Biology Core

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  • Created by: Amrita
  • Created on: 25-03-14 19:34
Carbohydrates, fats and proteins are used by the body to release energy and to build cells
Mineral ions and vitamins are needed in small amounts for healthy functions of the body
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A person is malnourished if their diet is not balanced. This may lead to a person being overweight or underweight
An unbalanced diet may also lead to deficiency diseases e.g Type 2 diabetes
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What is the metabolic rate and what does it vary with?
The rate at which all the chemical reactions in the cells are carried out. It varies with the amount of exercise you do and the proportion of muscle to fat in your body. It can also be affected by inherited factors
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When does a person lose mass?
When the energy content of the food taken is less than the amount of energy expended by the body
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Pathogens are microorganisms that cause infectious disease
Bacteria and viruses may reproduce rapidly inside the body and may produce toxins that make us feel ill. Viruses damage the cells in which they reproduce
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White blood cells help to defend against pathogens by...
Ingesting them and producing antibodies which destroy bacteria/viruses. They also produce anti toxins which counteract the toxins released by the pathogens
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The immune system of the body produces specific antibodies to kill a particular pathogen. This leads to immunity from that pathogen
In some cases, dead or inactive pathogens stimulate antibody production
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What did semmelweis do?
He recognised the importance of hand washing in the prevention of spreading infectious diseases. He managed to reduce the number of deaths from infectious diseases
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Some medicines help to relieve the symptoms of infectious diseases but do not kill the pathogens
Antibiotics help cure bacterial disease by killing infectious bacteria inside the body but they can't be used for viral pathogens which live and reproduce inside cells
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Overuse of antibiotics has increased the rate of development of antibiotic resistant strains of bacteria.
Now, antibiotics are not used to treat non-serious infections, so that the rate of development of resistant strains is lowered down
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How can people be immunised against a disease?
By introducing small quantities of dead or inactive forms of the pathogen into the body. It stimulates the white blood cells to produce antibodies that destroy the pathogens
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Uncontaminated cultures of micro-organisms are required for investigating the action of disinfectants and antibiotics. For this:
Petri dishes must be sterilised before use to kill unwanted microorganisms. The lid of the dish should be secured with tape to prevent the microorganisms from the air contaminating the culture.
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In school labs, cultures should be incubated at a max temp of 25 degrees, which greatly reduces the likelihood of growth of harmful pathogens
In industrial conditions, higher temperatures can produce more rapid growth
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Receptors and the stimuli they detect include:
Receptors in the eyes that are sensitive to light. Receptors in the ears that are sensitive to sound. Receptors on the tongue and in the nose that are sensitive to chemicals. Receptors in the skin that are sensitive to pain
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What do hormones do?
They regulate the functions of many organs and cells. They are secreted by glands and are usually transported to their target organs by the blood stram. e.g the release of an egg are controlled by hormones secreted by the pituitary gland
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Several hormones are involved in the menstrual cycle of a woman:
FSH is secreted by the PG and causes eggs to mature in the ovaries. LH stimulates the release of eggs from the ovary. Oestrogen is secreted by the ovaries and inhibits further production of FSH
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What are oral contraceptives?
Contraceptives that contain hormones to inhibit FSH production so that no eggs mature. They contain oestrogen and progesterone. Pills have a lower dose of oestrogen as they used to cause side effects
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What are plants sensitive to?
Light, moisture and gravity
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Their shoots grow towards light and against the force of gravity
Their roots grow towards moisture and in the direction of the force of gravity
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What is auxin?
A plant hormone that controls the growth of the tips of shoots and roots
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The responses of plant roots and shoots to light, gravity and moisture are the result of unequal distribution of hormones, causing unequal growth rates
Plant growth hormones are used in agriculture as weed killers and as rooting hormones
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How are drugs tested?
In the lab, using cells, tissues and animals. Very low doses are given to patients or people are given a placebo
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What are statins?
They are prescribed drugs that help reduce cholesterol levels and can have a significant effect on diabetic patients
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What is thalidomide?
A drug that was developed as a morning sickness pill. However many babies were born with severe limb abnormalities. It is now only used in the treatment of leprosy
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Misuse of illegal drugs such as heroin and ecstasy can have adverse effects on the heart and circulatory system
Cannabis contains chemicals which may cause people metal illneses
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Drugs change the chemical processes in people's bodies so that they become addicted to it and suffer withdrawal symptoms without it. e.g. Heroin and cocaine
There are several types of drugs than an athlete can use to enhance performance. Examples include stimulants that boost bodily functions such as heart rate and anabolic steroids which stimulate muscle growth
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What do plants compete for?
Light, space, water and nutrients
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What do animals compete for?
Food, mates and territory
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Animals may adapt for survival by means of:
Changes to surface area, thickness of insulating coat or amount of body fat
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Plants may be adapted to survive by means of:
Changes to surface area, water storage tissues, extensive root systems
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Lichens can be used as indicators of air pollution
Invertebrate animals can be used as water pollution indicators and concentration of dissolved oxygen in water.
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Environmental changes can be measured using non living indicators such as:
Oxygen levels, temperature or rainfall
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Radiation from the sun is the initial source of energy for most communities of living organisms
Green plants and algae absorb a small amount of the light that reaches them
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The amounts of material and energy contained in the biomass of organisms is reduced at each stage in a food chain because...
Some materials and energy are always lost in the organisms waste materials. Some energy is eventually transferred to the surroundings
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Living things remove materials from the environment for growth. They are returned either in waste materials or when living things die and decay
Materials decay because they are broken down by microorganisms. Microorganisms are more active and digest materials faster in warm, moist, aerobic conditions. The decay process releases substances that plants need to grow
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What is sexual reproduction?
The joining of male and female gametes. The mixture of the genetic information from two parents leads to variety in the offspring
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What is asexual reproduction?
No fusion of gametes. There is no mixing of genetic information and so no genetic variation in the offspring. These genetically identical individuals are known as clones
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Modern cloning techniques: Tissue Culture
Using small groups of cells from part of a plant
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Modern cloning techniques: Embryo transplants
Splitting apart cells from a developing animal embryo before they become specialised, then transplanting the identical embryos into host mothers
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Modern cloning techniques: Adult cell cloning
The nucleus is removed from an unfertilised egg cell. The nucleus from an adult body cell is then inserted into the egg cell. An electric shock causes the egg cell to divide to form embryo cells which are inserted in a female
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What is genetic engineering?
Genes from the chromosomes of humans and other organisms can be 'cut out' using enzymes and transferred to cells of other organisms
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New genes can be transferred to crops. Examples of GM crops include ones that are resistant to herbicides. GM crops generally show increased yields
There is an uncertainty about the effects of eating GM crops on human health. But they are an economic way of feeding poor populations
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What is Darwin's theory?
It states that all species of living things have evolved from simple life forms that first developed more than 3 billion years ago
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Why was the theory gradually accepted?
The theory challenged the idea that God made all the animals and plants and there was insufficient evident at the time
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Other cards in this set

Card 2

Front

An unbalanced diet may also lead to deficiency diseases e.g Type 2 diabetes

Back

A person is malnourished if their diet is not balanced. This may lead to a person being overweight or underweight

Card 3

Front

The rate at which all the chemical reactions in the cells are carried out. It varies with the amount of exercise you do and the proportion of muscle to fat in your body. It can also be affected by inherited factors

Back

Preview of the back of card 3

Card 4

Front

When the energy content of the food taken is less than the amount of energy expended by the body

Back

Preview of the back of card 4

Card 5

Front

Bacteria and viruses may reproduce rapidly inside the body and may produce toxins that make us feel ill. Viruses damage the cells in which they reproduce

Back

Preview of the back of card 5
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