Answer:
Evolution is driven by rare mutations that occur in the DNA of organisms. These mutations could be lethal, neutral and some advantageous. The lethal mutations cannot exist in a population because the offspring is unable to survive to term in pregnancy or dies just after birth. The neutral are ones that do not considerably affect the organisms – though they could result in a disadvantage. The beneficial ones are the one that is kept in the population by natural selection because they confer an advantage e.g in the fight for resources or escaping predation and etcetera. Therefore, it's like a game of chances by nature. Paleontologists discover many species of organisms some of which are imperfect because nature produced them but they died off because their mutations gave them a disadvantage against better-adapted individuals.
The <em>Tiktaalik</em> fish from 375 million years ago became extinct because it did not well-developed eardrum for detecting vibrations in water which is significant in survival.
Dinosaurs during development of feathers had many imperfect species before the right wings for flight were conjured up by nature. An imperfect species is the <u><em>Tianyulong confucius</em></u> had stiff feathers that lacked vanes hence were not ideal for flight
The TRUE statements are 'proteins often have more than one transmembrane domain'; 'they are regions of a transmembrane protein that actually pass through the lipid bilayer' and 'they are usually shaped like alpha-helices'.
A transmembrane domain is a membrane-spanning region within a protein. The transmembrane domains are hydrophobic regions that can be inserted into the cell membrane.
The transmembrane domains are usually shaped like alpha-helices.
This secondary structure (alpha-helices) causes the amino acid R-groups to project radially, thereby these side chains can interact with each other.
Proteins need only a single transmembrane domain to be anchored to the membrane, but they often have more than one.
For example, Acyl-coenzyme A cholesterol acyltransferases 1 and 2 (ACAT1 and ACAT2) have multiple transmembrane domains.
The transmembrane domains are regions of a transmembrane protein that actually pass through the lipid bilayer.
These domains contain amino acids with hydrophobic R-groups that pass through the membrane and interact with the hydrophobic tails of the fatty acid chains present in the lipid bilayer.
The transmembrane domains anchor transmembrane proteins to the lipid bilayer.
The interactions between amino acids of the transmembrane domains and fatty acids in the lipid bilayer help to anchor transmembrane proteins and stabilize the cell membrane.
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Viruses<span> are much, much smaller than </span>prokaryotes<span>. </span>Prokaryotic<span> and </span>Eukaryotic cells<span>are both alive, while </span>viruses<span> are not. </span>Viruses<span> have very few organelles, similar to the</span>prokaryotic cells<span>. They contain a plasma membrane, </span>cell<span> wall, RNA or DNA, and a protein capsule.</span>
The sequence of the mRNA that would result from transcribing a DNA template strand with the bases TACGCTAAT would be AUGCGAUUA.
<h3>What is transcription?</h3>
Transcription is the first stage of gene expression in which mRNA sequence is produced from a DNA template.
During transcription, the following applies to the DNA molecule being transcribed:
- Adenine base (A) is transcribed into Uracil (U)
- Guanine base (G) is transcribed into Cytosine (C) and vice versa.
- Thymine base (T) is transcribed into Adenine (A)
Therefore, the sequence of the mRNA that would result from transcribing a DNA template strand with the bases TACGCTAAT would be AUGCGAUUA.
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Asymmetry is the lack of symmetry.
