Answer:
Proteins and lipids exist as separate but loosely attached molecules that can move around
Explanation:
Cell membranes are mainly composed of lipids, proteins, and also carbohydrates. Phospholipids are the most abundant type of lipid and the main constituent of the cell membranes. Membrane proteins are divided into two types according to their interactions with the cell membrane: 1-integral (intrinsic) and peripheral (extrinsic) proteins. These peripheral proteins are loosely attached by ionic bonds or calcium bridges with the phosphate heads of the phospholipids; whereas integral membrane proteins contain side chains that interact with fatty acyl groups of the phospholipids. Cell membrane fluidity indicates how easily lipids (e.g., phospholipids and cholesterol) and proteins (e.g., intrinsic proteins) diffuse laterally in the cell membrane. This fluidity is affected by the amount of cholesterol, temperature, and the ratio of unsaturated to saturated fatty acids. Saturated fatty acids have no double bonds in the hydrocarbon chain, whereas unsaturated fatty acids have at least one double bond (these double bonds increase fluidity). Moreover, higher temperatures increase membrane fluidity, whereas cholesterol molecules function to regulate membrane fluidity: at high temperatures cholesterol molecules stabilize the membrane, whereas at low temperatures intercalate between phospholipids, thereby preventing them from clustering together.
Answer:
All the options are true except option D.
Explanation:
Archaea are a group of prokaryotic organisms i.e. they lack a membrane bound nucleus. They are one of the the three domains of life (the other two being bacteria and eukarya). Archeans possess a cell wall like bacteria but it is not composed of peptidoglycan, like bacteria cell wall.
Archeans are generally known to be found in very severe environmental conditions, hence, they are referred to as extremophiles e.g Some are thermoacidophiles i.e. thrive in very hot and acidic environment while others are extreme halophiles i.e. thrive in salty regions. Archeans known as methanogens produce methane gas as a product of metabolism from carbon dioxide and hydrogen.
However, the domain archeae was only found to be in existence recently after the domain bacteria, hence, they are not considered to evolve before the domain bacteria.
Glacial evidence discovered in South America demonstrates how climate change evidence has bolstered the notion of continental drift. Folded mountains in Africa and South America. Thus, the correct option is D.
Climate change is happening all across the planet on a daily basis. This is primarily due to human activities that have had an impact on the atmosphere and the earth.
<h3>
What is continental drift?</h3>
Continental drift is basically the hypothesis that the continents once constituted a single landmass, disintegrated, and drifted to their current places.
The discovery of glacial evidence in South America has led to a greater acceptance of the continental drift idea.
Finally, we can conclude that glacial evidence discovered in South America demonstrates how climatic change evidence supports the hypothesis of continental drift.
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Colder temperatures that last for a short period of time such as 3-4 days.
