Concept explainers
Genes that are expressed at all times at relatively constant levels are known as _____ genes.
- inducible
- repressible
- positive
- constitutive
- protein-encoding
Introduction:
Genes are functional units of DNA. Genes carry the hereditary information and pass it from one generation to the next. The availability of genes depends on the location and environment of the cell.
Answer to Problem 1TY
The correct answer is constitutive genes.
Explanation of Solution
Explanation/justification for the correct answer:
Constitutive genes are transcribed continuously in the cell at the constant level like the housekeeping genes transcribe important proteins (actin, GAPDH). These genes are required by all the cells for proper functioning and maintenance of cell.
The explanation for the incorrect answer:
Option A is incorrect.
Inducible genes are expressed in the cell when inducer binds to co-repressor. Inducer presence depends upon the concentration of certain substances in the cell. Thus, this is not the correct answer.
Option B is incorrect.
Repressible genes are expressed only in the presence of co-repressor. Thus, these genes are activated during specific times in the cell. Hence, the option is correct.
Option C is incorrect.
Genes which positively affect the transcription of genes are known as positive genes. Positive genes are not required by each cell. Thus, the option is not correct.
Option E is incorrect.
Protein coding is the process in which the DNA sequence is transcribed into a stretch of a polypeptide. The polypeptide produced through the process may or may not be continuously produced in the cell. Thus, it is incorrect.
The correct answer is d.
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Chapter 12 Solutions
Principles of Biology
- Pre-mRNAs in mitochondria are converted to maturemRNAs through ______editing, which makes translation ofthe transcripts possiblearrow_forwardMechanisms that inhibit TE activity include theproduction of transposition repressors throughalternative splicing and the action of _________ thatblock TE transcription.arrow_forwardLabel promoter and terminator regionsarrow_forward
- _____________ are molecular machines that excise introns from pre-mRNA and then join exons together.arrow_forwardGene expression is Usually regualated at the initiation of transcription. True Falsearrow_forwardRegarding the trp operon: when levels of tryptophan are low, the ___ hairpin forms, resulting in _____ of transcription. Group of answer choices 2-3; termination 3-4; termination 3-4; continuation 2-3; continuationarrow_forward
- When referring to attenuation in the regulation of the trp operon it would be safe to say that, when there are high levels of tryptophan available to the organism, ________. tryptophan inactivates the repressor protein translation termination of the trp operon is likely the trp operon is transcribed at relatively high levels the ribosomes stall during translation of the attenuator region transcription termination at the attenuator region is likelyarrow_forwardPromoters of the INS genearrow_forwardTrue or False: In eukaryotes, transcription is generally regulated by a combination of many factors which determines the expression of any given gene. False Truearrow_forward
- describe a scenario (as you would to a 12th grader) a physiological situation (protein need) that will result at the beginning of the central dogma process (transcription all the way to protein formation)arrow_forward"once cells have differentiated to their final specialized forms, they never again alter expression of their genes" is true or false.arrow_forward"After a sudden increase in transcription, a protein with a slow rate of degradation will reach a new steady state level more quickly than a protein with a rapid rate of degradation." is true or false.arrow_forward