DP Biology - Cell Respiration, Plants and photosynthesis

Aerobic respiration

a type of respiration where oxygen is consumed.

ATP

a nucleotide triphosphate that is a common source of energy in cells.

ATP synthase

an enzyme that utilizes the H+ electrochemical gradient to synthesize ATP.

Chemiosmosis

a process for making ATP using the energy stored in an electrochemical gradient of hydrogen ions.

Cristae

invaginations of the inner mitochondrial membrane.

Decarboxylation

a chemical reaction that involves the removal of CO2.

Electron tomography

a method used to generate a three-dimensional image of the inner mitochondrial membrane.

Electron transport chain

a group of proteins that accept and donate electrons in a series.

Endergonic

energy storing reactions.

Exergonic

energy releasing reactions.

Glycolysis

a metabolic pathway that breaks glucose down to pyruvate.

Link reaction

a decarboxylation reaction that occurs in the mitochondrion between glycolysis and the Krebs cycle.

Lysis

splitting

Mitochondrial matrix

a compartment inside the inner membrane of the mitochondrion.

Oxidation

the loss of electrons or loss of hydrogen.

Oxidative phosphorylation

the production of ATP through a series of oxidation and reduction reactions.

Phosphorylation

the addition of a phosphate group to a molecule.

Pyruvate

the end product of glycolysis.

Reduced NAD

the energy rich form of the hydrogen carrier.

Reduction

the gain of electrons or gain of hydrogen.

Fertilization

the action or process of fertilizing an egg or a female animal or plant, involving the fusion of male and female gametes to form a zygote.

Flowering

the process of producing conspicuous flowers.

Mutualistic relationship

an association between organisms of two different species in which each member benefits.

Pollination

the process of transfer of pollen from the anther to the stigma of a plant.

Shoot apex

the tip of a shoot, the apical or lateral shoot meristematic dome together with the leaf primordial, from which emerge the leaves and sub-adjacent stem tissue.

Auxin

a plant hormone that causes the elongation of cells in shoots and is involved in regulating plant growth.

Meristem

a region of plant tissue, found chiefly at the growing tips of roots and shoots and in the cambium, consisting of actively dividing cells forming new tissue.

Micropropagation

the propagation of plants by growing plantlets in tissue culture and then planting them out.

Shoot apex

the tip of a shoot, the apical or lateral shoot meristematic dome together with the leaf primordial, from which emerge the leaves and sub-adjacent stem tissue.

Stem

the main body or stalk of a plant or shrub, typically rising above ground, but occasionally subterranean.

Tropisms

the turning or bending movement of an organism or a part of an organism toward or away from an external stimulus, such as light, heat, or gravity.

Active transport

a transport mechanism where ions or molecules move against a concentration gradient, this movement requires energy.

Hydrostatic pressure gradient

the stress that develops when solutions containing different concentrations of solute in a common solvent are separated by a membrane that is permeable to the solvent, but not the solute.

Incompressibility of water

the incapability of water to lose volume in response to pressure.

Osmosis

the diffusion of fluid through a semi-permeable membrane from a solution with a low solute concentration to a solution with a higher solute concentration until there is an equal concentration of fluid on both sides of the membrane.

Phloem

the food-conducting tissue of vascular plants that conducts synthesized nutrients to different parts of the plants.

Sieve tubes

an element of phloem tissue consisting of a longitudinal row of thin-walled elongated cells with perforations in their connecting walls through which food materials pass.

Adhesive property

the joining of two different substances due to attractive forces that hold them, such as keeping the water drops on the surfaces of leaves.

Capillary tubing

a tube of small internal diameter that holds liquid by capillary action.

Cohesive property

the sticking together of similar molecules, such as one water molecule being attracted to another water molecule. It also causes water molecules to form drops.

Osmosis

net movement of water molecules through a semi-permeable membrane from an area of higher water potential to an area of lower water potential.

Potometer

a device used for measuring the rate of water uptake of a plant due to photosynthesis and transpiration.

Water tension

the force created by evaporation of water coupled with the cohesive and adhesive forces in plants, enough to support a column of water against the forces of gravity in plants and trees.

Transpiration

the loss of water by evaporation in terrestrial plants, especially through the stomata (accompanied by a corresponding water uptake from the roots).

Xylem

the woody tissue which supports and transport water in vascular plants.

Calvin cycle

the use of ATP and reduced NADP in the stroma to regenerate RuBP and generate carbohydrates in the light independent stage of photosynthesis.

Carbon fixation

the incorporation of inorganic CO2 into an organic molecule.

Chemiosmosis

the process of making ATP using the energy stored in a proton gradient.

Cyclic photophosphorylation

involves photosystem 1 in a pattern of electron flow where ATP is generated.

Light-dependent reactions

the reactions within photosynthesis that use light to generate ATP and reduced NADP.

Light-independent reactions

the photosynthetic reactions that take place within the stroma and use reduced NADP and ATP to generate carbohydrates.

Photoactivation

the production of energetic electrons in reaction centers through the absorption of light.

Photolysis

the splitting of water.

Photophosphorylation

the production of ATP using the energy of sunlight.

Photosystem 1

an integral protein transport system used in the light-dependent reactions - it can carry out cyclic photophosphorylation, and produces reduced NADP.

Photosystem 2

the first photosystem in the light-dependent reactions - it uses electrons from photolysis, and produces ATP.

Proton gradient

a difference in proton concentration on either side of a membrane.

Reduced NADP

produced by photosystem 1, it is an energy source for the Calvin cycle.

Rubisco

an enzyme that fixes CO2 to RuBP in the Calvin cycle.

RuBP

the molecule that reacts with CO2 during carbon fixation.

Stroma

the chemical medium between the inner chloroplast membrane and the thylakoid membrane.

Thylakoid space

the lumen of the thylakoid.

Thylakoid

the membrane that is the site of photosynthesis.

Triose phosphate

an intermediate in the Calvin cycle, also known as glyceraldehyde-3-phosphate.

Absorption spectrum

range of wavelengths of light that a pigment is able to absorb.

Action spectrum

range of wavelengths of light within which photosynthesis takes place.

Chlorophyll

main photosynthetic pigment of green plants.

Chloroplast

cell organelle that is the site of photosynthesis.

Chromatography

a method of separating and identifying the components of a complex mixture by differential movement through a two-phase system.

Limiting factors

an environmental factor, such as carbon dioxide or light intensity, that controls the process of photosynthesis.

Nanometre

one billionth (10-9) of a metre.

Photolysis of water

chemical decomposition of water induced by light.

Photosynthesis

the production of carbon compounds in cells using light energy.

Rate of photosynthesis

the rate of conversion of carbon dioxide and water to photosynthetic products.

Wavelength

the distance between peaks of a wave of light, which determines its colour.

Aerobic cell respiration

respiration requiring oxygen, involving the oxidation of glucose to carbon dioxide and water.

Anaerobic cell respiration

respiration in the absence of oxygen, involving the formation of lactic acid or ethanol.

Adenosine triphosphate (ATP)

a nucleotide that releases energy when its phosphate bonds are hydrolysed.

Carbon dioxide (CO2)

molecule resulting from oxidation of organic carbon compounds, and formed in the tissues and eliminated by the lungs.

Cell respiration

the controlled release of energy from organic compounds to produce ATP.

Ethanol

alcohol formed by microbial fermentation of carbohydrates.

Fermentation

anaerobic breakdown of glucose with the end-products of ethanol and carbon dioxide or lactic acid.

Glucose

monosaccharide that is an end product of carbohydrate metabolism, and is the chief source of energy for living organisms.

Metabolic pathways

a series of enzymatic reactions that converts one biological material to another.

Respirometer

apparatus for the measurement of respiratory gaseous exchange.

Yeasts

a unicellular fungus that lives in liquid or moist habitats.