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Description
Flashcards by Diana Domingues, updated more than 1 year ago
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Created by Diana Domingues
over 7 years ago
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| Question | Answer |
| Healthy diet | A diet that contains the right balance of the different foods you need and the right amount of energy. |
| Carbohydrates and fats | Used to release energy in the body |
| Proteins | Used for the growth and repair of cells |
| Mineral ions and vitamins | Used for healthy functioning of the body |
| Malnourished | Occurs when your diet is not balanced. May result in become overweight or underweight, and illnesses like type 2 diabetes and cholesterol |
| Metabolic rate | The rate at which reactions occur in the body |
| Metabolic rate depends on: | - Muscle to fat ratio - Amount of exercise you do - Inherited factors |
| Semmelweis | He encouraged doctors to wash their hands before and after treating their patients in order to control the spread of infection in hospitals |
| Pathogens | Microorganisms that cause infectious diseases. Eg. Bacteria and viruses |
| Why are bacteria harmful? | Produce toxins |
| Why are viruses harmful? | They reproduce inside cells causing death of the cell when the burst out to go reproduce inside other cells |
| How do white blood cells defend against pathogens? | - Contain antitoxins, which counteract toxins - Contain antibodies, which stick to the antigens of bacteria, which clump them together until they are ingested by another white blood cell - Ingest and digest pathogens (phagocytosis) |
| Why can't viruses by destroyed by antibiotics? | As they reproduce inside cells, using antibiotics to destroy the viruses will damage/destroy the cell as well |
| How do bacteria become resistant to antibiotics? | When antibiotics are overused, a mutation may occur in the bacteria, producing a new strain of antibiotic resistant bacteria. They will be able to survive and reproduce. Eg. MRSA |
| Painkillers | Medicines that help relieve the symptoms of the infectious disease, but do not kill the pathogen |
| Vaccine | Contains dead or weakened pathogens |
| How do vaccines cause immunization | They stimulate the white blood cells to produce antibodies against that particular strain of pathogen.. This makes the person immune against future infection, as the white blood cells will be able to produce the antibodies faster |
| What does MMR vaccination protect you against? | - Measles - Mumps - Rubella |
| How to ensure your bacteria culture is uncontaminated? | - Petri dishes and culture media must be sterilised before use to kill unwanted microorganisms - Inoculating loops used to transfer microorganisms to the media must be sterilised by passing them through a flame - The lid of the Petri dish should be secured with tape to prevent microorganisms from the air contaminating the culture. |
| Why do people culture microorganisms? | To investigate the action of disinfectants and antibiotics |
| What temperature should cultures be incubated in schools? | 25 °C |
| Why should cultures be grown at only 25 °C in schools? (Higher temperature = More rapid growth) | To reduce the likelihood of growing pathogens harmful to humans |
| Human nervous system | Enables us to react to our surroundings and coordinate our behaviour |
| Receptors | Detect stimuli (changes in the environment) Eg: Receptors in the eyes, ears, nose, tongue and skin. |
| Reflex actions | Automatic, rapid reactions to stimuli. Meant to protect you from potential danger. |
| Central Nervous system | Brain and spinal cord |
| Reflex action description: (From receptor to effector) | - Environmental stimulus is detected by receptors - Impulses from a receptor pass along a sensory neurone to the CNS - In the CNS, the impulses diffuse across the synapse between the sensory neurone and relay neurone, then from the relay neurone to the motor neurone - Impulses are then sent along the motor neurone to the effector |
| Effector | This coordinates a response to the original stimulus. Can be either a muscle (responds by contracting) or a gland (responds by secreting hormones) |
| Conditions that need to be controlled in the body | - Water - Ions - Temperature - Blood sugar levels |
| How does water leave the body? | - Via the lungs when we exhale - Via sweat - Via urine |
| How do ions leave the body? | - Via sweat - Via urine |
| Why does temperature need to be maintained at a constant 37°C ? | This is the temperature at which enzymes work best. If it was too hot, the enzymes would denature |
| Why do blood sugar levels need to be controlled? | To ensure cells are provided with a constant supply of energy for respiration. Too much blood sugar would result in diabetes |
| Hormones | Chemical messengers that coordinate processes within the body. They are secreted by glands and are transported to their target organ by the bloodstream |
| FSH (Follicle stimulating hormone) | Secreted by the pituitary gland, and causes eggs in the ovaries to grow and mature. Stimulates the ovaries to produce oestrogen |
| Oestrogen | Oestrogen is secreted by the ovaries, inhibits the production of FSH and stimulates the production of LH. Thickens the lining of the womb |
| LH (Luteinising hormone) | Released by the pituitary gland. Inhibits the production of oestrogen and stimulates the release of the eggs from the ovary |
| What hormones do oral contraceptives contain? | - Oestrogen and progesterone - The first birth control pills contained large amounts of oestrogen, which resulted in women suffering significant side effects - Nowadays, there is a low dose of oestrogen, or progesterone-only pills |
| IVF (In-vitro fertilisation) | The mother is given FSH and LH to stimulate the maturation of several eggs. The eggs are collected from the mother and fertilised by sperm from the father. The fertilised eggs develop into embryos. At the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus |
| Plants are sensitive to: | - Light - Moisture - Gravity |
| Shoots | - Grow towards light (phototropism) - Against the force of gravity (negative geotropism) |
| Roots | - Grow towards moisture (hydrotropism) - In the direction of the force of gravity (geotropism) |
| Auxin and phototropism | Auxin moves away from light, and concentrates on the side of the shoot away from the light. This causes an unequal distribution of auxin and an unequal growth rate The side of the shoot away from the light grows faster, causing the plant to bend towards the light |
| Auxin and geotropism | Auxin moves towards gravity, so concentrates on the lowest side of the root This causes an unequal distribution of auxin and an unequal growth rate The lowest side of the root now grows slower, causing the root to bend towards the force of gravity (downwards) |
| Use of plant growth hormones | - Weed killers (the plant grows too fast for itself to be able to support this rate of growth, causing the weed to die) - In rooting powder |
| Stages of drug testing | - In the lab, using cells and tissues - In the lab, using live animals - In clinical trials involving healthy volunteers (to see if drug is safe) - In clinical trials, using patients (to find the optimum dosage) |
| Blind trials | Patients are given either a placebo or the real drug. They do not know which they have been given, but the doctors do. |
| Double-blind trials | Patients are given either a placebo or the real drug. They do not know which they have been given, and neither do the doctors. |
| Statins | Used to lower the risk of heart and circulatory diseases |
| Thalidomide | Originally developed as a sleeping pill, but found that it helped relieve morning sickness during pregnancy. However, babies were born with severe limb abnormalities, as the drug had not been tested on pregnant women. Now used to treat leprosy |
| Result of thalidomide tragedy | Drug testing has become much more rigorous |
| Legal, recreational drugs | - Nicotine - Alcohol |
| Illegal, recreational drugs | - Cannabis - Ecstasy - Heroin |
| Effects of the misuse of illegal drugs | Adverse effects on the heart and circulatory system |
| Effects of cannabis | Can cause mental illness "Gateway drug" - builds up tolerance in the body, so individual has to switch to harder drugs to receive the same effect |
| Overall impact of legal drugs | Much more impact on health than illegal drugs, as more people use them. |
| Drugs | Substances that change the chemical processes in people's bodies, so that they may become dependent on the drug, and suffer withdrawal symptoms without them. |
| Performance enhancing drugs | - Stimulants (Boost bodily functions, such as heart rate) - Anabolic steroids (Stimulate muscle growth) |
| Plants compete for: | - Light - Space - Water - Nutrients |
| Animals compete for: | - Food - Mates - Territory |
| Extremophiles | Organisms that are adapted to live in very extreme environments. Eg. High levels of salt, high temperatures, high pressures |
| Adaptations of a polar bear: | - White fur (camouflage) - Thick layer of blubber/fat (insulation) - Thick fur (insulation) - Small surface-area/volume ratio (low heat loss) |
| Adaptations of a camel: | -Wide hooves (walk on sandy ground) - Long eyelashes (keep sand out) - Double eyelids (keep sand out) - Thin fur (more heat loss) - Large surface area (more heat loss) - Thick, leathery lips (can eat prickly plants) - Fur camouflage with sand |
| Cactus adaptations | - Thorns (deter predators) - Extensive root system (to get water) - No/thin leaves (less surface area for water evaporation) - Thick waxy cuticle (less water evaporation) - Fleshy tissues (water storage) |
| Changes in environment affecting distribution of organisms | - Change in competitor - Change in predator - Change in prey - Change in temperature - Change in rainfall |
| Organisms indicators of pollution | Lichens ~ Air pollution indicators, particularly sulfur dioxide Invertebrate animals ~ Water pollution indicators and indicators of amount of dissolved oxygen in water |
| Non-living indicators of environmental changes | Oxygen levels Temperature (thermometer) Rainfall (rain gauge) |
| What is the primary source of energy? | The sun |
| Why biomass of organisms reduced at each stage in a food chain? | - Some materials and energy are lost in the organisms’ waste materials. - Energy is used for respiration - Some organisms may not be eaten entirely (therefore less energy is transferred into the next stage) |
| How are materials returned to the environment? | - Waster materials - When material die and decay |
| Why do materials decay? | They are broken down (digested) by microorganisms/ decomposers |
| Optimum conditions for decomposers | - Warm conditions - Moist conditions - Aerobic conditions |
| Stable community | Processes that remove materials form the environment are balanced by processes who return them to the environment Materials are constantly recycled |
| Carbon cycle definition | The constant recycling of carbon |
| Carbon cycle | - CO2 is removed from the air by photosynthesis in plants - CO2 is released into the atmosphere by respiration of plants & animals - Carbon in plants/ animals may be ingested by other animals - When animals decay, decomposers respire, releasing CO2 - Combustion of fossil fuels releases CO2 |
| Why are organisms similar to their parents? | Their parents' genes (that control characteristics) are passed on in the gametes from which offspring develop |
| Chromosomes | Carry genes that control the development of different characteristics of an organism |
| Why do individuals have different characteristics? | - Different genes - Live in different environments - Combination of both |
| Sexual reproduction | The fusion of male and female gametes. The mixture of the genetic information from two parents leads to variety in the offspring |
| Asexual reproduction | No fusion of gametes and only one individual is needed as the parent. There is no mixing of genetic information and so no genetic variation in the offspring. (Genetically identical -clones) |
| Cuttings | Cloning techniques to produce plants quickly and cheaply. The cuttings are taken and placed in rooting powder, creating genetically identical plants |
| Tissue culture | Using small groups of cells from part of a plant and placing them in sterile agar jelly containing plant hormones and nutrients |
| Embryo transplants | Splitting apart cells from a developing animal embryo before they become specialised, then transplanting the identical embryos into host mothers |
| Adult cell cloning | Removing the nucleus from an unfertilised egg cell. The nucleus from an adult body cell is then inserted into the egg cell. An electric shock then causes the egg cell to begin to divide to form embryo cells. When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development. |
| Genetic engineering | Genes from the chromosomes of organisms can be ‘cut out’ using enzymes and transferred to cells of other organisms at an early stage in its development. The organism will then develop with those characteristics. |
| GM crops | Crops that have had their genes modified to increase yield, make them resistant to herbicides, insects, etc. |
| Concerns about GM crops | - Negative impact on population of insects and wildflowers. - Uncertainty about the effects of GM crops on human health |
| Darwin's theory of evolution | We evolved through Natural Selection from simple life forms that first developed more than 3 billion years ago. |
| Why was Darwin's theory gradually accepted? | - His theory challenged the idea that God made all organisms that live on Earth - There was insufficient evidence at the time - Mechanisms of inheritance and variation were not known until 50 years after the theory was published |
| Lamarck's theory | Based on the idea that characteristics acquired during an organism's lifetime can be inherited We now know this is not true |
| Natural selection | Genetic variation in organisms (or mutations in some cases) causes the organisms to have desired characteristics better adapted to their environment. This enables them to survive and reproduce, passing on their desired characteristics to their offspring, while other organisms without these characteristics may die out |
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