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3 years ago

Explain why hydrophobic molecules can easily cross the plasma membrane, while hydrophilic molecules cannot.

Biology

1 answer:

ziro4ka [17]3 years ago

4 0

<h2>Explanation:</h2>

Membranes are semipermeable lipid bilayers. Permeability refers to the ease with which molecules cross biological membranes. Because of the chemical and structural nature of the phospholipid bilayer (hydrophobic core), only lipid-soluble molecules are able to freely pass through the lipid bilayer because it attracts these non polar molecules.

Water soluble or hydrophilic molecules cannot pass through these lipid membranes because hydrophobic bilayer repels hydrophilic molecules. Ions and large polar molecules cannot pass through the lipid bilayer.

But more specifically, whether a molecule can pass through the membrane depends on its size and its electrical nature.

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If A/A ⋅ B/B is crossed with a/a ⋅ b/b and the F1 is testcrossed, what percentage of the testcross progeny will be a/a ⋅ b/b if

Alex787 [66]

Answer:

a) 25%; b) 50%; c) 45%; d) 38%

Explanation:

<h3 /><h3>a) Unlinked genes</h3>

A/A B/B X a/a b/b

F1: A/a B/b

Testcross A/a B/b X a/a b/b

The homozygous recessive individual only produces <em>ab</em><em> </em>gametes.

The F1 produces four types of gametes (each of them with a frequency of 1/4): <em>AB</em>, <em>Ab</em>, <em>aB </em>and <em>ab</em>.

25% of the progeny will be a/a b/b.

<h3>b) Completely linked genes</h3>

AB/AB X ab/ab

F1: AB/ab

Testcross AB/ab X ab/ab

The F1 produces only two types of gametes, the parentals (each of them with a frequency of 1/2): <em>AB</em> and <em>ab</em>.

50% of the progeny will be ab/ab.

<h3>c) 10 m.u. apart</h3>

AB/AB X ab/ab

F1: AB/ab

Testcross AB/ab X ab/ab

The F1 produces four types of gametes, the parentals <em>AB</em> and <em>ab </em>and the recombinants <em>Ab</em> and <em>aB</em>.

Since the genes are 10mu apart, 10% of the produced gametes will be recombinant and 90% will be parentals. Since there are two types of parental gametes, each of them has a frequency of 45%.

45% of the progeny will be ab/ab.

<h3>d) 24 m.u. apart</h3>

This is very similar to c).

Since the genes are 24mu apart, 24% of the produced gametes will be recombinant and 76% will be parentals. Since there are two types of parental gametes, each of them has a frequency of 38%.

38% of the progeny will be ab/ab.

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3 years ago

_____ act on the cns to suppress or slow bodily processes and reduce overall responsiveness.

stiks02 [169]

<span>Depressants............</span>

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3 years ago

A food company has designed new types of breakfast cereal and is now working to decide which cereal to mass produce and begin se

Rus_ich [418]

The food company’s questions are best answered by a combination of survey and scientific tools. To answer questions such as ‘which cereal's box is the best color?’ and ‘which cereal tastes the best to every eater?’ as well as ‘which cereal would sell the most boxes?’, the food company would need to conduct a survey to a group of people which resembles their target group most. The result would help them in answering those questions.

However, to answer ‘Which cereal contains the most sugar?’, the food company would need to use scientific tools to measure to sugar content in the cereal. This is the answer.

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3 years ago

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Which portion of the cell membrane is responsible for preventing unwanted materials from entering the cell?

kati45 [8]

Lysosomes, dead organelles, waste products and other unwanted substances are removed through lysosomes

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3 years ago

Who is studying animals in the wild considered to be somewhat experimentally out of control

KIM [24]

Studying animals in the wild is considered somewhat experimentally out of control because of several reasons.

<u>Explanation:</u>

Study of wild animals can be done using several methods but none will be as effective as studying captivated animals. Using stationary cameras is a method to observe animals in the wild. The stationary nature of the camera makes it necessary for the animals to appear within the field of the camera.

This is difficult in places of low animal density. In addition to that placing camera at a longer distance to watch a larger area decreases the resolution of the images. When it comes to shallow water systems, the field imagery used to track the aquatic species frequently gets affected by issues like sun flicker.

Unmanned aerial vehicles can also be used to track and study animals in the wild. This is good alternative but filming through dense canopies or turbid water is a limitation. Bio loggers can also be used for animal tracking but it is limited by weight since it has to be carried by animals.

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3 years ago