B3

Question 1

Levels of organisation

Answer 1

Cells, tissue, organ, organ system, organism

Question 2

Tissue

Answer 2

A group of similarly structured cells working together.

Question 3

Organ

Answer 3

Several tissues which together, perform a function

Question 4

Oesophagus

Answer 4

Has muscles init’s walls which contract to push food down in a process called ‘peristalsis’

Question 5

Liver

Answer 5

Produces ‘bile’, which travels to the small intestine to digest fat in food.

Question 6

Stomach

Answer 6

Food is broken into ‘chyme’ and is mixed with stomach acids, so protien enzymes can digest at the best PH

Question 7

Pancreas

Answer 7

Creates hormones which control glucose levels in blood

Question 8

Gall bladder

Answer 8

Stores bile, travels from here to small intestine

Question 9

Large intestines

Answer 9

Made up of colon, appendix and rectum. The colon absorbs water into the blood and any undigested material builds up in the rectum to leave via the anus.

Question 10

Small intestine

Answer 10

Food is kept moving through here and is digested by enzymes and bile.

Question 11

Carbohydrates

Answer 11

Contain simple sugars like glucose and sucrose and provide us with energy as glucose is used for resparation.

Question 12

Lipids

Answer 12

Fats (solids) and oils(liquids). Most important energy store, important for diet, cell membranes, hormones and nervous system. Made up of three fatty acids and glycerol.

Question 13

Proteins

Answer 13

Build cells and tissues and are the basis for enzymes, made up of chains of amino acids.

Question 14

Testing for starch

Answer 14

Place food on spotting tile, Use iodine on the food, solution turns blue-black if starch is present.

Question 15

Testing for sugar

Answer 15

Place food in test tube, add benedict’s solution to the food, place in warm water for 10 mins, benedict’s solution turns brick red if sugar is present.

Question 16

Test for lipids

Answer 16

Place food in test tube, add ethanol, shake test tube and leave for 1 min, pour solution in water and solution turns cloudy white if lipid is present.

Question 17

Test for protein

Answer 17

Place food in test tube, add biuret reagent. If protien is present, solution turns purple.

Question 18

Enzymes

Answer 18

Enzymes are biological catalysts (speeding up the reaction). They are specially shaped to break down food macromolecules.

Question 19

Active site

Answer 19

The part of an enzyme which is the correct shape to split substrates into products.

Question 20

Amylase

Answer 20

Breaks down carbohydrates into simple sugars in the mouth and the small intestine. Produced in the pancreas and the small intestine

Question 21

Pepsin

Answer 21

Breaks up protein molecules into it’s amino acids in the stomach. Is produced in the stomach, small intestine and the pancreas.

Question 22

Bile

Answer 22

Breaks down fat globules in the small intestine. Is produced in the liver and stored in the bile duct

Question 23

Lipase

Answer 23

Breaks down triglyceride molecules (fat) in the small intestine. Produced by the pancreas.

Question 24

How does temperature affect enzyme action?

Answer 24

Increases in temperature gives the enzymes more kinetic energy and thus digest faster however temperatures above 40 degrees will denature enzymes in most organisms.

Question 25

How does PH affect enzyme action?

Answer 25

A PH too high or too low can cause enzymes to denature. Best PH for amylase is about PH 4.0.

Question 26

Role of acid in digestion

Answer 26

In the stomach, PH 2.0 is the best for protease digestion

Question 27

Role of Bile

Answer 27

When food enters the small intestine it is covered in stomach acid but bile neutralises the acid. Fat gloubules before bile is added are too large to be digested by lipase but the bile emulsifies it, breaking it up to have a larger surface area