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*Biology iGCSE course 🧠🥼🥽 > YEAR 9 – Topic 3 – Movement In And Out Of Cells And Biological Molecules > Flashcards

YEAR 9 – Topic 3 – Movement In And Out Of Cells And Biological Molecules Flashcards

1
Q

What is diffusion?

A

Diffusion is the movement of particles from an area of high concentration to low concentration. Particles move down a once traction gradient. It is a passive process (doesn’t require energy).Eg. CO2 moving in and out of a leaf.

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2
Q

In diffusion…

A

Molecules move down a concentration gradient.

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3
Q

Diffusion does NOT need….

A

– Energy

– Membranes

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4
Q

What factors affect the rate of diffusion?

A

– Temperature (temp increase, particles gain more energy, move faster, speed up the rate)
– Concentration gradient(steeper concentration gradient = faster diffusion)
– Surface area of membrane (larger= more particles can go through the membrane)
– Diffusion distance (smaller distance = quicker because less space for particles to move through).
- How much space there is in the container

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5
Q

Give an example of diffusion in living and non-living systems :

A

Living: water/ oxygen moving in and out of a plant cell.

Non-living: perfume being sprayed into a room.

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6
Q

What is osmosis?

A

Osmosis is the movement of water particles from an area of high water concentration to low water concentration through a partially permeable membrane. Eg. Water moving in and out of a cell.

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7
Q

In osmosis…

A

Water moves down a concentration gradient from a high concentration OF WATER to a low concentration OF WATER

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8
Q

What does osmosis require?

A

Water and a partially permeable membrane with a concentration gradient across it

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9
Q

Osmosis does NOT require…

A

Energy

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10
Q

Give an example of osmosis in living and non-living systems :

A

Living: potato cylinders

Non living: visking tube

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11
Q

What factors affect the rate of osmosis?

A

Temperature, concentration gradient, surface area and space that it perform osmosis over.

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12
Q

What is active transport?

A

The movement of particles from an area of low concentration to an area of high concentration, using energy.

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13
Q

Active transport DOES need…

A

Energy

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14
Q

Molecules in active transport…

A

Move AGAINST (up) a concentration gradient.

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15
Q

What factors affect the rate of active transport?

A

Temperature, concentration gradient, surface area and space that it transport over.

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16
Q

Active transport does NOT need…

A

A membrane

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17
Q

What chemical elements are present in carbohydrates?

A

Carbon, Hydrogen and Oxygen.

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18
Q

What is the structure of carbohydrates?

A

Polymers (long chains of amino acid monomers)

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19
Q

Which carbohydrates are Monosaccharides?

A

– Glucose
– Fructose
– Galactose

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20
Q 
What is glucose?
Include...
What type of sugar it is
What its chemical formula is 
And what it looks like!!!
A

Glucose is a monosaccharide.
This means it is the simplest form of sugar.
Chemical formula is C6H12O6
<=> like a squashed hexagon!!!

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21
Q

How do you test for glucose?

What do positive and negative results look like?

A
  1. Put some glucose solution into a test tube.
  2. Add a few drops of Benedict’s Solution.
  3. Put the test tube into a beaker of hot/boiling water.
    Positive = Brick red precipitate
    Negative = Blue solution (no precipitate)
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22
Q

What carbohydrates are disaccharides?

A

– Maltose
– Sucrose
– Lactose

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23
Q

What is a disaccharide?

A

It is two monosaccharides joined together.

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24
Q

Name the two sugars that make up Sucrose…

A

Glucose + Fructose

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25
Q

Name the two sugars that make up Maltose…

A

Glucose + Glucose

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26
Q

Name the two sugars that make up Lactose…

A

Glucose + Galactose

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27
Q

What is starch’s function in nature?

A

– Plants use starch as an energy source.

– Animals break down starch to get energy.

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28
Q

What is the function of starch in our diet?

A

Starch is a source of sugar, and hence energy, in an animal’s diet.

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29
Q

What is the solubility of starch?

A

Starch is insoluble in water unless it has been heated up.

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30
Q

How do you test for starch?

What do positive and negative results look like?

A
  1. Put some starch solution in a test tube
  2. Add a few drops of iodine
    Positive = Blue Black
    Negative = Orange/Brown
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31
Q

What is a polysaccharide?

A

Polysaccharides are carbohydrates that are made up of monosaccharides or disaccharides.

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32
Q

What is glycogen’s function in nature?

A

It is a store of energy in….
– animals
– fungi
– bacteria

33
Q

What is the function of glycogen in our diet?

A

Glycogen is stored in animals’ bodies particularly in the muscles and the liver.

34
Q

What is the solubility of glycogen?

A

Glycogen isn’t very soluble in water unless heated up.

35
Q

What is cellulose’s function in nature?

A

Cellulose is the material that makes up the cell wall in a plant.

36
Q

What is the function of cellulose in our diet?

A

It thickens food and is a source of fibre, but we can’t digest it. It helps food move through the digestive system.

37
Q

What is the solubility of cellulose?

A

Cellulose is insoluble in water.

38
Q

What carbohydrates are Polysaccharides?

A

– Starch
– Glycogen
– Cellulose

39
Q

What are lipids?

A

– Fats

– Oils

40
Q

What chemical elements are present in lipids?

A

Carbon, Hydrogen and Oxygen (but less oxygen that is present in carbohydrates)

41
Q

What is the structure of lipids and what are they made up from?

A

They are structured in an ‘E’ like shape.

They are made up of one glycerol molecule and 3 fatty acids.

42
Q

Are animal fats solid or liquid at room temperature?

A

Solid - but they will melt if warmed up

43
Q

Are plant fats solid or liquid at room temperature?

A

Liquid - this means that they are called oils.

44
Q

Are fat molecules soluble or insoluble in water?

45
Q

Name 4 functions of fats in the human body.

A
  1. Warmth and insulation
  2. Energy store
  3. Protects organs
    (4. Phospholipids are in cell membranes)
46
Q

How do you test for lipids (fats)?

What do positive results look like?

A
  1. Put some oil (fatty substance) into a test tube.
  2. Add 2cm3 of ethanol.
  3. Shake
  4. Add 2cm3 of water.
  5. Shake
    Positive = Cloudy White Emulsion
47
Q

What is the structure of proteins?

A

Proteins are long chained molecule made of different amino acids.

48
Q

What chemical elements are present in proteins?

A

Nitrogen, Carbon, Oxygen and Hydrogen

49
Q

What are 4 of the uses of proteins in the human body?

A
  1. Antibodies - fight disease and infection
  2. Enzymes - speed up reactions
  3. Structure - growth / repair e.g. muscles/scabs
  4. Hormones -
50
Q

What are 3 foods that are high in protein?

A
  1. Red meat
  2. Pulses
  3. Fish
51
Q

How do you test for protein?

What do positive results look like?

A
  1. Put some protein solution into a test tube and add Biuret’s solution (see steps 2 and 3).
  2. Add a few drops of copper sulphate.
  3. Add a few drops of sodium hydroxide.
  4. Shake/stir if results are not immediately clear.
    Positive = Purple/ dark blue
    Negative = stays pale blue
52
Q

What is an amino acid?

A

Amino acids are what makes up proteins.

52
Q

What is the difference between an essential amino acid and a non essential amino acid?

A

We need to eat the essential ones because our body does not naturally produce them.
Our bodies naturally produce the non essential ones so we don’t need to eat them.

54
Q

What does the enzyme break down/put together?

A

The substrate

54
Q

What is an enzyme?

A

It is a biological catalyst which means they speed up a reaction without being used up. (They are NOT alive)

54
Q

What is an active site?

A

This is the surface of the enzyme where the substrate joins on.

55
Q

What do enzymes do to metabolic reactions?

What would happen without them?

A

They speed them up.

Without them we would die! This is because reactions in our body just won’t happen fast enough.

57
Q

What could be an example of a substrate?

A

Protein suspension

58
Q

What does a substrate have which makes it fit an enzyme?

A

A complimentary shape

58
Q

What is an enzyme called when the temperature or pH affects it?

A

A denatured enzyme

60
Q

How can enzymes can be affected by pH?

A

The active site becomes denatured at too high or too low a pH and so won’t function properly. This happens at different levels for different enzymes. But there will be a pH where the enzyme is at its optimum.

61
Q

Name 3 metabolic reactions.

A
  1. Respiration
  2. Photosynthesis
  3. Digestion
62
Q

What 5 things do all enzymes have in common?

A
  1. They are all are proteins – they are made up of long chains of amino acids.
  2. Enzymes control only one specific reaction each.
  3. They all have specially shaped active site that only fits one particular substrate.
  4. They are not used up in the reaction an can therefore be reused many times.
  5. Enzymes are affected by the temperature and pH of their surroundings.
63
Q

How can enzymes can be affected by heat?

A

The active site becomes denatured at too high or too low a temperature and so won’t function properly. This happens at different levels for different enzymes. But there will be a temperature where the enzyme is at its optimum.

64
Q

Fill in the gaps!

Digestion is the breakdown of _______ _______ molecules into _______ _______ molecules.

A
  1. Large
  2. Insoluble
  3. Small
  4. Soluble
66
Q

Describe experiments to investigate how enzyme activity can be affected by changes in pH.

A

Add amylase enzyme to a starch solution and then add some buffer solution to fix the pH. At regular time intervals withdraw a few drops and test for starch with iodine into a spotting tile. When the iodine no longer changes colour, there is no more starch, stop the timer. Use different buffer solutions with different pHs and compare how fast the reaction happens.

67
Q

Describe experiments to investigate how enzyme activity can be affected by changes in temperature.

A

Add amylase enzyme to a starch solution and place in a water bath in a certain temperature. At regular time intervals, withdraw some of the solution and drop it into a spotting tile and add iodine. When the iodine no longer changes colour, stop the timer. Do the same experiment again but at different temperatures, and compare results.

68
Q

What is a hypotonic solution?

A

The concentration of solutes is lower in the solution than in the cell.
This means that there is a higher concentration of water outside the cell. Key
O= water ‘=solutes
. Cell Solution
O’O’O’O’O | OOOOOO
O’O’O’O’O | OOOOOO
O’O’O’O’O | OOOOOO

69
Q

Hypotonic solutions make an animal/plant cell….

A

explOdes/expands

Animal ^ / plant ^

70
Q

What is a hypertonic solution?

A 
The concentration of solutes is higher in the solution. 
This means there is a higher concentration of water inside of the cell.
Key 
O= water ‘=solutes
.      Cell            Solution 
OOOOOO | O’O’O’O’O
OOOOOO | O’O’O’O’O
OOOOOO | O’O’O’O’O
71
Q

Hypertonic solutions make an animal/plant cell….

A

All shRinks/Just inside

Animal ^ / Plant ^

72
Q

What is an isotonic solution?

A 
An isotonic solution is where the concentration of solutes is the same in the solution as in the cell. There is no concentration gradient.
Key 
O= water ‘=solutes
.      Cell            Solution 
O’O’O’O’O | O’O’O’O’O
O’O’O’O’O | O’O’O’O’O
O’O’O’O’O | O’O’O’O’O
73
Q

Isotonic solutions make an animal/plant cell…

A

StayS the Same

74
Q

What is a passive process?

A

A process that doesn’t require energy is described as passive.

75
Q

What happens when you increase the concentration gradient in diffusion?

A

You will in crease the rate of diffusion.

76
Q

What enzyme breaks down carbohydrates?

A

Amylase breaks down carbohydrates. It happens in your mouth, from your saliva.

77
Q

What enzyme breaks down proteins?

A

Protease breaks down proteins. This happens in your stomach.

78
Q

What enzyme breaks down fats?

A

Lipase breaks down fats. This happens in the small intestine and is produced in the pancreas.

*Biology iGCSE course 🧠🥼🥽 (11 decks)

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