Unit 3 Lesson 6: chordate evolution and diversity quick check answers.
1. B
2. D
3. B
4. B
5. B
Answer:
The correct order is: 6) Sarcoplasmic reticulum releases calcium ions, 2) Calcium ions bind to troponin, 5) Tropomyosin moves to expose active sites of actin, 4) ATP is split into ADP and P, 1) Myosin head binds to actin, 7) ADP and P released from myosin, 3) Myosin cross-bridges bend, pulling actin toward center of sarcomere.
Explanation:
The ability to contract is an important property of the muscle cells and is fundamental to animals because muscles not only make locomotion possible but are also responsible for the correct functioning of organs (including the heart).
The mechanism behind muscle contraction is the sliding of filaments in a structure called sarcomere, which mostly involves the presence of actin and myosin filaments.
For muscle contraction to happen, there needs to be a <u>stimulus coming from the nerve that innervates said muscle</u>. This stimulus generates the release of <u>calcium ions</u> that will bind to a protein called troponin and will lead to the exposure of the active site of actin so it can bind to the myosin head. <u>This process requires ATP</u>.
For mitosis, two cells are created, and for meiosis, four cells are produced. So the answer is B. Because in mitosis, the chromosome replicates once and divides once. In meiosis, the chromosome replicates once and divides twice. That's why the cell has half of the chromosomes after meiosis.
The mentioned case represents secondary succession.
Secondary succession is one of the two kinds of ecological succession of plant life. Secondary succession refers to a procedure initiated by an incident, like harvesting, forest fire, hurricane, and others, which minimizes an already settled ecosystem to a lesser population of species.
Thus, it can be said that the secondary succession takes place in preexisting soil on the other hand primary succession takes place in a place devoid of soil.
Secondary succession is the ecological succession, which takes place after the initial succession has been disrupted and certain plant and animal species do prevail. It is usually faster in comparison to primary succession.
They are less likely to be separated during crossing over.
