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ki77a [65]
3 years ago
14

Helps activate T cells, which are produced in bone marrow but mature in the thymus gland HELLPP

Biology
1 answer:
love history [14]3 years ago
3 0

Answer:

peptide antigens by MHC class II molecules

Explanation:

Helper T cells are activated by peptide antigens by MHC class II molecules. These antigens express on the surface of antigen-presenting cells (APCs). After activation, the T helper cells divide and secrete cytokines  to assist the immune response.

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Identify plants and make assumptions on past climate condition
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Which characterisic of life destinguishes a fire and a flowering plant
worty [1.4K]

Answer:

The correct answer from the options is Growth.

Explanation:

There are seven basic characteristics of life which separate living things from non- living things.

Growth is one of the characteristics which separate a living thing from a non- living thing. The plants use essential macromolecules for growing. The fire will not have macromolecules to grow. Hence, growth is the option that is correct.

Other options like defined boundary are incorrect because both plants and animals have a defined boundary.

8 0
4 years ago
What's portal of entry?
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A portal of entry<span> is the site through which micro-organisms enter the susceptible host and cause disease/infection. Infectious agents enter the body through various </span>portals<span>, including the mucous membranes, the skin, the respiratory and the gastrointestinal tracts.</span>
6 0
4 years ago
Which statement best describes the purpose of Earth's spheres?
kondaur [170]

Answer:

and they work together to drive the processes of the planet.

Explanation:

Earth has four 'spheres,' called the geosphere, hydrosphere, biosphere and atmosphere. These spheres each have unique properties and features, but they are not isolated on Earth, and they work together to drive the processes of the planet.

5 0
3 years ago
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Cite particularly the difference in the synthesis of the two biomolecules in animals and plants.
Sonja [21]

Answer:

The preceding section reviewed the major metabolic reactions by which the cell obtains and stores energy in the form of ATP. This metabolic energy is then used to accomplish various tasks, including the synthesis of macromolecules and other cell constituents. Thus, energy derived from the breakdown of organic molecules (catabolism) is used to drive the synthesis of other required components of the cell. Most catabolic pathways involve the oxidation of organic molecules coupled to the generation of both energy (ATP) and reducing power (NADH). In contrast, biosynthetic (anabolic) pathways generally involve the use of both ATP and reducing power (usually in the form of NADPH) for the production of new organic compounds. One major biosynthetic pathway, the synthesis of carbohydrates from CO2 and H2O during the dark reactions of photosynthesis, was discussed in the preceding section. Additional pathways leading to the biosynthesis of major cellular constituents (carbohydrates, lipids, proteins, and nucleic acids) are reviewed in the sections that follow.

Go to:

Carbohydrates

In addition to being obtained directly from food or generated by photosynthesis, glucose can be synthesized from other organic molecules. In animal cells, glucose synthesis (gluconeogenesis) usually starts with lactate (produced by anaerobic glycolysis), amino acids (derived from the breakdown of proteins), or glycerol (produced by the breakdown of lipids). Plants (but not animals) are also able to synthesize glucose from fatty acids—a process that is particularly important during the germination of seeds, when energy stored as fats must be converted to carbohydrates to support growth of the plant. In both animal and plant cells, simple sugars are polymerized and stored as polysaccharides.

Gluconeogenesis involves the conversion of pyruvate to glucose—essentially the reverse of glycolysis. However, as discussed earlier, the glycolytic conversion of glucose to pyruvate is an energy-yielding pathway, generating two molecules each of ATP and NADH. Although some reactions of glycolysis are readily reversible, others will proceed only in the direction of glucose breakdown, because they are associated with a large decrease in free energy. These energetically favorable reactions of glycolysis are bypassed during gluconeogenesis by other reactions (catalyzed by different enzymes) that are coupled to the expenditure of ATP and NADH in order to drive them in the direction of glucose synthesis. Overall, the generation of glucose from two molecules of pyruvate requires four molecules of ATP, two of GTP, and two of NADH. This process is considerably more costly than the simple reversal of glycolysis (which would require two molecules of ATP and two of NADH), illustrating the additional energy required to drive the pathway in the direction of biosynthesis.

4 0
3 years ago
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