Protein is assembled inside cells by an organelle called a ribosome. Ribosomes are found in every major cell type and are the site of protein synthesis.
Answer:
Selective transport enables the substances to move rapidly through the cell membrane (for instance, H2O, O2 and CO2), while other substances pass through the cell membrane more slowly. Moreover, there are also compounds that can't pass through this barrier.
Explanation:
The selective transport of the substances across the cell membrane enables the cell to maintain the homeostasis of the system by maintaining the ionic equilibrium on both sides of the cell membrane. Moreover, selective transport also is required for carrying out cellular mechanisms, since this mechanism enables the entry and the exit of macromolecules used by the cell to maintain its function and structure.
The most common mechanisms of selective transport are diffusion and transport active. Endocytosis and exocytosis are active transport process where proteins, lipids, and different types of macromolecules are transported to both sides of the cell membrane through vesicles. Polar molecules (such as for instance, calcium and iron ions) may be transported via transport active, while hormones and vitamins may be transported via passive diffusion.
Frontal lobe
Frontal lobe is situated near the front of the head and it is the most forward of the four lobes of the cerebral cortex. The frontal lobe is the area responsible for primary motor functions and some of the most complex cognitive processes such as memory, problem solving, sexual behaviors, emotional expression, language, and judgment.
Answer:
C
Explanation:
The origin of replication refers to the site at which DNA replication begins. The process of DNA replication - which occurs prior to cell division - generates a new copy of the DNA.
DNA replication involves unwinding of the DNA double helix, creating a Y shape called the replication fork. The two strands are then replicated, and now there are two DNA molecules, each containing one "old" DNA strand and one "new" DNA strand.
The first stage at the origin of replication is that the enzyme helicase begins splitting apart the strands of a DNA molecule. (C)
The answer is not A, as the two DNA strands are already in the double helix. The answer is not B, as the enzyme responsible for copying the DNA sequence is DNA polymerase, not RNA polymerase. The answer also cannot be D, because although short RNA primers are involved in DNA replication, this does not occur at the origin of replication.
Phenomena such as star explosions, neutron stars, black holes etc. are studied with the help of extremely powerful and sensitive telescopes.
These sophisticated instruments are able to see more than our own eyes can. Thus, they detect wavelengths outside of those found in our visible spectrum, such as X-rays etc.
The most sophisticated telescopes are those that are placed in space such as the Hubble or Spitzer Space Telescope. In this way, these instruments are able to circumvent the Earth's atmosphere that may block the view of the sky. Thus, in space, they have the optimal conditions to observe and study in detail such phenomena.
