Answer:
Solutes dissolved in water on either side of the cell membrane will tend to diffuse down their concentration gradients, but because most substances cannot pass freely through the lipid bilayer of the cell membrane, their movement is restricted to protein channels and specialized transport mechanisms in the membrane.
Explanation:
The activation of the suprachiasmatic nucleus is stimulated by the presence of the light waves. This activation leads to the release of the hormone serotonin. Serotonin promotes the wake cycle of the person along with his internal clock. However, when the light is absent, then the pineal gland, which is present at the top of the middle of the brain, secretes the hormone melatonin. The melatonin regulates the sleep cycle of the person.
Hence, the blanks can be filled with 'serotonin and melatonin' respectively.
Answer:
The correct answer would be 37.
Egg or sperm or gametes are cells produced by the process of meiosis and carry half the number of chromosome (n) present in a parental cell (2n).
Meiosis is a type of cell division which results in the formation of four daughter cells each having exactly half the number of chromosome present in parent cell.
The sperm unite or fertilize with egg which restore the chromosome number (2n) in the zygote.
Answer:
D
Explanation:
During metaphase of cell division, the chromosomes line up in the metaphase plate and the spindle fibers from the poles extend and attach to the centromeres of the chromosomes. The spindle then contracts and pull different chromosomes to the opposite poles of the cell before the parent cell divides. If spindle fibers do not form, then the chromosomes will not separate during anaphase.
Therefore, the final cell after mitosis will be a cell with double the number of chromosomes -because if you remember, during interphase, genetic material is replicated so each daughter cell can have its copy-. Due to quality control in the process of cell divisison, this cell will mostly undergo apoptosis, otherwise, it could develop into cancer.
