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Oksi-84 [34.3K]
2 years ago
13

Prior to its export from the nucleus, what modifications must be made to a mRNA molecule in eukaryotic cells?

Biology
1 answer:
mamaluj [8]2 years ago
8 0

Answer: Option A

Explanation:

Before the mRNA which has been processed from DNA is taken and transported to the ribosomes in the cytoplasm for the translation process, some modifications are made to the mRNA before transport. This includes

1. Capping: addition of 5'-5' phosphate bonds to the 5' terminus of the mRNA. Forms the cap structure that is essentials for binding to ribosomes via special proteins attached to the cap structure

2. Addition of poly(A) tail: a poly(A) addition signal (AAUAAA) is attached to the 3' terminus of the mRNA. They are important in translation initiation and degradation prevention

3. Splicing: this is likely the most remarkable processing in eukaryotes. It involves the removal of intron regions by excision from the present-mRNA and then ligating the exon regions together giving rise to the mRNA.

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1. More receptors result in<br> _sensitivity<br> increased, decreased
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Answer: increased

Explanation: the more you have the better you can tell where something is acting on you, ie touch

7 0
3 years ago
Is the movement of water along the concentration gradient
Nuetrik [128]

Answer:

<em>- Is the movement of water along the concentration gradient: </em><em>Osmosis</em><em>. </em>

<em>- Is the use of energy to move the particles against the concentration gradient: </em><em>Active transport</em><em>. </em>

<em>- Is the movement of particles by diffusion without energy: </em><em>Simple diffusion</em><em>. </em>

<em>- Is the movement of particles along the concentration gradient: </em><em>Passive transport</em><em>.</em>

Explanation:

The mechanisms of cellular transport involve all the processes that the cell carries out to incorporate substances into its interior or send them to the extracellular space, through its semipermeable cell membrane.

<h3>- Osmosis</h3>

Is a type of transport that consists of the passage of water from a space with a lower concentration of solutes to one with a higher concentration, in order to reach equilibrium, following a concentration gradient.

The concentration gradient is given by the difference in concentration between two substances, which indicates the direction in which molecules, such as water, should move from one place to another.

<h3>- Active transport</h3>

Unlike passive transport mechanisms, which depend on a concentration gradient that determines the movement of particles, in active transport there are two characteristics that define it:

The passage of substances into the cell against a concentration gradient.

The use of energy to carry out this process.

In this case, the passage of substances through the cell membrane will be according to the requirements of the cell, or when they cannot pass through the membrane.

<h3>- Simple diffusion</h3>

According to the characteristics of the cell membrane, some substances can pass freely through it while others require special mechanisms. When a molecule is able to pass through the membrane without the use of special mechanisms or energy we speak of simple diffusion.

In a cell membrane, whose composition is by hydrophobic or non-polar lipid molecules, simple diffusion allows the passage of non-polar molecules, gases and alcohol.

<h3>- Passive transport</h3>

Refers to the mechanism of entry and exit of substances from the cell that does not require the use of energy.

The mechanisms involved in the passive transport of the cell are simple diffusion, osmosis, facilitated diffusion - which requires special conveyors or channels - and ultrafiltration, which depends on hydrostatic pressure. Examples of substances using this mechanism are lipid molecules, water and electrolytes.

Learn more:

Lipidic bilayer and cellular transport brainly.com/question/6955159

3 0
3 years ago
For plants living in a dry areas, explain a possible conflict between the need to obtain carbon dioxide for photosynthesis and t
ahrayia [7]

Plants living in dry areas face conflict.

EXPLANATION:

  • Since they live in dry areas they will undergo more transpiration.

  • If they open stomata during the day there will be excessive loss of water vapor that will result in their death.

  • Therefore plants living in this area open the stomata during the night to obtain Carbon dioxide.

  • This checks the loss of water through transpiration and provides the carbon dioxide for photosynthesis.

7 0
2 years ago
Viruses and bacteria can both be pathogens,
ad-work [718]

Answer:

True

Explanation:

Bacteria generate toxins which can be classified as either exotoxins or endotoxins. Exotoxins are generated and actively secreted; endotoxins remain part of the bacteria. Usually, an endotoxin is part of the bacterial outer membrane, and it is not released until the bacterium is killed by the immune system.Most viral infections eventually result in the death of the host cell. The causes of death include cell lysis, alterations to the cell's surface membrane and various modes of programmed cell death. Some viruses cause no apparent changes to the infected cell.

3 0
3 years ago
Read 2 more answers
What do you need to eat food?
stealth61 [152]
Any eating utensil that you can find
6 0
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