AS - Unit 2 - Food and health Flashcards
What is a balanced diet?
One that contains all the nutrients required for health in appropriate proprtions
What is obesity?
When a person is 20% or more heavier than the recommended weight for their height
Give 6 things that good nutrition will give you
Provide better health Ensure a stronger immune system You become ill less often Help you learn more effectively Make you stronger Make you more productive
What are proteins essential for?
Growth and repair of muscle and other body tissues
What is our main source of energy in our diet?
Carbohydrates
Why are fats important in our diet?
Important in:
Cell membranes
Waterproofing
Absorption of fat-soluble vitamins
Why are vitamins essential to our diets?
They play many important roles in the chemical processes taking place inside cells.
Why are minerals vital to our diets?
They are essential to the body’s normal function
Why is it important to be hydrated?
Water is used to transport many substances around the body
60% of the human body is water
Why is fibre and roughage important in our diets?
This is the indigestible part of our food, but it is essential for healthy functioning of the digestive system
How do you calculate BMI?
Mass in kg/ (height in m)2 (squared)
What is the average value of BMI for a healthy person?
18.5-25
Give 6 problems with the body which are caused by obesity
Cancer Cardiovascular disease Type 2 diabetes Gallstones Osteoarthritis High blood pressure (hypertension)
What can excess salt in your diet cause?
It will decrease the water potential of your blood
Bringing more water into the blood
The blood pressure increases
Putting the body into hypertension
What type of fats are beneficial to your diet and where can you find them?
Unsaturated fats are good for you, these are found in plants such as avocados
Olive oil is also a good source of unsaturated fat
What are lipoproteins?
A combination of lipid, cholesterol and protein used to transport fats and cholesterol around the body
Why is cholesterol in the blood?
Cholesterol is essential to the normal functioning of the body. It is found in cell membranes and in the skin
It is used to make steroid sex hormones and bile
Therefore cholesterol must be transported around the body.
Fats are not soluble in water so cholesterol has to find a way to be transported around the body
It is transported in the blood in the form of lipoproteins
These are tiny balls of fat combined with protein
What are the two forms of lipoproteins?
High-density lipoprotein (HDL)
Low-density lipoprotein (LDL)
What is high-density lipoprotein?
They are produced by the combination of unsaturated fats, cholesterol and protein.
They tend to carry cholestrol from the body tissues back to the liver
Liver cells have receptor sites that allow the HDLs to bind to their cell surface membranes
In liver, cholesterol is used in cell metabolism or broken down
Therefore, high levels of HDLs are associated with reducing blood cholesterol levels
What is low-density lipoprotein?
Produced by the combination of saturated fats, cholesterol and protein
These tend to carry cholesterol from the liver to the tissues
If too much saturated fat and cholesterol is consumed in the diet then the concentration of LDLs in the blood will rise
What does a high concentration of LDLs cause in the body?
Deposition in the artery walls
How do different fats affect the LDL receptors on tissue cells?
Saturated fats: Thought to decrease the activity of the LDL receptors. Therefore as blood LDL concentration rises, less is removed from the blood and they are deposited in the artery walls
Polyunsaturated fats: Increase the activity of the LDL receptors and so decrease the concentration of LDL in the blood
Monounsaturated fats: Seem to help remove LDLs from the blood
What increases the concentration of LDLs in the blood?
Eating a lot of saturated animal fats
What concentration of lipoproteins is it important to keep in the body?
Maintain a low proportion of LDLs in the blood
Maintain a high proportion of HDLs in the blood
What is selective breeding?
Humans select the individual organisms that are allowed to breed according to chosen characteristics
What are fertilisers?
Minerals needed for plant growth, which are added to soil to improve its fertility
What is a pesticide?
A chemical that kills pests
What is a fungicide?
A chemical that kills fungi
What is an antibiotic?
A chemical that kills or prevents reproduction in bacteria
How do most plants store energy?
As the carbohydrate starch
Give 5 ways we can make plant food production more efficient
Improve the growth rate of crops
Increase the size of yield from each plant
Reduce losses of crops due to diseases and pests
Make harvesting easier by standardising plant size
Improve plant responses to fertilisers
Give 3 ways animal food production can be more efficient
Improve the rate of growth
Increase productivity
Increase resistance to disease
What are the three stages to selective breeding?
Isolation
Artificial selection
Inbreeding or line breeding
How has cattle been bred to produce the best yield of desired products for human consumption?
They breed cattle for a high milk yield or for meat production. Dairy cows can produce over 40 litres of milk a day
How are salmon bred to produce the best yield of desired products for human consumption?
Farmed salmon have been selected to grow more quickly so that time-to-market has been cut by 30%.
The meat also has less fat content, better colour and texture
How have egg laying chickens been selectively bred for a better yield?
They have been selectively bred to produce over 300 eggs a year, while their unselected relatives will produce 20-30 a year
What four ways can microorganisms spoil our food?
Visible growth of microorganisms on food (mould)
Microorganisms that use external digestion (the food will be reduced to mush)
The bacterium Clostridium botulinum
Microorganisms that can cause infection (salmonella)
10 ways we can prevent food spoilage?
Cooking Pasteurising Drying, salting and coating in sugar Smoking Pickling Irradiation Cooling and freezing Canning Vacuum wrapping Plastic or paper packaging
What four foods are made by using microorganisms?
Yogurt
Cheese
Bread - yeast
Alcohol - yeast
Give 6 advantages of using microorganisms to produce food
Production of protein can be many times faster than that of animal or plant protein
Production can be increased or decreased according to demand
No animal welfare issues
Good source of proteins for vegetarians
Contains no animal fat or cholesterol
Single celled protein (SCP) production could be combined with removal of waste products
Give 5 disadvantages of using microorganisms to produce food
People might not want to eat fungal protein or food that has been grown on waste
Microorganisms are grown in huge fermenters and need to be isolated from the material on which they grow
Has to be purified to ensure it is uncontaminated
Infection - conditions used to produce the microorganism is the idea conditions for pathogenic organisms
does not have the taste or texture of traditional protein sources
What is health?
A state of mental, physical and social well-being, not just the absence of disease
What is disease?
A departure of good health caused by a malfunction of the mind or body
What is a parasite?
An organism that lives in or on another living thing, causing harm to its host
What is a pathogen?
An organism that causes disease
What 6 things to you need in order to be classed as healthy?
Free from disease Able to carry out all the normal physical and mental tasks expected in modern society well fed, with a balanced diet Usually happy, with a positive outlook Suitably housed with proper sanitation Well integrated into society
What is transmission?
The way in which a parasitic microorganism travels from one host to another
How can a pathogen cause disease?
Travel from one host to another
Get into the host’s tissues
Reproduce
Cause damage to the host’s tissues