Answer:
When a muscle cell contracts, the myosin heads each produce a single power stroke.
Explanation:
In rest, attraction strengths between myosin and actin filaments are inhibited by the tropomyosin. When the muscle fiber membrane depolarizes, the action potential caused by this depolarization enters the t-tubules depolarizing the inner portion of the muscle fiber. This activates calcium channels in the T tubules membrane and releases calcium into the sarcolemma. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. When calcium binds to the troponin C, the troponin T alters the tropomyosin by moving it and then unblocks the binding sites. Myosin heads bind to the uncovered actin-binding sites forming cross-bridges, and while doing it ATP is transformed into ADP and inorganic phosphate which is liberated. Myofilaments slide impulsed by chemical energy collected in myosin heads, <u>producing a power stroke</u>. The power stroke initiates when the myosin cross-bridge binds to actin. As they slide, ADP molecules are released. A new ATP links to myosin heads and breaks the bindings to the actin filament. Then ATP splits into ADP and phosphate, and the energy produced is accumulated in the myosin heads, which starts a new binding cycle to actin. Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
Answer:
A nerve impulse from one neuron affects the activity of a neighboring neuron at a point of interaction called the: SYNAPSE
Explanation:
A NEURON(or nerve cell) has 3 parts:
1. The dendrites(multiple)
2. The axon
3. The cell body
A SYNAPSE is an area where the dendrites of one neuron communicates with the axon of another neuron.
At the synapse, nerve impulses are transmitted from one neuron to the other. This is possible through substances called NEUROTRANSMITTERS. There is no direct contact between the axon of one neuron and dendrites of another neuron.
Answer:
false because atom are the smallest classification of matter
Following are the statements:
1. Main phagocytes in circulation
2. Like eosinophils, they are involved in inflammation and allergic reactions
3. Phagocytic cells that leave circulation and differentiate into macrophages
4. Display no antigen specificity but are active against tumor and virally infected cells
Answer:
1. Neutrophils
2. Basophils
3. Monocytes
4. Natural killer cells
Explanation:
Neutrophils can be described as the most abundant type of white blood cells. They make up to 55%- 75% of the immune system.
Basophils can be described as white blood cells which are made in the bone marrow.
Monocytes can be described as white blood cells which are the largest and differentiate into macrophages and myeloid lineage dendritic cells.
Natural killer cells can be described as white blood cells which play a role in providing innate immunity.
It can help by opening closed doors to new findings. I can understand what Infections or virus I may get and be able to treat it. I will be able to get educated about my surroundings and be able to study them to succeed at understanding what causes what. In the end, I hope this helped.Goodluck
