Module 6: Cloning And Biotechnology Flashcards
What is cloning?
Creating a genetically identical copy of an organism or cell.
Produced by asexual reproduction so no gametes are involved.
True or False: Cloning can occur naturally.
True
Plant cloning
Many plants can reproduce asexually using meristem cells, in a process called vegetative reproduction
Vegetative organs of plants include:
Root and shoot tips
Axillary buds (where leaves and the stem meet)
Vascular cambium (between xylem and phloem)
Naturally, over time a young, miniature plant (a plantlet) forms at these locations and remains attached to its parent plant
These plantlets are clones of their parent (as no other DNA has been introduced)
At maturity, the plantlet becomes detached from its parent and can live independently, when it is capable of photosynthesizing by itself
The new plants all have the same phenotype, so are uniform, making growing and harvesting easier
Plants that are hard to grow from seeds can be propagated, eg. orchids for the horticulture industry
Some plants have horizontal stems or runners that form over the soil surface, pointing sufficiently far away so that a new plant at that location will not be overshadowed by its parent, or in competition for water or soil nutrients
Roots form under the nodes of runners, called adventitious roots
The runner dies when the plantlet is self-sustaining
Strawberries, peppermint and spider plants reproduce in this way
Vegetative propagation.
Many methods of propagation do not require seeds as it is not sexual reproduction that is occurring, it is asexual reproduction
A well as runners, plants can propagate asexually using tubers, rhizomes, bulbs, suckers, and offsets
All modes of vegetative propagation contain modified stems that can generate meristematic tissue
Potato tubers are swollen modified roots that form eyes on their surface
Eyes can sprout new growth (called ‘chitting’)
The starch stored in the tuber fuels the early growth of the new plant
Ginger forms rhizomes, a modified stem that grows horizontally underground
New growth stems from nodes in the rhizome, forming new stems and adventitious roots
The section used in cookery is the rhizome
Onions and garlic form bulbs that can grow adventitious roots underground and leafy shoots above ground
Suckers are growths that appear from the root systems of many trees and shrubs, which can provide meristematic tissue for vegetative propagation
Examples are poplars, cherries and plums
Offsets are small, virtually complete daughter plants that have been asexually produced on the mother plant
Examples are tulips and lilies
Gardeners and horticulturalists can use these techniques to propagate desirable species asexually, effectively and at less cost than utilising sexual reproduction techniques
This is done by taking cuttings and dividing up plants into different clumps or sections
What is the primary purpose of biotechnology?
The primary purpose of biotechnology is to manipulate living organisms or their components to develop products and technologies.
Fill in the blank: The process of creating a genetically identical organism from a somatic cell is called __________ cloning.
somatic cell
What is a stem cell?
A stem cell is a unique type of cell that can develop into many different cell types in the body.
What technique is commonly used to produce genetically modified organisms (GMOs)?
Recombinant DNA technology
What is the main ethical concern associated with cloning?
The main ethical concern is the potential for loss of genetic diversity and the welfare of cloned animals.
True or False: All cloned organisms are genetically identical to their donors.
False
What is the term for the technique where a nucleus from a somatic cell is inserted into an egg cell?
Nuclear transfer
List one application of cloning in agriculture.
Cloning can be used to produce genetically identical plants with desirable traits.
What is gene therapy?
Gene therapy is the technique of altering the genes inside an individual’s cells to treat or prevent disease.
Fill in the blank: __________ is a method of cloning that involves creating a copy of a DNA sequence.
Polymerase chain reaction (PCR)
What is a clone?
A clone is an organism or cell that is genetically identical to another organism or cell.
True or False: Cloning is only performed on animals.
False
What is the significance of Dolly the sheep in the context of cloning?
Dolly was the first mammal to be cloned from an adult somatic cell, demonstrating that specialized cells could be used to create a clone.
What is a transgenic organism?
A transgenic organism is one that has had a foreign gene deliberately inserted into its genome.
Fill in the blank: __________ is a technique used to create a population of genetically identical plants from a single parent plant.
Tissue culture
True or False: Cloning can be used to produce organs for transplantation.
True
What is the role of plasmids in genetic engineering?
Plasmids are used as vectors to transfer genetic material into host cells.
What is the term for the process of using living organisms to produce useful products?
Bioprocessing
What is somatic cell nuclear transfer (SCNT)?
Cloning technique where the nucleus of a somatic cell (any cell apart from reproductive cell) is transferred to an enucleated (got nucleus removed) egg cell.
Fill in the blank: __________ refers to the use of microorganisms to break down pollutants in the environment.
Bioremediation
What is one potential benefit of cloning endangered species?
Cloning endangered species may help increase their population and prevent extinction.
What is the term for the DNA sequence that is recognized and cut by restriction enzymes?
Restriction site
True or False: Cloning can only be performed in a laboratory setting.
False
How should a plant cutting be taken for cloning?
Stem is cut between leaf and nodes. Replanted and allowed to grow, sometimes using plant hormones too.
How can we produce artificial clones of plants?
- Tissue culture - sample placed on various nutrient containing mediums to encourage cell division and shoot growth.
- Micropropagation - material produced from tissue culture is rapidly multiplied to produce a large no. plants.
Evaluate the use of artificial cloning in plants.
Large no. plants can be produced regardless of weather conditions.
Reduces genetic variation, making them susceptible to disease.
Evaluate the use of artificial cloning in plants.
Large no. plants can be produced regardless of weather conditions.
Reduces genetic variation, making them susceptible to disease.
Example of natural animal cloning?
Monozygotic twins - embryo splits to produce 2 genetically identical individuals.
2 ways to produce artificial clones for animals?
- Somatic cell nuclear transfer - adult somatic cell fuses with enucleated egg cell. This cell develops into an embryo which is inserted back into womb.
- Embryo splitting - same processes where twins form, but artificially.
Describe the technique used to culture organisms.
Aseptic technique - everything must be sterile to prevent unwanted microorganisms in culture.
Summarise 3 steps of growing microorganisms.
- Sterilisation- part of aseptic technique.
- Inoculation - microorganisms spread in agar by spreading in lines.
- Intubation - placed in warm environment to grow for 24-48 hours.
What is asexual reproduction?
Offspring arise from a single organism so they are genetically identical. Doesn’t involve fusion of gametes.
Describe some examples of asexual reproduction.
Binary fission - parent cell simply divides into two like bacteria.
Spores - special cells released by the parent become new organisms. Fungi.
Fragmentation - severed body parts grown into new organisms. Sea stars.
Explain the method to produce natural plant clones.
Vegetative propagation - new plant grows from sections of roots stems or leaves which are cut off from parent.
List the advantages of vegetative propagation.
The plants cultivated are genetically identical to their parents.
Plants can be cultivated faster as compared to growing them from seeds.
Cons of vegetative propagation?
Vegetative propagated plants are short-lived, small compared to seed propagated plants
No new varieties can be produced
Skilled persons are required and often expensive compared to seed propagation
More susceptible to diseases as the entire plant may get affected as there is no genetic variation
Pros and cons of sexual and asexual reproduction?
Sexual - high genetic variability, adaptation.
Courtship is time/resource consuming.
Asexual - saves energy, courtship is non issue. Low genetic variability, adaptation to environment is difficult.
Immobilised enzymes
An immobilised enzyme is an enzyme that is attached to an insoluble material to prevent mixing with the product
Enzymes can be immobilised in several ways:
Attached to an inert substance
Enclosed in a capsule
Contained within a partially permeable membrane
Advantages of immobilised enzymes
There is no enzyme in the product (the product is uncontaminated) and therefore there is no need to further process or filter the end product
The immobilised enzyme can be reused multiple times which is both efficient and cost-effective (enzymes are expensive)
Immobilised enzymes have a greater tolerance of temperature and pH changes (immobilisation often makes enzymes more stable)
Disadvantages of immobilised enzymes
Specialist expensive equipment is required
Immobilised enzymes are more costly to buy, so are unlikely to be financially worthwhile for smaller industries
The rate of reaction is sometimes lower when using immobilised enzymes as the enzymes cannot freely mix with the substrate
Immobilised enzymes in industry
There are many industrial and medical applications of immobilised enzymes, including production of the following:
Lactose-free dairy products such as milk
Enzyme: Lactase
Converts lactose to glucose and galactose
Semi-synthetic penicillin which overcomes issues of penicillin resistance
Enzyme: Penicillin acylase
Converts the original form of penicillin into one which is effective against penicillin-resistant organisms
Enzymes are often immobilised for use in industrial processes as it means the enzyme can be reused in future processes rather than being discarded after it has been used once
Reusing the enzyme also avoids the need to separate the enzyme from the product in downstream processing
The immobilised enzymes are contained within a column through which the substrate is filtered in solution
As the substrate runs through the column, enzyme-substrate complexes are formed and products are produced
These products then flow out of the column, leaving the enzymes behind to catalyse the reaction again
Production of Artificial Clones in Plants
Micropropagation and tissue culture
Many plant cells are totipotent, unlike animal cells, and therefore an entire plant can be reproduced from any of these cells
Creating clones of cauliflowers is used to demonstrate totipotency through the production of tissue culture
Cauliflower is used because it is comprised mostly of actively dividing cells and can withstand being handled
A small piece of the plant is cut, this is called an explant, which is then grown into a new clone of the original plant
Care must be taken to disinfect the explant and to use aseptic techniques to avoid fungi from colonising the growth medium and causing the micropropagation to fail
This technique is used by scientists to reproduce endangered species of plants where relatively little source material exists
METHOD: Micropropagation and tissue culture
Equipment: goggles, disinfectant (usually a bleach solution), scalpel, gloves, forceps, cauliflower, agar growth medium containing sterilant, container, marker pen.
Wipe all surfaces with disinfectant and soak all apparatus in sterilant
It is important to ensure a sterile environment so that no fungi contaminate the experiment, which would result in seeing a fungal growth rather than an explant growth
Break off a small floret of cauliflower from the plant then using a scalpel, cut a thin section of the floret (about 5-10mm long)
This thin section is the explant
Sterilise the explant by soaking it in sterilising solution for 15 minutes, swirling the explant around within the solution every 5 minutes
This ensures that the explant is sterile and therefore only cauliflower cells are present
Take out the explant using sterilised forceps and add it to a container of agar growth medium
The growth medium contains all the nutrients that the plant needs for growth and also contains a sterilant to ensure no contamination occurs throughout the experiment
Leave the container holding the agar growth medium and the explant on a sunny windowsill for 3 weeks
Results for this experiment?
The result of this experiment is to grow a complete cauliflower clone from an explant
This shows that the cells in the explant have the capability to produce all the different cell types that make up a full cauliflower plant, hence they are totipotent
The complete cauliflower plant can then be distributed to commercial growers/garden centres in large numbers
