Answer:
The cells need water to maintain their metabolic functions, the way water enters through cells membranes is by osmosis.
Explanation:
The cell membrane is a lipidic bilayer composed of phospholipids and embedded proteins. Phospholipids have the characteristic of being amphiphilic which means that possess hydrophilic and lipophilic characteristics. The most common way is by osmosis, that is a mechanism that moves water from high concentration to less concentration of water. In the cell membrane, there are is channels of proteins called aquaporins that facilitate the pass of water through the membrane. Also, as water is a very small molecule without charge, this characteristic allows passing a limit amount of water molecules through the hydrophilic characteristic of membranes.
The producers at the beginning of the Earth's food chain are plants.
Answer:
prokaryotes and eukaryotes both have ribosomes
Explanation:
because both have ribosomes but those ribosomes are not the same kind
Answer:
Sam is correct. It is a chemical change and the contents should be in D. for compound.
Explanation:
This answer is correct because I just took the USA test prep
Good Luck!
Answer:
Glucose entering the intestines from the villus.This is by active transport.The latter is defined as the movement of molecules and solutes from the region of lower concentration to the region of higher concentration against the concentration gradient.
Explanation:
All the above options depends on the diffusion gradients from one higher region to another.e.g oxygen passing from high concentration from outside to lower concentration in blood stream,like wise Co2 from higher concentration from inside to outside,with passive diffusion lipids and water enter the small intestine(note amino acid and glucose,and fructose are different).
Active transport( through sodium dependent transporter) transports glucose to the intestine from the villus.This is movements against concentration gradient because,glucose molecule are concentrated in intestine,and needed by the cells, in the body.Therefore they must be transported as a fast rate inn the blood .
However the absorption by the villi is very slow,therefore active transport is needed to move these against the concentration gradient into the intestine.And finally the blood.
If this were to be moved by passive diffusion,the high concentration in the intestine will force this back into the villi
Therefore extra energy is needed by active transport for the glucose molecules to enter the intestine from the villus.
