Biology Higher Tier B3 Edexcel

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These are my notes from working through pages I needed to catch up on in the Edexcel 360Science book, (that's where all the numbered titles come from). 

4. Eating Well

A balanced diet simply means a diet that consists of the right balance of nutrients, fibres and water.

The four main food groups are: breads and cereals; milk and milk products; meat and alternatives; fruits and vegetables.

Body Mass Index (BMI) = Body Mass (Kg)/ (Body height)² (m²)

If someone has a body mass of over 30 they're considered obese. Obese people are subject to more health issues than say someone with a healthy BMI, these include risks of heart disease and risk of joint problems.

It is important to have a healthy and balanced diet. To have a balanced diet it is vital to eat foods from all the food groups in a healthy proportions so that you can get all the nutrients, fibres and water that your body needs. 

Depending on your own basal metabolic rate your body will need more or less food than someone that say does twice as much exercise as you. If you eat more than is needed for your energy needs, the result is gaining weight.

Obesity is a serious problem with lots of health risks. People with higher BMIs are expected to live for a shorter period of time than someone with a healthy BMI. Obese people are also more prone to have heart attacks or suffer from heart disease, as well as other health issues like joint problems.

5. Feeding the world.

Plants are bred to have to increase desirable characteristics by taking two plants with different characteristics and crossing them (hybridisation) by making them reproduce asexually into the new hybrid variety.

A hybrid plant is a plant that has two inheritable characteristics and is there for better because of it.

Examples of characteristics bred into plants are: higher yeild, resistance to herbicides, resistance to weather, resistance to disease, etc.

Genetic engineering: the techniques used to identify, isolate and insert useful genes from the genetic material of cells of one species into the genetic material of another species.

Genetic modification: A species into which genes are transferred are said to be genetically modified. The genes are transferred using the techniques of genetic engineering.

Food made from SCP (Single- Cell Protein) are high in protein and vitamins and minerals. They're also fast growing where as animals and plants can take many weeks or even months to grow to full size. This is why they are ideal to feed the world- (especially developing counties) however there are ethical problems with genetic engineering. (which is the identification, isolation and inserting of a gene from one species genetic material into another species genetic information) *sorry to repeat that, but i did to get that definition into my head*

The advantages of producing SCP over crops are that it is fast- much faster than breading the plants through hybridisation which can take up to ten years…

Comments

Ele.

Thanks for putting the name of the text book, sometimes people don't, it's a rel help to other students!

Keep up the good work, and good luck in exams!

Ele (moderator)

Al

Excellent resource, it would especially help those whom are studying for the Exam this Thursday (tomorrow).

Much appreciated, and keep uploading!

Naseem

Excellent resource, thanks

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