Nutrition Flashcards
What are nutrients used for?
Energy (e.g for movement for keeping warm)
Growth
Repair of damaged tissues
Replacing old or worn out cells
What are the food groups?
Proteins Carbohydrates Lipids (fats + oils) Vitamins Minerals Fibre Water
What happens when you don’t have a balanced diet?
Malnutrition
Definition of malnutrition:
The condition that develops when the body does not get the right amount of vitamins, minerals and other nutrients it needs to maintain healthy tissues and organs
What two things can malnutrition refer to?
Undernutrition and overnutrition
What is undernutrition?
When you don’t get enough nutrients. This can include starvation or deficiency diseases
What is overnutrition?
When you get more nutrients than you need e.g obesity
What types of foods are carbohydrates?
Bread, potatoes, chickpeas, pasta
What are the functions of carbohydrates in the body?
For energy (they are high in energy)
What happens if there is a lack of carbohydrates in the diet?
Tiredness
What types of food are sources of protein?
Fish, nuts, cheese, eggs, beans, lentils, chicken
What are the functions of protein in the body?
To build and repair tissues
To make enzymes for digestion
To make antibodies to fight infections
What happens if there is a lack of protein in the diet?
Kwashiorkor (distended stomach, stunted growth)
What foods are lipids?
Vegetable oil, butter, whole milk, cheese
What are the functions of lipids in the body?
For an energy store
For insulation
To make cell membranes
What happens if there is a lack of lipids in the diet?
Not enough energy-tiredness
Coldness- not enough fat
What are the three types of vitamins?
A,C and D
What foods are high in vitamin A?
Carrots, Liver, Sweet potatoes, Squash, Fish, Cheese
What are the functions of vitamins A in the body?
Helps cells to grow and keeps skin healthy
Helps eyes to see in poor light
What happens if there is a lack of vitamin A in the diet?
Frequent and persistent skin infections, acne, dry and scaly skin
Night blindness
What foods contain vitamin C?
Oranges and lemons (CITRUS FRUITS), peppers, strawberries
What are the functions of vitamin C in the body?
Healthy skin, teeth and gums
Keeps the lining of the blood vessels healthy
What happens if there is not enough vitamin C in the diet?
Scurvy- bleeding gums, wounds do not heal
What are foods with vitamin D?
Exposure of sun makes skin produce vitamin D
Fish, cheese, eggs, liver, milk
What are the functions of vitamin D in the body?
Strong bones
To prevent soft bones and bowing of the legs
What happens if there is a lack of vitamin D in the body?
Rickets
What are the two mineral ions?
Calcium and Iron
What foods contain Calcium?
Milk, eggs, cheese
What are the functions of Calcium in the body?
To prevent rickets, for strong bones, for normal blood clotting.
What happens if there is not enough calcium in the diet?
Rickets
What foods contain iron?
Red meats, liver, kidneys, leafy green vegetable such as spinach, peas and beans
What are the functions of iron in the body?
To make haemoglobin in red blood cells
What happens if there is not enough iron in the body?
Anemia - tired often - out of breath easily
What functions does water have in the body?
For digestion
Regulating the body temperature
To protect joints, tissues and the spinal cord
What happens if there is not enough water in the diet?
Dehydration and, eventually, death
What foods contain dietary fibre?
Nuts and seeds, potatoes with skin, whole grain bread, barley, fruit and vegetables
What functions does dietary fibre have in the body?
To help the digestive system push waste material out of the body
What happens when there is not enough dietary fibre in the diet?
Constipation
Diarrhoea if too much is eaten
What is equation to find the energy content in a food sample?
Energy in food (J) = mass of water (g) ✖️temperature change of water(degrees C)✖️4.2
Energy per gram of food (J/g) = energy in food (J) / mass of food (g)
At the start, the shredded wheat contains chemical energy, what energy changes must take place as the shredded wheat burns?
Chemical ➡️ thermal, light and sound energy
Why do we calculate the energy produced by 1g of (shredded wheat) rather than calculating every (shredded wheat).
Because every shredded wheat is a different mass and you cannot compare it to other substances unless it is per gram for every substance
Why is it important to relight the (shredded wheat) if it stopped burning under the test tube?
So that all of the energy in the (shredded wheat) is burned and calculated so that the calculation is accurate
What is the calorimeter?
The calorimeter is a devise which is an accurate way of calculating the energy value in foods
How is the calorimeter more accurate than doing it by ourselves?
- It captures more of the thermal energy released by burning
- It measures the temperature change more accurately
What does the calorimeter provide to ensure it is accurate?
- oxygen to encourage complete combustion
- a jacket of water to provide insulation and absorb most of the heat released
- a heat transfer coil to capture the heat in the gases released by burning
- a stirrer to mix the warm and cool water before measuring the temperature
What factors effect the amount of energy we need?
Age, Activity levels, Pregnancy, Climate
How does age affect the amount of energy we need?
Children need more energy when they are growing, but still tend to need less than adults because adults are bigger
How does activity levels affect the amount of energy we need?
People who are more active use up more energy as they are moving more and therefore need more energy
How does pregnancy affect the amount of energy we need?
Pregnant women need more energy as they need to supply their baby with all of its’ needs as well as their’ own
How does climate affect how much energy we need?
People living in cold conditions need more nervy from food as they need to work harder to keep their body temperature at 37 degrees that someone in a warmer climate
What is digestion?
The process by which large molecules are broken down (hydrolysed) into smaller molecules that can be absorbed into the blood. Digestion is necessary to ensure that nutrients from food can travel into every cell in our body via our blood
What does the mouth do in digestion?
Mechanical digestion by teeth and tongue.
Saliva from the salivary glands lubricate food to make it easier to swallow and contains the salivary amylase which begins to break down starch.
What does the oesophagus do in digestion?
Waves of muscle contractions move the swallowed food, now called a bolus, to the stomach by a process called peristalsis. This occurs throughout the alimentary canal and is made easier by fibre which keeps the bolus bulky and soft.
What does the stomach do in digestion?
A ring of muscle called a sphincter allows the food to enter the stomach.
enzymes to digests proteins are released along with hydrochloric acid which helps the enzymes to work at their best and kills bacteria.
the muscular wall churns food (more physical digestion) to produce a liquid called chime
What does the liver do in digestion?
Makes a bile which emulsifies fats to make them smaller and easier for enzymes to digest
What does the gall bladder do in digestion?
Stores bile from the liver
from here it passes along the bile duct into the small intestine where it neutralises the stomach acid in the chime
What does the pancreas do in digestion?
This is a gland that secretes the enzymes carbohydrate, protease and lipase
it also releases sodium hydrogen carbonate which makes the small intestine an alkaline environment which is best for the enzymes working there.
What does the small intestine (duodenum/ileum) do in digestion?
The wall of the small intestine releases carbohydrates, proteases and lipases which work with the secretions from the pancreas and gallbladder to finish digestion.
the digested food is then absorbed into the blood
What are the two parts of the small intestine?
The duodenum and ileum
What does the large intestine (colon) do in digestion?
Water and some vitamins are absorbed here
if not enough water is absorbed e.g. due to infection then diarrhoea will occur resulting in watery faeces
constipation occurs when there is a lack of water and/or fibre in the diet
What does the large intestine (rectum) do in digestion?
The indigestible food,bacteria and dead cells from the lining of the elementary canal are compacted and stored here.
the waste is now called faeces
What does the large intestine (anus) do in digestion?
The faeces are now egested through a sphincter
What is the alimentary canal?
- a continuous tube bennining at the mouth and ending at the anus.
- the salivary glands, liver, pancreas and gall bladder are all parts of the digestive system, but NOT part of the ailmentary canal
- they secrete substances to aid digestion into the alimentary canal via ducts
What is peristalsis and how does it work?
- food moves along the alimentary canal because muscles in the alimentary canal contract
- the food bolus is pushed from behind as the muscles contract until the food bolus has been moved to the anus.
- Fibre in the food keeps the bolus bulky and soft, making peristalsis easier.
- mucus lubricates the bolus so that peristalsis is easier
What are the two types of digestion?
Chemical and physical
What is physical digestion?
- Large pieces of food are physically/mechanically broken down into smaller pieces e.g by teeth and muscles in the stomach wall
- this allows the food to be swallowed and provides a larger surface area for enzymes to act upon
What is chemical digestion?
- this is when food is chemically broken down from large, insoluble molecules into small, soluble molecules by enzymes.
- some molecules e.g glucose, vitamins, minerals and water are already small enough to be absorbed, but most need digesting by enzymes first.
What is an enzyme?
A biological catalyst that speeds up the rate of reactions
What are the four main digestive enzymes?
Amylase, Maltase, protease and lipase
Where is amylase made?
In the mouth and pancreas
Where does amylase work?
In the mouth and small intestine
What is the substrate of amylase?
Starch
What is the product of digestion by amylase
Maltose
Where is maltase made?
Small intestine
Where does maltase work?
Small intestine
What is the substrate of maltase?
Maltose
What is the product of digestion by maltase?
Glucose
Where is protease made?
Stomach, pancreas, small intestine
Where does protease work?
Stomach, small intestine
What is the substrate of protease?
Protein and smaller chains of amino acids
What is the product of digestion by protease?
Smaller chains of Amino acids
Single amino acids
Where is lipase made?
Pancreas, small intestine
Where does lipase work?
Small intestine
What is the substrate of lipase?
Lipids
What is the product of digestion with lipase?
Fatty acids and glycerol
How are the proteases in the stomach different to those in the pancreas?
- Stomach proteases break down large proteins into smaller ones containing only a few amino acids
- pancreas proteases break these smaller chains into single amino acids
What is the digestion of starch?
Starch is digested to maltose by amylase and then the maltose is digested to glucose by maltase.
What are the two other chemicals included in digestion?
Hydrochloric acid and bile
What is hydrochloric acid in digestion?
- is found in the stomach
- helps kill pathogens (bacteria) and provides an acidic environment which allows protease enzymes to work at their best
What is bile in digestion?
- made by liver and stored in gall bladder then flows into the small intestine via the bile duct
- bile salts emulsify fats (breaks large droplets of fat into small droplets so that there is an increased surface area for lipase to work
- lipase digests fat into fatty acids and glycerol
- sodium hydrogen carbonate in the bile neutralises stomach acid and so it provides the right pH for pancreatic enzymes to work.
How do the small soluble parts of digestion get into the blood?
The diffuse into the blood
What are the adaptations of the small intestine for absorption?
It is long and has a huge surface area
How does the length of the small intestine help it with absorption?
- the small intestine is over 6m long
- the food takes time to travel such a distance and so there is time to absorb the products of digestion
- it provides a larger surface area for faster absorption
What provides the small intestine with its huge surface area?
Caused by finger like projections called villi on the small intestine wall
What things make villi in the small intestine adapted?
Each villi is lined with cells that have microvilli
The villus has a very thin lining
Each villus is well supplied with blood capillaries
Each villus contains a lacteal
How do the microvilli on a villi help it with absorption?
Each villus is lined with cells that have microvilli
It further increases surface area
How does the thin lining of a villus help it with absorption?
The lining layer of cells in each villus is extrthin so that digested food products do not have far to diffuse to get into the blood- a short diffusion distance
How is the fact that villi are well supplied with blood capillaries help them with absorption?
The blood capillaries take away the digested food and supply fresh blood. This maintains a steep concentration gradient between the small instestine and the blood capillaries so that diffusion happens faster
How does the lacteal in each villus help it with absorption?
These lacteals are part of the lymphatic system that carries lipids separately to other food molecules because fat does not dissolve well in the blood
