The cell membrane separates the intracellular environment from the extracellular environment outside of the cell. A phospholipid is composed of a phosphate group and a lipid. It is composed of a hydrophilic, polar phosphate head and two hydrophobic fatty acid tails.
The structure of the bilayer is such that the tails are shielded from contact with water, creating a selectively-permeable barrier which will be impermeable to most hydrophilic molecules.
So, the answer is A) To maintain balance of water and nutrients in the cell.
The answer is letter D.
A group of white blood cells that has of small and large lymphocytes.
The small lymphocytes bear variable cell-surface receptors for antigen and are
responsible for adaptive immune responses. There are two main group of small
lymphocyte—B lymphocytes (B cells) and T lymphocytes (T cells). Large granular
lymphocytes are natural killer (NK) cells, lymphocytes of innate immunity.
Answer:
When the stomach digests food, the carbohydrate (sugars and starches) in the food breaks down into another type of sugar, called glucose. The stomach and small intestines absorb the glucose and then release it into the bloodstream.
Explanation:
The five proteins of the myofilaments are the following:
<span>1.
</span>Myosin, shaped like a golf club, with two
polypeptides intertwined to form a shaftlike tail and a double globular head,
or cross-bridge, projecting from it at an angle.
<span>2. </span>Fibrous actin is like a bead necklace—a string
of subunits called globular (G) actin. Each G actin has an active site that can
bind to the head of a myosin molecule.
<span>3. </span>Tropomyosin. It blocks the active sites of six
or seven G actins and prevents myosin cross-bridges from binding to them when a
muscle fiber is relaxed.
<span>4. </span>Troponin a smaller calcium-binding protein bound
to each tropomyosin molecule.
<span>5. </span>Titin (connectin), run through the core of a
thick filament, emerge from the end of it, and connect it to a structure called
the Z disc.
The chemical information for making proteins is carried in the DNA, which is found on the chromosomes in the cell nucleus.
