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4 years ago

A cell membrane is very specific about what it allows across. How does this help the cell?

Biology

2 answers:

Juli2301 [7.4K]4 years ago

7 0

It is better for the cell if most molecules are prevented from entering.

Tcecarenko [31]4 years ago

7 0

Answer: it allows the passage of small molecules for nutrition and metabolism

Explanation:

A cell membrane constitutes the physical edge, that keeps the cellular content separated from the extracellular environment, and delimits the shape of the cell.

The lipid bilayer of the membrane acts as a barrier that separates two aqueous media: the medium, where the cell lives, and the cellular internal environment. The cells require nutrients from the outside and must eliminate waste substances from the metabolism. In this way, the membrane keeps their internal environment stable. The membrane has a selective permeability, since it allows the passage of small molecules, which are lipophilic; but regulates the passage of non-lipophilic molecules. Then, most of the water-soluble ions and molecules which are unable to spontaneously cross this barrier, require the concurrence of special carrier proteins or protein channels.

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A woman's father has ornithine transcarbamylase deficiency (OTD), an X-linked recessive disorder producing mental deterioration

ruslelena [56]

Answer:

Part A - Dd

Part B - 50%

Part C - Option E

Part D - dY

Part E - 50%

Part F - 50%

Explanation:

Given,

Let the allele for dominant trait (wild type) be "D" and the allele for recessive ornithine transcarbamylase deficiency (OTD) be "d"

A X-linked recessive gene affects male offspring in a family tree though a female remains a carrier until it mates with a male with the a recessive diseased allele.

Part A

Father's genotype would be Dd. Hence it will pass d gene (X diseased gene ) to her daughter.

Thus , Woman's genotype is Dd

Part B

Genotype of Normal man - DD

DD * Dd

DD, Dd, Dd, DD

One of the two males will have ornithine transcarbamylase deficiency (OTD), an X-linked recessive disorder producing mental deterioration hence, the probability is 50%

Part C

Option E is correct

Only one of the female offspring will have ornithine transcarbamylase deficiency (OTD), an X-linked recessive disorder which will be expressed if other allele is also X linked recessive.

Hence, The chance of being a carrier will be one out of two female offspring i.e 50% and and chance of having OTD is 0%

Part D

Part E

dY * Dd

DY, dY, dD, dd

one out of the two female is diseased. Hence, the probability is 50%

Part F

50%

3 0

4 years ago

{ WARNING IF YOU ANSWER THIS YOUR NOTIFICATIONS WILL BLOW }

Jet001 [13]

Answer:

Albert Einstein is a German-born physicist and scientist who has created many ideas and theories relating to the study of relative. He is famously known for creating the famous equation $e = mc^{2}$ (Energy equals mass times the speed of light squared).

He was involved in the help of creating nuclear powered- mechanisms (not for destroying things, but for helpful, everyday things). Matter has an inherent amount of energy to it, mass can be converted (under the right conditions) to pure energy, and energy can be used to create massive objects that did not exist previously. Nuclear fission takes place when a heavy atomic nucleus, such as uranium, breaks into two or more smaller pieces with the release of some energy. During this process some of the mass of the original atom is converted into energy in accordance with the equation $e = mc^{2}$ .

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3 years ago

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D. The stomata will close until enough water is lost.
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