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: Blue because of google lol
Answer:
New species can appear gradually through small changes in an ancestral species.
Explanation:
The new species that appear are due to hereditary variations that occur in a population. The adaptive variations are said to confer a selective advantage to organisms possessing them. The result of variations is that well adapted individuals are able to survive and reach the reproductive age and pass over their favourable characteristics to their offspring.
Answer:
DNA from a gene of interest can be inserted into a plasmid, then the modified plasmid can be inserted into a bacterial cell to replicate a gene of interest many times.
Explanation:
Plasmids are the extra-chromosomal circular DNA present in bacterial cells. Plasmids are able to replicate themselves independent of genetic DNA. Their ability to self replicate allows them to maintain themselves in the bacterial cells. This is why plasmids are used as cloning vectors in recombinant DNA technology.
A gene of interest is isolated from the donor cell and is inserted into the plasmid. The recombinant plasmid is introduced into bacterial cells where it replicates the ligated desired gene and allows the gene cloning. For example, the human insulin gene is ligated with plasmid and the recombinant plasmid is introduced in <em>E. coli</em> where it replicates the human insulin gene and allows the production of desired copies of the gene.
Answer:
- Hydrogen ion concentration is lower in the mitochondrial matrix than in the intermembrane space.
- Oxidative phosphorylation relies on the hydrogen ion concentration gradient generated and maintained by the electron transport chain.
- Hydrogen ions enter the mitochondrial matrix via facilitated diffusion.
Explanation:
Oxidative phosphorylation is a metabolic pathway by which Adenosine Triphosphate (ATP) molecules are produced through the transfer of electrons from NADH or FADH2 to molecular oxygen (O2). The hydrogen (H+) ions are pumped from the mitochondrial matrix to the intermembrane space, and this movement of protons generates an electrochemical gradient across the mitochondrial membrane which is used by the ATP synthase to produce ATP. This gradient is generated by the movement of electrons through a series of electron carriers (e.g., cytochrome c and ubiquinone) that are embedded in the inner mitochondrial membrane. The movement of these H+ ions across the semipermeable mitochondrial membrane moving down their electrochemical gradient is named chemiosmosis and is an example of facilitated diffusion.
