Dr. Alexander Winemann is a Biologist who specializes in organic chemistry.
The correct answer is T helper cells. <span>T helper cells are important because they have the ability to stimulate other cells to kill the foreign particles (viruses, bacteria, fungi, parasites).T helper cells help other cells in the immune response by recognizing foreign antigens and by secreting cytokines that then activate T and B cells.</span>
Answer:
A vascular plant is any one of a number of plants with specialized vascular tissue. The two types of vascular tissue, xylem and phloem, are responsible for moving water, minerals, and the products of photosynthesis throughout the plant. As opposed to a non-vascular plant, a vascular plant can grow much larger.
Explanation:
The statement "The American Psychological Association is the only organization that can approve psychological research studies." is false.
Answer:
Amniocentesis is an invasive method that involves the aspiration of 10-20 ml of fetal water through the abdominal wall under ultrasound-guided control. In most cases, the procedure is performed around the 16th week of gestation. The fetal water sample contains fetal cells, mostly cells of fetal skin and the epithelium of the urinary tract.
Chorionic Villus Sampling (CVS) biopsy is performed between weeks 11 and 12 of gestation. During biopsy, with ultrasound guidance, the tissue of the chorionic fossa is aspirated mainly across the abdomen (transabdominal pathway). The biopsy specimen is of fetal origin and belongs to the outer layer of blastocyst cells or the trophoblast (outer layer of the placenta). Very often, the biopsy specimen contains tissue of the decidua (mucous membrane of the uterus) that is of maternal origin, and it is necessary to remove the maternal tissue before any treatment of the sample.
Explanation:
The amniocentesis procedure carries a risk of miscarriage of 0.5-1%. After aspiration of the fruit of the water, the sample is centrifuged to separate the cells from the amniotic fluid. Separate cells are seeded on a nutrient medium (cell culture) that stimulates cell growth. After about 14 days, the cell culture is further used for various genetic or biochemical analyzes such as karyotyping.
The advantage of chorionic biopsy is the amount of biological material, which is sufficient for the whole a number of different laboratory procedures. Also, a great advantage is the timing of the procedure as it allows diagnosis in the first trimester of pregnancy, but the chorionic biopsy procedure itself carries a risk of miscarriage of 1-2%.
