When something needs to be transported against its concentration gradient, or a molecule is too big to simply diffuse through a membrane, active transport has to be used. So active transport requires energy (ATP).
Examples:
1. Antiport pumps: transport one substance in one direction while transporting another substance the other way. An example of this is the sodium-potassium pump.
2. Symport pumps - uses a substance that wants to move from an area of high concentration to low concentration and carries another substance against its concentration gradient. An example of this is the sodium-glucose transport protein
3. Endocytosis - large amounts of extra cellular fluid can be taken into a cell - needs ATP to bind proteins in the cell membrane and causes them to change their shape...which eventually causes the surrounding of the fluid to be brought in (a vesicle).
4.exocytosis - opposite of above
Answer: no
Explanation: some of the cells look the same but some don’t and this is basically saying that they are not all the same. There is like 4 different types of cells.
Answer:
D. Both a and c are correct.
Explanation:
The tragedy of the commons is a situation in a shared-resource system where individual users, acting independently according to their own self-interest, behave contrary to the common good of all users by depleting or spoiling the shared resource through their collective action.
It damages our environment (plants, animals) and impacts local tourism. It is smelly and dirty, and carries germs, bacteria and viruses. Places with a high degree of littering see a decreases in property values, and are more likely to be the site of fires.
Pollution is a negative externality. Economists illustrate the social costs of production with a demand and supply diagram. The social costs include the private costs of production incurred by the company and the external costs of pollution that are passed on to society.
Blowing litter can cause automobile accidents as well as land and air pollutions
