Mitosis is the division that results in two “daughter” cells. Both of these daughter cells have the same number of chromosomes as the “parent” cell.
Mitosis consists of 4 phases: prophase, metaphase, anaphase, and telophase.
Prophase: the DNA is copied and the chromosomes pair up
Metaphase: the chromosomes line up in the middle of the cell
Anaphase: sister chromatids are pulled apart from each other towards opposite sides of the cell
Telophase: the cell begins to pinch in the middle and separates into two identical daughter cells
Answer:
The correct answer is 3: "<em>High levels of Ca2+ are expected to be found </em><em>within the sarcoplasmic reticulum</em>".
Explanation:
Muscular contraction is a highly regulated process that depends on free calcium concentration in the cytoplasm. Amounts of cytoplasmic calcium are regulated by <u>sarcoplasmic reticulum</u> that functions as a storage of the ion.
When a nerve impulse reaches the membrane of a muscle fiber, through acetylcholine release, the membrane depolarizes producing the entrance of calcium from <u>extracellular space</u>. The impulse is transmitted along the membrane to the sarcoplasmic reticulum, from where calcium is released. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. The calcium channel in the sarcoplasmic reticulum controls the ion release, that activates and regulates muscle contraction, by increasing its cytoplasmic levels. When <em>calcium binds to the troponin C</em>, <em>the troponin T alters the tropomyosin by moving it and then unblocks the binding sites,</em> making possible the formation of <em>cross-bridges between actin and myosin filaments.</em> When myosin binds to the uncovered actin-binding sites, ATP is transformed into ADP and inorganic phosphate.
Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
Answer
I added 4 and 5 as an attachment due to time constraint.
Explanation:
1. at a steady state ca2+ taken by vesicle = 40n/mol
enclosed volume of CSR = 5μ/mg
concentration of ca2+ in vesicle =
40*10⁻⁶/5x10⁻⁶
= 0.008
= 8x10⁻⁹mol/L
2. radius of circle =75nM
volume = 150nm
volume of vesicle = 4/3 x pi x r³
= 1.33 x 3.14 x (75x10⁻⁹)³
= 1.77 x 10⁻²¹
when we convert this we get
1.77x10⁻¹⁸L since 1m³ is equal to 100oL
surface area =4x3.14x(75x10⁻⁹)²
= 12.56x5.625⁻¹⁵
= 7.065x10⁻¹⁴m²
this is 7.065x10⁻¹⁰cm²
3. number of vesicle/CSR
= 5x10⁻⁶/1.77x10⁻¹⁸
= 2.824x10¹²
surface are = 2.824x10¹² x7.06x10⁻¹⁰
= 19.95x10²
He difference between acute stress and chronic stress is one of severity and time. Acute stress is short lived and may not have very severe effects on you. Chronic stress is when you are under stress<span> on an ongoing basis and can lead to physical disease, mental disorder and spiritual dark nights of the soul.</span>