Complex carbohydrates

• Glucose and other monosaccharides

  Monomers used to make polymers known as polysaccharides
• Polysaccharides


  • Used for energy storage
  • Used for making cellulose for cell walls
  • Made from many monomers
• Formation of a glycosidic bond

  1. Addition of glucose to the end of an existing polysaccharide chain

  2. 1,4 glycosidic bond formed between C1 and C4
• Unbranched polysaccharide chains are formed when all glucose monomers are added via 1,4 glycosidic bonds
• Branching points in polysaccharides are formed by adding a glucose monomer to carbon 6 via a 1,6 glycosidic bond
• Energy storage polysaccharides


  • Amylose
  • Amylopectin
  • Glycogen
• Amylose and amylopectin


  Forms of starch
• Glycogen


  • Very similar to amylopectin but has more 1,6 glycosidic bonds and more branches
  • Sometimes called 'animal starch'
• The three energy storage polysaccharides are made from glucose monomers
• Cellulose


  • Long chain molecule made from β glucose monomers
  • Not used for energy storage, but for making the cell walls of plants
• Cellulose has a different structure and role compared to the energy storage polysaccharides
• Endocrine glands include the pituitary gland, thyroid gland, parathyroid glands, adrenal glands (including the adrenal medulla), pancreas, ovaries/testes, and pineal gland.
• Asexual reproduction


  The production of new individuals from a single organism without the fusion of gametes. All the individuals formed in this way form a clone of genetically identical organisms.
• Binary fusion


  A single organism becomes two independent organisms
• Budding


  A new plant develops from an outgrowth known as the bud. A bud is generally formed due to cell division at one particular site.
• Asexual spore formation


  Spores are asexual reproduction bodies that are surrounded by a hard protide cover to withstand unfavorable conditions. Under favorable conditions, the spores germinate and grow into new plants.
• Fragmentation


  A new plant is produced from a portion of the parent plant. Each section or a part of the plants develop into a mature, fully grown individual.
• Disadvantages and advantages of asexual reproduction

  • Disadvantages
  • Advantages
• Vegetative propagation


  A form of asexual reproduction of a plant. Only one plant is involved and the offspring is a result of one parent. The new plant is genetically identical to the parent.
• Principles of cutting


  1. Stem with at least one node or bud is cut

  2. Stem is covered in a thin layer of soil

  3. New shoots grow from buds and a new underground stem (rhizome) is formed
• Principles of tissue culture

  1. Removal of meristematic cells from the plant (explant)

  2. Explant is immersed in a well-aerated solution containing a balance of auxin and cytokinin to stimulate cell growth and division and nutrients (sucrose, and inorganic ions K, Mg and nitrates) and is sterile to prevent fungi and bacteria

  3. Undifferentiated cells in the explants divide by mitosis to produce callus

  4. Callus is placed in agar jelly with nutrients to produce root and shoot

  5. When the plant is large enough it's placed in sterile soil
• Importance of vegetative propagation

  • New plants are easily established where these are not viable and do not grow
  • Gives a reliable supply because of the uniform appearance
  • Plants are genetically identical
  • Plants are uniform size which helps with harvesting and packaging
  • Used to generate large numbers of new, genetically identical plants
• Strawberry plant flower doesn't need a partner to reproduce
• Asexual or clonal reproduction is expected to reduce genotypic diversity and slow down adaptation through reduced selection efficacy, yet the evolutionary consequences of clonal reproduction remain unclear for many natural populations.