Answer:
Stem cell is the special type of cell that can differentiate to give any cells in the body. Cell therapy nowadays are using stem cell in order to replace damaged tissue.
Researchers are finding out ways to treat diseases like diabetes, Parkinson's, spinal cord injury and heart injury etc. These cells have the ability to repair damaged heart cells after a heart attack. They can also treat neurological problems.
Answer:
except natural killer cells.
Explanation:
The Helper T cells produce cytotoxic T cells and help B cells, but not natural killer cells
Answer:
Both facilitated diffusion and active transport are selective processes. Only selective molecules are allowed to cross the membrane. They utilize carrier proteins to move across the membrane.
Explanation:
Diffusion is the process by which molecules move across a membrane respective of the concentration gradient. The plasma membrane is a <em>selectively permeable membrane</em> which allows specific molecules to move across the concentration gradient.
Molecules migrate from a region of higher concentration to a lower concentration in case of diffusion. It can be classified into simple diffusion and facilitated diffusion. These are examples of <em>passive transport</em>.
In facilitated diffusion molecules move across the concentration gradient with the help of <em>carrier proteins or channel proteins</em>. The carrier proteins bind to the molecule which has to be transported and change conformation to allow it to cross the membrane. For example glucose molecule is carried across through <em>GLUT transporter</em>. <em>Channel proteins</em> open a channel inside the membrane and molecules get transported across the gradient.
Active transport carries molecules against the concentration gradient with the assist of energy. ATP hydrolysis is utilized to generate energy. As a result of active transport, the molecules are aggregated on one side of the membrane.
The right answer is vein (it contains blood and has valves).
The infra-cardiac veins of small and medium caliber possess this system of fight against gravity. The valves consist of a dense connective tissue, surmounted by endothelial cells, corresponding to a fold of the intima. They allow blood circulation in the sense organ / heart but prevent venous reflux.
Answer:
this is a common ... saw incredible similarities between birds and the theropod dinosaurs (especially ... Like all other reptiles, birds have scales (feathers are produced by tissues similar to ... for theropods are often more serious for the "thecodont" pseudo-hypothesis.
Explanation:
