Cloning and Biotechnology

• clones are genetically identical organisms, formed via mitosis (no gametes)
• cloning is the process of producing clones. can be natural or artificial
• types of natural cloning in plants:

  vegetative propagation, runners, tubers, rhizomes, bulbs, corms, leaves
• vegetative propagation is when parents undergo asexual reproduction to form clones
• runners form a clone as a new plant grows at the end of a lateral stem
• tubers form clones as buds form on the tuber (swollen underground stem) and produce new shoots
• Rhizomes form clones by growing long, modified stems that grow horizontally under the soil

  • new plants are produced at nodes along the stem
• bulbs produce clones as buds form from old bulbs
• corms/bulbotubers are a short, vertical, swollen underground plant stem that serves as a storage organ that some plants use to survive winter or other adverse conditions
• advantages to plants of producing clones:

  • clones can be made quicker than seeds can germinate
  • if conditions are good for parents, also good for offspring
  • only one parent is needed
• disadvantages to plants of producing clones:

  • no genetic diversity
  • population susceptible to disease and changes in the environment
  • overcrowding
  • selection is not possible
• ways of artificially cloning plants:

  using a tissue culture or micropropagation
• steps in micropropagation:

  1. tissue sample scraped from parent plant and sterilised with ethanol to prevent infection (taken from meristem tissue - shoot tips and buds)

  2) tissue sample placed in agar growth medium containing nutrients and auxins

  3) samples develop into tiny plantlets (mitosis forms a callus of identical cells)

  4) plantlets planted into compost
• ways of artificially cloning animals:

  splitting embryos and somatic cell nuclear transfer (SCNT)
• the process of splitting embryos when cloning high milk yield cows:

  1. egg and sperm collected from two high value cows

  2) the egg is fertilised in in vitro fertilisation

  3) the embryo grows in vitro to 16-cell embryo

  4) the embryo is split into several segments

  5) each segment is implanted into different surrogate mothers

  6) each calf born is a clone of each other (not a clone of parents)
• the process of nuclear transfer (SCNT) which formed Dolly the sheep:

  1. mammary cells removed from sheep which will be cloned

  2) ovum (egg) collected from a different sheep

  3) nucleus is removed from ovum

  4) a single mammary cell with a nucleus is combined with a enucleate ovum (No nucleus) via electro-fusion

  5) this forms a reconstructed cell with ovum of one individual and nucleus of another

  6) 'culture' in tied oviduct of a different sheep

  7) recover early embryo

  8) implant embryo in surrogate mother ewe's uterus

  9) dolly born - clone of first female (mammary cell female)
• biotechnology is the industrial use of living organisms or their biological processes to produce food, drugs and other products
• microorganisms are used in biotechnology because:

  • grow rapidly
  • produce proteins and metabolites into the surrounding medium which can be harvested
  • can be genetically engineered
  • grow at relatively low temperatures
  • can be grown anywhere in the world
  • produce pure products
  • grow on otherwise useless or toxic materials
• uses of biotechnology:

  food, pharmaceutical drugs, enzymes
• biotechnology is used in food for:

  • ethanol in alcohol
  • lactic acid for yoghurt/ cheese
  • CO2 makes bread rise
• biotechnology is used in pharmaceutical drugs such as

  • penicillin
  • insulin
• biotechnology uses enzymes such as:

  • protease and lipase in washing powder
  • lactase makes lactose-free milk
  • pectinase - extract juice from fruit
• yoghurt is made by:

  • milk that has undergone fermentation by bacteria
  • bacteria convert lactose to lactic acid, coagulates milk
• cheese is made by:

  • milk is pre-treated with a culture of bacteria that can produce lactic acid from lactose
  • milk mixed with rennet which has enzyme rennin - coagulates milk
  • resulting solid (curd) is separated from liquid, curd pressed into moulds
• process of baking:

  • yeast added to dough and proving/fermenting - yeast respires anaerobically
  • produces CO2 bubbles - dough rises - alcohol evaporates during cooking process
• alcoholic beverages are made by:

  • anaerobic respiration of yeast
  • wine - grapes have yeast on skin - produce CO2 and alcohol
  • beer - brewed using barley grains that are beginning to germinate - process of malting, as grains germinate, convert starch to maltose - respired by yeast - produces CO2 and alcohol
• single-cell protein (SCP) is used in producing food by:

  • microorganisms used to manufacture protein - used as food
  • usually use fungal protein or mycoprotein (single-cell protein)
• advantages of using microorganisms:

  • production of protein is faster than animal/plant protein
  • biomass produced has high protein content
  • production can be increased/decreased due to demand
  • no animal welfare issues
  • provide a good source of protein
  • protein contains no animal fat or cholesterol
  • can easily be genetically modified to adjust amino acid content of protein
  • SCP production could be combined with removal of waste products
  • production is independent of seasonal variations
  • not much land required
• disadvantages of using microorganisms:

  • some people may not want to eat fungal protein/ food grown on waste
  • isolation of the protein - grown in huge fermenters, need to be isolated from material on which they grow
  • protein has to be purified to ensure isn't contaminated
  • microbial biomass can have high proportion of nucleic acids, must be removed
  • amino acid profile may be different from traditional animal protein, can be deficient in methionine
  • infection - conditions for growth ideal for pathogens
  • palatability - protein doesn't have taste/texture of traditional protein sources
• safety precautions when culturing microorganisms:

  • incubated at 25 degrees - reduce likelihood of pathogens
  • petri dishes and culture medium sterilised before use
  • inoculating loops sterilised with flame
  • lid is dish secured with tape - prevent contamination
  • dishes stored upside down to stop condensation dropping
• if 2^x = 1042, how do you calculate x:

  log2(1042) = x

  no. of divisions = x = 10.03
• the 4 phases on population growth curves:

  lag phase, exponential growth phase, stationary phase, death phase
• in the lag phase:

  • organisms adjusting to their surrounding (taking in water, growing, switching genes on and off, making enzymes)
  • active cells but not reproducing
  • numbers do not build up very quickly
  • length of this phase depends on conditions
• in the exponential growth phase:

  • organisms multiply rapidly
  • size of population doubles every generation
  • (plenty of space and nutrients : not much waste)
  • in bacteria generation time can be as little as 30 mins
  • pH decreases (more acidic) - CO2 produced
• in the stationary phase:

  • organisms reduce reproduction and start to die
  • lack of food, waste or metabolites build up
  • births = deaths (reproduction rate = death rate)
• in the death phase:

  • death rate higher than reproduction rate
  • food run out, waste or metabolites at toxic levels
  • in a closed system this would lead to extinction
• metabolites are substances produced by metabolism
• metabolism is the sum of all reactions occurring in the body
• primary metabolites are substances produced by an organism as part of its normal growth

  • they are produced most of the time so their concentrations match the population size
• examples of primary metabolites:

  proteins, amino acids, enzymes

  nucleic acids

  ethanol and lactate