Year 8 Science | Digestion Flashcards
Name the 7 food groups
Carbohydrates, proteins, fats/lipids, fibre, vitamins, minerals, water
State 2 examples of food rich in carbohydrates
Rice and pasta
What are the two types of carbohydrate?
Simple (sugars), complex (starch e.g. in pasta and bread)
State 3 examples of food rich in protein
Fish, meat and eggs
What do proteins do in the body?
repair tissues and make new cells for growth
State 3 examples of food rich in fat
Butter, cheese and chocolate
What 3 jobs do lipids (fats and oils) do in the body?
energy store, insulation to keep you warm, protect organs
State 3 examples of food rich in minerals and vitamins
Fruit and vegetables
Why do we need vitamins and minerals?
Tiny amounts are essential for keeping us healthy
State 2 examples of food rich in fibre
Brown bread and cereal
Why do we need fibre?
It keeps food moving through the gut, prevents constipation
Why do we need to drink water?
Our cells are 70% water and we need to replace water we lose (e.g. sweating etc)
Where can you find out how much energy is in a food?
on the label, given in kJ (kilojoules)
What affects how much energy we need
age, body size, activity levels
What 3 risk increase from being underweight?
poor immunity, lack of energy, lack of vitamins and minerals
What 3 risks increase from being overweight?
heart disease, stroke, diabetes
What word is used when you don’t have enough of something?
deficiency
What problem is linked to vitamin A deficiency
night blindness - unable to see in dim light
What problem is linked to vitamin D deficiency?
rickets, immune system problems
What problem is linked to vitamin C deficiency
scurvy
Define “balanced diet”
Eating a variety of foods in the correct proportions
What is digestion?
Large nutrient molecules from food are broken down into small molecules the body can use
What order does food pass through the digestive system?
Mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus
How does food pass through the gut?
Muscles push the food along
How do the small molecules get into the blood?
They pass through the wall of the small intestine (diffusion)
How is the small intestine adapted?
covered in villi (big surface area), good blood supply (to carry away the food)
What is the oesophagus/gullet?
Tube that links mouth to stomach
What happens in the stomach?
Food is mixed with digestive juices and acids
What happens in the small intestine?
Digestion is completed, small molecules pass into blood stream
What happens in the large intestine?
Water is absorbed out of the undigested food, forming faeces
What happens in the rectum?
Faeces are stored
What is the anus?
Ring of muscle though which faeces passes
What do bacteria do in digestion?
They make vitamins and help break food down
What do bacteria in the gut live on?
Fibre
What is the role of the teeth in digestion?
Break down food into smaller pieces
How do large molecules get broken into smaller ones?
Digestive juices contain enzymes
Which enzyme breaks down carbohydrates?
carbohydrase (e.g. amylase), found in saliva
Which enzymes break down proteins
proteases (stomach and small intestine)
Which enzymes break down lipids?
lipases (small intestine)
