Answer:
Unlike typical mammalian red blood cells, those from amphibians, such as frogs, contain a DNA-bearing nucleus that is visible in the center of the cell. The circulatory system of amphibians is rather unusual, their hearts having three chambers, two atria, and a single ventricle.
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The design of the amphibian circulatory system is curious because blood accumulates oxygen in the lungs and is then returned to the heart before being pumped into the rest of the circulatory system. Therefore, a mixing between oxygenated and deoxygenated blood occurs as blood returning to the heart from the lungs is mixed with incoming blood from the body. Frogs handle this situation by having a very slow metabolism and by absorbing some oxygen through their skin. In addition, the ventricle does have some directional control over the distribution of the blood.
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The presence of a nucleus in amphibian red blood cells allows researchers easy access to large quantities of amphibian DNA. Frog blood has both a solid and a liquid portion. The liquid plasma carries solid elements such as red and white blood cells. Blood can be collected from frogs and the red blood cells isolated by centrifugation. After removal of the residual plasma, purified cells can be treated with specific enzymes and detergents to digest the cellular envelope and release DNA from its protein complex. The DNA is then useful for scientific studies and experiments.
Featured in: Phase Contrast
Explanation:
Answer:
Eyelashes, wing of a fly, feather of an owl, the tip of your nose, the horn of a goat, your kidney, a maple leaf, a blade of grass, claw of a crab, and petal of a rose.
Explanation:
You have to ask yourself on each one if it is living or non-living.
The phase after ovulation (release of an egg) is called luteal phase. The stimulating follicle hormone (fsh) and luteinizing hormone (lh) are produced in the pituitary.
The FSH promotes the growth of an egg in the follicle while the LH facilitates its release from the follicle. Once the egg is released, the two hormones decrease, resulting in the rise of estrogen and progesterone.
