in the nucleolus of the cell
Answer: a. True.
Explanation:
<em>Lactobacillus </em>is a genus of gram-positive, facultative or microaerophilic bacteria that produce lactic acid. <u>They are normally found in different parts of the body such as the mouth, digestive tract and vagina</u>. Lactobacilli usually do not cause disease, although they can cause dental caries. Some lactobacilli have a homofermentative metabolism, that is, they produce lactic acid from sugars, which makes their environment acidic and inhibits the growth of pathogenic bacteria. Some species of Lactobacillus are used in the industry for the production of yogurt, cheese and other fermented foods.
<em>Escherichia coli</em> is a bacterium that is part of the microbiota of the gastrointestinal tract of various animals. It is a gram-negative bacillus, facultative anaerobe, and the most abundant commensal of the microbiota of the gastrointestinal tract where, together with other microorganisms, it is essential for the correct functioning of the digestive process. It also participates in the production of B and K vitamins.
<em>Rhizobium </em>is a genus of gram-negative soil bacteria that fix atmospheric nitrogen and live in symbiosis with certain plants (such as leguminous plants) in their roots, after a process of infection induced by the plant itself through the secretion of lectin, to which they provide the nitrogen necessary for the plant to live and which in return gives it shelter. Fixation is the combination of molecular nitrogen (N2) with hydrogen or oxygen to give ammonium or oxides that are incorporated into the biosphere. Molecular nitrogen, which is the major component of the atmosphere, is inert and not directly usable by most living things. Therefore, it involves the incorporation of a significant amount of nitrogen into the biosphere.
<u>Therefore, all three are considered beneficial</u>.
Answer:
1. genetic drift; 2. natural selection; 3. gene flow; 4. natural selection
Explanation:
<u>1. A fish net captures twenty fish, all who happened to have large spots:
</u>
The mechanism of evolution that is playing out in this situation is most likely <u>genetic drift.</u> Genetic drift occurs when a random change occurs, resulting in the selection of a number of individuals by chance, rather than based on their level of fitness. The fish with large spots allele were selected against by chance, not necessarily because the fish with the small spot alleles were better fitted.
<u>2. Small spotted fish escape from predators better:</u>
The situation here is <u>natural selection</u>. The small spotted fish possess a greater fitness as they become well adapted to escaping from predators better than the large spotted fish, which gives confers on them a greater fitness to be selected for against the large spotted fish.
<u>3. 15 large spotted fish move into this population:</u>
The movement or introduction of new individuals i<u>
</u>nto a population is what is referred to as <u>gene flow</u> in evolution, which is another mechanism of evolution that changes the allele frequency of the original population.
<u>4. Fish-eating birds catch large spotted fish more easily:</u>
This is another example of natural selection. The small spotted fish possess a greater fitness which makes them not easily preyed upon by Fish-eating bird easily, compared to large spotted fish. <u>Natural selection</u> favors the fish with small spotted alleles against the large spotted fish, and as a result, more small spotted fish would survive and reproduce more offspring with the small spotted alleles compared to those with large spotted alleles.
Answer:
Eukaryote cells have a membrane-bound nucleus and prokaryotic cells do not
Explanation:
Answer is membrane protein
Plasma membrane or cell membrane is made of lipoprotein (lipid and protein). The structure of the plasma membrane is based on the fluid mosaic model which gives basic description of the structure and behavior of membranes. The plasma membrane is a mosaic of phospholipids, cholesterol and proteins. Many proteins can move within the plasma membrane through membrane diffusion. The membrane proteins regulates the coming and going of substances into and out of the cell.
