Inheritance
What are somatic cells?
Cells that do not contain gametes
What is mutation?
A sudden and random change in the structure of a gene or in the chromosome number
What is an ecosystem?
A community of organisms living and interacting with each other and its non-living environment
What is monoculture farming?
The growing of a single crop or livestock species on a large scale on the same piece of land
What is biotechnology?
The use of living systems or organisms to develop products for the benefit of mankind
What are the parental phenotypes of Van Gogh's parents? (Hint: They both had normal vision while Van Gogh was colourblind)
XNY
XNXn
What are the differences between discontinuous and continuous variation?
Discontinuous variation: Traits that are easily distinguishable and are not affected by environmental conditions
Continuous variation: Traits that have a range and are brought about by the combined additive effects of genes
What is a biological equilibrium?
The condition in which the relative sizes of the different populations remain constant
What are renewable natural resources? (If you don't get this correct we are cutting ALL of your points)
Resources that can be replaced in the ecosystem by natural cycles as long as humans do not overuse them
What is the purpose of stirring paddles in a fermenter?
Paddles that help to stir and mix well the microorganisms with the air bubbles and nutrient fluid, while also preventing microorganisms from settling to the bottom of the fermenter
What are homologous chromosomes?
Identical paired chromosomes with the same shape, same genes and same sequence of genes
What are three examples of mutagenic chemicals?
Mustard Gas/Tar/Formaldehyde
What are the three types of consumers?
Herbivore: An organism that obtains energy and nutrients by feeding directly on plants
Carnivore: An organism that obtains energy and nutrients from feeding on animals
Omnivore: An organism that obtains energy and nutrients from both plants and animals
Why are forests cleared?
For urban development/For growing food crops/For farming livestock/For firewood/To collect wood for construction and paper
What are the bacteriums used to form human insulin, penicillin and mycoprotein?
Escherichia Coli, Penicillium, and Fusarium
How does a nucleus divide by mitosis?
A nucleus contains two chromosomes, which each divide into two daughter chromosomes attached together.
The chromosomes line up along the equator of the cell, and the daughter chromosomes separate and move apart.
Two identical daughter nuclei are formed, and the cell divides into two identical cells, each with two chromosomes.
How do soya bean breeders maximise high oil content in seeds?
Breeders first analyse plants and select those which produce seeds with a high oil content. These seeds have a good genetic combination for oil combination. These plants produce seeds which are then allowed to grow into new plants and self-fertilise. The resultant seeds with the highest oil content are selected and used again. This process repeats until pure-bred plants that produce seeds with the highest oil content are produced.
Why do food chains usually have fewer than five trophic levels?
Energy transfer along the food chain is inefficient. Energy is transferred to the environment as heat during respiration, and it is also transferred to faeces, excretory products and uneaten body parts. About 90% of the energy is lost as food is passed from one trophic level to the next. Hence, there is insufficient energy to support a long food chain.
What are the steps taken in Artificial insemination?
Female animals are treated with hormones so that they super-ovulate. Sperm are extracted from the males and checked to make sure that they are of a good quality. The sperm are then introduced into the uterus of the female. The embryos produced are then removed from the females and transferred to the uteri of other females, which have been treated with hormones to make their uteri ready for implantation of the embryos.
What are the advantages of using insulin made by bacteria?
The insulin produced is identical to human insulin and does not incite an allergic reaction
It is easier and cheaper to produce insulin in large quantities
There is no risk of contamination by disease-causing microorganisms like bacteria
There are no ethical concerns
How are proteins made?
The region of DNA carrying the gene unwinds and unzips, causing the DNA strands to separate
One of the DNA strands called the template is used to make the mRNA. The mRNA creates a copy of the message in the gene and leaves the nucleus through the nucleus pore
The mRNA attaches to a ribosome in the cytoplasm, which translates the message in the mRNA into a sequence of amino acids, which join together to form a protein, which grows longer until the mRNA is fully translated.
What are the adaptations of xerophytes and their purpose?
Needle-like leaves: Surface area to volume ratio reduced, reducing the rate of transpiration
Thick waxy cuticle: Reduces rate of water loss by evaporation
Sunken stomata: Causes water vapour to accumulate in the depressions outside the stomata
Hairs: Trap water vapour that diffuses outside the stomata, reducing the diffusion gradient of water vapour between the leaf and the atmosphere, reducing the rate of transpiration
What are the phases in the sigmoid population growth curve? Describe what occurs in each phase.
Lag phase: The population growth increases slowly as there is only a small number of organisms
Log phase: There is a rapid increase in population size due to maximum growth rate. There are optimal conditions, with abundant resources and a lack of diseases and predators
Stationary phase: Limiting factors and environmental resistance set in. The death rate equals the birth rate and the population size becomes constant
Death phase: The death rate is higher than the birth rate and the population size starts to drop
Describe how eutrophication occurs, and its side effects.
Nitrates and phosphates in untreated sewage or fertilisers enhance the growth of algae and water plants. They are used in the synthesis of proteins and nucleic acids, which increases the growth and multiplication of algae.
Overcrowding of algae prevents sunlight from reaching submerged plants, causing them to die due to a lack of sunlight. These dead plants are decomposed by aerobic bacteria and fungi, which use up oxygen in the water. They multiply rapidly, using up all of the oxygen in the water, causing the death of organisms such as fish.
What is pectinase and how is it used in fruit juice production?
Pectinase: An enzyme produced during the ripening of fruit, which breaks down pectin, a component of cell walls in fruit, causing the cells to separate and the fruit to turn soft
Fruit juice is made by crushing fruit to separate the liquid juice from the solid pulp. The suspended solids are made up of pectin, cellulose and starch, which cloud the juice. Pectinase, amylase and cellulase are added to break down these polysaccharides to sugars. The sugars dissolve in the water to produce clearer and sweeter juice.