M21. Nutrition Flashcards
What does good nutrition provide?
- better health
- stronger immune system
- ill less often
- learn more effectively
- stronger
- more productive
What are the 7 components necessary for a healthy diet?
- carbohydrates
-protein - fat
-vitamins
-minerals
-water
fibre
Why do we need carbohydrates
they are our main source of energy
Why do we need protein?
essential for growth and repair, structure etc
Why do we need fats?
essential source of energy, important in a cell membrane production, waterproofing, absorption of fat-soluble vitamins, thermal insulation, electrical insulation and padding.
Why do we need vitamins?
they play important rules in the chemical processes taking place inside cells. Some are water soluble and some are fat soluble.
Why do we need minerals?
inorganic elements occuring in the body that are essential to its normal functions
Why do we need water?
its essential to body function, as it is used for transporting substances and is a main component of the body.
Why do we need fibre?
although it provides no energy or nutrition, it is essential for healthy functioning of the digestive system.
What proportion of our foods should be carbs, fats and protein?
carbs; 57%
protein 13%
fats 30%
What is malnutrition caused by? is it just too little?
caused by an unbalanced diet
no, the worlds biggest form of malnutrition is obesity
What is obesity caused by?
consuming too much energy, the excess energy is deposited as fat in the adipose tissues.
What is obesity?
a condition in which excess fat deposition impairs health, and is usually defined as when a persons body mass index (BMI) is at 30 or above. (20% over recommended for height)
What is the measurement for BMI?
mass in kg / height in metres squared
Who have a higher risk of health problems due to obesity, apples or pears?
apples
Has obesity levels risen or fallen in the last 30 years?
risen, for everyone, including children
How many deaths a year are thought to be obesity related?
300,000
Which 3 problems are obesity thought to be the most important dietary factor for? what else has obesity been linked to?
cancer
cardiovascular disease
type 2 diabetes
linked to; gall stones, osteoarthritis, high blood pressure (hypertension)
What is coronary heart disease a result of?
CHD is a result of deposition of fatty substances in the walls of the coronary arteries, known as atherosclerosis
This narrows the size of the lumen, restricting blood flow to the heart muscle, which may cause oxygen starvation.
What can be eaten to reduce the risk of coronary heart disease?
fibre, oily fish and alcohol in moderate consumption
What happens if you eat excess salt?
- decrease water potential of blood, so more water is held in the blood, increasing blood pressure.
- which can lead to hypertension (where the diastolic pressure is maintained at a level that is too high, so it damages the inner lining of the arteries
What is the result of hyper tension?
it can damage the inner lining of the arteries, which is one of the early stages of atherosclerosis
Which fats are thought to be best for your health, and which are worst?
best; polyunsaturated/ monounsaturated / unsaturated ie plant oils.
worst; saturated ie animal fats
What does cholesterol have similar properties to?
triglyceride
Where is cholesterol mostly found?
meat, eggs and dairy products
it is also made in the liver from saturated fats
What percentage of deaths due to coronary heart disease have been linked to high cholesterol?
45-47% of deaths
What concentration of cholesterol should be in the blood?
below 5.2 mmol dm3
Why is cholesterol essential?
why is it in the blood?
-it is found in cell membranes and in the skin
- it is used to make steroid sex hormones and bile
its in the blood as it needs to be transported to carry out these functions.
is cholesterol soluble in water?
no, its a fat.
What must cholesterol be transported in the blood as?
lipoproteins (as these are dissolvable)
What are the two types of lipoproteins
HDLs High density lipids
and LDLs Low density lipids
What determines which cells take up HDLs and which take up LDLs?
the cells have receptors that either take up LDLs or HDLs
What are HDLs made up of?
unsaturated fats, cholesterol and protein
What do HDLs do?
tend to carry cholesterol from the body tissues back to the liver, where the cells have receptor sites that allow the HDLs to bind to their surface membranes
they are associated with reducing blood cholesterol levels. As they reduce deposition in the blood artery walls by atherosclerosis and may even help to remove the fatty depositions of atherosclerosis.
What does the liver do with cholesterol?
breaks it down , or used in cell metabolism to make bile.
What are LDLs made up of?
saturated fats, cholesterol and protein
What do LDLs do?
They carry cholesterol from the liver to the tissues
What happens if too much saturated fat and cholesterol is taken in?
LDL levels will rise, and if it gets too high then there is deposition in the artery walls.
How do saturated, polysaturated and monosaturated fats affect LDL receptors?
saturated; decrease the activity of the LDL receptors, so as blood LDL levels rise, less is removed from the blood, so there is more in the blood- so it is deposited in the artery walls.
- Poly and mono unsaturated fats, increase the activity of the LDL receptors, so decreases the concentration of LDL in the blood
Which lipoproteins do we aim to have a high concentration of, and which do we aim to have a low concentration of?
high; HDL
low; LDL
What affect does each of these have on the concentration of LDLs/HDLs:
- alot of saturated fat
- low fat diet
- alot of unsaturated fats
- moderate amount of polyunsaturated fats
- moderate amount of monounsaturated fats
- increase LDLs
- reduce LDLs and HDLs
- increase HDLs
- reduce LDLs
- reduce LDLs
Why are plants a good thing to eat
As they store energy as starch (carbohydrates) , they absorb minerals such as nitrate
What are herbivores?
animals that make use of the makeup of plants when they eat and digest them.
What is an omnivore?
Something that eats both plants and herbivorous animals.
How can you make the production of plants more efficient?
- improve growth rate of crops
- increase the size of yield from each plant
- reduce losses of crops due to disease and pests
- make harvesting easier by standardising plant size
- improving plant response to fertilisers.
How can we make the production of animals more efficient?
improve the rate of growth
increase productivity
increase resistance to disease.
What is selective breeding?
where humans select the individual organisms that are allowed to breed according to chosen characteristics
What are fertillisers ?
minerals needed for plants to grow, which is added to the 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.
What are the 3 stages of selective breeding?
isolation
artificial selection
inbreeding/ line breeding
what is selective pressure?
An external pressure that drives evolution in a particular direction
What is marker-assisted selection
where a section of DNA is used as a marker to recognise to desired characteristic, so once offspring have been produced- they can be checked for the marker- which allows selection at a very early stage.
Give 3 examples of selective breeding
- cattle bred for high milk yield/ meat production
- salmon are farmed 30% quicker,more disease resistant, better colour and texture, and less fat content.
- chickens bred for meat/egg production.
Give 2 examples of marker-assisted selection
- tomatoes have been bred for improved disease resistance. As the allele responsible for the resistance against yellow leaf curl virus was identified and bred into domestic tomatoes.
- Apples have been bred to increase disease resistance.
What are the 3 most common ingredients for fertillisers?
phosphate
nitrate
potassium
