Answer:
Please find the explanation below
Explanation:
Virus is an organism that has been a topic of debate in biological sciences. This debate is based on whether virus should be classified as a living thing or not. However, it has been shown that viruses possess characteristics or properties of both living and non-living things.
The living thing characteristics include;
- Ability to reproduce or replicate (in living cells only and not on their own).
The nonliving characteristics include;
- Lack of cells, which is a strong criterion for every living thing in accordance to the universal cell theory.
- Inability to self-replicate i.e. reproduce on their own without a living host.
Answer:
Power stroke (myosin head bends) coupled with the release of ADP and phosphate
Explanation:
Muscle contraction results from myosin heads adhering to actin and attracting it inwards. It uses ATP. Myosin adhers to actin at a binding site of its globular actin protein and adheres at another binding site for ATP (hydrolyzed ATP to ADP, Pi and energy)
ATP binding prompts myosin to detach from actin, ATP is changed to ADP and inorganic phosphate, Pi by ATPase. The energy formed at this process orientates myosin head to a “cocked” direction.
The myosin head goes in the direction of the M line, holding the actin with it in the process causing the filaments to orientate nearly 10 nm in the direction of the M line--- power stroke (force is produced), the sarcomere reduces in length and the muscle contracts.
Note: The power stroke is seen when ADP and phosphate disattaches itself from the myosin head.
At the terminal point of the power stroke, the myosin head as low-energy, followed by ADP release.
The attached image shows the cross-bridge muscle contraction cycle, which is activated by Ca2+ sticking to the actin active site. And how actin moves in relation to myosin.
The correct order of the following events on the mass flow of materials in the phloem is:
- Leaf cells produce sugar by photosynthesis.
- Solutes are actively transported into sieve tubes.
- Water diffuses into the sieve tubes.
- Sugar moves down the stem.
Correct answer: letter C.
This is because the mass flow of materials in the phloem must pass through all these processes in a consecutive and orderly manner, from the cell to the stem, in order to allow nutrients and other vital materials to reach from the plant roots to the leaves and fruits.
<h3>How is this transport of nutrients and other vital materials achieved?</h3>
This is accomplished by the transport of solutes through the phloem's network of channels, which contain fluids, mineral salts, vitamins and other nutrients essential to plant health. Mass flow also helps distribute oxygen and carbon dioxide to all parts of the plant. These materials are necessary for plant respiration and growth.
Learn more about the phloem:
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Answer:
I think it is A Parasitic one
Explanation:
