Tag: photosynthesis
Questions Related to photosynthesis
In photosynthesis, there is an (a)
-
Reduction of $H _{2}O$.
-
Oxidation of $H _{2}O$.
-
Oxidation of $CO _{2}$.
-
Oxidation of $NO _{2}$.
The process of photosynthesis occurs in two stages light reaction and dark reaction. The light reaction involves oxidation of water (photolysis i.e., light dependent splitting of water), which releases oxygen as a by product. The photolysis of water also releases electrons, which are used to drive electron flow in the thylakoid membrane ultimately this electron flow results in the synthesis of ATP and $NADPH _2$. These products ATP and $NADPH _2$ are used up subsequently in the process of dark reaction.
Manganese, calcium and chloride ions present in PS-II play an important role in.
-
Absorption of light
-
$CO _2$ assimilation
-
Photolysis of water
-
ATP synthesis
As we know that the PS-II or photosystem II constantly supplies electrons during the light reaction.
In photosynthesis, photolysis of water is used in
-
Reduction of NADP
-
Oxidation of NADP
-
Oxidation of FAD
-
None of these
Manganese and chlorine is required in plants for
-
Nucleic acid synthesis
-
Plant cell wall formation
-
Photolysis of water during photosynthesis
-
Chlorophyll synthesis
The process of water dissociation during photosynthesis is called as photo-oxidation of water. It requires the presence of Mn++, Ca+ and Cl- , a water oxidising enzyme and an unknown substance Z.
Water has high specific heat due to
-
Its dipole nature
-
Smaller angle between hydrogen atoms and oxygen atom
-
Hydrogen bonds amongst molecules
-
All of the above
Water has high specific heat due to hydrogen bonds amongst molecules. Due to high specific heat, water minimizes changes in temperature. Hydrogen bonds are broken when it absorbs heat. Similarly, hydrogen bonds are formed when water releases energy in the form of temperature. This decreases the temperature of water.
The source of $O _{2}$ liberated in photosynthesis in green plants is
-
Photosynthetic enzyme
-
Carbohydrate present in leaf
-
Water
-
Carbon dioxide
When the chlorophyll molecule is excited by light, the energy level of an electron in its structure is boosted to a higher energy level and this excited chlorophyll moves rapidly the reaction center of the photosystem I where it transfers its extra energy to an electron which is then expelled from the reaction center and is accepted by the first member of a chain of electron carriers and ultimately reaches NADP$^+$, reducing it to NADPH. The reaction center has lost an electron and this electron hole is filled by stripping electrons from water which leaves hydrogen ion (H$^+$) and molecular oxygen (O$ _2$). The pathway of electrons from water to NADP$^+$ has Z shape called as Z scheme.
Which of the following pigment is soluble in water?
-
Chlorophyll
-
Carotene
-
Anthocyanin
-
Xanthophyll
Anthocyanins are water-soluble vacuolar pigments, that may appear red, purple, or blue depending on the pH. Anthocyanins occur in all tissues of higher plants, including leaves, stems, roots, flowers, and fruits.
Photolysis of water involves
-
Excitement of water
-
Evolution of oxygen
-
Breakdown of water by light
-
Splitting of water into its ions, $H^+$ and $OH$
Photolysis, as the name suggests, is the breakdown of water in the presence of sunlight to form H⁺ and O₂ and electron. This takes place during the light phase of photosynthesis in the PS-II. This creates the oxygen which is the net product of photolysis.
Source of protons within the chloroplasts is
-
Water
-
Excited chlorophyll
-
Carbon dioxide
-
Rubisco
Chemiosmotic hypothesis explains how ATP is synthesized in the chloroplast. ATP synthesis is linked to the development of a proton gradient across the membrane of the thylakoid of chloroplast and proton accumulation is towards the inside of the membrane i.e., in the lumen. Source of protons within the chloroplasts is water. The splitting of water molecule takes place on the inner side of the membrane and so the protons (hydrogen ions) are produced, they accumulate within the lumen of the thylakoids. Thus, the correct answer is option A.
Which of the following helped in confirming that oxygen evolved in photosynthesis comes from water?
-
$H _2 \,\,\, ^{18}O$
-
$^{14}CO _2$
-
$^{15}NO _3$
-
$^{3}H _2O$.
In the process of photosynthesis, water acts as a stable oxygen donor. To prove the theory radioisotopic technique was used.