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Biology > Chapter 3 - Chemistry Of Life > Flashcards

Chapter 3 - Chemistry Of Life Flashcards

0
Q

What are several atoms together called?

A

A molecule.

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1
Q

What is an atom?

A

Smallest unit of an element. Cannot be broken down further.

Fundamental structural unit of all matter (liquid, gas & solid)

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2
Q

What is a substance with different types of atoms called?

A

A compound.

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3
Q

What are atoms composed of?

A

Positively charged particles called protons.
The negatively charged particles called electrons.
The neutrally charged particles called neutrons.

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4
Q

How do you calculate the atomic number?

A

The number of protons found in an atom.

It’s different for different elements.

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5
Q

What is the atomic mass?

A

The amount of protons and neutrons present in an atom.

Electrons are insignificant in weight so are not counted.

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6
Q

What is an ion?

A

When an atom loses or gains an electron it becomes an ion.

Addition of an electron will produce a negatively charged ion, while the loss of an electron will produce a positively charged ion.

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7
Q

Why can only electrons be added or lost?

A

This is because an addition or loss of a proton will produce a different element.

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8
Q

Give an example of a common molecule.

A

Water is a stable unit.

It has 1 oxygen atom and 2 hydrogen atoms which are joined together by a chemical bond.

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9
Q

What is an element?

A

Substance consisting of only one kind of atom. Is distinguishable by its atomic number.

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10
Q

Give some examples of major elements and their symbols.

A

Carbon C
Oxygen O
Hydrogen H
Nitrogen N

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11
Q

Give an example of an ultra trace element and where it’s used.

A

Iron Fe; is a component of haemoglobin in red blood cells.

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12
Q

Give an example of trace elements and where it’s used.

A

Sodium Na; helps transmission of nerve impulses.
Magnesium Mg; help in protein synthesis.
Calcium Ca; main component of bones and teeth.

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13
Q

What is the symbol of potassium and an example of where it is used?

A

K

It’s required in muscle contractions and transmissions of nerve impulses.

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14
Q

What is the symbol of phosphorus and an example of it being used in plants.

A

P

It is involved in cell division and the formation of flowers/seeds.

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15
Q

What is the symbol of sulphur and give an example of it being used.

A

S

Component of some proteins and vitamins in the body.

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16
Q

There are 2 types of compounds. What are they?

A

Inorganic compounds are those without carbon.

Organic compounds are those with carbon.

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17
Q

Give a more detailed account of what an organic compound is.

A

It contains carbon and hydrogen. Is usually big and complex, macromolecules.
Associated with living organisms.
(Carbohydrates, lipids, proteins)

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18
Q

Give a more detailed account of what an inorganic compound is.

A

Do not contain carbon and is associated with non-living organisms.

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19
Q

Why is water important?

A

Fundamental solvent for chemical reactions of living beings.

Main means of substance transportation between cells & tissues.

Responsible for maintenance of adequate temperature for functioning of the organism.

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20
Q

Why is water a polar molecule?

A

It is an angular spatial structure. Hydrogen lends electron to oxygen. O becomes more negatively charged whilst H becomes more positive.

The geometry of the molecule makes it polar, with negative and positive poles.

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21
Q

Why is water an excellent solvent?

A

The electrical activity (attraction & repulsion) of its poles, helps separate and mix these substances.

Increasing the number of molecules collisions and speed of reactions.

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22
Q

What are water soluble substances?

A

They are polar molecules (electrically charged areas) which are soluble in water.

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23
Q

What are fat soluble substances?

A

There are non polar (electrically neutral) because they dissolve other non polar substances.

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24
Q

Why is water important for enzyme activity?

A

The biological catalysts depend on water to reach their substrate and bind with them.

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25
Q

What are waters properties?

A

Molecular polarity, thermal stability, liquid in most environments, acid-base neutrality, small molecular size and low chemical reactivity.

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26
Q

What is cohesion?

A

Water is attracted to other water.

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27
Q

What is adhesion?

A

Water is attracted to other materials too.

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28
Q

What allows trees to pull water from their roots?

A

Surface tension. Cohesion of water molecules at the surface of a body if water. The hydrogen binding causes water to stick together.

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29
Q

Give an example in animals and humans, where water is used for lubrication.

A

Mucus is excreted externally in snails to aid movement.

Pleural fluid aids movement in lungs during breathing.

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30
Q

Water also has some supportive functions. Mention a couple.

A

Amniotic fluid found in the womb acts as a shock absorber.

Aids plants turgid pressure.

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31
Q

What is hydrolysis?

A

Breakdown of large molecules by the addition of water.

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32
Q

What are carbohydrates made up of?

A

Carbon, hydrogen and oxygen.

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33
Q

Name all 3 monosaccharides.

A

Glucose, fructose and galactose.

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34
Q

Name all 3 disaccharides.

A

Maltose, sucrose and lactose.

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35
Q

Name all 3 polysaccharides.

A

Starch, glycogen and cellulose.

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36
Q

What are monosaccharides?

A

Basic building blocks of carbohydrates, cannot be broken down further. (Soluble in water)

Also known as simple sugars.

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37
Q

What is glucose used for? And what is its chemical structure?

A

C6 H12 O6

Most common, found in lots of polymers. End product in digestion of starch.

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38
Q

Where is fructose found?

A

Sweet fruits and honey.

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39
Q

Where is galactose found?

A

Milk.

40
Q

What is an isomer?

A

Have the same chemical structure but structurally different (Eg: fructose and galactose)

41
Q

What is the bond found in between carbohydrates.

A

Glycosidic bond.

42
Q

What is a condensation reaction? Give an example.

A

When 2 monosaccharides form a disaccharides, the reaction involves the formation of a water molecule.

43
Q

What is maltose?

A

Glucose & glucose.
Formed in digestion of starch by analyse.
Eg: brewing of beer starts with malt made from germination of barley.

44
Q

What is sucrose?

A

Glucose and fructose.

Common in plants, because it’s less reactive than glucose. It’s the main transport sugar (cane sugar)

45
Q

What is lactose ?

A

Galactose and glucose.

Found in mammalian milk and main source if energy for infants.

46
Q

What are polysaccharides?

A

Long chains of monosaccharides.

47
Q

What is starch?

A

Plant storage.

Insoluble and forms starch granules inside many plant cells.

48
Q

What is glycogen?

A

Made by animals as their storage and found mainly in liver/muscle. Because it’s highly branched, it can be broken down easily.

49
Q

What is cellulose?

A

Only found in plants, main component of cell walls.

Contains b-glucose.

50
Q

What’s the difference between a-glucose and b-glucose?

A

In a-glucose in which the hydroxyl group in C1 sticks down from the ring (starch & glycogen), while cellulose contains b-glucose, has a hydroxyl group which sticks up from the ring.

51
Q

What are proteins?

A

The most complex and most diverse group of compounds.

52
Q

What are in proteins?

A

Carbon, hydrogen, oxygen, nitrogen and sulphur sometimes.

53
Q

Mention some examples of proteins used in structure.

A

Collagen (bone, cartilage, tendon), keratin (hair), actin (muscle)

54
Q

Give 3 examples of enzymes.

A

Amylase, pepsin and catalase.

55
Q

Give 2 examples of hormones.

A

Insulin and glucagon.

56
Q

What is the basic form of protein called?

A

Amino acid.

57
Q

What is the bond found in between proteins called?

A

Peptide bond.

58
Q

What is a dipeptide?

A

It’s when 2 amino acids form together through a condensation reaction.
(3 amino acids together form a tripeptide)

59
Q

How many amino acids are there?

A

20

60
Q

What is a polypeptide?

A

Largest protein molecule.

Amino acids polymerisation to form polypeptides is part of protein synthesis.

61
Q

What are in lipids?

A

Mixed groups of hydrophobic compounds. Carbon, oxygen and hydrogen.

62
Q

What is a triglyceride?

A

1 glycerol and 3 fatty acids.

Called fats/oils.

63
Q

Where does protein synthesis take place?

A

In ribosomes, it requires a RNA template. Sequence of amino acids in a chain is determined by the sequence of genetic code in DNA.

64
Q

What are enzymes?

A

They are proteins and biological catalysts.

65
Q

Why are catalysts needed in the body?

A

They increase the rate of reactions significantly.

66
Q

Mention 3 examples of enzymes which are catalysing metabolic reactions within the cell.

A

Respiration, photosynthesis, and digestion.

67
Q

What is the area of an enzyme, in which all reactions takes place called?

A

Active site.

68
Q

Give an example of an enzyme, and what it reacts with.

A

Amylase which breaks down starch.

69
Q

What’s unique about enzymes?

A

They are highly specific, therefore most molecules won’t fit into their active site.

70
Q

What do enzymes usually need in order for them to work properly?

A

Cofactors / Coenzymes

71
Q

In all chemical reactions what is a substrate converted into?

A

Products.

72
Q

Describe how enzymes are reaction mechanisms.

A

In a enzyme catalysed reaction, the substrate first binds to the active site of the enzyme, forming an enzyme-substrate complex (ES). Then the enzyme is converted into products while attached to the enzyme, finally these products are released.
Then the enzyme is free to start again.

73
Q

Mention 2 qualities enzymes possess.

A

They are reusable and they are very specific.

74
Q

The substrate molecule fits into the active site of the enzyme, what is this mechanism sometimes referred to as?

A

The lock and key mechanism.

75
Q

Once in the active site, how does the enzyme transform the substrate into a product?

A

It usually distorts the shape. For example, a bond within the substrate could be broken, causing it to break into 2 products.

Alternatively, the conditions within the active site can be quite different from outside (such as pH, water concentration, charge) therefore a reaction is more likely to occur.

76
Q

What factors affect the rate of enzyme reactions?

A

Temperature, pH, Substrate concentration, Inhibitors and covalent modification.

77
Q

In the case of temperature, do enzymes have an optimal temperature?

A

Yes, which is around 40 degrees Celsius in humans.

However, different enzymes have different optimal levels due to their environment such as the Arctic Snow Flea works best at -10 degrees Celsius.

78
Q

Why does the temperature, increase productivity in enzymes?

A

Both the enzyme and substrate have more kinetic energy, so they collide more often.
Also, more enzymes overcome the (greatly reduced) activation energy.

79
Q

What happens to enzymes at 0 degrees Celsius?

A

They still work, however they work much slower.

80
Q

What happens to enzymes after they reach their optimum temperature?

A

They become denatured. This causes the enzyme to lose shape, especially it’s active site, therefor the substrate can no longer be catalysed.

At very high temperatures, this is irreversible.

81
Q

What are enzymes optimum pH levels?

A

For most enzymes, it’s about pH 7-8.

82
Q

Give an example of an enzyme which works well under extreme pH levels.

A

Protease, found in stomach, which have an optimum pH of 1.

83
Q

How would enzyme concentration affect the rate of reaction?

A

It would increase the rate of reaction linearly, because there would be more enzyme molecules available to catalyse the reaction.

At very high enzyme concentration, the substrate concentration may become rate-limiting, so the rate would stop increasing.

84
Q

How would the substrate concentration affect the rate of reaction?

A

As the substrate concentration increases, the rate increases because more substrate molecule can collide with enzyme molecules.

At higher concentrations, the enzyme molecules become saturated with substrate, leaving few free enzyme molecules.

85
Q

Why does covalent modification affect the rate of reaction?

A

Some enzymes are controlled by other enzymes, for example by cutting the protein chain or adding a phosphate group.

This modification can’t urn an inactive enzyme into an active one, or vice versa.

86
Q

What is an inhibitor?

A

They inhibit the activity of enzymes, reducing the rate of reactions.

They are found naturally, but are also used artificially in drugs or pesticides.

87
Q

There are 2 kinds of inhibitors, name them.

A

Competitive and non-competitive inhibitors.

88
Q

What are competitive inhibitors?

A

They have a similar structure to the normal substrate molecule, and can fit into the active site of the enzyme.

It therefore, competes with the substrate for the active site, slowing down reaction time.

89
Q

Give an example of a competitive inhibitor.

A

Sulphonamide anti-bacterial drugs.

90
Q

What are non-competitive inhibitors?

A

It is quite different to the structure of the substrate molecule, and does not fit into the active site.

It binds to another part of the enzyme molecule, changing the shape of the whole enzyme, including the active site do that is can no longer catalysed substrate molecules, reducing the amount of active enzymes

91
Q

There are 2 types of inhibitors. Name them below.

A

Reversible inhibitors, which bind fairly weakly and can be washed out,

Irreversible inhibits are those that bind tightly and cannot be washed out. Such as poisons like cyanide.

92
Q

What is DNA?

A

Deoxyribonucleic acid.

It is a polymer made up of subunits called nucleotides.

93
Q

What does each nucleotide compose of?

A

A 5-Carbon sugar called deoxyribose.
A phosphate group.
A nitrogenous base.

94
Q

There are 4 nitrogenous bases. Mention them all.

A

Adenine, thymine, cytosine and guanine.

95
Q

How is DNA structured?

A

Usually in a double helix.

96
Q

What bond is found in between nucleotides?

A

Phosphodiester bonds

97
Q

2 of the nitrogenous bases are always found together, what is this called? And which ones are always found together?

A

Complimentary base pairing.

Adenine and Thymine
Guanine and Cytosine (AT Giovanni Curmi)

98
Q

How are the 2 strands of DNA aligned together?

A

They run antiparallel.

One is oriented 5’ to 3’, the other 3’ to 5’

Biology (10 decks)

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