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Ratling [72]
3 years ago
13

Your lab group is experimenting with the diffusion of molecules across a membrane. Dialysis tubing is used as a model cell membr

ane because is it semi-permeable, allowing small molecules to cross the membrane, but NOT larger molecules, like starch. A starch solution is placed in the dialysis tubing and then the dialysis tubing is placed in an iodine and water solution. Iodine is used as an indicator for the presence of starch. Normally, iodine is a yellow-brown color (on the left), but in the presence of starch, it turns a deep purple (right). After observing the experimental setup for 20 minutes, the iodine solution remains brown, but the starch solution inside the dialysis tubing is purple and swollen. What CANNOT be concluded from the results? A) Iodine is a small molecule and diffused through the dialysis tubing INTO the starch solution. B) Starch is a large molecule and could NOT diffuse through the dialysis tubing into the iodine solution. C) Starch requires ATP energy for transport and therefore cannot cross the dialysis tubing into the iodine solution. Eliminate D) The starch solution is hypertonic to the iodine solution, causing water to move across the dialysis tubing INTO the starch solution.
Biology
2 answers:
BlackZzzverrR [31]3 years ago
7 0

Answer:

answer is d on usatestprep

Explanation:

Serga [27]3 years ago
7 0

Answer:

D- Starch crosses the cell membrane at E.

Explanation:

E is a membrane protein that can be used for facilitated diffusion, in which large or charged molecules can move across the cell membrane. Facilitated diffusion is passive transport, meaning molecules diffuse from high to low concentration, without the need for ATP energy, using a transport protein. Only small, nonpolar molecules can diffuse through the phospholipid bilayer directly.

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fiasKO [112]

The vestibulocerebellum helps regulate balance and eye movement. Moreover, the spinocerebellum helps regulate body and limb movement and the cerebrocerebellum helps regulate in planning movements.

The vestibulocerebellum is a region of the cerebellum which involved in balance and body position in space.

The spinocerebellum is involved in controlling lateral descending systems in order to regulate distal limb muscles.

The cerebrocerebellum is involved in motor planning by connecting the motor and premotor cortices.

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2 years ago
One characteristic of all living organisms is that they have genetic information. What is the name of this genetic information a
Aloiza [94]

Answer:

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Explanation:

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2 years ago
In a population, surrounded with dark gray rocks, there lived 2 types of beetles, a gray beetle and a white beetle. In the start
Svetlanka [38]

Directional selection favors one of the extreme phenotypes over the other one. <u>Option C is correct</u>. Natural selection is the evolutive force, and 0.40, 0.40, and 0.20 are the new genotypic frequencies.

<h3>What is directional selection?</h3>

Directional selection is one type of natural selection. Let us remember that natural selection is an evolutive force.

Directional selection increases the proportion of individuals with an extreme phenotypic trait.

There must be a selective pressure or environmental pressure acting on populations to lead the species to increase the number of individuals expressing that extreme phenotype.

This selection presents more frequently in those cases in which interactions between living organisms and the environment modify in the same direction.

In the exposed example,

  • two original phenotypes ⇒ gray and white
  • substrate color ⇒  dark gray rocks
  • environmental pressure ⇒ birds preying on beetles

- Grey beetles managed to camouflage with rocks since their gray color was similar.

- White beetles were exposed on the dark gray rocks, so they were easily seen by birds.

- Predation by birds was an environmental pressure that had a stronger influence on the white phenotype.

Natural selection favored gray-colored beetles, who could survive and reproduce.

Assuming a diallelic gene expressing complete dominance codes for beetles color, we can suggest that the frequency of one of the homozygous genotypes increased, while the other decreased to near cero. Heterozygous individuals kept the allele coding for the white phenotype.

Among the options, <u>C is the correct one</u>. Natural selection is the evolutive force, and 0.40, 0.40, and 0.20 are the new genotypic frequencies.

You can learn more about natural selection and  directional selection at

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brainly.com/question/12226774

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Lesechka [4]

Answer: dehydration synthesis; water

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Weathering can be caused by rain,snow,heat,and as well as wind.

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