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.
In prokaryotes, new mutations accumulate quickly in populations, while in eukaryotes, new mutations accumulate much more slowly. The primary reasons for this are prokaryotes reproduce quickly and have vast populations.
<h2> Prokaryotes V/S Eukaryotes</h2><h3>Prokaryotes</h3>
Prokaryotes are organisms consisting of cells that don't have cell nuclei or any organelles that are enclosed in membranes. It follows that prokaryote's DNA is not contained within a nucleus.
The following components could be found in a normal prokaryotic cell:
- The membrane enclosing and guarding the cell is known as the cell wall.
- All of the cell's internal components, excluding the nucleus, are called cytoplasm.
- Some prokaryotic cells have filaments made of proteins called flagella and pili.
- A nucleoid is a cell structure that resembles a nucleus and contains genetic material.
- A plasmid is a little DNA molecule with independent reproduction.
<h3>Eukaryotes</h3>
Eukaryotes are organisms made up of cells with membrane-bound organelles and a nucleus that contains DNA in the form of chromosomes. Eukaryotic organisms can have several cells or just one cell. Eukaryotes make up all animal life. Protists, fungi, and plants are examples of additional eukaryotes.
Learn more about Prokaryotes and Eukaryotes here:-
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Glucose levels are usually lowest in the morning, before the first meal of the day, and rise after meals for an hour or two by a few millimoles. Blood sugar levels outside the normal range may be an indicator of a medical condition. A persistently high level is referred to as hyperglycemia; low levels are referred to as hypoglycemia. Diabetes mellitus is characterized by persistent hyperglycemia from any of several causes, and is the most prominent disease related to failure of blood sugar regulation. There are different methods of testing and measuring blood sugar levels.
Answer:
B
Explanation:
Amount of energy decreases as it goes higher up the trophic levels.
Cell - neuron, egg, bacteria, perenchyma
tissue - bone
organ - leaf, flower, eye
organ system - blood, human skeleton
organism - mushroom, bear
not 100% sure but tried
