoses)
136
What types of bonds connect **branched glycogen** chains of glucose?
alpha-1,6-glycosidic linkages as formed by glycogen branching enzyme
137
In gas chromatography, what molecules elute FIRST?
non-polar molecules // lower boiling point molecules
138
What part of the kidney is the glomerular filtrate concentration greatest?
The medullary part of the collecting duct
139
What types of molecules can freely pass through the cell membrane?
small, uncharged
planar, hydrophobic (even if large and cyclic)
140
How can enzymes NOT alter a reaction?
by changing the \*primary structure\* of the substrate (note: they can change the shape of the substrate or the pH)
141
What are the effects of aldosterone and where does it act?
Increases reabsorption of Na+, water follows osmotically
Increases blood volume and pressure
Acts on distal convoluted tubule and collecting duct
142
What are the effects of ANP?
Decreases sodium reabsorption, decreasing water reabsorption
Decreases blood pressure
143
What are the effects of antidiuretic hormone (vasopressin)?
Increase water reabsorption by inserting aquaporins into **collecting duct**
Increase blood pressure
Lower blood osmolarity
144
What is the effect of parathyroid hormone on the kidney?
Increases calcium reabsorption in distal convoluted tubule - no regulation effects on BP
145
What direction are afferent and efferent arterioles going, respectively?
afferent - arriving at the organ
efferent - exiting the organ
146
What elutes first in HPLC and RP-HPLC respectively?
HPLC - non-polar compounds elute first (polar stationary phase, non-polar mobile phase/eluent)
RP-HPLC - polar compounds elute first (non-polar stationary phase)
147
In recrystallization, what is done to the solid that you want to analyze?
The solid is dissolved at high temperatures and then cooled and reprecipitated then filtered out
148
What is a nuclear localization sequence?
A sequences that tags proteins for transport into the nucleus
149
What is Ubiquination?
It tags a protein to be degraded by proteosomes
150
What type of protein is denatured via reduction?
Cysteine residues due to di-sulfide bonds!!!
