The major way in which therapeutic cloning and reproductive cloning differ is that
|A)||reproductive cloning cannot in reality be accomplished, while therapeutic cloning can.|
|B)||therapeutic cloning seeks to provide cells and tissues for use in treatment of human diseases.|
|C)||reproductive cloning can only be done in plants, therapeutic cloning only in animals.|
|D)||reproductive cloning uses adult stem cells, therapeutic cloning uses embryonic stem cells.|
|E)||There is no difference: both processes seek to obtain a genetically pure individual.|
A regulatory gene codes for a protein that activates the genes in an operon.
Which of the following is true regarding the control of gene expression in eukaryotes?
|A)||Control occurs exclusively at the level of transcription.|
|B)||mRNA must be translated immediately upon arrival at the ribosomes or it is degraded.|
|C)||A DNA region of active gene expression is called unpacked genes.|
|D)||Transcriptional control is the most important level of gene control.|
|E)||Transcription activators are RNA binding proteins that speed up transcription.|
Euchromatin, areas of active gene expression in eukaryotes, can only become genetically active when histone proteins are physically moved.
After it is synthesized, mRNA
|A)||may linger in the nucleus before moving into the cytoplasm.|
|B)||has its exons removed and its introns spliced.|
|C)||passes into a nuclear pore where it is "capped."|
|D)||binds to the nuclear protein IF-2.|
|E)||is immediately shuttled to the ribosomes and translated.|
|A)||ribosomal proteins that assist in translation.|
|B)||associated with the nucleosomes.|
|C)||involved in mRNA processing.|
|D)||shuttles that take processed RNA through nuclear pores.|
|E)||enzyme complexes that degrade proteins.|
Transcription factors are RNA molecules that assist RNA polymerase in binding to a promoter region of DNA.
Which of the following is not true?
|A)||Transcription factors can be used repeatedly at many different promoter regions.|
|B)||Transcription activators do not bind to promoter regions.|
|C)||An enhancer region of DNA is adjacent to the promoter.|
|D)||DNA can form loops before certain genes can be transcribed.|
|E)||One regulatory protein can have a decisive effect on the final gene products.|
What purpose does a cell-signaling pathway serve in a multicellular organism?
|A)||activation of specific genes in the receiving cells|
|B)||stimulation of the cell cycle in receiving cells|
|C)||coordination of environmental responses|
|D)||coordination of metabolic activity in receiving cells|
|E)||Any of these could be a purpose for a cell-signaling pathway.|
The types of cells most likely to become cancer cells are the highly specialized cells of the body, such as nerve cells.
Which of the following is not true of cancer cells?
|A)||They show a high degree of contact inhibition.|
|B)||They do not undergo apoptosis.|
|C)||They release a growth factor that stimulates angiogenesis.|
|D)||They produce enzymes.|
|E)||Their chromosomes are abnormal.|
|B)||produce proteins that inhibit the cell cycle.|
|C)||may code for growth factors.|
|D)||become tumor-suppressor genes when they mutate.|
|E)||are the result of an oncogene which has mutated.|
|A)||is an enzyme that degrades chromosomes.|
|B)||is found in all adult cells.|
|C)||inhibits DNA replication.|
|D)||is highly active in cancer cells.|
|E)||is a particular DNA sequence on the ends of chromosomes.|
To metastasize, cancer cells must enter a blood vessel or a lymphatic vessel.
Which of the following is not a suspected cause of cancer?
Cloning is a natural process for some organisms.
Lactose metabolizing enzymes are produced when RNA polymerase binds to the operator on the lac operon in the absence of lactose.
In a normal cell, Ras is a continuously active protein that functions in signaling pathways, several of which promote the cell cycle.
Chronic myelogenous leukemia (CML) is caused by which of the following:
|A)||inheritance of the BRCA1 and BRCA2 genes|
|C)||absence of telomere shortening|
|E)||a point mutation|
Which of the following is not true of tumor suppressor genes?
|A)||They code for proteins that inhibit the cell cycle.|
|B)||They code for proteins that promote apoptosis.|
|C)||They may become non-functional thus allowing tumors to develop.|
|D)||They activate proto-oncogenes.|
|E)||Mutations occurring in tumor suppressor genes can lead to "loss of function" mutations.|