Uses of Biological Resources Flashcards
What three factors limit the rate of photosynthesis in crops grown in controlled environments?
- Temperature: Higher temperatures increase the reaction rate as particles gain kinetic energy, speeding up enzyme-catalyzed reactions.
- Light intensity: Increased light boosts the rate of photosynthesis.
- Carbon dioxide concentration: More CO₂ speeds up photosynthesis.
How are temperature, light intensity, and CO₂ concentration controlled in glasshouses?
- Temperature: Artificial heaters are used to reach optimum levels.
- Light intensity: Artificial lighting supplements natural light.
- Carbon dioxide: CO₂ levels are increased by burning paraffin wax.
What additional environmental factor should be controlled in glasshouses besides temperature, light, and CO₂?
Humidity control is crucial. Maintaining optimal humidity helps manage transpiration rates and prevents fungal diseases
What benefits do polythene tunnels provide in outdoor crop production (3 points)?
- Protect crops from harsh weather (rain, wind, high temperatures).
- Prevent the entry of pests.
- Slightly increase the internal temperature.
Why are fertilizers used in agriculture and what are some common examples (4 points)?
Purpose: To increase crop yield by providing essential nutrients.
Examples:
* Nitrates: For amino acid and protein synthesis.
* Potassium: To strengthen plants and boost disease resistance.
* Phosphorus: Important for ATP production and enzyme synthesis.
* Magnesium: Needed for chlorophyll production.
What ecological problem can result from the overuse of fertilizers?
Overuse can lead to eutrophication, which disrupts aquatic ecosystems.
What are the main types of pests that can reduce crop yield (3 types)?
- Insects and animals that eat crops.
- Weeds that compete for nutrients, water, and space.
- Fungi that infect and cause diseases in crops.
What are the two main approaches to controlling pests in agriculture?
- Chemical Control: Using pesticides such as insecticides, herbicides, and fungicides.
- Biological Control: Introducing natural predators or competitive species to control pests.
What are the types of pesticides and their primary effects on pest populations (3 advantages)?
- Insecticides: Kill insect pests.
- Herbicides: Kill plant pests (weeds).
- Fungicides: Kill fungal pests
Advantages:
1. They can kill the entire pest population
2. Are inexpensive and easily accessible
3. Have immediate effect
What are the disadvantages of using chemical pesticides (4 points)?
- They are non-selective, affecting both harmful and beneficial organisms.
- Require repeated application.
- Pests may develop resistance over time.
- They accumulate in food chains (bioaccumulation)
What advantages does biological control offer over chemical pesticides (4 points)?
- It is specific to the pest species.
- Effects are long-lasting without needing reapplication.
- No resistance develops in pests.
- There is no bioaccumulation or pollution.
What are the disadvantages of biological control methods (3 points)?
- They do not completely eliminate the pest species.
- They may disturb the existing food chain.
- They take longer to show effectiveness.
Describe the role of yeast in the production of bread. (4 points)
- Yeast performs anaerobic respiration, producing ethanol and carbon dioxide.
- Enzymes from yeast break down starch into glucose for energy.
- The produced CO₂ is trapped in dough, causing it to rise.
- During baking, ethanol evaporates and yeast dies due to high temperatures.
How does lactobacillus contribute to yoghurt production (4 points)?
- Equipment is sterilized, and milk is pasteurized to eliminate competing bacteria.
- After cooling, lactobacillus is added to ferment lactose into lactic acid.
- The increase in acidity causes the milk to clot and form yoghurt.
- Cooling the yoghurt stops the fermentation process.
What is an industrial fermenter and what conditions are controlled within it (6 points)?
Industrial fermenter: A container used to culture large quantities of microorganisms (bacteria and fungi).
Controls include:
1. Aseptic precautions: Sterilization by steam.
2. Agitation: Stirring for even distribution of nutrients, heat, and organisms.
3. Temperature: Monitored by probes and regulated via a water jacket.
4. pH: Controlled with probes and buffer solutions.
5. Oxygenation: Ensuring sufficient O₂ for aerobic respiration.
6. Nutrition: Supply of essential nutrients and ammonia
What measures are taken to ensure high yields in fish farming (7 points)?
- Water quality: Use of filters and regular oxygen pumping.
- Predation control:
Intraspecific: Separating small and large fish.
Interspecific: Using nets to prevent predation by other species. - Disease management: Adding antibodies.
- Feeding: Providing food in small, regular amounts.
- Waste management: Regular cleaning of tanks, nets, and fences.
- Selective breeding: Using fish with desired traits for reproduction.
What are the environmental concerns associated with fish farming?
Fish farming can lead to water pollution and may spread diseases to wild populations if not managed properly.
What is selective breeding and how is it carried out (in animals & plants)?
Definition: Choosing individuals with desired traits to breed, then selecting offspring with those traits over many generations.
Application:
* In plants: Select and cross plants with favorable characteristics while preventing undesired ones from reproducing.
* In animals: Choose and breed animals with desired traits, then select the best offspring for further breeding.
What is genetic engineering and what is its main objective?
Definition: Modifying an organism’s genome by introducing a gene from another species to give a desired characteristic.
Goal: To enhance traits such as crop yield, pest resistance, and nutritional value.
Define transgenic, restriction enzymes, and ligase enzymes.
- Transgenic: The transfer of genetic material from one species to another.
- Restriction enzymes: Enzymes that cut DNA at specific sites.
- Ligase enzymes: Enzymes that join pieces of DNA together.
How are genetically modified bacteria used to produce human proteins like insulin (4 points)?
- The human insulin gene is cut with a restriction enzyme.
- A bacterial plasmid is also cut using the same enzyme.
- Ligase enzyme joins the human insulin gene with the plasmid, forming recombinant DNA.
- The plasmid acts as a vector to transfer the insulin gene into bacteria, which then reproduce in a fermenter to produce insulin.
What benefits do genetically modified crops offer (3 points)?
- Increased crop yield.
- Enhanced resistance to pests and herbicides.
- Ability to produce additional vitamins (e.g., golden rice rich in vitamin A).
What is micropropagation and how is it performed (5 points)?
It is plant cloning
Process:
1. Sterilize a Petri dish.
2. Use a scalpel to cut an explant from a plant with desired traits.
3. Transfer the explant into an agar gel containing auxins and nutrients.
4. Provide light and water to stimulate growth.
5. The explant develops roots and grows into a complete plant, producing many identical copies.
What are the stages involved in cloning a mammal (4 points)?
- Remove a diploid nucleus from a body cell.
- Enucleate an ova (remove its nucleus).
- Insert the diploid nucleus into the enucleated ova and stimulate it (often by an electric shock) to start dividing into an embryo by mitosis.
- Implant the embryo into the uterus of a surrogate mother.
What is pharming and how is it achieved using cloned transgenic animals (definition, steps, and example)?
Pharming: The process of producing useful human proteins by using transgenic animals.
Steps:
1. Create a transgenic animal with a gene that causes it to produce a desired compound (e.g., in its milk).
2. Clone the animal to form a herd or flock, ensuring all individuals produce the same compound.
Examples: Production of antibodies for cancer therapy or blood clotting factor IX for haemophilia.
What are the benefits of using cloned transgenic animals in biotechnology (3 points)?
- They produce genetically identical offspring.
- Large numbers of clones can be generated quickly.
- They can be used to produce organs for transplant and other therapeutic compounds.
