B3 Flashcards

1
Q

What is a tissue?

A

A group of cells with similar structure and function

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2
Q

What are organs?

A

Collections of tissues performing specific functions

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3
Q

How are organs organised?

A

Into organ systems which work together to from organisms

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4
Q

What are organ systems?

A

Groups of organs that perform specific functions in the body

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5
Q

What is the digestive system in a mammal?

A

An organ system where several organs work together to digest and absorb food

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6
Q

What are carbohydrates made up of?

A

Units if sugar

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7
Q

What are simple sugars?

A

Carbohydrates that contain only one or 2 sugar units

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8
Q

What do complex carbohydrates contain?

A

Long chains of simple sugar units bonded together

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9
Q

What do lipids consist of?

A

3 molecules of fatty acids bonded to a molecule of of glycerol

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10
Q

What are protiens made up of?

A

Long chains of amino acids

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11
Q

What is the test for starch?

A

Iodine

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12
Q

What is the test for sugar?

A

Benedict’s

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13
Q

What is the test for protien?

A

Biuret

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14
Q

What must be used during food tests?

A

Safety goggles

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15
Q

What are the steps to prepare for food tests?

A
  1. Take food sample and grind with distilled water using a mortar and pestle to make a paste
  2. Transfer paste to a beaker and add more distilled water, stir so the chemicals in the food dissolve in the water
  3. Filter the solution to remove suspended food particles.
  4. Then test for each food
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16
Q

What are the steps when testing for starch?

A
  1. Place 2mc cubes of food solution into a test tube
  2. Add a few drops of iodine solution that is orange
  3. If starch is present the iodine will turn blue-black, if their is no starch the iodine will stay orange
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17
Q

What are the steps when testing for sugar?

A
  1. Place 2cm cubes of food solution into a test tube
  2. Add 10 drops of denedict’s solution which is blue
  3. Place test tube into a water bath or beaker with boiled water and leave for 5 minuites
  4. If sugars are present the Benedict’s solution will change colour, if green then their is a small amount of sugar, if yellow then their is more sugar present but if brick red then their is a lot of sugar present
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18
Q

What are the steps for testing for protein?

A
  1. Put 2cm cubed of food solution and 2cm cubed of biuret solution which is blue
  2. If protein is present the solution will turn purple
19
Q

What are the steps for testing lipids?

A

1.When preparing the solution, we do not filter the solution
2. Put 2cm cubed of food solution to a test tube
3. Add a few drops of distilled water and a few drops of ethanol
4. Then gently shake the solution
5. If lipids are present then a white cloudy emulsion forms

20
Q

What do catalysts do?

A

Increase the rate of chemical reactions without changing chemically themselves

21
Q

What are enzymes?

A

Biological catalysts

22
Q

What do enzymes do?

A

Catalyse specific reactions in living organisms due to the shape of their active site

23
Q

What are active sites?

A

Long chains of amino acids that are folded to produce a molecule that has a unique shape so it can bind to a specific substrate molecule

24
Q

What happens when the substrate bunds to the active site?

A

The reaction is catalysed by the enzyme

25
Q

What is metabolism?

A

The sum of all the reactions in a cell or the body

26
Q

State 3 ways enzymes catalyse specific types of metabolic reactions

A
  1. Building large molecules from lots of smaller ones
  2. Changing one molecule to another
  3. Breaking down large molecules into smaller ones
27
Q

What are the 2 ways that affect enzyme action?

A

Temperature and pH

28
Q

How do temperatures affect the rate of enzyme action?

A

High temperatures denature the enzyme, changing the shape of the active site

29
Q

How does pH affect the rate of enzyme action?

A

It either makes it work very efficiently or stop it working

30
Q

What is denaturation?

A

When the active sites shape has changed and the substrate can no longer fit

31
Q

What is digestion?

A

The breakdown of large insoluble molecules into soluble substances that can be absorbed into the blood across the wall of the small intestine

32
Q

What are digestive enzymes produced by?

A

Specialised cells in glands and in the lining of the digestive system

33
Q

What do carbohydrates such as amylase do?

A

Catalyse the breakdown of carbohydrates to simple sugars

34
Q

What do proteases do?

A

Catalyse the breakdown of proteins to amino acids

35
Q

What does catalyse mean?

A

Speed up

36
Q

What does lipases do?

A

Catalyse the breakdown of lipids to fatty acids and glycerol

37
Q

What does amylase break down starch into?

A

Simple sugars

38
Q

What is the steps for testing the effect of pH on the rate of reaction of amylase?

A
  1. Place one drop of iodine solution into each well of a spotting tile
  2. Put 2cm cubes of starch solution into a test tube, 2cm cubed of amylase solution into another and 2cm cubed of pH 5 buffer solution into a final test tube
  3. Place all 3 test tubes in a water bath at 30 degrees celcuis for 10 minuites
  4. Combine the 3 solution into 1 test tube and mix with a stirring rod
  5. Put the mixture into the water bath and start a stop watch
  6. After 30 seconds, put 1 drop of solution to a well in the spotting tile, this is should turn blue/black
  7. Repeat this every 30 seconds untill the iodine remains orange
  8. This shows starch is no longer present
  9. Record the time for this in a table
  10. Repeat this several times but using different pH buffers eg pH 7
39
Q

What is wrong with taking a measurement every 30 seconds?

A

It only gives a rough time eg the reaction could be complete after 121 seconds for 149

40
Q

Where do protease enzymes of the stomach work best in?

A

Acidic/ acid conditions

41
Q

How does the stomach help protease enzymes work effectively?

A

By producing hydrochloric acid which maintains a low pH

42
Q

Enzymes of the pancreas and the small intestine work best in what conditions?

A

Alkaline solutions

43
Q

What does bile produced by the liver and released through bile ducts do?

A

Neutralises acid and emulsifies fats