George MacDonald helped collect and build models of mosquitoes for Sir Ronald Ross. Hope this helps :). <span />
On the Galapagos Islands, Darwin also saw several different types of finch, a different species on each island. ... Finches that ate small nuts and seeds had beaks for cracking nuts and seeds. Darwin noticed that fruit-eating finches had parrot-like beaks, and that finches that ate insects had narrow, prying beaks.
Options missing:
a) The pH of the environment should be relatively high.
b) The pH of the environment should be relatively low.
c) The pH of the environment would not matter.
d) The environment should be set to the biochemical standard state.
Answer:
a) The pH of the environment should be relatively high.
Explanation:
For optimal function an enzyme needs a certain environment or condition. As temperature increases, the rate of enzyme activity also increases. As temperature increases toward its optimum point of 37 degrees Celsius (98.6 F), hydrogen bonds relax and make it easier for the hydrogen peroxide molecules to bind to the catalase.
The part of the enzyme where this reaction takes place is called the active site. A temperature that is higher or lower than this optimum point changes the shape of the active site and stops the enzyme from working. This process is called denaturation.
Enzyme pH levels also change the shape of the active site and affect the rate of enzyme activity. Each enzyme has its own optimal range of pH in which it works most effectively. In humans, catalase works only between pH 7 and pH 11. If the pH level is lower than 7 or higher than 11, the enzyme becomes denaturated and loses its structure. The liver sustains a neutral pH of about 7, which creates the best environment for catalase and other enzymes.
General acid catalysis would require histidine to be protonated at pH values (pH 8.0) optimal for enzymatic activity which is relatively high.
<h2>The given statement is true</h2>
Explanation:
Iron absorption occurs in the duodenum and upper jejunum of small intestine
- At physiological pH ferrous iron is rapidly oxidized to the insoluble ferric form
- Gastric acid lowers the pH in the duodenum which enhances the solubility and uptake of ferric iron
- Once iron gets inside the enterocyte it can be stored as ferritin;Ferritin is a hollow spherical protein which helps in storage and regulation of iron levels within the body
- Ferritin molecule have ferroxidase activity which helps in the mobility of Fe2+ out of the enterocyte by ferroportin
- Transferrin is the major iron transport protein which transports iron through blood
- Fe3+ binds to transferrin so Fe2+ transported through ferroportin must be oxidized to Fe3+
- Fe2+ needs to be oxidized first so that it can be transported through ferroportin
- Once iron gets inside the cell it can be used for various cellular processes
