Answer:
To ensure their survival by reproducing
Answer:
They are opened either by the binding of ligands or by changes in electric potential across the membrane
Explanation:
Ion channels are the integral membrane proteins that form pores or holes for the transport of specific ions, such as potassium ions (K+), Na+, etc. Most ion channels are selective and allow only a single type of ion to pass through. These ion channels facilitate the diffusion of ions down the concentration gradient and do not require ATP.
Ion channels are mostly gated. Some ion channels open in response to change in the concentration of ions and electric charges across the membrane. Some ion channels open and close in response to the binding of specific molecules called a ligand. For example, binding of two molecules of acetylcholine to the receptor on the motor endplate of a neuromuscular junction opens an ion channel in the ACh receptor through which Na+ can flow across the membrane.
Answer:
Deforestation and the burning of fossil fuels
Explanation:
Deforestation leads to less carbon dioxide to oxygen production, and burning fossil fuels releases large amounts of carbon dioxide.
Answer:
Question: Two requirements for gas exchange which are accomplished by the gills in a fish include:
1. Water flowing in opposite directions across the gill lamellae for gas exchange, in other words, respiration is experienced by the fish.
2. The fish allows water through its mouth, then forces the water to drain through the gills supporting gill lamellae, and enhancing gas exchange.
Question: How does their structure help to satisfy these requirements?
1. The rows of gill filaments with numerous folds through diffusion makes sure oxygen from the water moves from a place of more concentration to the blood of the fish which has less concentration causing the removal of carbon dioxide.
2. The large surface area of the gill means it has to maximize the low percentage of dissolved oxygen in the water compared to the higher percentage of oxygen in the air makes it possible for water to pass through the mouth and empty through the gills after the mouth is closed.
