The correct answer is: A) The polarity of membrane phospholipids
Factors that affect membrane permeability are
1. Chemicals :
Some of the organic solvents such as chloroform and ethanol can dissolve the membrane and thus, destroy the selective permeability of the membrane.
2. Temperature :
Too high temperatures denature the protein that are in the structure of the membrane destroying its selective permeability. On the other hand, too low temperature slows down molecule movements and the permeability decreases.
3. Cholesterol:
Increases the permeability by reducing the barrier formed by phospholipids’ heads
4. The saturation of hydrocarbon tails in membrane phospholipids:
Saturated fatty acids decrease permeability of the membrane because they get very close together, which makes it harder for the molecules to pass through.
Answer:
Protein
Explanation:
This is because protein is a macronutrients and it is the building blocks which is important for building body mass and they are found through out the body, in the muscles, bones, skin, hair e.t.c
Protein can be gotten from both plants and animals.
The animal protein include meat, diary products, fishes e.t.c.
The plants protein include beans, r.t.c.
Answer:
E. are found in nitrogen-fixing cyanobacteria AND are used to protect nitrogenase.
Explanation:
Heterocysts are specialized cellular compartments found in nitrogen fixing cyanobacteria. They provide the ideal anaerobic environment for nitrogen fixation since nitrogenase enzyme cant work in presence of oxygen. Hence, in a cyanobacteria both the oxygen requiring photosynthesis process and the oxygen sensitive nitrogen fixation process takes place simultaneously.
Heterocysts have an additional cell wall made of glycolipid that provides a hydrophobic barrier to oxygen. They are involved in production of nitrogenase and other proteins that are required for nitrogen fixation. They also degrade photosystem II which is responsible for producing oxygen and produce proteins which remove any remaining oxygen.
