Answer:
A. It decreases the activation energy needed to start the reaction
Explanation:
Organic catalyst which speed up the rate of organic chemical reaction is living cells are called enzymes.They have specific reaction site called active sites.This must be in prefect shape with the substrate for the organic chemical reaction to take place
When this occurs the minimum amount of  energy of  reaction to  activate or stimulate  the the atoms and molecules of the substrate to undergo chemical reaction is  lowered.This energy of reaction is celled activation energy.
Catalase thought its active sites lowers the activation energy so that the molecules of H2O2 could break down to C02 and H2 faster,thereby reducing the time for theses product to form.The is the general roles of enzyme.To increase the rate of chemical reaction,by reducing the activation  energy.
 
        
             
        
        
        
You would be referring to the <em>plant </em>cell.
Answer:
 Chloroplasts may be seen on all six sides of a plant cell, which is a three-dimensional entity with typically moderately rounded corners (not in the centre because a big central vacuole fills a very large part of the volume). Chloroplasts are constantly being rearranged by the cell since they are not set in place. Chloroplasts are typically located close to so-called periclinal cell walls, which are oriented in the same 2D orientation as the leaf surface under low light. Chloroplasts seem to "escape" to the anticlinal walls in bright light. Better light harvesting in low light by exposing every chloroplast to light and photoprotection by mutual shading in strong light are likely the fitness benefits provided by this behavior. In the dark, chloroplasts also gravitate toward the anticlinal walls. Thin leaves of submerged aquatic plants like Elodea can be used as microscope specimens to observe chloroplast motions. One can gauge how much light gets through a leaf in land plants. What I just said concerning the top layer(s) of leaves' "palisade parenchyma cells" is accurate. Most of the chloroplasts are found in these cells. Numerous cells in the spongy parenchyma under the palisade layer lack well marked peri and anticlinal walls.
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How did plant cells incorporate chloroplasts in their DNA?</h2>
Chloroplasts must reproduce in a manner akin to that of some bacterial species, in which the chloroplast DNA is duplicated first, followed by binary fission of the organelle (a kind of protein band that constricts so that two daughter organelles bud off). As a result of some chloroplast DNA actually being integrated into the plant genome (a process known as endosymbiotic gene transfer), it is now controlled in the nucleus of the plant cell itself.
 
        
             
        
        
        
Where they have there effect on the tissues cells
        
             
        
        
        
Phenotypes are the way the animal looks, the Genotypes are the the genetic makeup: like BB or Bb or bb
        
             
        
        
        
From what i know, in sickle cell anemia the blood is lack of oxygen. 
The haemoglobin run from the blood cell because reacted with nitric oxide, and so thats why the shape of the blood change into sickle-shaped like.