B2 - Organisation

Question 1

what are cells?

Answer 1

the basic building blocks of all organisms

Question 2

what are tissues?

Answer 2

group of cells with a similar structure and function

Question 3

what are organs?

Answer 3

several tissues working together for a specific function

Question 4

what are organisms?

Answer 4

living things

Question 5

food contains 3 main nutrients, what are they?

Answer 5

carbohydrates (eg starch), protein, lipids

Question 6

what is the purpose of digestion?

Answer 6

to break down large food molecules so they can be absorbed in the bloodstream

Question 7

what happens in the mouth, in terms of the digestive system?

Answer 7

food is chewed by the teeth.
enzymes in the saliva begin to digest starch

Question 8

what happens in the oesophagus, in terms of the digestive system?

Answer 8

allows the food to be transported from the mouth to the stomach

Question 9

what happens in the stomach, in terms of the digestive system?

Answer 9

enzymes begin the digestion of protein.
contains hydrochloric acid which helps enzymes to digest proteins.
food spends several hours here.
the churning action of the stomach muscles turns the food into a fluid, which increases SA for enzymes to digest

Question 10

what is the purpose of the hydrochloric acid in the stomach?

Answer 10

to help enzymes to digest proteins

Question 11

what is the purpose of the churning action in the stomach?

Answer 11

to turn the food into a fluid, to increase SA so it can be digested easily

Question 12

what happens in the small intestine, in terms of the digestive system?

Answer 12

the walls of the SI release enzymes to continue digestion of protein and lipids.
the small food molecules are absorbed into the bloodstream

Question 13

what happens in the liver, in terms of the digestive system?

Answer 13

while the food is in the SI, the liver releases bile which speeds up the digestion of lipids and neutralises the stomach acid

Question 14

what happens in the pancreas, in terms of the digestive system?

Answer 14

while the food is in the SI, the pancreas releases enzymes which continue the digestion of starch and protein and starts the digestion of lipids

Question 15

what happens in the large intestine, in terms of the digestive system?

Answer 15

water is absorbed into the bloodstream

Question 16

what are the new products of digestion used for?

Answer 16

they are used to build new carbohydrates, lipids and proteins
the glucose may used in respiration

Question 17

what are the 2 adaptations of the small intestine that allow it to absorb food molecules?

Answer 17

1. very large SA - 5m long
2. the interior contains millions of villi, this increases SA

Question 18

what are the 3 adaptations of villi to allow it rapidly diffuse products into the bloodstream (absorption)?

Answer 18

1. contains microvilli, which increases SA, more space for absorption
2. has a very good blood supply so the bloodstream rapidly removes the product of digestion. this increases the concentration gradient
3. thin membrane -> short diffusion path