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Photosynthesis

Description: This test contains 25 multiple choice questions on photosynthesis.
Number of Questions: 25
Created by:
Tags: light reaction dark reaction stroma grana etc Life Processes Coordination in Life Processes Photosynthesis Legal Aptitude/ Awareness Legal Terms General Knowledge General Awareness
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The conversion of smaller phosphoglyceraldehyde molecules into larger sugar units by plants is done through _______.

  1. enzyme hydrolysis

  2. dehydration synthesis

  3. polypeptide linkage

  4. energy-releasing catabolism


Correct Option: B
Explanation:

It is a type of condensation reaction, in which, monomers join together into polymers, while losing water molecules. This process is carried out, by losing from one of the monomers and (H) from another monomer. The two unstable monomers join together, and they combine forming water. When small organic sugar molecules are chemically joined, a water molecule must be removed.

In purple sulphur bacterial photosynthesis, ________.

  1. water provides the electrons

  2. organic substance is electron donor

  3. hydrogen sulfide provides the electrons

  4. oxygen is not released 


Correct Option: C
Explanation:

Chromatiaceae is a family of purple sulphur bacteria. e.g. Chromatium. These are short, Gram-negative rods, ~1 µm in diameter and 3-4 µm long. They are able to use sulphur and sulphide, as the sole photosynthetic electron donor and sulphur can be oxidized to sulphate. These bacteria use an inorganic sulphur compound, such as, hydrogen sulfide, as an electron donor.

Which of the following factors affects the light reactions of photosynthesis?

  1. Carbon dioxide concentration

  2. Temperature

  3. Air pollution

  4. Light intensity


Correct Option: D
Explanation:

Only the light reactions of photosystem I and II are light dependent.

Which of the following options is not an internal factor affecting photosynthesis?

  1. Age of leaf

  2. Amount of water available

  3. Hormones

  4. Carotenoids


Correct Option: B
Explanation:

The amount of water available will affect the rate of photosynthesis because if the plants do not have enough water, stomata will be shut and plants will be deprived of carbon dioxide.

Which of the following can perform photophosphorylation?

  1. Autotrophs

  2. Hetrotrophs

  3. Chemotrophs

  4. Lithotrophs


Correct Option: A
Explanation:

Only the autotrophs can perform photophosphorylation. It means electrons once emitted from photsystem 1(P 700) returns back to it after passing through a series of electron carriers, in an electron transport system. A P700 molecule is a pigment, which can absorb the sunlight of wavelength, around 700 nanometer.

Who proposed the law of limiting factors?

  1. Henri Braconnot

  2. Julius von Sachs

  3. Frederick Frost Blackman

  4. Louis-Jean-Marie Daubenton


Correct Option: C
Explanation:

Frederick Frost Blackman proposed the law of limiting factors. A process is contingent on a variety of factors, like the rate is limited by the speed of the slowest factors. This minimum value is the optimum value, which indicates the highest rate and a maximum value above which no photosynthesis can occur.

Who coined the term 'Cyclic photophosphorylation'?

  1. Frederick Frost Blackman

  2. Mitchell

  3. Sachs

  4. Arnon


Correct Option: D
Explanation:

Cyclic photophosphorylation was the term,  named by the scientist Arnon. The synthesis of ATP from ADP during light reaction of photosynthesis,  is called photophosphorylation.

Grana are _____.

  1. found in the thylakoid lumen

  2. found in chloroplasts

  3. found in the thylakoid proteome

  4. found in thylakoid integral membrane proteins


Correct Option: B
Explanation:

A granum (plural grana) is a stack of thylakoid discs. Chloroplasts can have from 10 to 100 grana. Grana are connected by stroma thylakoids, also called intergrana thylakoids or lamellae.

Chlorophyll is a _________ protein.

  1. Fe

  2. P

  3. Mg

  4. K


Correct Option: C
Explanation:

Chlorophyll is the molecule that traps this 'most elusive of all powers' - and is called a photoreceptor. It is found in the chloroplasts of green plants, and this is what makes,  green plants, green. The basic structure of a chlorophyll molecule is a porphyrin ring, co-ordinated to a central atom, Mg. This is very similar in structure to the heme group found in hemoglobin, except that in heme, the central atom is iron, whereas in chlorophyll,  it is magnesium.

Leaves do not contain _______.

  1. stomata

  2. palisade cells

  3. meristematic cells

  4. parenchyma cells


Correct Option: C
Explanation:

Meristematic cells give rise to all three fundamental mature cell types. Their major function is cell division, and so their cell cycle indeed cycles. The walls are thin, the vacuole is largely missing, the plastids are immature, etc.

Which of the following cells are invested with lignin?

  1. Collenchyma cells

  2. Sclerenchyma cells

  3. Parenchyma cells

  4. Meristematic cells


Correct Option: B
Explanation:

These cells are hard and brittle. The cells develop an extensive secondary cell wall (laid down on the inside of the primary wall). This wall is invested with lignin, making it extremely hard. Lignin, plus suberin and/or cutin, make the wall waterproof as well.

Which of the following cells provides fibres that can be spun and woven?

  1. Sclerenchyma cells

  2. Collenchyma cells

  3. Parenchyma cells

  4. Meristematic cells


Correct Option: A
Explanation:

Functions for sclerenchyma cells,  include discouraging herbivory and conduction.  Sclerenchyma includes the fibers used for making thread and fabric, particularly the fibers from flax,  that are spun and woven into linen.

Which of the following layers of a leaf is not a photosynthetic tissue?

  1. Upper epidermis

  2. Palisade cells

  3. Spongy layers

  4. Lower epidermis


Correct Option: A
Explanation:

This is a single layer of cells containing few or no chloroplasts. The cells are quite transparent and permit most of the light that strikes them,  to pass through, to the underlying cells. The upper surface is covered with a waxy, waterproof cuticle, which serves to reduce water loss,  from the leaf.

Which of the following subatances is an inorganic source of carbon for organic compounds?

  1. CO2

  2. C2H6

  3. C6H12O6

  4. CH4


Correct Option: A
Explanation:

An organic compound is any member of a large class of chemical compounds, whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic and CO2 acts as an inorganic source of carbon, for organic compounds.

Which of the following substances releases oxygen in photosynthesis?

  1. CO2

  2. Water

  3. C6H12O6

  4. None of these


Correct Option: B
Explanation:

The absorbed energy is used in splitting the water molecule, into the two components (Hydrogen and Oxygen) and releasing electrons. The free molecular oxygen is given out as a by-product and the energy of electrons, is used to add one inorganic phosphate to ADP to form ATP whereas, the H+ ions are picked by NADP+ which is reduced to NADPH.

Light from which of the following spectrums is not absorbed by chlorophyll?

  1. All the portion of the spectrum

  2. None of the portion of the spectrum

  3. The green portion of the spectrum

  4. The blue portion of the spectrum


Correct Option: C
Explanation:

Chlorophyll, the green pigment common to all photosynthetic cells, absorbs all wavelengths of visible light, except green, which it reflects, to be detected by our eyes.

In non-cyclic photophosphorylation, the light energy is used to ______.

  1. oxidize ferredoxin

  2. split CO2 molecules

  3. phosphorylate NADP

  4. split H2O molecules


Correct Option: D
Explanation:

The hydrogen ions also called protons, are made available by splitting up of water. Non-cyclic photophosphorylation needs a constant supply of water molecules. The net result of non-cyclic phosphorylation is the formation of oxygen, NADPH and ATP molecules. Oxygen is produced, as a waste product of photosynthesis.

The carbon used by green plants in photosynthesis is derived from ________.

  1. H2O

  2. CO2

  3. C6H12O6

  4. Ferredoxins


Correct Option: B
Explanation:

Carbon dioxide, either in the atmosphere or in solution in surface waters, is the major source of carbon for living organisms. It is converted to organic form, by the autotrophs, which use it as sole carbon source. The most important in this conversion, are the photosynthetic autotrophs (seed plants on land and algae in water) that carry out oxygen producing type of photosynthesis.

Cyclic photophosphorylation includes ______.

  1. formation of ATP from ADP and P

  2. reduction of NADP to NADPH2

  3. splitting of H2O

  4. formation of oxygen, NADPH and ATP


Correct Option: A
Explanation:

Photosynthetic phosphorylation or photophosphorylation is the process of phosphate group transfer into ADP to synthesize energy rich ATP molecule making use of light, as external energy source. Down flow of protons from high to low concentration along H+ conc. gradient through ATPase complex, provides the energy that allows an ATP synthase enzyme, to produce ATP from ADP + Pi

The enzymes necessary for carbon fixation are present in _______.

  1. Grana

  2. Stroma

  3. Cristae

  4. Chloroplast envelope


Correct Option: B
Explanation:

The material within the chloroplast, is called the stroma. It contains one or more molecules of small circular DNA. It also contains ribosomes, however most of its proteins, are encoded by genes contained in the host cell nucleus, with the protein products, transported to the chloroplast. The enzymes necessary for carbon fixation, occur in the stroma of the chloroplast.

Which of the following colours is reflected by green plants?

  1. Red

  2. Blue

  3. Green

  4. Yellow


Correct Option: C
Explanation:

Green light is the least useful to photosynthesis. The best evidence for this, is that most plants appear green under white light. The green light is either reflected from the plant or passes through, allowing us, to see it. The other colours present in the white light, are absorbed.

Cyclic photophosphorylation results in _______.

  1. both PS I and PS II being involved

  2. formation of oxygen NADPH and ATP molecules

  3. splitting of water

  4. ATP formation only


Correct Option: D
Explanation:

Photosynthetic phosphorylation or photophosphorylation is the process of phosphate group transfer into ADP to synthesize energy rich ATP molecule making use of light, as external energy source. Down flow of protons from high to low concentration along H+ conc. gradient through ATPase complex provides the energy, that allows an ATP synthase enzyme, to produce ATP from ADP + Pi

Photosynthesis involves the conversion of solar energy into _______.

  1. potential energy

  2. electrical energy

  3. chemical energy

  4. nuclear energy


Correct Option: C
Explanation:

The energy released in chemical reactions is known as chemical energy. Energy can also be stored in matter as chemical energy which depends on how the particles of matter are arranged. Therefore, chemical energy depends on the positions of objects and is a form of potential energy.

Who discovered that only the green parts of plants can carry out photosynthesis?

  1. Helmont

  2. Joseph Priestley

  3. Ingen-Housz

  4. Jean Senebier


Correct Option: C
Explanation:

Ingen-Housz was a Dutch physiologist, biologist and chemist. He is best known for showing that light is essential to photosynthesis and thus having discovered photosynthesis. He also discovered that plants, like animals have cellular respiration.

During ATP synthesis, protons leave the stroma by the process of ______.

  1. active transport

  2. facilitated diffusion

  3. endocytosis

  4. osmosis


Correct Option: A
Explanation:

Oxygen and carbon dioxide enter and leave the cell via simple diffusion. Water enters and leaves via osmosis. During the day the leaf takes in carbon dioxide and releases oxygen and water vapour. Since it is also using energy, it will also give off small amounts of carbon dioxide. At night, it is not carrying on photosynthesis, so the oxygen and water vapour, are not being given off. The carbon dioxide that is being produced by respiration, is used in the dark reactions making sugar. Living cells need ATP to carry on active transport. Using energy, ions and small molecules may be pumped into or out of a cell, even against a concentration gradient.

 

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