Answer:
The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can be done by digestive enzymes, hydrochloric acid. Mechanical digestion in the stomach results in the formation of bolus.
Explanation:
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Complete question:
Knowledge of the amino acid sequences is important for several reasons. What is NOT one of those reasons
- Amino acid sequences determine the three-dimensional structures of proteins.
- Knowledge of the sequence of a protein can help to prevent mutations.
- The sequence of a protein reveals much about its evolutionary history.
- The sequence of a protein is necessary to determine its function.
Answer:
Knowledge of the sequence of a protein can help to prevent mutations.
Explanation:
<em>Amino acids connect to each other by peptidic bonds </em>to form a <em>linear polymer</em>. The number of amino acids composing the chain and the order in which they are arranged determines the primary structure of the protein.
The secondary structure is the folding that the polypeptide chain adopts thanks to the formation of <em>hydrogen bonds between the atoms that form the peptide bond.</em>
<u>Protein functions depend on their aminoacids sequences</u><u>.</u> <u>The primary structure of the proteins determines the three-dimensional one</u>. Proteins with different functions have different sequences. And among species, proteins with similar functions have similar structures.
By knowing the sequence of amino acids, we can predict the function of the protein and we can classify them into different families. Integrants of these groups have at least 25% of their sequences identical to each other.
Also, the knowledge of the sequence allows establishing evolutionary and genetic relationships between different species.
When a mutation occurs in the sequence -an alteration in the primary structure- the protein function is modified. BUT knowing the sequence of a protein CAN NOT help to prevent mutations.
DNA is found in all living cells and in once living cells.
The first known single-celled organisms appeared on Earth about 3.5 billion years ago, roughly a billion years after Earth formed. More complex forms of life took longer to evolve, with the first multicellular animals not appearing until about 600 million years ago.
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The evolution of multicellular life from simpler, unicellular microbes was a pivotal moment in the history of biology on Earth and has drastically reshaped the planet’s ecology. How life originated and how the first cell came into being are matters of speculation, since these events cannot be reproduced in the laboratory. Nonetheless, several types of experiments provide important evidence bearing on some steps of the process.
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It was first suggested in the 1920s that simple organic molecules could form and spontaneously polymerize into macromolecules under the conditions thought to exist in primitive Earth's atmosphere. At the time life arose, the atmosphere of Earth is thought to have contained little or no free oxygen, instead consisting principally of CO2 and N2 in addition to smaller amounts of gases such as H2, H2S, and CO. Such an atmosphere provides reducing conditions in which organic molecules, given a source of energy such as sunlight or electrical discharge, can form spontaneously. The spontaneous formation of organic molecules was first demonstrated experimentally in the 1950s, when Stanley Miller (then a graduate student) showed that the discharge of electric sparks into a mixture of H2, CH4, and NH3, in the presence of water, led to the formation of a variety of organic molecules, including several amino acids. Although Miller's experiments did not precisely reproduce the conditions of primitive Earth, they clearly demonstrated the plausibility of the spontaneous synthesis of organic molecules, providing the basic materials from which the first living organisms arose.
What <span>substances it depends plants make there own glucose by using sunlight and CO2. It then releases Oxygen </span><span />
