Unit 7 Flashcards
Why is food required for organisms to live?
- For growth - food provides substances needed for making new cells and tissues.
- As a source of energy - energy is required for the chemical reactions which keep organisms alive.
- For repair - food provides the substances needed to replace worn or damaged tissues.
What is a balanced diet?
A diet which contains the appropriate amounts of various food substances needed in order to maintain a healthy standard of living.
What sort of substances does a balanced diet contain?
Substances like:
- Carbohydrates
- Lipids
- Protein
- Vitamins
- Mineral salts
- Plant fibre
- Water
What is energy used for in organisms?
- To keep internal body processes working (ex. Heart beating and breathing).
- To maintain a steady body temperature.
- To meet the energy requirements of any work and activities.
How much energy is in 1gram of carbohydrates or protein?
About 16-17kJ
How much energy is in about 1gram of fat?
About 37kJ
How many kJ of energy does the average person need to obtain each day?
About 12000kJ
What factors does the amount of energy required by a person vary?
- Occupation
- Level of activity
- Age
- Gender (females tend to require less energy as on average they have a smaller body mass than males).
What is basal metabolism?
Where essential body functions such as: circulation, breathing, body temperature, brain function and other essential chemical processes are maintained during sleep.
What are proteins used for in the body?
To build up the amino acids needed to build up body structures and proteins.
What do vegans need to do?
They needed to make sure they eat variety of foods which contain the essential substances needed to maintain a healthy life.
What are three factors which may alter a persons food requirements?
- Pregnancy
- Lactation
- Growing children
What substances does a pregnant woman need to ensure they obtain in adequate quantities?
- Protein (for making the baby’s tissues).
- Calcium and vitamin D (required for bone development in the baby).
- Iron (required to make haemoglobin in the baby’s blood).
What is lactation?
The production of breast milk.
What substances does a lactating woman require?
Proteins, vitamins and calcium to produce milk of adequate quality and quantity.
What is ingestion?
The taking in of substances such as food and drink into the body through the mouth.
What is mechanical digestion?
The breakdown of food into smaller pieces without chemical change to the food molecules.
What is chemical digestion?
The breakdown of large insoluble food molecules into small soluble molecules.
What is absorption?
The movement of small food molecules and ions through the wall of the intestine into the blood.
What is assimilation?
The movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.
What is egestion?
The passing out of food that has not been digested or absorbed, as faeces, through the anus.
What is angina?
Chest pains due to a reduced blood supply to the heart.
How does a heart attack occur?
When the diet contains too much fat, fatty substances can build up in the blood vessels and reduce the diameter of these blood vessels. Blot clots can then form leading to a heart attack.
What is mastication?
The
What is kwashiorkor?
A type of protein-energy malnutrition that happens typically in a developing country where a mother has a baby, if they have a second baby soon after the first baby may be weaned on a diet with inadequate amounts of protein.
What are the symptoms of kwashiorkor?
- Dry skin
- Pot belly
- Weakness
- Irratibility
What is marasmus?
A form of malnutrition due to inadequate amounts of carbohydrates and protein.
What are the symptoms of marasmus?
- Extremely thin and weak
- Reduced fat and muscle tissue
- Skin is thin and hangs in folds
How is marasmus different from kwashiorkor?
Kwashiorkor is where there is a lack of protein but enough energy, with marasmus there is a lack of both of these.
What foods is iron typically present in?
- Red meat
- Nuts
- Shellfish
- Dark green and leafy vegetables usually
What disease can a lack of iron cause?
A lack of iron in the diet can cause anaemia.
What is iron needed for?
Iron is needed to produce haemoglobin.
What is haemoglobin?
The protein in red blood cells responsible for transporting oxygen to respiring tissues.
What are the symptoms of anaemia?
- Feeling weak
- Tired
- Irritable
What is significant about vitamin D compared to other vitamins?
It is the only vitamin that the body can manufacture (when the skin is exposed to sunlight).
What foods can provide vitamin D?
- Oily fish
- Butter
- Milk
- Egg yolk
What is vitamin D responsible for?
Vitamin D helps in the absorption of calcium and phosphorus through the gut wall.
What happens when a person has a lack of vitamin D?
Bone is made of a mineral called calcium phosphate. A lack of vitamin D therefore results in poor calcium and phosphate deposition in bones. This leads to softening of the bones.
What can a lack of vitamin D in children cause?
Rickets, the weight of the body can deform the bones in the legs.
What is a lack of vitamin D in adults cause?
Osteo-malacia, adults with osteo-malacia can be very susceptible to fracturing bones if they fall.
What is the alimentary canal?
A tube running through the body through which food passes through.
What is the inside of the alimentary canal lined with?
The epithelium which is formed by a layer of cells.
What does the epithelium produce?
Mucus
What is the purpose of mucus?
To lubricate the lining of the alimentary canal and protect it from wear and tear. It also can protect the lining of the canal from attack by digestive enzymes.
Where can digestive enzymes be produced?
- In cells in the alimentary canal
2. In glands which are outside the alimentary canal
How do enzymes produced in glands enter the alimentary canal?
Through tubes called ducts.
What are examples of digestive glands?
- Salivary glands
2. Pancreas
What is peristalsis?
Where areas of circular muscles contract one after another to create a wave of contraction which pushes food through alimentary canal.