A nucleus consists of a nuclear membrane that surrounds it, within the membrane there is a nucleolus which can be compared metaphorically to the yolk of an egg in appearance. The nucleolus is surrounded by nucleoplasm which is quite like the cytoplasm.
Answer:
Earth's outer core is a fluid layer about 2,400 km thick
Explanation:
composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. Its outer boundary lies 2,890 km beneath Earth's surface
Answer:
The prolonged electrical depolarization of cardiac muscle cells -that occurs during contraction- is due primarily to the persistent influx of calcium ion
Explanation:
The action potential of the heart muscle is longer with respect to skeletal muscle (around 300 milliseconds), and this is due to the activity of calcium (Ca⁺⁺ ) in the intracellular compartment.
The initial depolarization of cardiac muscle fiber depends on the entry of sodium (Na⁺) into the cell. However, for the action potential to occur and be maintained, Ca⁺⁺ must increase its cytoplasmic levels, which depends on:
- The increase in intracellular sodium induces the release of Ca⁺⁺ from the sarcoplasmic reticulum.
- Calcium entry from the extracellular space through the voltage dependent Ca⁺⁺ channels.
- The entry of extracellular Ca⁺⁺ causes the release of more Ca⁺⁺ ions by the sarcoplasmic reticulum, further increasing its intracellular concentration.
This is how the ion that guarantees the duration of the action potential of the cardiac muscle cell is the Ca⁺⁺.
Learn more:
Calcium, sodium and cardiac muscle cells brainly.com/question/4473795
Answer:
b. making an observation and asking a question
Explanation:
In scientific method there need to be a situation to be study. In this description, the scientist first observed that in a certain region there is some kind of trees and the other variable is the great amount of deer.
After making different observations, and some research of other areas similar to the one that is study, she is asking what is the relation among the animals and the trees.
The next step will be to formulate a hypothesis using all the data and the two variables that she observed.
The correct answer is:
nucleic acids
Explanation:
Nucleic acids are biopolymers, or humble biomolecules, necessary for all known methods of life. They are formed of nucleotides, which are monomers comprised of three components: a 5-carbon sugar, a phosphate group, and a nitrogenous base..Nucleic acids are the basic unit of heritage, they develop all the genetic element of living things.This genetic information defines how individual cells and entire organisms grow and function
