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3 years ago

How do you think the first cell came into existence? (using your own words.) (2 sentences)

Biology

2 answers:

lara31 [8.8K]3 years ago

6 0

Answer:

It has been hypothesized that there were four steps that occurred to create the first living cell:

1. The Abiotic (Nonliving) synthesis and accumulation of small organic monomers like amino acids or nucleotides

2. The Joining of monomers into polymers

3. The origin of an effective, low-risk method of replication ( RNA World )

4. The self-assembly of molecules into droplets that had chemical characteristics inside different from the environment outside.

zalisa [80]3 years ago

3 0

I think that the enclosure of self-replicating RNA in a phospholipid membrane. The first cell is thought to have arisen by the enclosure of self-replicating RNA and associated molecules in a membrane composed of phospholipids.

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⚠⚠⚠⚠⚠⚠One fossil is found in a deeper layer of rock than another one. How is this evidence of change over time of living things

Mademuasel [1]

Some of the evidence comes from fossils, and some comes from studies that show how similar living things are to one another. By the 1930s, scientists had also learned about genes. As a result, they could finally explain how characteristics of organisms could pass from one generation to the next and change over time

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3 years ago

Which of the following best describes an aspect of a membrane's molecular structure that causes it to be selectively permeable?

atroni [7]

Answer:

d. Transport proteins within the membrane serve as a tunnel for molecules to enter the cell.

Explanation:

Solutes are typically moved across the cell through either passive or active transport. The cells, surrounded by a bilipid layer or plasma membrane is amphiphlic- its polar, hydrophilic lipid heads face outwards, while their non-polar hydrophobic lipid tails face inwards towards each other.

While lipid-soluble molecules move across the layer easily, it is also difficult for charged and also large molecules to move across its surface, into the cell. Transmembrane channels, embedded within the membrane, help to maintain selective permeability as transport proteins, pores and gated channels. Simple diffusion happens as a method of passive transport in cells through plasma membranes.

The solutes travel through the plasma membrane in the process of diffusion from regions of high concentration to regions of low concentration; this occurs without the use of energy. Molecules moving against their concentration require active transport mechanism to cross the membrane.

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3 years ago

After the first day or so of fasting, most of the body's stores of __________ are depleted.

liubo4ka [24]

After the first day or so of fasting, most of the body's stores of glycogen are depleted.

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3 years ago

Read 2 more answers

What can scientists look at to help them prove that our modern-day animals evolved from extinct animals?

Dmitriy789 [7]

Answer:

Their skeletal structure and possibly how they look but usually not. You can also look at the way they live and the biomes they live in.

Explanation:

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3 years ago

Suppose you discovered a mutant yeast whose glycolytic pathway was shorter because of the presence of a new enzyme catalyzing th

Ganezh [65]

Answer:

The correct answer is the formation of pyruvate from glucose willl be energetically less favorable.

Explanation:

According to the question matunt yeast has a shorter glycolytic pathay catalysing a follwing reaction

Glyceraldehyde-3-phosphate+H2O+NAD+ = 3-phosphoglycerate

So in the mutatant the formation of 1,3- bisphosphoglycerate is not occurring.The glyceraldehyde-3-phosphate is directly converted into 3-phosphoglycerate.

As a result the substrate level phosphorylation step that deals with formation of 3-phosphoglycerate from 1,3 bisphosphoglycerate is not occurring.

From this point of view it can be said that less energy will be formed in the mutant during glycolysis than that of normal one.

So the formation of pyruvate from glucose will be energetically less favorable.

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2 years ago