Answer:
d. Ribosome
f. Cell wall
Explanation:
In humans 80s type of ribosome is present and in bacteria 70s type of ribosome is present. Human cells do not have cell wall while bacterial cells have peptidoglycan cell wall. These differences can be targeted by the potential antibacterial agents.
For example, tetracycline antibiotic inhibits the binding of important molecules to bacterial ribosome which ultimately inhibits the protein synthesis in bacteria. Vancomycin antibiotic on other hand inhibits the cell wall formation in bacteria by inhibiting peptidoglycan synthesis.
If a red blood cell is placed in a hypertonic solution, the cell would shrink.
Hypertonic solution means that the solution has a lower water potential than the other side (which is the cell's cytoplasm in this case), and by that, water molecules would have a tendency to flow from a region of higher water potential to a region of lower water potential. This movement of water molecules is called osmosis. But note that a semi-permeable membrane (a membrane which can decide what substances can go in and out, the cell membrane is an example) has to be present in osmosis, or else the movement may be regarded as diffusion.
As the water molecules flowed away from the red blood cell cytoplasm, the cell loss so much water that the membrane has nothing much to hold and thus the cell shrinks.
The scientist credited with being the first person to observe bacteria and call them as small animalcules is B. Anton van Leeuwenhoek.
Friction is a force resisting the movement between 2 objects. (slows or stops the movement)
Answer:
A. Organ
Explanation:
Leaf is an essential part of plant that is involved in photosynthesis and also in exchange of gases. It is made up of epidermis, which is thick one, and is present at lower and upper surface of leaf. Between upper and lower epidermis, mesophyll is present while cuticle is present outside of the epidermis. Xylem and phloem and other connective tissues are arranged in the leaf in such way that it maintains the shape as well as effective transfer of nutrients and water in the leaf. Leaf is an organ, made up of all these tissues to form a complex structure.
