Plant Biochemistry
- Lecture Notes, Study Materials and Important questions answers

Subject : Plant Biochemistry

A leaf cell consists of several metabolic compartments

1. A leaf cell consists of several metabolic compartments - Answer (click here)
2. The cell wall gives the plant cell mechanical stability - Answer (click here)
3. Vacuoles have multiple functions - Answer (click here)
4. Plastids have evolved from cyanobacteria - Answer (click here)
5. Mitochondria also result from endosymbionts - Answer (click here)
6. Peroxisomes are the site of reactions in which toxic intermediates are formed - Answer (click here)
7. The endoplasmic reticulum and golgi apparatus form a network for the distribution of biosynthesis products - Answer (click here)
8. Functionally intact cell organelles can be isolated from plant cells - Answer (click here)
9. Various transport processes facilitate the exchange of metabolites between different compartments - Answer (click here)
10. Translocators catalyze the specific transport of metabolic substrates and products - Answer (click here)
11. Ion channels have a very high transport capacity - Answer (click here)
12. Porins consist of β-sheet structures - Answer (click here)

The use of energy from sunlight by photosynthesis is the basis of life on earth

1. The use of energy from sunlight by photosynthesis is the basis of life on earth - Answer (click here)
2. How did photosynthesis start? - Answer (click here)
3. Pigments capture energy from sunlight - Answer (click here)
4. The energy content of light depends on its wavelength - Answer (click here)
5. Chlorophyll is the main photosynthetic pigment - Answer (click here)
6. Light absorption excites the chlorophyll molecule - Answer (click here)
7. An antenna is required to capture light - Answer (click here)
8. How is the excitation energy of the photons captured in the antennae and transferred to the reaction centers? - Answer (click here)
9. The function of an antenna is illustrated by the antenna of photosystem II - Answer (click here)
10. Phycobilisomes enable cyanobacteria and red algae to carry out photosynthesis even in dim light - Answer (click here)

Photosynthesis is an electron transport process

1. The photosynthetic machinery is constructed from modules - Answer (click here)
2. A reductant and an oxidant are formed during photosynthesis - Answer (click here)
3. The basic structure of a photosynthetic reaction center has been resolved by X-ray structure analysis - Answer (click here)
4. How does a reaction center function? - Answer (click here)
5. Two photosynthetic reaction centers are arranged in tandem in photosynthesis of algae and plants - Answer (click here)
6. Water is split by photosystem II - Answer (click here)
7. The cytochrome-b6/f complex mediates electron transport between photosystem II and photosystem I - Answer (click here)
8. Photosystem I reduces NADP - Answer (click here)
9. In the absence of other acceptors electrons can be transferred from photosystem I to oxygen - Answer (click here)
10. Regulatory processes control the distribution of the captured photons between the two photosystems - Answer (click here)

ATP is generated by photosynthesis

1. A proton gradient serves as an energy-rich intermediate state during ATP synthesis - Answer (click here)
2. The electron chemical proton gradient can be dissipated by uncouplers to heat - Answer (click here)
3. H -ATP synthases from bacteria, chloroplasts, and mitochondria have a common basic structure - Answer (click here)
4. The synthesis of ATP is effected by a conformation change of the protein - Answer (click here)

Mitochondria are the power station of the cell

1. Biological oxidation is preceded by a degradation of substrates to form bound hydrogen and CO2 - Answer (click here)
2. Mitochondria are the sites of cell respiration - Answer (click here)
3. Degradation of substrates applicable for biological oxidation takes place in the matrix compartment - Answer (click here)
4. How much energy can be gained by the oxidation of NADH? - Answer (click here)
5. The mitochondrial respiratory chain shares common features with the photosynthetic electron transport chain - Answer (click here)
6. Electron transport of the respiratory chain is coupled to the synthesis of ATP via proton transport - Answer (click here)
7. Plant mitochondria have special metabolic functions - Answer (click here)
8. Compartmentation of mitochondrial metabolism requires specific membrane translocators - Answer (click here)

The Calvin cycle catalyzes photosynthetic CO2 assimilation

1. CO2 assimilation proceeds via the dark reaction of photosynthesis - Answer (click here)
2. Ribulose bisphosphate carboxylase catalyzes the fixation of CO2 - Answer (click here)
3. The reduction of 3-phosphoglycerate yields triose phosphate - Answer (click here)
4. Ribulose bisphosphate is regenerated from triose phosphate - Answer (click here)
5. Besides the reductive pentose phosphate pathway there is also an oxidative pentose phosphate pathway - Answer (click here)
6. Reductive and oxidative pentose phosphate pathways are regulated - Answer (click here)

Phosphoglycolate formed by the oxygenase activity of RubisCO is recycled in the photorespiratory pathway

Polysaccharides are storage and transport forms of carbohydrates produced by photosynthesis

1. Starch is synthesized via ADP-glucose - Answer (click here)
2. Degradation of starch proceeds in two different ways - Answer (click here)
3. Surplus of photosynthesis products can be stored temporarily in chloroplasts as starch - Answer (click here)
4. Sucrose synthesis takes place in the cytosol - Answer (click here)
5. The utilization of the photosynthesis product triose phosphate is strictly regulated - Answer (click here)
6. In some plants assimilates from the leaves are exported as sugar alcohols or oligosaccharides of the raffinose family - Answer (click here)
7. Fructans are deposited as storage compounds in the vacuole - Answer (click here)
8. Cellulose is synthesized by enzymes located in the plasma membrane - Answer (click here)

Nitrate assimilation is essential for the synthesis of organic matter

1. Nitrate assimilation is essential for the synthesis of organic matter - Answer (click here)
2. The reduction of nitrate to NH3 proceeds in two reactions - Answer (click here)
3. Nitrate assimilation also takes place in the roots - Answer (click here)
4. Nitrate assimilation is strictly controlled - Answer (click here)
5. The end product of nitrate assimilation is a whole spectrum of amino acids - Answer (click here)
6. Glutamate is the precursor for chlorophylls and cytochromes - Answer (click here)

Nitrogen fixation enables plants to use the nitrogen of the air for growth

1. Nitrogen fixation enables plants to use the nitrogen of the air for growth - Answer (click here)
2. Legumes form a symbiosis with nodule-inducing bacteria - Answer (click here)
3. N2 fixation can proceed only at very low oxygen concentrations - Answer (click here)
4. The energy costs for utilizing N2 as a nitrogen source are much higher than for the utilization of NO3- - Answer (click here)
5. Plants improve their nutrition by symbiosis with fungi - Answer (click here)
6. Root nodule symbioses may have evolved from a pre-existing pathway for the formation of arbuscular mycorrhiza - Answer (click here)

Sulfate assimilation enables the synthesis of sulfur containing compounds

1. Sulfate assimilation enables the synthesis of sulfur containing compounds - Answer (click here)
2. Sulfate assimilation proceeds primarily by photosynthesis - Answer (click here)
3. Glutathione serves the cell as an antioxidant and is an agent for the detoxification of pollutants - Answer (click here)
4. Methionine is synthesized from cysteine - Answer (click here)
5. Excessive concentrations of sulfur dioxide in the air are toxic for plants - Answer (click here)

Phloem transport distributes photoassimilates to the various sites of consumption and storage

1. Phloem transport distributes photoassimilates to the various sites of consumption and storage - Answer (click here)
2. There are two modes of phloem loading - Answer (click here)
3. Phloem transport proceeds by mass flow - Answer (click here)
4. Sink tissues are supplied by phloem unloading - Answer (click here)

Products of nitrate assimilation are deposited in plants as storage proteins

Phloem transport distributes photoassimilates to the various sites of consumption and storage

1. Globulins are the most abundant storage proteins - Answer (click here)
2. Prolamins are formed as storage proteins in grasses - Answer (click here)
3. 2S-Proteins are present in seeds of dicot plants - Answer (click here)
4. Special proteins protect seeds from being eaten by animals - Answer (click here)
5. Synthesis of the storage proteins occurs at the rough endoplasmic reticulum - Answer (click here)
6. Proteinases mobilize the amino acids deposited in storage proteins - Answer (click here)

Lipids are membrane constituents and function as carbon stores

1. Lipids are membrane constituents and function as carbon stores - Answer (click here)
2. Polar lipids are important membrane constituents - Answer (click here)
3. Triacylglycerols are storage compounds - Answer (click here)
4. The de novo synthesis of fatty acids takes place in the plastids - Answer (click here)
5. Glycerol 3-phosphate is a precursor for the synthesis of glycerolipids - Answer (click here)
6. Triacylglycerols are synthesized in the membranes of the endoplasmatic reticulum - Answer (click here)
7. Storage lipids are mobilized for the production of carbohydrates in the glyoxysomes during seed germination - Answer (click here)
8. Lipoxygenase is involved in the synthesis of oxylipins, which are defense and signal compounds - Answer (click here)

Secondary metabolites fulfill specific ecological functions in plants

1. Secondary metabolites often protect plants from pathogenic microorganisms and herbivores - Answer (click here)
2. Alkaloids comprise a variety of heterocyclic secondary metabolites - Answer (click here)
3. Some plants emit prussic acid when wounded by animals - Answer (click here)
4. Some wounded plants emit volatile mustard oils - Answer (click here)
5. Plants protect themselves by tricking herbivores with false amino acids - Answer (click here)

A large diversity of isoprenoids has multiple functions in plant metabolism

1. A large diversity of isoprenoids has multiple functions in plant metabolism - Answer (click here)
2. Higher plants have two different synthesis pathways for isoprenoids - Answer (click here)
3. Prenyl transferases catalyze the association of isoprene units - Answer (click here)
4. Some plants emit isoprenes into the air - Answer (click here)
5. Many aromatic compounds derive from geranyl pyrophosphate - Answer (click here)
6. Farnesyl pyrophosphate is the precursor for the synthesis of sesquiterpenes - Answer (click here)
7. Geranylgeranyl pyrophosphate is the precursor for defense compounds, phytohormones, and carotenoids - Answer (click here)
8. A Prenyl chain renders compounds lipid-soluble - Answer (click here)
9. The regulation of isoprenoid synthesis - Answer (click here)
10. Isoprenoids are very stable and persistent substances - Answer (click here)

Phenylpropanoids comprise a multitude of plant secondary metabolites and cell wall components

1. Phenylpropanoids comprise a multitude of plant secondary metabolites and cell wall components - Answer (click here)
2. Phenylalanine ammonia lyase catalyzes the initial reaction of phenylpropanoid metabolism - Answer (click here)
3. Monooxygenases are involved in the synthesis of phenols - Answer (click here)
4. Phenylpropanoid compounds polymerize to macromolecules - Answer (click here)
5. The synthesis of flavonoids and stilbenes requires a second aromatic ring derived from acetate residues - Answer (click here)
6. Flavonoids have multiple functions in plants - Answer (click here)
7. Anthocyanins are flower pigments and protect plants against excessive light - Answer (click here)
8. Tannins bind tightly to proteins and therefore have defense functions - Answer (click here)

Multiple signals regulate the growth and development of plant organs

1. Multiple signals regulate the growth and development of plant organs and enable their adaptation to environmental conditions - Answer (click here)
2. Signal transduction chains known from animal metabolism also function in plants - Answer (click here)
3. Phytohormones contain a variety of very different compounds - Answer (click here)
4. Auxin stimulates shoot elongation growth - Answer (click here)
5. Gibberellins regulate stem elongation - Answer (click here)
6. Cytokinins stimulate cell division - Answer (click here)
7. Abscisic acid controls the water balance of the plant - Answer (click here)
8. Ethylene makes fruit ripen - Answer (click here)
9. Plants also contain steroid and peptide hormones - Answer (click here)
10. Defense reactions are triggered by the interplay of several signals - Answer (click here)
11. Light sensors regulate growth and development of plants - Answer (click here)

A plant cell has three different genomes

1. A plant cell has three different genomes - Answer (click here)
2. In the nucleus the genetic information is divided among several chromosomes - Answer (click here)
3. The DNA of the nuclear genome is transcribed by three specialized RNA polymerases - Answer (click here)
4. DNA polymorphism yields genetic markers for plant breeding - Answer (click here)
5. Transposable DNA elements roam through the genome - Answer (click here)
6. Viruses are present in most plant cells - Answer (click here)
7. Plastids possess a circular genome - Answer (click here)
8. The mitochondrial genome of plants varies largely in its size - Answer (click here)

Protein biosynthesis occurs in three different locations of a cell

1. Protein biosynthesis occurs in three different locations of a cell - Answer (click here)
2. Protein synthesis is catalyzed by ribosomes - Answer (click here)
3. Proteins attain their three-dimensional structure by controlled folding - Answer (click here)
4. Nuclear encoded proteins are distributed throughout various cell compartments - Answer (click here)
5. Proteins are degraded by proteasomes in a strictly controlled manner - Answer (click here)

Biotechnology alters plants to meet requirements of agriculture nutrition and industry

1. Biotechnology alters plants to meet requirements of agriculture, nutrition and industry - Answer (click here)
2. A gene is isolated - Answer (click here)
3. Agrobacteria can transform plant cells - Answer (click here)
4. Ti-Plasmids are used as transformation vectors - Answer (click here)
5. Selected promoters enable the defined expression of a foreign gene - Answer (click here)
6. Genes can be turned off via plant transformation - Answer (click here)
7. Plant genetic engineering can be used for many different purposes - Answer (click here)