B3 - Organisation and the Digestive System

Question 1

What do cells do to become specialised cells?

Answer 1

Differentiate

Question 2

What are the levels of organisation?

Answer 2

Cells->Tissue->Organ->Organ System-> Organism

Question 3

What is tissue?

Answer 3

Tissue is a group of cells with similar structure. They function and work together. For example, muscular tissue contracts to bring movement.

Question 4

What is an organ?

Answer 4

an aggregation (collection ) of different tissues working together to carry out specific functions

Question 5

What is an organ system?

Answer 5

a group of organs that work together to carry out specific functions

Question 6

Give an example of a specialised cell

Answer 6

Sperm Cell

Question 7

give an example of a type of tissue

Answer 7

Muscular Tissue

Question 8

give an example of an organ

Answer 8

Stomach

Question 9

give an example of an organ system

Answer 9

Digestive System

Question 10

What is emulsification?

Answer 10

Emulsification is the process of bile breaking large fatty globules into smaller fatty globules to increase the surface area the lipids to make it easier for for lipase to break down the lipids.

Question 11

What is neutralisation?

Answer 11

In your stomach there is a protease enzyme called pepsin. Pepsin works best in an acidic PH, so your stomach produces hydrochloric acid to provide this environment. Your Stomach has a layer of mucus to protect its self against this acid. In your small intestine the enzymes work best in an alkaline PH rather than acidic. When the acidic mixture moves into your small intestines an alkaline fluid called bile neutralises the acid, this lets the enzyme work more efficiently

Question 12

What is carbohydrase?

Answer 12

enzymes that speed up the breakdown of carbohydrates into simple sugars

Question 13

What are carbohydrates?

Answer 13

molecules that contain only carbon, hydrogen, and oxygen. They provide the energy for the metabolism and are found in foods such as rice, potatoes, and bread

Question 14

What is a catalyst?

Answer 14

a substance that speeds up the rate of another reaction but is not used up or changed itself

Question 15

What is a denatured Enzyme?

Answer 15

When an an enzyme’s molecular structure is broken down so it no longer functions

Question 16

What is the digestive system?

Answer 16

organ system where food is digested and absorbed

Question 17

What are enzymes?

Answer 17

biological catalysts, usually proteins

Question 18

What are fatty acids?

Answer 18

part of the structure of a lipid molecule (Triglyceride)

Question 19

What is glycerol?

Answer 19

part of the structure of a lipid molecule (Triglyceride)

Question 20

What is lipase?

Answer 20

enzymes that speed up the breakdown of lipids into fatty acids and glycerol

Question 21

What are lipids?

Answer 21

Molecules made of carbon, hydrogen and oxygen. They are found in fats and oils.

Question 22

What is the metabolism?

Answer 22

the sum of all the reactions taking place in a cell or the body of an organism

Question 23

What is protease?

Answer 23

enzymes that speed up the breakdown of proteins into amino acids

Question 24

What are proteins?

Answer 24

molecules that contain carbon, hydrogen, oxygen, and nitrogen and are made of long chains of amino acids. They are used for building the cells and tissues of the body and to form enzymes

Question 25

What are simple sugars?

Answer 25

small carbohydrate units, for example glucose

Question 26

What are simple sugars?

Answer 26

small carbohydrate units, for example glucose

Question 27

Where is bile stored and produced?

Answer 27

Bile is stored in the gallbladder and produced in the liver

Question 28

How is the small intestine adapted to absorb food efficiently?

Answer 28

They have villi which increase the surface area to make it easier to absorb soluble food molecules by diffusion.

Question 29

How does an enzyme work?

Answer 29

Enzymes contain a very specifically shaped active site, this shape is complementary to the shape of 1 specific substrate. The enzyme and substrate bind together (like a lock and key) to form an enzyme substrate complex. The enzyme then catalysers the breakdown of the substrate into the products. It would not catalyse the breakdown of another substrate as the enzymes active site is only a specific shape to 1 substrate. The enzyme is not used up or changed in any way during this process

Question 30

Describe the process of food moving through the digestive system

Answer 30

Food starts in the mouth, it is ground up into small pieces by your teeth. A carbohydrase enzyme called amylase is produced by the salivary glands and breaks down starch into simple sugars. The oesophagus then pushed the food down into the stomach. Food enters the stomach through a ring called the sphincter. Food is mixed with hydrochloric acid so that pepsin has the correct PH conditions to work in. The stomach strong muscular walls to churn the food. Food then moves through to your small intestine. As food enters your small intestine bile is squirted onto the mixture to perform neutralisation and emulsification. In the small intestine many enzymes help digest food. The food is then squeezed into the large intestine where water is absorbed. The faeces then moves into your rectum and eventually out your anus.

Question 31

Where is carbohydrase found?

Answer 31

In the mouth, In the small intestines

Question 32

Where is protease found?

Answer 32

In the stomach, In the small intestine

Question 33

Where is lipase found?

Answer 33

In the small intestine

Question 34

How is the small intestine adapted to absorb food efficiently?

Answer 34

They have villi which increase the surface area to make it easier to absorb soluble food molecules by diffusion.

Question 35

How is the small intestine adapted to absorb food efficiently?

Answer 35

They have villi which increase the surface area but also have thin walls, this makes it easier to absorb soluble food molecules by diffusion.

Question 36

Where is carbohydrase produced?

Answer 36

in the pancreas and the salivary glands

Question 37

Where is carbohydrase produced?

Answer 37

in the pancreas and the salivary glands

Question 38

What enzyme breaks Hydrogen Peroxide into Water+Oxygen and where is it found?

Answer 38

Catalase found in the liver

Question 39

What are carbohydrates made of?

Answer 39

Simple sugars such as Glucose

Question 40

What do carbohydrates do?

Answer 40

Carbohydrates are our main source of energy

Question 41

What are proteins made of?

Answer 41

amino acids

Question 42

What do lipids do?

Answer 42

Lipids are the most efficient energy store in your body

Question 43

What colour Iodine Solution turn when there is a positive result for starch?

Answer 43

From yellow-red to blue-black

Question 44

What do proteins do?

Answer 44

Proteins are used for the building up of cells and tissue in your body. They are also used to make Enzymes, Hormones and Antibodies

Question 45

What effect does temperature have on the rate of an enzyme controlled reaction?

Answer 45

As temperature increases enzyme activity increases until peaking at around 37~C. After 40~C the enzyme activity starts to decrease rapidly before completely stopping at around 55~C. This is because as temperature increases the enzymes and substrate gain more kinetic energy and have more collisions with each other. At around 40~C is the optimum temperature for Enzyme-substrate collisions. After 40~C the active site of the enzyme begins to change shape and therefore none of the collisions will be successful. After around 40~C the enzyme has become denatured and stops working.

Question 46

What is the effect of PH on an amylase reaction?

Answer 46

The rate of an amylase reaction increases with increasing PH until peaking at around a PH of 7 with a rate of 14.3. After a PH of 7 the rate of an amylase reaction starts to decrease towards a rate of 3.3 at a PH of 8 . This is because the shape of an enzymes active site comes from the forces between different parts of the protein molecule. When the PH is changed this can affect the forces between the molecule. This can change the shape of the molecule and therefore the active site. This causes the specific shape of the enzyme to be lost and for the enzyme to become denatured.

Question 47

Describe the practical experiment of PH on an amylase reaction

Answer 47

1) Use the syringe to place 2cm^3 of amylase solution into a test tube
2) Use another syringe to add 1cm^3 of PH Buffer solution to the test tube
3) Place the test tube into a water bath set at 30~C and leave for 5 minutes
4) Whilst waiting add a drop of iodine solution into each dimple of a spotting tile
5) After 5 minutes, use another syringe to add 2cm^3 of starch to the solution, start the stop clock. Mix using a plastic pipette
6) Remove 1 drop of the mixture after 10 seconds and add to the first drop of iodine on your spotting tile
7) Wait another 10 seconds, the remove a second drop of the mixture to add to the next drop of the iodine
8) Repeat step 7 until the iodine solution and the mixture remains orange
9) Record the time taken for the amylase to fully digest the starch
10) Repeat the whole procedure with a different PH buffer

Question 48

Describe how to test for starch

Answer 48

1) Place a small amount of food on the spotting tile
2) Add a few drops of iodine solution onto the food
3) Iodine solution will turn black-blue if starch is present
4) Repeat steps 1-3 for other types of food
5) Record all of your results in a results table

Question 49

Describe how to test for sugar

Answer 49

1) Place a small amount of food in a test tube
2) Add enough Benedicts solution to cover food
3) Place the test tube in a warm water bath for 10 minutes
4) Benedicts solution will turn brick red on heating if a sugar is present
5) Repeat steps 1-4 for for other types of food
6) Record all of your results in a results table

Question 50

Describe how to test for lipids

Answer 50

1) Place a small amount of food in a test tube
2) Add a few drops of ethanol
3) Shake the test tube and leave for 1 minute
4) Pour the solution into a test tube of water
5) Ethanol added to the solution should create a cloudy white layer if a lipid is present
6) repeat steps 1-5 for other food
7) Record all of your results in a results table

Question 51

Describe how to test for proteins

Answer 51

1) Place a small amount of food in a test tube
2) Add 1cm^3 of Biuret Solution
3) Biuret Solution will turn purple if a protein is present
4) Repeat steps 1-3 for other foods
5) Record all of your results in a results table

Question 52

What are the 2 formulas for the rate of reaction?

Answer 52

rate of reaction = amount of product formed/time

rate of reaction = amount of reactant used/time