Not all areas on Earth's surface receive the same amount of radiation because Earth's surface ___

Why enzymes are necessary for many cellular reactions?

solmaris [256]

They catalyze a reaction, making it operate at several orders of magnitude faster than it would otherwise, and don't change the end products

Think of it this way, if someone were to perform surgery sure they could probably do it alone... but things go much faster if there's an assistant (enzyme) there handing them the stuff they need

6 0

3 years ago

What trend does the graph show?

Dvinal [7]

You didn't put an image of the graph lol

4 0

3 years ago

Read 2 more answers

Please help me!!!! Will give 17 points!!!!!!

Aliun [14]

Answer:

uneed to read and work this out

4 0

3 years ago

(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

3 years ago

The process that starts with dna and ends with 2 dna is called

Vikki [24]

Answer:

Vague, but I think you are talking about duplication or mitosis

Explanation:

Mitosis is duplicating DNA to make two geneticly identical daugher cells

Duplications is just unwinding the DNA to make a second copy

3 0

3 years ago

Not all areas on Earth's surface receive the same amount of radiation because Earth's surface ____.