A scientist is trying to determine if a nucleic acid is RNA. What features should the molecule have?

1 answer:

4 0

To fully understand the processes occurring in present-day living cells, we need to consider how they arose in evolution. The most fundamental of all such problems is the expression of hereditary information, which today requires extraordinarily complex machinery and proceeds from DNA to protein through an RNA intermediate. How did this machinery arise? One view is that an RNA world existed on Earth before modern cells arose (Figure 6-91). According to this hypothesis, RNA stored both genetic information and catalyzed the chemical reactions in primitive cells. Only later in evolutionary time did DNA take over as the genetic material and proteins become the major catalyst and structural component of cells. If this idea is correct, then the transition out of the RNA world was never complete; as we have seen in this chapter, RNA still catalyzes several fundamental reactions in modern-day cells, which can be viewed as molecular fossils of an earlier world.

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Under normal conditions, blood sugar levels are controlled within a narrow range by negative feedback. Two hormones are involved

GarryVolchara [31]

Answer:

Sensors or sensory receptors must sense any change in blood glucose levels.

Explanation:

A feedback system includes a receptor, control center, and effector. The receptors serve to sense the deviation from homeostasis and send the nerve impulses or chemical signals to the respective control center. The control center receives input from receptors and sends nerve impulses or chemical signals to the effectors to bring about the desired change to restore homeostasis.

Negative feedback regulation of blood sugar includes sensing the rise or drop in blood sugar levels by sensory receptors. This sensory information is sent to the control center which in turn commands the effectors (pancreas) to secrete insulin or glucagon hormones to lower down or raise the blood glucose levels. Feedback regulation does not work in the absence of any of the components (sensory receptor, control center, and effector).

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The DNA sequence TTG is changed to TCG and produces a new protein. Which type of mutation is this?

dalvyx [7]

The answer is missense. Hope this helps!

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What is an arthropods exoskeleton, or your fignernail,made of?

BartSMP [9]

The answer you are looking for is chitin.

According to a page that I found with info on the subject,

"All arthropods have bodies divided into segments and covered with a hard EXOSKELETON. This tough casing is made of a protein called chitin, which is also found in human fingernails."

https://www.factmonster.com/dk/encyclopedia/nature/arthropods

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Assuming that each replication fork moves at a rate of 500 base pairs per second, how long would it take to replicate the

mixas84 [53]

Vffesefy y the nonschool credence

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When discussing the Earth's magnetic field we could say that the Earth has a

frez [133]

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