Answer:
1.A tissue is a collection of similar cells that work together to perform a specific job.
An organ is a collection of different tissues that work together to perform a specific job. The function of a part of an organism is what it actually does (it's job)
2.The structure of the alveoli as a web of blood vessels surrounding an air sac allows blood cells take in oxygen and bring it into the lungs (organ)
The answer is <span>Bacillus cereus
It is a bacteria responsible for some foodborne illnesses that can be found on rice products, potatoes, and pasta. This can be prevented through time and temperature control. The effect on a person having this kind of bacteria is nausea and diarrhea.
One solution to prevent this is to give the right temperature through right cooling so germs cannot multiply. </span>
<span>C. It binds to the coding region and adds nucleotides to the growing end of the DNA.
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Answer and Explanation:
Ribosomes are the primary structure for protein synthesis. They can be found in the rough endoplasmic reticulum or floating in the cytosol.
Free ribosomes are not attached to any cytoplasmic structure or organelle. They synthesize proteins only for internal cell use. Other ribosomes are attached to the membrane of the endoplasmic reticulum and they are in charge of synthesizing membrane proteins or exportation proteins. Free and attached ribosomes are identical and they can alternate their location. This means that although free ribosomes are floating in the cytosol, eventually, they can get attached to the endoplasmic reticulum membrane.
Synthesis of proteins that are destined to membrane or exportation starts in the cytoplasm with the production of a molecule portion known as a <u>signal aminoacidic sequence</u>. This signal sequence varies between 13 and 36 amino acids, is located in the <u>amino extreme</u> of the synthesizing protein, and when it reaches a certain length, it meets the <u>signal recognizing particle</u>. This particle joins the signal sequence of the protein and leads the synthesizing protein and associated ribosome to a specific region in the Rough endoplasmic reticulum where it continues the protein building. When they reach the membrane of the endoplasmic reticulum, the signal recognizing particle links to a receptor associated with a pore. Meanwhile, the ribosome keeps synthesizing the protein, and the enlarged polypeptidic chain goes forward the reticulum lumen through the pore. While this is happening, another enzyme cuts the signal sequence, an action that requires energy from the ATP hydrolysis. When the new protein synthesis is complete, the polypeptide is released into the reticulum lumen. Here it also happens the protein folding (which is possible by the formation of disulfide bridges of proteins are formed) and the initial stages of glycosylation (the oligosaccharide addition).
Once membrane proteins are folded in the interior of the endoplasmic reticulum, they are packaged into vesicles and sent to the Golgi complex, where it occurs the final association of carbohydrates with proteins. The Golgi complex sends proteins to their different destinies. Proteins destined to a certain place are packaged all together in the same vesicle and sent to the target organelle. In the case of membrane proteins, they are packaged in vesicles and sent to the cell membrane where they get incrusted.
There are certain signal sequences in the <u>carboxy-terminal extreme</u> of the protein that plays an important role during the transport of membrane proteins. A signal as simple as one amino acid in the c-terminal extreme is responsible for the correct transport of the molecule through the whole traject until it reaches the membrane.
Natural selection<span> acts upon two major sources of genetic variation: </span>mutations<span> and</span>recombination<span> of </span>genes<span> through sexual </span>reproduction<span>. Most </span>mutations<span> do not affect the reproductive fitness of individuals -- some may be beneficial, some may be harmful, and </span>many<span> may be neutral. </span>Mutation rates<span> per gene are generally low</span>
