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8 Cards in this Set
- Front
- Back
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List the seven components in a balanced diet and describe what they're used for.
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Carbohydrates - main source of energy
Proteins - growth/repair of muscle/other body tissues Fats - energy source; cell membranes; waterproofing; absorption of fat-soluble vitamins. Vitamins - chemical processes inside cells. Minerals - inorganic elements occuring in body that are essential to its normal functions Water - body function; transporting substances around body. 60% of body is water. Fibre/roughage - indigestible part of food; essential for healthy functioning of the digestive system. |
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Explain why a high ratio of HDL to LDL in the blood is considered to be a healthy sign.
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HDLs carry cholesterol back to the liver. In the liver, the cholesterol is used in metabolism or broken down. Therefore a high concentration of HDLs can help to reduce cholesterol concentrations in the blood and is associated with reduced deposition in the artery walls. LDLs carry cholesterol from the liver to the tissues. They are associated with increased deposition in the artery walls.
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Explain the difference between natural selection and artificial selection.
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Natural selection is selection of particular varieties that are well adapted to the environment. They are selected by environmental forces or pressures. Artificial selection is selection by humans to achieve the exaggeration of certain features.
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Describe three ways to prevent food spoilage and explain how they can help preserve foods.
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cooking - heating the food denatures the enzymes and their proteins and kills the microorganisms.
cooling/freezing - slows down enzyme activity so their metabolism, growth, and reproduction is very slow. pickling - this uses an acid pH to kill microorganisms by disrupting their DNA structure. |
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Describe the difference between a parasite and a pathogen.
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A parasite is an organism that lives in or on its host for all or part of its life; it causes harm and gains nutrition from the host. A pathogen is any organism that causes disease.
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List two diseases caused by each of the following: viruses, bacteria, fungi, and protoctista.
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virus - cold, influenza
bacteria - tuberculosis, pneumonia fungi - plant rust, athlete's foot protoctist - sleeping sickness, malaria |
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Explain why someone with AIDS is more likely to catch opportunistic diseases.
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AIDS is caused by the HIV virus. The virus attacks the cells of the immune system - T helper cells and macrophages. These cells normally help to mediate the immune response. If they are killed by viral action, the person will have a weak immune system and will be more susceptible to infections.
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Explain why people in the less economically developed countries are more likely to suffer from infectious diseases.
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- Nutrition may not be as good so their immune systems are not as strong.
- No funding to provide vaccinations to protect all the people - Filthy water filled with infectious pathogenic organisms - Poor housing conditions, promoting the transmission of pathogens |
