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3 years ago

As an environment changes, and some organisms have a higher fitness than others, natural selection acts directly on what.

1 answer:

4 0

Natural selection acts directly on a population's gene pool, but individuals evolve.
Natural selection acts directly on genotype, but individuals evolve.
Natural selection acts directly on individuals, but genes evolve.
Natural selection acts directly on phenotype, but populations evolve.

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Which protein does Hypercholesterolemia code for

Allushta [10]

It belongs to the Low Density Lipoprotein receptor. It 's a cell surface receptor that recorgnizes the apoprotein B100, which is known to be located on the outer phospholipid layer of LDL particles. It also recognizes the apoE protein as well.

7 0

3 years ago

Comment on why do you think cells prefer to use carbohydrates as a source of energy before they use fats and proteins.

kompoz [17]

Answer:

This can be explained based on structure, and on metabolisms of carbohydrate.

Explanation:

Carbohydrate has a relatively simple structural composition than the either protein or fatty acids. The C, H and Oxygen molecules are of relatively fewer in number and few chains than fats and protein.Thus cells will spend less energy to break bonds(catabolisims) among these molecules during cellular respiration pathways to trap the energy.

In addition glucose the end products of carbohydrate did not need any processing before it enters glycolysis, Kreb's Cycle and oxidative phosphorylation pathways to generate energy for the cells.

Conversely, for protein to be used it has to be first deaminated(removal of amino acid) by the liver before it enters glycolysis,while fats needs to be broken down and undergo beta oxidation with the long chains removed before it can form acetyl CoA. Therefore cells will prefer few steps, less endergonic pathways of glucose than longer more endergonic amino acids and fatty acid pathways.

Furthermore, glucose can be used in cellular respiration to produce energy either aerobically or anaerobically, while fats can only be used anaerobically. Therefore, since cells usually prefer to thrive in aerobic conditions they breakdown glucose easily during this period, and when lack of oxygen occurs they switched to anaerobic, Thus, the versatility of glucose to oxygen concentration makes glucose a better choice. Besides if fats was used anaerobically, ketone bodies build up which may be toxic to the cells.

4 0

3 years ago

Which gland produces T3 and T4?

Leokris [45]

Answer:

1. The gland that produces T3 and T4 is the thyroid (first option).

2. True. The adrenal gland produces and allows the secretion of the hormone involved in the fight and flight response.

3.The symptom that is not correctly matched with the organ system is joint pain, which is related to the joint system, not the skeletal system.

4. False. Negative feedback loop inhibits the production and release of hormones.The symptom that is not correctly matched with the organ system is Joint pain - skeletal system

Explanation:

1. Thyroid gland is a small organ of no more than 30 grams found in the neck, in front of the trachea. This gland produces thyroglobulin, which when joined with iodine can synthesize triiodoythyronine (T3) or thyroxine (T4).

The main function of the thyroid gland is the regulation of organic metabolism, while it can also mediate the body's response to other hormones.

2. Adrenal gland is located in the upper pole of each kidney and is responsible for the secretion of several substances that help with the body's activity.

In the gland's marrow, a substance called adenaline is produced, with properties such as hormone and neurotransmitter, one of the main substances produced to deal with stress and the adaptation response called fight and flight.

The adrenaline produced in the adrenal medulla can strengthen muscles, increase heart rate and blood pressure, and increase the body's resistance to the presence of stressors or threats to physical integrity.

3. Joint pain is related to inflammation of the joint soft tissues, which belong to the joint system. Unlike joint pain, bone pain occurs as a result of injury to the periosteum -the thin membrane that covers the bones- which is related to the skeletal system.

Painful inflammation of the joints is called arthritis, and is one of the main causes of disability to perform normal body movements.

4. Feedback is a control mechanism of the endocrine system. Negative feedback loop occurs in response to a stimulus, resulting in the inhibition of mechanisms that promote the synthesis and release of substances.

An example of negative feedback is the sufficient production of thyroid hormones, which sends a signal to the hypothalamus, which in turn inhibits the production of TSH - thyroid stimulating hormone - at the level of the pituitary gland. If the pituitary does not release TSH, production of thyroid hormones ceases.

Learn more:

Thyroid feedback loop brainly.com/question/4967372

4 0

3 years ago

Explain how a fossil mold is different from a fossil cast

Furkat [3]

A cast is a 3-D example of an object of the past created when a mold fills up with sediment like mud, sand or volcanic ash. Fossils can form when hard parts of a fossil are replaced by other minerals.

4 0

3 years ago

Read 2 more answers

How many bones are in the human ear?

Ostrovityanka [42]

The ear has the tinest bones in the body. There are three bones in the ear. Hopes this helps you.

5 0

3 years ago