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BIOLOGY IGCSE > Unit 2 Biology > Flashcards

Unit 2 Biology Flashcards

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1
Q

What is diffusion?

A

Diffusion is when particles move from an area of high concentration to an area of low concentration as a result of their random movement

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2
Q

Where does the energy of diffusion come from?

A

Kinetic energy

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3
Q

What is the concentration gradient?

A

Area of high concentration to an area of low concentration

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4
Q

What does passive process mean?

A

It does not require energy

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5
Q

What are three factors that affect diffusion?

A

Temperature
Surface area to volume ratio
Concentration gradient

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6
Q

List 4 ways to get a faster rate of diffusion:

A

Higher temperature
Larger surface area
Smaller size of particles
Higher gradient

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7
Q

In which medium does diffusion occur the fastest?

A

Gas

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8
Q

What is osmosis?

A

Osmosis is the diffusion of water molecules from a region of high concentration to a region of low concentration through a partially permeable membrane

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9
Q

What is a partially permeable membrane?

A

A partially permeable membrane has holes to allow water molecules to pass through but are too small to let larger molecules pass through

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10
Q

How do water particles in osmosis diffuse?

A

From high concentration to low concentration

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11
Q

What does a dilute solution mean?

A

Has a high concentration of molecules

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12
Q

What does concentrated solution mean?

A

Has a low concentration of molecules

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13
Q

What are plant and animal cells surrounded by?

A

Partially permeable plasma

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14
Q

What does a cell wall provide for a plant cell

A

Support

Protection

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15
Q

Why is water important for cells?

A

For chemical reactions

Support

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16
Q

What is active transport?

A

Active transport is the movement of particles from an area of low concentration to an area of high concentration using energy in the form of ATP

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17
Q

What happens during active transport?

A

Protein carriers in the cell membrane pick up particles and move them against the concentration gradient

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18
Q

What minerals do plants need to absorb?

A

Phosphorus
Nitrogen
Potassium

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19
Q

How is active transport used in plants

A

Is the soil as a low concentration of minerals then the roots can absorb it against the concentration gradient

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20
Q

What are organic molecules

A

Organic molecules are biological molecules

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21
Q

Which elements does carbohydrates have

A

C
H
O

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22
Q

What elements do lipids have?

A

C
H
O

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23
Q

What elements do proteins have?

A 
C
H
O
N
S
P
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24
Q

What elements do nucleus acid have?

A 
C
H
O
N
P
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25
Q

What are monomers?

A

Monomers are subunits that make up a large organic molecule

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26
Q

What is a polymer?

A

Polymers is a large molecule made up of a long chain of repeating monomers

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27
Q

What is condensation

A

Condensation is the process of turning monomers into polymers by removing water

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28
Q

What is hydrolysis?

A

Hydrolysis is the use of water to break down polymers into monomer

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29
Q

What percentage of our body is water?

A

70%

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30
Q

Why is water important to living organisms?

A

Chemical reactions
Transport glucose around the body
Dissolves enzymes
Kidneys will remove waste products

31
Q

carbohydrates

Monomers?

A

Glucose

32
Q

Carbohydrates

Polymers

A

Disaccharide-sucrose

Polysaccharide - starch

33
Q

Carbohydrates

Function

A

Primary fuel
Form cell walls
Storage of available energy

34
Q

Proteins

Monomers

A

Amino acid

35
Q

Proteins

Polymer

A

Polypeptide

36
Q

Proteins

Functions

A 
Digest food 
Transport oxygen 
Provides immunity 
Form structures
Energy stored for developing embryo
37
Q

Lipids

Monomers

A

Glycérol and fatty acids

38
Q

Lipids

Polymer

A

Triglyceride

39
Q

Lipids

Function

A

Fat stores long term energy

Cushion vital organs from damage

40
Q

Nucleic acid

Monomers

A

Nucleotide

41
Q

Nucleic acid

Polymer

A

Double stranded helix

42
Q

Nucleic acid

Functions

A

Carries genetic info

Determines proteins made in cells and what they develop into

43
Q

Why can’t lipids be polymers

A

They do not form large molecules bc they are not made of monomers

44
Q

What is the food test for starch?

A

Add 1ml of iodine solution
Mix well

Colour change
Brown to blue black

45
Q

What is the food test for Protein?

A

Add 1ml of biuret solution into an Aqueous solution of the food
Mix well

Colour change
Pale blue to purple

46
Q

What is the food test for reducing sugar?

A

Add 1ml of Bénédicte solution
Place in water bath for 2min

Colour change
Blue to brick red

47
Q

What is the test for lipids?

A

Add 1ml of ethanol
Mix well

Colour change
It turns milky white

48
Q

What is flaccid

A

Floppy

49
Q

What is turgid?

A

Firm

50
Q

What is phagocytosis?

A

Phagocytosis is when particles are engulfed by the cel surface membrane flowing around them

51
Q

What is plasmolysed?

A

Plasmolysed is when the cell membrane peels away from the cell wall.

52
Q

What is cellular metabolism?

A

The total number of chemical reactions that occur constantly in each living cell

53
Q

What are biochemical pathways?

A

Chemical reactions in cells occur in a series of controlled steps and each step in the pathway is controlled by an enzyme

54
Q

What is an enzyme?

A

A protein catalyst which speeds up the rate of the reaction without undergoing any change itself

55
Q

What do enzymes bind with?

A

They bond specifically to a substrate molecule and convert it to a product molecule. They are not used up in a reaction and so can be recycled.

56
Q

What do enzymes do?

A

Enzymes reduce the amount of energy required to begin the reactions

57
Q

What is the structure of an enzyme?

A

Enzymes are made of proteins that have been folded so that they have a specific active site which binds to its substrate.

58
Q

How does enzyme action happen?

A
  1. Enzyme and substrate are available
  2. Substrate binds with enzyme
  3. Substrate is converted to product
  4. Products are released
59
Q

How is the enzyme affected by temperature?

A

Enzymes work best at 37 degrees

However at high temperatures the enzymes protein structure is permanently changed so that the substrate can no longer bind to the active site.It becomes denatured

60
Q

What is the optimal temperature?

A

The temperature at which the enzyme works best at

61
Q

How is the enzyme affected by the pH?

A

Each enzyme works best at a particular pH

Enzymes can dénature by extreme pH changes.

62
Q

What pH does trypsin work in?

A

8

63
Q

What pH does pepsine work in?

A

2

64
Q

What pH does catalase work in?

A

7

65
Q

What does heat do to enzymes?

A

More collisions between enzymes and substrate

66
Q

What is turgor pressure?

A

Turgor pressure is water pressure acting against an inelastic cell wall

67
Q

What is the test for Vitamin C?

A

Add DCPIP until the colour changes permanently

from Blue to colourless

68
Q

What happens to a plant cell when placed in a solution of lower water potential?

A

It will become flaccid

69
Q

What happens when a RBC is added to a solution of lower water potential?

A

It will become crenated

70
Q

What will happen when RBC is added to a solution of high water potential?

A

It will swell up and burst

71
Q

Define Tissue

A

Group of cells with similar structure to carry out a specific function

72
Q

Define Organ

A

Group of tissues working together to carry out a specific function

73
Q

Define Organ System

A

Group of organs with related function to carry out a specific function

BIOLOGY IGCSE (16 decks)

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