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Nina [5.8K]
3 years ago
11

Question 5 of 30

Biology
1 answer:
11Alexandr11 [23.1K]3 years ago
8 0

Answer:

The answer is option A.

A bacterium is a living cell, but a virus is not.

Hope this helps you

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How do temperature and concentration of monounsaturated phospholipids change the rate at which molecules permeate the plasma mem
Nikitich [7]

Answer: At low temperatures the fluidity of the membrane decreases and it favors fluidity. The higher the concentration of unsaturated fatty acids, the less tightly the phospholipids can bind and the more fluid (more permeable).

Explanation:

The plasma membrane is a lipid layer that delimits the entire cell, dividing the extracellular medium from the intracellular (the cytoplasm of a cell). They are composed of phospholipids, which are molecules composed of glycerol, a phosphate group and two lipid chains (such as fatty acids). Glycerol is a three-carbon molecule that functions as the backbone of this membrane. A geometry is formed that allows the phospholipids to line up side by side to form broad sheets. They are insoluble in water, but their unique geometry causes them to aggregate in layers without any energy input, as they possess a hydrophilic phosphate head and a hydrophobic tail consisting of the two fatty acid chains. The hydrophilic heads of the phospholipids in a bilayer membrane face outward and are in contact with the aqueous fluid inside and outside the cell. Because water is a polar molecule, it readily forms electrostatic (charge-based) interactions with the phospholipid heads.

Selective permeability is a property of the plasma membrane and other semipermeable membranes that allow only certain particles to pass through them. In this way,<u> those particles that are needed by the cell can enter the cell and those that are not useful to the cell are prevented from entering</u>. In the same way, the cell can eliminate the particles it has produced as waste. In this way, the entry and exit of substances through the membrane is regulated and the correct functioning of the cell is achieved.

For a particle to be able to cross the plasma membrane it must have a size equal to or smaller than the pores of the membrane, it must have the opposite charge to the charge of the membrane or simply have a neutral charge, and if it is larger than the pores it must be dissolved in a solution, decreasing its size and thus be able to enter the cell through the membrane.  

Plasma membranes are fluid and this fluidity depends on their lipid composition and temperature. Depending on the temperature, membrane lipids can be found in two different states or phases: gel (solid-like, with more rigid hydrocarbon chains) and liquid crystal (more fluid, with more mobile hydrocarbon chains). At low temperatures the fluidity of the membrane decreases and in these conditions the increase of its concentration favors fluidity. The temperature at which the transition from one state to the other occurs is the phase transition temperature (Tc). At values below Tc, the bilayer is in the gel state and at higher values it passes to the liquid crystal. It should be noted that there is an equilibrium between the gel state and the liquid crystal state and that the characteristics of the lipids of the bilayer condition the transition temperature. In the case of bilayers consisting of only one type of lipid, the Tc is well defined. But biological membranes are complex lipid mixtures and the transition from one state to another occurs over a range of temperatures. The presence of short-chain or unsaturated fatty acids reduces the transition temperature, while saturated fatty acids and the increase in the length of the hydrocarbon chains cause this temperature to rise. <u>Then, phospholipids with unsaturated fatty acid tails cannot bind as tightly due to the bent structure of their tails. For this reason, a membrane of unsaturated phospholipids remains fluid at lower temperatures than a membrane of saturated phospholipids</u>.  

The fluidity of a membrane is the ability of a molecule to move through it.<u> In short, the higher the concentration of unsaturated fatty acids, the less tightly the phospholipids can bind and the more fluid (more permeable) the membrane will be even at low temperatures</u>. However, <u>at low temperatures the fluidity of the membrane decreases (lower permeability) but the effect will depend on the composition of the fatty acids</u>. To determine the exact permeability, it is necessary to relate the concentration of unsaturated bonds and the length of the fatty acids in the phospholipids and the temperature.

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Nucleic Acid structure consists of _____________________ nucleotide. There is a________________________ bond between nucleotides
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One? and phosphodiester or maybe covalent
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PLEASE HELP ME!!!!!! <br> What happens to the muscles when the weight is lowered?
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C is the answer to the question

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Approximately 60% of human genes are also found in fruit flies. About 97.5% of human genes are also found in mice. What does thi
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This evidence suggest that all three living creatures that are mentioned have a common ancestor, even though they have been split into different types of groups of living organism millions of years ago.

Science suggests that all of the living organisms on the planet have a common ancestor. Since we are talking about a common ancestor that lived few hundred million years ago, the living organisms split into different groups, and they do not resemble each other nowadays. The fruit fly is an insect, and the humans and mice are mammals, so they are into totally different groups, and it is easy to see by the genetic evidence that they are very distantly related, but the humans and mice are much more closely related because they belong to the same super family, and their connection is much more recent.

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Which best describes the process of editing a conclusion?
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