BB Flashcards
1
Q
what stabilizes free oligonucleotides (mRNA transcripts)?
A
polyadenylation
2
Q
how is polyadenylation stabilizing?
A
poly-A tail: important for nuclear export/translation + stability of mRNA
tail shortens over time
when tail is short enough, mRNA is enzymatically degraded
3
Q
type 1 restriction enzyme:
A
cuts DNA at/near specific recognition nucleotide sequence (restriction sites)
4
Q
type 1 enzymes cleave at sites near or far from recognition site
A
FAR
5
Q
type 1 restriction enzymes require both
A
ATP and s-adenosyl-L-methionine to function
6
Q
type II enzymes cleave within or at
A
short specific distances from their recognition sites and often require magnesium
7
Q
type III restriction enzymes cleave at
A
sites a short distance from their recognition sites
require ATP (don’t hydrolyze it)
8
Q
type IV restriction enzyme target
A
modified (e.g. methylated, hydroxymethylated) DNA
9
Q
A
10
Q
if the function of colonic chloride transporters is impaired, what would happen
A
decreased waste fluidity
11
Q
why would insulin not travel via the macula communicans pathway?
A
insulin would be too large as it’s a peptide hormone
11
Q
inhibiting acetylcholine would cause
A
flaccid paralysis
12
Q
acetylcholine is responsible for
A
propagating nerve impulses across neuromuscular juction
13
Q
by inhibiting acetylcholine release, the toxin interferes with
A
nerve impulses and causes flaccid paralysis of muscles
14
Q
gas chromatography separates molecules based on
A
affinity
requires molecules be vaporized
15
Q
mass spectrometry is used to measure the
A
size of one molecule
not useful to separate two molecules
16
Q
thin layer chromatography (TLC) separates molecules based on
A
affinity
not useful to separate 2 large molecules by size
17
Q
size-exclusion chromatography can be used to
A
separate two proteins by size
18
Q
antibodies are made to
A
recognize and bind specific epitopes of biomolecules like proteins
19
Q
antigens are
A
surface proteins that identify markers on cells/molecules
20
Q
antigens interact with
A
antibodies and wouldn’t be able to bind/isolate a toxin
21
Q
why is calcium most likely to use a protein channel to cross the eukaryotic cell membrane?
A
Ca^2+ are charged and unable to pass through the membrane without an ion channel
22
Q
the addition and removal of acetyl groups does what
A
regulates DNA expression
23
Q
removing acetyl groups from lysine residues of histones would have what effect?
A
gene silencing
24
tight junctions are areas where the
membranes of two closely-joined cells stick to each other tightly
form a nearly impenetrable barrier
25
sequence of transmission for impulses from transcranial magnetic stimulation (CNS --> PNS)
cerebral cortex
spinal cord
efferent neurons
skeletal muscle cells
26
which of the following processes is involved in the motor-evoked potential elicited by transcranial magnetic stimulation?
Na+ influx
Ca2+ release
27
how is self-renewal of undifferentiated stem cells a trait of cancer stem cells?
cancer stem cells may be able to resist chemo --> replication/differentiate as needed
28
peptide bonds found in the backbone of proteins are especially stable because they
exhibit resonance stabilization around the carbonyl carbons
29
a peptide is an
amide linkage b/w amine group of 1 AA and the carboxylic acid group of another AA
30
amides are stable because
they show resonance stabilization b/w the lone pair on the nitrogen and the double bond in the carbonyl group
31
In prokaryotes, genes can exist as operons that are transcribed into a polycistronic mRNA, containing multiple genes in a single transcript. In eukaryotes, transcripts exist only as monocistronic mRNA containing a single gene. What fundamental genetic difference is responsible for this distinction?
in eukaryotes, each gene has its own transcription initiation site
32
In miRNA-directed gene silencing, a small RNA binds to another mRNA molecule and suppresses its expression. Which of the following terms describes the process through which this binding occurs?
hybridization
describes a process of binding with complementary nucleotides
33
charge of basic residues
positive
34
at physiological pH, what are the charges on the COOH and amino terminals?
-1 on deprotonated COOH
+1 on protonated amino
7.4 physiological pH
35
adaptive immunity is directed against
particular pathogens to which the body has been previously exposed
36
what is the advantage of adaptive immunity?
pathogens are remembered by specialized cells --> quicker response in case of 2nd exposure
37
antibodies are produced by
B-lymphocytes
38
what differentiates eosinophils from erythrocytes?
eosinophils contain a membrane bound nucleus
39
Which of the following enzymes should the researchers add to the cell samples if they want to reverse the general catalytic effects of protein kinase A?
protein phophatase 1
40
a kinase will add OR remove a
add a phosphate group to substrate
41
removal of a phosphate group is done by which enzyme
phosphatase enzymes
42
A rapid mechanism is thought to govern the localization of AQP5 in response to changes in extracellular osmolarity. If this mechanism is independent of both PKA activity and S156 phosphorylation, which of the following will most likely be observed?
According to the passage, aquaporins “transport water in response to osmotic gradients.” An osmotic gradient is simply a concentration difference; in this case, it is the difference in solute concentration between the cell interior and its external environment. A very hypotonic, or dilute, environment will create a greater osmotic gradient than an isotonic environment, which would be similar in concentration to the cell. Thus, we can infer that aquaporins, including AQP5, will localize to the plasma membrane to a greater extent in hypotonic than in isotonic conditions. Water tends to flow down its concentration gradient, from areas of low solute (high water) concentration to areas of high solute (low water) concentration.
Here, then, water should flow from the hypotonic exterior of each cell into the more solute-rich interior, as depicted below.
43
Increasing plasma concentration of aldosterone is most likely to be followed by which of the following?
Increased sodium reabsorption in the distal tubule
44
aldosterone is released from
the adrenal cortex in response to low BPp
45
primary function of aldosterone
increase sodium reabsorption in distal tubule and collecting duct
46
what does aldosterone regualate
upregulates sodium-potassium pumps along nephron lining
47
3-2-1 NOKIA
3 Na Out of nephron, toward blood
2 K in toward nephron, away from blood
1 ATP
48
When normal human cells are grown in culture, they only undergo mitosis a limited number of times – typically 50 divisions. After this limit is reached, cells become apoptotic. This eventual cell death is likely the result of:
DNA polymerase not be able to completely replication chromosome ends during each cell division cycle
49
during mitosis, telomeres get
progressively shorter
eventually chromosomes lose their telomeres and can't reproduce
leads to cell death
50
A student finishes an experiment involving several types of highly pathogenic bacteria. She wishes to dispose of the agar plates and micropipette tips she used. Which of the following procedures should she carry out?
Place all materials in an open metal container and autoclave the container to kill bacteria via heat
51
What is the most likely transmission mechanism for the passage of Leigh syndrome from parent to child?
The inheritance pattern described in the prompt is one in which females transmit Leigh syndrome to all of their offspring. This means Leigh syndrome is a maternally-transmitted disease. Because it is also a cytoplasmically inherited disorder, it will be transmitted through cytoplasmic components, of which mitochondria are examples.
52
The researchers participating in the experiments described above were assigned to conduct new experimentation, also on Leigh syndrome-positive mouse specimens. As a precursor step, it was decided to create a new population of Leigh syndrome-positive mice. What would be the option most likely to be successful in creating this population?
Induction of intentional mutations in the mitochondria of pre-fertilization ova
53
receptor tyrosine kinases do what when ligands bind?
dimerize and phosphorylate each other
54
electrons flow from cytochromes with
low reduction potential to high reduction potential
55
reduced potential indicates an
oxidized molecule's affinity for electrons
56
insulin is a product of
pancreatic beta cells
57
insulin promotes
glucose uptake by certain tissues
decreases liver glucose production
supports glycogenesis
58
what is released into the duodenal lumen during digestion?
BILE (aids in mechanical digestion of lipids)
59
peristalsis involves which organs/structures
esophagus
stomach
small intestine
large intestine
60
small intestine divisions
duodenum
jejunum
ileum
61
what kind of digestion is done in the small intestine
chemical
62
absorption occurs across the
epithelial cells lining the small intestine
63
after absorption in the small intestine, what happens
any undigestible material passes to the large intestine
water and electrolytes are absorbed to form solid feces
64
what lines the abdominal cavity?
peritoneum
made of 2 tissue layers
65
first layer of peritoneum is called
the parietal layer (lines abdominal wall)
66
second layer of peritoneum is called
the vascular layer (covers many organs of abdominal cavity)
67
peritoneal cavity is the
space between 2 layers of peritoneu
68
endocrine pancreas secretes hormones involved in
regulation of blood glucose into bloodstream
69
exocrine pancreas secretes
digestive enzymes and bicarbonate into the small intestine to help w/ digestive processes and neutralize the acidity of chyme
70
final portion of GI tract is
large intestine
71
3 subdivisions of large intestine
cecum
colon
rectum
72
subdivisions of colon
ascending colon
transverse colon
descending colon
sigmoid colon
from proximal to distal
73
the order of peristaltic contractions
cecum
ascending colon
transverse colon
descending colon
sigmoid colon
74
hydrolysis of a glycerophospholipid produces
two fatty acids for every glycerol molecule produced
75
what will an X-ray of the lungs of an asthmatic reacting to cat dander look like?
hyperexpanded lung volumes
76
why would the lungs of someone w/ asthma reacting to cat dander be hyperexpanded?
airway is clogged w/ mucus
bronchiole constriction
wheezing occurs as airways are forced to push harder w/ diaphragm to get air out
77
muscle that makes up diaphragm?
skeletal
78
neurotransmitter associated w/ the diaphragm
acetylcholine
79
the diaphragm is innervated by which nerve?
phrenic nerve
80
phrenic nerve originates in
both the cerebral cortex (voluntary breathing) and brain stem (involuntary control)
81
viral infection would lead to an increase in which pathways?
aerobic respiration
pentose phosphate pathway
82
why would viral infection lead to an increase in PPP?
PPP is involved in producing essential precursors for nucleotide synthesis (necessary for DNA rep and RNA transcription)
83
a heart murmur caused by failure of the AV valves to close properly would most likely be classified as a
systolic murmur b/c this would allow regurgitation of blood from ventricles to the atria during systole
84
bile is sometimes referred to as intestinal soap because
it emulsifies fat in the intestines like soap emulsifies fat on your hands when you wash them
85
high concentration of ATP stimulates production of
both pyrimidines and purines
86
PRPP is a precursor to
purines and pyrimidines
87
conversion of NADP+ to NADPH is what kind of reaction
reduction
88
as NADP+ accepts electrons, what is oxidized
g6p
89
loss of a CO2 molecule is called
decarboxylation
90
PP pathway replenishes what
NADPH
91
NADPH is used by which major pathway
fatty acid biosynthesis
92
NADPH cannot be used to generate ATP via the
ETC and ox phos
93
NADH is needed for what
etc and ox phos
94
double stranded DNA is not involved in which process
mitosis
95
explain dna recombination
recombination aka crossing over in meiosis
begins w/ double stranded DNA break followed by invasion of opposite starand
96
balanced and unbalanced Robertsonian translocations involve
double stranded DNA breaks so that two chromosomes can exchange long arms
97
translocation is the
addition and deletion of genetic material
98
what can translocation cause?
severe congenital abnormamlities
termination of pregnancies
99
southern blots are used to
analyze extracted DNA for a potential DNA segment
can not provide info about chromosome structure
100
karyotyping is capable of detecting
a missing chromosome
101
fluorescent in situ hybridization uses what to...
fluorescent DNA to bind to chromosomes and detect a translocation
102
when something is a transcription factor, it must be localized in the
nucleus
103
when something is a transcription factor, it does what to DNA
binds it
104
a strong lewis acid will be electron-
poor
105
a strong lewis base will be electron-
rich
106
a strong lewis acid will want to be bonded to
leaving groups
107
a strong lewis base will be
surrounded by leaving groups
108
in the absence of electron transport, what is no longer needed
oxygen
109
oxygen is the final
electron acceptor in ETC
110
when the etc is not available to make ATP, cells rely on
anaerobic respiration (glycolysis)
111
glycolysis requires what to make ATP
glucose
112
long retention times on the size-exclusion chromatography (SEC) column means
SMALL molecules (oligomers)
113
small molecules on SEC column means
they are more volatile and have shorter retention times on GC
114
short SEC retention time means that
oligomers are large and less volatile
longer GC retention times
115
when less phosphate is reabsorbed from filtrated back to blood, what happens
hypophoshatemia
decreased phosphate in blood
116
decreased phosphate in blood leads to
decreased vit D levels/production
117
PTH is secreted by
4 small parathyroid glands located posterior to the thyroid
functions to increase serum Ca2+ levels
118
exogenous corticosteroids would provide negative feedback to the
hypothalamic-pituitary-adrenal axis and inhibit both CRH and ACTH
119
dendritic cells are one type of
APC (antigen-presenting cell)
120
APCs have a direct role in all types of rejection, T or F?
false
121
epinephrine acts on what to activate adenylate cyclase
GPCRs
122
adenylate cyclase is activated to
convert ATP to cAMP
123
what would negatively regulate PFK in glycolysis?
high citric acid levels as they would slow down glycolysis
reducing available acetyl-CoA to krebs cycle
124
the greater an element's oxidation potential, the more...
readily the atom will lose an electron and the more reactive the element is
125
if antibodies stimulated a downstream response, the muscles would
contract rather than feel weak
126
antibodies aren't enzymes, they cannot
directly degrade antigens
127
muscle weakness in Myasthenia occurs when antibodies are
bound to acetylcholine receptors and endogenous acetylcholine cannot bind
muscles can't contact despite signal from motor neuron
128
in the GI tract, cholesterol is a precursor to
bile salts
129
cholesterol serves as precursor to the synthesis of:
steroid hormones
bile salts
vitamin D
130
in the context of the GI tract, the liver synthesizes
cholesterol
exports it as bile salts
131
after liver synthesizes cholesterol and exports it as bile salts, they are stored in the
gallbladder
132
when needed, the gallbladder releases...
bile salts into the small intestine
133
what happens to the bile salts in the small intestine?
bile salts help emulsify dietary fats and facilitate their absorption
134
insulin is what kind of hormone?
peptide hormone
135
insulin is produced by the
pancreas
regulates blood glucose levels
136
exocrine pancreas is responsible for
secretion of digestive enzymes
majority of pancreas
137
digestive enzymes produced by exocrine pancreas are released into the
pancreatic duct
connects to the common bile duct
eventually empties into duodenum of small intestine
138
main enzymes secreted by exocrine pancreas include
amylase (breaks down carbs)
lipase (breaks down lipids)
proteases (breaks down proteins)
139
endocrine pancreas is composed of
islets of Langerhans
140
islets of Langerhans produce and secrete
insulin and glucagon
directly into bloodstream to regulate blood glucose
141
insulin is secreted by what cells
beta-islet cells
promotes uptake of glucose by cells
conversation of glucose to glycogen in liver + muscles
142
glucagon is produced by what cells
alpha-islet cells
stimulates conversion of glycogen to glucose in liver
and breakdown of lipids to release fatty acids as an energy source
143
exocrine pancreas does what?
releases its products (digestive enzymes) into GI tract
144
endocrine pancreas does what?
releases its products (hormones) into blood
145
duodenum receives
bile from liver and pancreatic enzymes to further digest food
146
jejunum is where
most nutrient absorption occurs
147
ileum absorbs
bile salts, vitamin B12, any remaining nutrients
148
large intestine includes
cecum, rectum, anus
149
large intestine primarily absorbs
water + electrolytes
150
appendix is a
small, finger-like projection attached to the cecum
reservoir for beneficial bacteria
151
major difference between digestion and absorption of lipids and carbs:
lipids are transferred w/ lymphatic ducts before entering circulation
152
lipid digestion starts in the
stomach
gastric lipase initiates breakdown of triglycerides into diglycerides/fatty acids
153
monoglycerides and free fatty acids are absorbed by
enterocytes and incorporated into chylomicrons
154
chylomicrons are
large lipoprotein particles
155
how do chylomicrons enter the bloodstream
too large to enter directly
enter the lymphatic system via lacteals before being released into the bloodstream
156
lipids are chemically digested in the
duodenum
157
carbohydrate digestion occurs in the
small intestine
158
lipid absortion begins in the
small intestine
159
CCK is a
peptide hormone
part of digestive system
160
what produces CCK
I-cells in the mucosal lining of the small intestine
and the brain
161
CCK functions
stimulating release of bile from gallbladder
promoting pancreatic enzyme secretion
slowing down gastric emptying
162
CCK helps regulate the
digestion and absorption of nutrients, particularly fats
163
during fasting, the body relies on
stored energy sources like glycogen and fats to meet energy demands
164
during fasting, CCK levels in blood are generally low since...
there is no need for its digestive functions such as bile release or pancreatic enzyme secretion
165
when a meal with fats is consumed, CCK levels do what?
rise in response to nutrients in the small intestine
166
increase in CCK levels helps stimulate the
gallbladder to release bile for fat emulsification/absorption
167
