Biological Molecules Flashcards

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1
Q

What are polymers?

A

Large, complex molecules composed of long chains of monomers joined together

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2
Q

What reaction is necessary for a polymer to form?

A

Condensation reaction

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3
Q

What molecule does a condensation reaction release?

A

Water

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4
Q

How are polymers broken down?

A

Hydrolysis reaction

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5
Q

What molecule is added in a hydrolysis reaction?

A

Water

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6
Q

What are the monomers in carbohydrates?

A

Monosaccharides

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7
Q

Name three monosaccharides

A

Glucose, Fructose, Galactose

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8
Q

What type of sugar is glucose?

A

A hexose sugar

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9
Q

Name the two types of glucose and the differences structurally?

A

Alpha - H on top of first carbon molecule

Beta - H on the bottom of first carbon molecule

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10
Q

What is a disaccharide?

A

Two monosaccharides joined together via a condensation reaction

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11
Q

What bond forms between tow monosaccharides?

A

Glycosidic bond

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12
Q

Sucrose =

A

glucose + fructose

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13
Q

Maltose =

A

glucose + glucose

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14
Q

Lactose =

A

glucose + galactose

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15
Q

What can be used to test for the presence of reducing sugars?

A

Benedicts test

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16
Q

What is a polysaccharide?

A

When two or more monosaccharides are joined together by condensation reactions

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17
Q

Name three polysaccharides

A

Starch
Glycogen
]Cellulose

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18
Q

How do plants store excess glucose?

A

As starch

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19
Q

What is starch?

A

A mixture of two polysaccharides of alpha-glucose called amylose and amylopectin. It is insoluble in water so makes it a good storage molecule as it does not affect water potential

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20
Q

Give details about amylose

A

Long, unbranched chain of a-glucose which is compact so good storage molecule

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21
Q

Give details about amylopectin

A

Long, branched chain of a-glucose which has side branches to allow enzymes that break down glucose to easily attach

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22
Q

How is excess glucose stored in animals?

A

As glycogen

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23
Q

Why does glycogen having loads of branches made it a good storage molecule?

A

Loads of branches means that stored glucose can be released quickly and it is also very compact

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24
Q

What is Cellulose?

A

Long, unbranched chains of beta-glucose. The cellulose chains are linked together by Hydrogen bonds to form strong fibrils called microfibrils. This provides structural support for cells (e.g. plant cell walls)

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25
Q

What is the function of glycogen?

A

Acts as an energy store

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26
Q

Give three reasons why Starch is a good storage molecule?

A

> Can’t leave the cell as it is large
Insoluble in water so does not affect water potential
Compact

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27
Q

How can you test for the presence of starch?

A

Iodine test / blue-black = positive result

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28
Q

What do the hydrogen bonds between alpha-glucose do in amylose?

A

Help to hold amylose in its helical structure

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29
Q

What do all lipids contain?

A

Hydrocarbons

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30
Q

What do Triglycerides contain?

A

1 glycerol with 3 fatty acids

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31
Q

The tails of the fatty acids are….

A

hydrophobic - repel water

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32
Q

The heads of fatty acids are…

A

hydrophilic - attract water

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33
Q

What are the two types of fatty acids?

A

> Saturated = don’t have any double bonds between carbon atoms
Unsaturated = do have double bonds between carbon atoms

34
Q

What bond is formed between a triglyceride molecule and what reaction is it?

A

Ester Bond and Condensation reaction

35
Q

What do Phospholipids contain?

A

1 glycerol, 2 fatty acids and 1 phosphate group

36
Q

What are the properties/functions of triglycerides?

A

Used as energy storage molecules as they have long hydrocarbon tails which contain lots of chemical energy which is released. They are also insoluble in water so do not affect water potential of the cell

37
Q

What are the properties/functions of Phospholipids?

A

Make up the bilayer of cell membranes (which control what enters and leaves the cell). Hydrophilic heads and hydrophobic tails so face outwards - tails are touching

38
Q

What test can be used to find the presence of lipids in a solution?

A

Emulsion test = shake, add water, shake, milky white

39
Q

What are the monomers of proteins?

A

Amino acids

40
Q

When is a dipeptide formed?

A

When two amino acids join together

41
Q

What is a polypeptide?

A

When two or more amino acids join together

42
Q

Proteins are made up of one or more……….

A

polypeptide

43
Q

What general structure do amino acids have?

A
  1. A carboxyl group (-COOH)
  2. An amino acid group (-NH2)
  3. An R group (variable group)
44
Q

How many amino acids do all living organism have?

A

20 amino acids

45
Q

How are amino acids linked together?

A

By bonds called peptide bonds via a condensation reaction

46
Q

What is the Primary structure of a protein?

A

Sequence of amino acids in the polypeptide chain

47
Q

What is the Secondary structure of a protein?

A

Folding of the amino acid sequence
- Formation of:
> alpha helix or beta-pleated sheets

48
Q

What is the Tertiary structure of a protein?

A

Further folding of the secondary structure where ionic, disulphide ()covalent) and hydrogen bonds form - 3D structure

49
Q

What is the Quaternary structure of a protein?

A

Several polypeptide chains held together by bonds - 3D structure

50
Q

Give some examples of proteins?

A

Enzymes - roles in metabolism
Antibodies - immune response
Transport proteins - cell membrane
Structural proteins - support

51
Q

What is used to test for proteins?

A

Biuret test - Lilac = positive result

52
Q

What are enzymes?

A

Biological catalysts that speed up reactions by reaching the activation energy

53
Q

When a substrate first into an enzymes active site, what does it form?

A

An ES-complex - this lowers the activation energy

54
Q

What does the ‘lock and key’ model suggest?

A

Active site is already complementary to the substrate

55
Q

What does the ‘induced fit’ model suggest?

A

The active site changes shape slightly to become complementary to the substrate

56
Q

Give some key enzyme properties?

A

Very specific as they usually catalyse one reaction due to complementary substrates that will fit into the active sites. The active sites’ shape is determined by the tertiary structure > if this changes, the enzyme denatured as the substrates can no longer fit

57
Q

What is the Primary structure of a protein determined by?

A

A gene so if a mutation occurs in that gene, it could change the tertiary structure of the enzyme produced

58
Q

Give four factors affecting enzyme activity?

A

> temperature
pH
substrate concentration
enzyme concentration

59
Q

What do competitive inhibitors do?

A

Compete with the substrate to bind to the active site, as it has a similar shape, to reduce the arte of reaction

60
Q

What do non-competitive inhibitors do?

A

Bind to anywhere on the enzyme but the active site and changes its shape so the substrate no longer fits in and so can longer bind

61
Q

What is the function of DNA?

A

To store your genetic information (it is found in the nucleus of a cell in eukaryotic animals)

62
Q

What is the function of RNA?

A

To transfer genetic information from the DNBA to the ribosomes to make proteins

63
Q

What is a nucleotide?

A

A type of biological molecule which is made from:
> a pentose sugar
> a nitrogen-containing organise base
> a phosphate group
- They are the monomers that make up DNA and RNA

64
Q

What do many nucleotides joined together form?

A

Polynucleotide strands/chains via a condensation reaction between the phosphate group of one and the sugar of another

65
Q

What bond is formed between the phosphate group and sugar of two nucleotides to forma polynucleotide?

A

Phosphodiester bond

66
Q

What is the chain of phosphates and sugars known as?

A

A sugar-phosphate backbone

67
Q

What is the structure of DNA?

A

Double helix structure, two strands, long, coiled up very tightly, compact

68
Q

What is the specific sugar for a DNA nucleotide?

A

Deoxyribose sugar

69
Q

What are the four possible bases in DNA?

A
Adenine
Thymine
Guanine
Cytosine
(ATGC)
70
Q

The two polynucleotide strands are said to be……………

A

antiparallel - run in opposite directions

71
Q

What is the specific sugar for a RNA nucleotide?

A

Ribose sugar

72
Q

What are the four possible bases in RNA?

A

Adenine
Uracil
Guanine
Cytosine

73
Q

What are the differences between DNA and RNA?

A

DNA = Thymine, RNA = Uracil
RNA strands are much SHORTER than DNA
RNA = ribose, DNA = deoxyribose sugars
RNA = single nucleotides, DNA = double nucleotides

74
Q

Describe the stages of DNA replication:

A
  1. DNA Helicase breaks the H+ bonds between bases
  2. The original strand acts as a template for a new strand and complementary base pairing occurs between free nucleotides and exposed bases on both strands
  3. Condensation reaction joins the nucleotides together using DNA polymerase > Hydrogen bonds form between bases
  4. This is known as Semi-Conservative replication
75
Q

What is the full name for ATP?

A

Adenosine Triphosphate

76
Q

ATP is a …….. of energy

A

store

77
Q

Give some main functions of water:

A

1, Important in metabolic reactions

  1. Solvent so substances need to dissolve in it
  2. Aids temperature control because it has a high latent heat of vaporisation
  3. Cohesive molecules which helps transportation in plants - xylem
78
Q

What charge does water have?

A

Polar molecules - it has a partial negative charge on one side and a slight positive charge on the other

79
Q

What is latent heat?

A

The heat energy needed to change a substance from one state to another (e.g. from a liquid to a gas/evaporation)

80
Q

Name four important inorganic ions

A

Hydrogen ions = water, enzymes
Phosphate ions = DNA, RNA and ATP
Sodium ions = synapses/co-transport
Iron ions = in haemoglobin