B3 Nutrition, Digestion and Respiration Flashcards
Name the 7 components of a healthy diet:
Carbohydrate
Protein
Fat (lipids)
Fibre
Vitamins
Minerals
Water
State the difference between simple and complex carbohydrates.
Simple carbohydrates are individual glucose (sugar) molecules.
Complex carbohydrates (starch) are made of a long chain of glucose molecules bonded together.
Why do we need carbohydrates in our diet?
Carbohydrates provide a source of energy.
Why do we need protein in our diet?
Protein is needed for growth and repair of body tissue.
Why do we need fat (lipids) in our diet?
Fats (lipids) are used for insulation and as a store of energy.
Why do we need fibre in our diet?
Fibre (roughage) is needed for good gut health as it keeps food moving through our digestive system.
Why do we need vitamins and minerals in our diet?
Vitamins and minerals are needed in small amounts to keep us healthy.
Why do we need water in our diet?
Water is the main component of blood and cytoplasm in our cells.
Why does our body need iron?
Iron is a mineral that is important for red blood cells.
Why does our body need calcium?
Calcium is a mineral that is needed for strong bones and teeth.
What are ‘calories’ a measure of?
Energy in food.
What do the units kJ and kcal mean?
kJ means kilo Joules, or thousand Joules
kcal means kilo calories, or thousand calories
What is the recommended daily ‘calorie’ (kcal) intake for an average adult male and female.
2500 kcal for a male
2000 kcal for a female
State any factors that affect daily calorie need.
Age
Weight (build)
Biological sex
Activity levels (occupation)
Health
Other - Metabolism, outside temperature, weight loss regime etc.
What is a nutritional deficiency?
When there is not enough of a particular nutrient in the diet to maintain good health.
What deficiency is caused by a lack of vitamin C, what are the symptoms, and how can it be avoided?
Scurvy
Red lips, gums and tongue.
Eat more fresh fruit (and veg).
What deficiency is caused by a lack of vitamin D (and calcium) and what are the symptoms, and how can it be avoided?
Rickets
Soft or deformed bones
Eat more oily fish and dairy products (More sunlight - not diet)
What deficiency is caused by a lack of iron and what are the symptoms, and how can it be avoided?
Anaemia
Tiredness, pale/yellow skin and nails
Eat more red meat, pulses and leafy greens
State 4 health conditions that obese people are at an increased risk of developing.
(Type 2) Diabetes
Heart disease
Some types of cancer
Stroke
What factors can lead to increased risk of heart disease?
Too much fat in diet
Too much sugar in diet
Other lifestyle factors e.g. drugs
What must be done to a food sample prior to testing it for nutrients and why?
It should be crushed up with water and strained to remove solids.
State the test for starch and what you would expect from a positive result.
Test sample with drops of iodine.
Orange/brown iodine should turn blue/black if starch present.
State the test for lipids (fats) and what you would expect from a positive result.
Add sample to ethanol (and water), then shake well.
Clear ethanol should turn cloudy if fats present.
State the test for glucose (sugar) and what you would expect from a positive result.
Add blue benedicts solution to sample and place in hot water bath (approx 85°C) for 3-5 minutes.
Colour change to green/yellow shows small quantity of glucose.
Colour change to orange/brick red shows large quantity of glucose.
State the test for protein and what you would expect from a positive result.
Add blue biuret solution to sample and shake.
Colour change to purple/pink if protein present.
What is the function of digestion?
To break down food so that nutrients can be absorbed.
State the difference between mechanical and chemical digestion and give an example of each.
Mechanical - through forces e.g. Chewing, stomach contractions
Chemical - through chemical reactions e.g. Acid in stomach, enzymes
What factors affect rate of diffusion?
Temperature
Concentration gradient
Length of diffusion pathway
State the adaptations of the small intestine and how they aide nutrient absorption.
Long - higher surface area and more time for absorption
Villi (and microvilli) - higher surface area
Rich blood supply - maintains a high concentration gradient
Thin walls (one cell thick) - short diffusion pathway
What is the functions of enzymes in digestion.
To break down large food molecules into smaller molecules so that they can be absorbed into the blood.
Name the enzyme used to break down starch (carbohydrates) and the small molecules it is broken down into.
Carbohydrase (Amylase)
Starch is broken down into glucose.
Name the enzyme used to break down protein and the small molecules it is broken down into.
Protease
Protein is broken down into amino acids.
Name the enzyme used to break down fats (lipids) and the small molecules it is broken down into.
Lipase
Fats are broken down into fatty acids and glycerol.
Why is it beneficial to have certain bacteria living within the human digestive system?
Bacteria…
Break down some nutrients that enzymes can’t break down
Produce essential vitamins (B and K)
Reduce chances of harmful bacteria
What is respiration?
A chemical reaction that releases energy from glucose.
Write the word equation for aerobic respiration.
Glucose + Oxygen → Carbon Dioxide + Water
Within which organelle (part of cell) does respiration occur?
Mitochondria
Write the word equation for anaerobic respiration in animals.
Glucose → Lactic acid
Write the word equation for anaerobic respiration in plants and yeast.
Glucose → Carbon dioxide + Ethanol
State the alternative name given to anaerobic respiration in yeast.
Fermentation
Compare aerobic and anaerobic respiration
Aerobic
Reactants are glucose and oxygen
Products are carbon diaxide and water
Occurs slowly
Releases lots of energy
Anaerobic
Reactant is Glucose
Product is lactic acid
Occurs quickly
Releases less energy
