How are the asthenosphere and the mantle related?

(a) Identify the most likely mode of transport across the membrane for substance L. Explain how information provided helps deter

Viefleur [7K]

Active transport occurs against the electrochemical gradient. It needs energy to move molecules from the lower concentration side to the higher concentration side. The mode of transport is active transport. 

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There are three main different types of transport across the membrane

Simple diffusion ⇒ Does not need energy to occur
Facilitated transport ⇒ Does not need energy to occur
Active transport ⇒ Needs energy to occur

Active transport is the transport of molecules that move against the electrochemical gradient, so it does need energy to happen.

Molecules move from the lower concentration side to the higher concentration side of the membrane.

Carrier proteins are in charge of active transport. The needed energy might proceed from the ATP molecules or the membrane's electric potential.

In the exposed example, a scientist wants to determine how substance L enters a cells in a culture.

The cells maintain a 120 mM intracellular concentration of substance L.

Varying external concentrations of substance L (10 to 100 mM) in culture medium (Table 1).

Table 1. Rate of entry of substance L into mammalian cells in culture

External concentration of substance(mM) Rate of entry of substance L

10 5%

20 25%

30 45%

40 65%

50 80%

60 90%

70 95%

80 100%

90 100%

100 100%

Now, we need to identify the most likely mode of transport across the membrane for substance L, and explain how information provided helps determine the most likely mode of transport.

We know that the intracellular concentration is 120mM.

As we can see, this concentration exceeds all of the culture media concentrations. Yet, the substance keep moving into the cell.

As the concentration inside the cell is always higher than the concentration outside, we can assume that this is not passive transport because the molecule transport is going against its concentration gradient.

Hence, the remaining option is active transport. And as said before, we can see it because the substance keeps crossing the membrane toward the cell interior despite its concentration being higher in the interior of the cell than in the exterior.

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6 0

2 years ago

Describe the probable effects on an ecosystem if all the plants were to die

liberstina [14]

If all the plants will die then the food chain will go different directions and the animals will die those plants are the producer of the food chain

6 0

3 years ago

The principle difference between where salt marshes and mangrove forests grow is _______.

bekas [8.4K]

Mangrove forests cannot withstand freezing temperature that is why they can only grow at tropical and subtropical latitudes whereas salt marshes grow in middle to high latitudes. Mangrove forests can be recognized by their tangle of roots that allow them to stand still on stilts above water. The roots of the mangrove trees slow the movement of tidal waters causing the sediments to settle out of water and build up the muddy bottom. For salt marshes, they are coastal wetlands that are flooded and drained by salt water brought by tidal waves. The difference between the two is that mangrove forests are woodlands and salt marshes are coastal wetlands.

5 0

2 years ago

Why does light change direction when shined through water?

Molodets [167]

The slowing down of the ray of light also causes the light to change direction

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Which organelle in the plant cell would mainly help the cell take water or get rid of water?

aliya0001 [1]

Plants regulate their water levels in two main ways: Stoma and Vacuoles.

Stoma are bean shaped cells on the leaf that allow water and gas to exit. They open and close to regulate water.

Vacuoles are organelles that store water and fluids, which help regulate them.

4 0

3 years ago