Living Organisms are Interdependant
- All organisms are dependant on the energy from the Sun .
- Plants absorb a small percentage of this energy for photsynthesis- this energy is stored in chemicals which make up the cells.
- Autotroph- An organism that produces its own organic compounds.
- Heterotrophs- An organism that must eat other organisms for its source of organic compounds.
- Energy is transferred between organisms in an ecosystem when organisms are eaten and when dead organisms and waste is fed on by decay organism
- Energy passes out of a food chain- it is used for life processes in the organism, escapes as heat, excreted as waste and is uneaten. This limits the length of food chains.
- Soil is composed of biomass (living and dead organisms), inorganic materials, air and water (with dissolved mineral ions).
1 of 12
- In photosynthesis, light energy is absorbed by chlorophyll, energy used to rearrange the atoms of CO2 and H2O to produce glucose.
- This glucose may be converted into chemicals needed for growth of plant (cellulose, protein, chlorophyll), converted into starch for storage or used in respiration to release energy.
- Starch is a better storage molecule than glucose because it is insoluble and has little effect of the osmotic balance of the cell.
- Energy released by respiration may be used to synthesise polymers required by the plant cell (glucose to starch and cellulose, or glucose to nitrate to amino acids to proteins).
- Plant roots absorb nitrates by active transport.
- Rate of photosynthesis may be limited by low levels of heat, CO2 and light.
- Most scientists agree that human activity is causing an increased level of atmospheric CO2.
2 of 12
- Symbiosis- Any association between 2 organisms (clownfish and sea anemone).
- Commensalism- A relationship between 2 organisms of different species where one gains, and the other neither gains nor loses (seed pods on clothes).
- Parasitism is a close association between 2 organisms which is beneficial to the parasite, but harmful to the host.
- Tapeworms have adapted an enzyme-resistant cuticle to protect from digestion.
- Parasites are important causes of human disease and have an impact on food production.
- The evolution of a parasite is closely linked to that of the host.
3 of 12
- Sickle-cell anaemia is a genetic disorder caused be a faulty recessive allele of the gene that codes for haemoglobin.
- Haemoglobin is the protein that carries O2 molecules in red blood cells.
- Red blood cells with sickle-cell haemoglobin are stretched into a rigid "sickle" shape.
- These rigid red blood cells get stuck in small blood cells, causing acute pain and extreme tiredness.
- Carriers of the sickle-cell allele have a higher resistance to malaria than people who do not- sickle-cell trait.
- Where malaria is common, natural selection favours people with sickle-cell trait- the frequency of the sickle-cell allele is higher in these areas.
4 of 12
- Bacteria and fungi make many useful organic compounds very efficiently.
- Bacteria any fungi can be grown on a large scale (fermentation) to include-
- Production of antibiotics- Fungus grows in a tank of nutrient solution and the antibiotic is secreted into the solution.
- Production of single-cell protein- Microorganisms can be grown from simple starting nutrients, they reproduce quickly. Microbial biomass is grown for food called single-cell protein.
- Enzymes for food manufacture (rennin)- Most rennin for cheese comes from industrially grown fungi.
5 of 12
Genetic Modification and Testing
- The main steps of genetic modification=
- 1.Isolating and replicating the required gene.
- 2. Transferring the gene into a new cell.
- 3. Use of a vector (virus or plasmid.)
- Genetic modification includes bacterial synthesis of drugs and hormones (insulin) and disease resistance in crop plants.
- There are economic,social and ethical implications for the release of genetically modified organisms.
- The use of DNA technology in genetic testing=
- 1. Isolating DNA from white blood cells.
- 2. Production of gene probe.
- 3. Use of UV or autoradiography to locate gene probe
6 of 12
Aerobic and Anaerobic respiration
- Energy is released from food chemicals in the process of respiration.
- Aerobic respiration requires oxygen.
- Anaerobic respiration takes place in muscle cells where there is a shortage of oxygen, and leads to a build up of lactic acid.
- Oxygen is needed to break down the lactic acid (oxygen debt).
- Aerobic respiration releases more energy per glucose molecule than anaerobic respiration.
- Anaerobic respiration may be advantageous to human being and other organisms in certain conditions (predator running after prey).
7 of 12
Muscles and ATP
- Energy released during respiration is used to synthesise a chemical called ATP- the "energy currency" of living things.
- Muscle tissue contracts when provided with energy (ATP) from respiration.
- During exercise, respiration in muscle cells increases to provide additional energy for movement.
- Muscle cells require a faster supply of O2 and glucose, and removal of CO2- this need is met by increasing heart and breathing rates.
- "Normal" measurements for factors such as heart rate and blood pressure are given within a range, and that individuals vary.
8 of 12
Blood and Blood types
- Components and functions of the blood=
- 1. Red Blood Cells- transporting oxygen.
- 2. White Blood Cells- fighting infection.
- 3. Platelets- blood clotting at injury sites.
- The ABO blood type system describes antigens on the surface of red blood cells and antibodies in the blood plasma.
- For blood transfusions the donor and recipient must be matched to avoid clotting.
- ABO blood type is determined by a single gene with 3 alleles (A, B, O).
- A and B are co-dominant, O is recessive to both.
9 of 12
Structure of the Circulatory system
- Double circulation- A circulatory system where the blood passes through the heart twice for every complete circulation of the body.
- Valves act like one-way doors to keep the blood flowing in 1 direction- stop it flowing backwards.
- Tissue fluid is formed as blood passes through capillary beds.
- This assists the exchange of chemicals by diffusion between capillaries and tissues (to include O2, CO2, glucose and urea).
10 of 12
Skeletal System and Sport Injuries
- Vertebrates have an internal skeleton for support and movement.
- Muscles can only move bones at a joint by contraction, operate in antagonistic pairs.
- The specific properties of ligaments (tough and elastic), cartilage (smooth) and tendons (tough and inelastic) enable them to function effectively.
- Common injuries can be caused by excessive exercise (to include sprains, dislocations, torn ligaments or tendons).
- The symptoms of sprains can include redness, swelling, bruising and pain.
- A physiotherapist is used to prescribe exercises for injuries to treat skeletal-muscular injuries.
11 of 12
Folllowing a Training Programme
- Factors in a person's medical or lifestyle history should be disclosed before treatment begins or exercise regime starts (medication, alcohol, tobacco).
- This information on general health is needed to decide on the best programme or treatment.
- Regular contact between trainers and clients is needed to make sure that the programme is being successful
- Personal medical and fitness info must be recorded and stored accurately and made available to others on the health/fitness team
- Treatments often have side-effects and are weighed against the benefits
- There are many ways to achieved a target- cure, recovery, rehabilitation or enhanced fitness
- Any assessment of progress needs to take into account the accuracy of the monitoring technique and the reliability of the data obtained
12 of 12