1. Contraction
2. Actin
3. Tendons
4. Epidermis
5. Dermis
6. Acne
7. A nerve signal from the brain arrives at the intersection of the nerve and muscle cells and releases acetylcholine from the neuron. This triggers chemical changes in the muscle cell involving ions, including Ca2+. Calcium triggers the thick filaments, made of myosin, to attach to the thin filaments, made of actin, in the muscle cell, and the myosin pulls the actin toward the center of the muscle cell. ATP causes the release of the actin fibers, allowing the muscle to relax and the process to begin again.
For Penn Foster.
Answer:
Endoplasmic reticulum.
Explanation:
Protein synthesis, sorting and transport is the important mechanism for the synthesis of protein in the body and the transport of the protein to its specific site or organ. The protein must reaches to its final destination for its proper functioning.
KDEL ( K- leucine, D is aspartic acid, E is glutamic acid and L is lysine ) is the stretch of a specific amino acid that are responsible for the protein molecule to target at its specific site. KDEL is specific for the transport of peptides to the endoplasmic reticulum.
Thus, the correct answer is option (A).
It radiates light and heat, or solar energy, which makes it possible for life to exist on Earth. Plants need sunlight to grow. Animals, including humans, need plants for food and the oxygen they produce. Without heat from the sun, Earth would freeze.
Newton's law of gravity defines the attractive force between all objects that possess mass. Understanding the law of gravity offers profound insights into the way our universe functions. Newton, upon observing an apple fall from a tree, began to think along the following lines: The apple is accelerated, since its velocity changes from zero as it is hanging on the tree and moves toward the ground. Thus, by Newton's 2nd Law there must be a force that acts on the apple to cause this acceleration. Let's call this force "gravity", and the associated acceleration the "acceleration due to gravity". Then imagine the apple tree is twice as high. Again, we expect the apple to be accelerated toward the ground, so this suggests that this force that we call gravity reaches to the top of the tallest apple tree. <span>Newton knew that the force which caused the apple's acceleration (gravity) must be dependent upon the mass of the apple. And since the force acting to cause the apple's downward acceleration also causes the earth's upward acceleration (Newton's third law), that force must also depend upon the mass of the earth. </span>
