Nitrogen cycle Nitrogen is a major constituent of several of the most important plant substances.
Leaves and leaf structure The structure of the chloroplast and photosynthetic membranes Stages of photosynthesis Non-cyclic phosphorylation the Z scheme Chemiosmosis and ATP synthesis Cyclic phosphorylation The light-independent reactions Summary of stages of photosynthesis Factors affecting the rate of photosynthesis Test your knowledge Photosynthesis Photosynthesis is the process by which plants, some bacteria and some protistans use the energy from sunlight to produce glucose from carbon dioxide and water.
This glucose can be converted into pyruvate which releases adenosine triphosphate ATP by cellular respiration.
Oxygen is also formed. Photosynthesis may be summarised by the word equation: Chlorophyll is a complex molecule. Several modifications of chlorophyll occur among plants and other photosynthetic organisms.
All photosynthetic organisms have chlorophyll a. Accessory pigments absorb energy that chlorophyll a does not absorb. Accessory pigments include chlorophyll b also c, d, and e in algae and protistansxanthophylls, and carotenoids such as beta-carotene.
Chlorophyll a absorbs its energy from the violet-blue and reddish orange-red wavelengths, and little from the intermediate green-yellow-orange wavelengths. Chlorophyll - click on image to open All chlorophylls have: Leaves and leaf structure Plants are the only photosynthetic organisms to have leaves and not all plants have leaves.
A leaf may be viewed as a solar collector crammed full of photosynthetic cells. The raw materials of photosynthesis, water and carbon dioxide, enter the cells of the leaf, and the products of photosynthesis, sugar and oxygen, leave the leaf.
Water enters the root and is transported up to the leaves through specialized plant cells known as xylem vessels. Land plants must guard against drying out and so have evolved specialized structures known as stomata to allow gas to enter and leave the leaf. Carbon dioxide cannot pass through the protective waxy layer covering the leaf cuticlebut it can enter the leaf through the stoma the singular of stomataflanked by two guard cells.
Likewise, oxygen produced during photosynthesis can only pass out of the leaf through the opened stomata. Unfortunately for the plant, while these gases are moving between the inside and outside of the leaf, a great deal of water is also lost.
Cottonwood trees, for example, will lose gallons about dm3 of water per hour during hot desert days. The structure of the chloroplast and photosynthetic membranes The thylakoid is the structural unit of photosynthesis. Only eukaryotes have chloroplasts with a surrounding membrane.
Thylakoids are stacked like pancakes in stacks known collectively as grana. The areas between grana are referred to as stroma. While the mitochondrion has two membrane systems, the chloroplast has three, forming three compartments.
Structure of a chloroplast Stages of photosynthesis When chlorophyll a absorbs light energy, an electron gains energy and is 'excited'. The excited electron is transferred to another molecule called a primary electron acceptor. The chlorophyll molecule is oxidized loss of electron and has a positive charge.
Photoactivation of chlorophyll a results in the splitting of water molecules and the transfer of energy to ATP and reduced nicotinamide adenine dinucleotide phosphate NADP.
The chemical reactions involved include: The Light dependent reactions, a light-dependent series of reactions which occur in the grana, and require the direct energy of light to make energy-carrier molecules that are used in the second process: The light-dependent reactions When light energy is absorbed by a chlorophyll molecule its electrons gain energy and move to higher energy levels in the molecule photoexcitation.
Sufficient energy ionises the molecule, with the electron being 'freed' leaving a positively charged chlorophyll ion. This is called photoionisation. In whole chloroplasts each chlorophyll molecule is associated with an electron acceptor and an electron donor.
These three molecules make up the core of a photosystem. Two electrons from a photoionised chlorophyll molecule are transferred to the electron acceptor. The positively charged chlorophyll ion then takes a pair of electrons from a neighbouring electron donor such as water.I am also looking for the students to be able to describe the general structures of plants that are involved in the process of photosynthesis.
I then ask the students to describe similarities and differences between photosynthesis and cellular respiration. RUBISCO, the enzyme involved in photosynthesis, is also the enzyme involved when taking CO2.
More efficient than C4 and CAM plants under cool and moist conditions and under normal light because requires fewer enzymes. Photosynthesis is the process by which higher plants manufacture dry matter through the aid of chlorophyll pigment, which uses solar energy to produce carbohydrates out of water and carbon dioxide.
The overall efficiency of this critical process is somewhat low, and its mechanics are. Name the element which is involved in (i) the synthesis of auxin (ii) fixation of CHAPTER – PHOTOSYNTHESIS IN HIGHER PLANTS 1.
Define the following: Photosystem, photolysis of water, Rubisco, translocation 2. Which photosystem will work if only longer wavelengths of light are given to a. This nutrient is involved in photosynthesis and plant structure.
Blossom end rot is also a result of inadequate calcium. Another common symptom of calcium deficiency in leaves is the curling of the leaf towards the veins or center of the leaf. Many times. Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms' activities.
This chemical energy is stored in carbohydrate molecules, such as sugars.