Biology - Humans as Organisms Flashcards
What are carbohydrates important for?
Provide fuel (energy) for the body
What are proteins important for?
Growth and repair
What is fibre important for?
Helps move food through the digestive system
What causes obesity? Use the concept of energy to describe your answer.
When someone takes in more energy from their diet than they use up.
What determines the amount of energy someone needs each day?
Their body mass and level of activity
What are the main two steps to breaking down food (what happens in the mouth and then what happens in the digestive system)?
Breaking down food mechanically by chewing
Breaking down food chemically with enzymes
How does bacteria in the stomach get killed?
There is hydrochloric acid in the stomach which is a low pH
Where in the digestive system is food absorbed?
Small intestines
Where in the digestive system is water absorbed?
Large intestines
What three types of enzymes does the pancreas make?
Protease to digest protein
Carbohydrase to digest carbohydrates
Lipase to digest lipids
What is the role of enzymes in the digestive system and why is it important to help us absorb food?
Break down large molecules into smaller soluble ones so that it can pass through the gut wall and go into the bloodstream
What are the finger-like projections found in the small intestines which help to absorb food? And how are these adapted to do so?
Villi:
Thin outer layer of cells
Good blood supply
Large surface area
What is the role of good bacteria in the gut?
They produce enzymes that help digest food.
They produce useful hormones and vitamins
They reduce the possibility of harmful bacteria growing in the intestines
Which two nutrients does the body get the most energy from?
Fats and carbohydrates
Where in the body are blood cells produced?
In the bone marrow
