Answer:
The mechanisms of transport across the cell membrane are as follow: 1- simple diffusion, 2- facilitated diffusion, 3- primary active transport and 4-secondary active transport
Explanation:
The cell membrane is a selectively permeable structure capable of transporting substances by different mechanisms. Simple diffusion is a type of passive transport (i.e. does not require energy) where non-polar molecules (e.g. O2, CO2) pass across the membrane by a process that does not require energy from the cell. Facilitated diffusion is another type of passive transport where larger polar molecules (e.g., glucose and amino acids) pass across the membrane by using specific transmembrane integral proteins. On the other hand, primary active transport is a type of active transport that uses chemical energy (e.g., ATP) to move substances such as metal ions (Na+, K+, Ca2+) across the cell membrane against their concentration gradient. Finally, secondary active transport is another type of active transport where transporter proteins are used to couple the movement of ions (e.g., H+ protons) down their electrochemical gradient to the transport of another ions/solutes against their concentration/ electrochemical gradient.
George Mendel chose to use purebred plants in his experiments because they have a variety of traits.
The most accurate classification of the common forms of coronary artery disease and hypertension is that they are complex disorders which result from gene-environment interactions. For example, almost 60% of CAD cases are found in South East Asia, that too when their population if just 20% of the total world's population. This is due to the environmental interactions with the genetic disposition of the people of this region.
C.) viruses need a living host to reproduce... this is cause by viruses being Dioxyriboneuclicacid(DNA) surrounded by a protien shell so viruses are not alive per say.... but they get into cells and use living cells to reproduce
