Consider statements about biotechnology: 1. Transgenic organisms contain foreign DNA. 2. Cloning produces genetically identical copies. 3. Gene therapy cures all genetic diseases. Which are correct?
A. 1 and 3 only
B. 1 and 2 only
C. 1, 2 and 3
D. 2 and 3 only
Answer: Option B
Solution (By JKSSB Mock Tests)
Transgenic organisms (plants or animals) have been genetically modified to contain and express foreign DNA (a transgene) from another species. Cloning is a technique used to produce genetically identical copies of a biological entity, such as a cell, organism, or DNA sequence. Gene therapy is an emerging technique aimed at treating or curing genetic diseases by introducing functional genes, but it is still largely experimental and does not currently cure all genetic diseases. Thus, statements 1 and 2 are correct.
Explanation:
Gene therapy involves correcting a genetic defect by introducing a functional gene into a patient's cells. The first clinical gene therapy was given in 1990 to a 4-year-old girl with Adenosine Deaminase (ADA) deficiency, a severe combined immunodeficiency (SCID) caused by a mutation in the ADA gene. The functional ADA gene was introduced into her lymphocytes using a retroviral vector.
Explanation:
The umbilical vein carries oxygen-rich and nutrient-rich blood from the placenta to the fetal circulation. The two umbilical arteries carry deoxygenated blood and waste from the fetus to the placenta. In the adult, veins typically carry deoxygenated blood, but umbilical vein is an exception.
Explanation:
Lenticels are small, raised pores in the bark (periderm) of woody stems and roots that permit gas exchange between internal tissues and the atmosphere. Stomata are on leaves, hydathodes are for guttation, sclereids are sclerenchyma cells. Lenticels are filled with loosely arranged complementary cells and are visible as small dots on the surface of bark.
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