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【单选题】
If a gene is expressed at relatively constant rate in almost all the cells, it is called a(an) （ ）
A.
inducible gene
B.
constant gene
C.
housekeeping gene
D.
repressible gene
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参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】Among the following factors, which one could deliver the aminoacyl-tRNA to the A site of ribosome?（ ）
A.
IF-2
B.
EF-Tu
C.
EF-G
D.
EF-Ts
【多选题】The factors that form the lung retraction force are（ ）
A.
Thoracic retraction
B.
Alveolar surface tension
C.
Airway resistance
D.
Pulmonary surfactant
E.
Elastic retractive force of lung
【多选题】Which of the following statements about the effect of the sympathetic nerve on the heart is correct（ ）
A.
Increase heart rate
B.
Enhance myocardial contractility
C.
Slow heart rate
D.
Reduce stroke volume
E.
Increase the conduction velocity
【多选题】The basic processes of urine production include（ ）
A.
Concentration and dilution of manifold
B.
Glomerular filtration
C.
Secretion and excretion of renal tubules and collecting ducts
D.
Reabsorption of renal tubules and collecting ducts
E.
Transfer to bladder for storage via ureter
【单选题】Which transcription factor can recognize and bind to TATA box? （ ）
A.
TFII E
B.
TFII B
C.
TFII D
D.
TFII H
【多选题】Which are ture in the following statements about synapses （ ）
A.
Na+ entrying into the synaptosome can promote transmitter release
B.
Postsynaptic potentials can be summed up
C.
Postsynaptic potentials can be divided into excitatory and inhibitory potentials
D.
Local potential changes in the postsynaptic membrane are called postsynaptic potentials
E.
The dendrites of one neuron are in contact with the cell bodies or processes of other neurons
【单选题】Which statement is true about oncogenes?（ ）
A.
Oncogenes are only present in cancer cells
B.
Hypermethylation happens in their promoter region
C.
Their products inhibit cell proliferation
D.
They are usually activated in cancer development
【单选题】The specific sequence on the N terminus of secretory protein is called （ ）
A.
secretory peptide
B.
signal sequence
C.
signal petidase
D.
signal peptide
【单选题】The most efficient step of gene expression regulation is （ ）
A.
transcription initiation
B.
translation initiation
C.
activation of chromosomes
D.
transcription termination