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Biology Paper 1 > Biological Molecules > Flashcards

Biological Molecules Flashcards

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
What is the function of glycogen?
Acts as an energy store
26
Give three reasons why Starch is a good storage molecule?
> Can't leave the cell as it is large > Insoluble in water so does not affect water potential > Compact
27
How can you test for the presence of starch?
Iodine test / blue-black = positive result
28
What do the hydrogen bonds between alpha-glucose do in amylose?
Help to hold amylose in its helical structure
29
What do all lipids contain?
Hydrocarbons
30
What do Triglycerides contain?
1 glycerol with 3 fatty acids
31
The tails of the fatty acids are....
hydrophobic - repel water
32
The heads of fatty acids are...
hydrophilic - attract water
33
What are the two types of fatty acids?
> Saturated = don't have any double bonds between carbon atoms > Unsaturated = do have double bonds between carbon atoms
34
What bond is formed between a triglyceride molecule and what reaction is it?
Ester Bond and Condensation reaction
35
What do Phospholipids contain?
1 glycerol, 2 fatty acids and 1 phosphate group
36
What are the properties/functions of triglycerides?
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
What are the properties/functions of Phospholipids?
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
What test can be used to find the presence of lipids in a solution?
Emulsion test = shake, add water, shake, milky white
39
What are the monomers of proteins?
Amino acids
40
When is a dipeptide formed?
When two amino acids join together
41
What is a polypeptide?
When two or more amino acids join together
42
Proteins are made up of one or more..........
polypeptide
43
What general structure do amino acids have?
1. A carboxyl group (-COOH) 2. An amino acid group (-NH2) 3. An R group (variable group)
44
How many amino acids do all living organism have?
20 amino acids
45
How are amino acids linked together?
By bonds called peptide bonds via a condensation reaction
46
What is the Primary structure of a protein?
Sequence of amino acids in the polypeptide chain
47
What is the Secondary structure of a protein?
Folding of the amino acid sequence - Formation of: > alpha helix or beta-pleated sheets
48
What is the Tertiary structure of a protein?
Further folding of the secondary structure where ionic, disulphide ()covalent) and hydrogen bonds form - 3D structure
49
What is the Quaternary structure of a protein?
Several polypeptide chains held together by bonds - 3D structure
50
Give some examples of proteins?
Enzymes - roles in metabolism Antibodies - immune response Transport proteins - cell membrane Structural proteins - support
51
What is used to test for proteins?
Biuret test - Lilac = positive result
52
What are enzymes?
Biological catalysts that speed up reactions by reaching the activation energy
53
When a substrate first into an enzymes active site, what does it form?
An ES-complex - this lowers the activation energy
54
What does the 'lock and key' model suggest?
Active site is already complementary to the substrate
55
What does the 'induced fit' model suggest?
The active site changes shape slightly to become complementary to the substrate
56
Give some key enzyme properties?
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
What is the Primary structure of a protein determined by?
A gene so if a mutation occurs in that gene, it could change the tertiary structure of the enzyme produced
58
Give four factors affecting enzyme activity?
> temperature > pH > substrate concentration > enzyme concentration
59
What do competitive inhibitors do?
Compete with the substrate to bind to the active site, as it has a similar shape, to reduce the arte of reaction
60
What do non-competitive inhibitors do?
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
What is the function of DNA?
To store your genetic information (it is found in the nucleus of a cell in eukaryotic animals)
62
What is the function of RNA?
To transfer genetic information from the DNBA to the ribosomes to make proteins
63
What is a nucleotide?
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
What do many nucleotides joined together form?
Polynucleotide strands/chains via a condensation reaction between the phosphate group of one and the sugar of another
65
What bond is formed between the phosphate group and sugar of two nucleotides to forma polynucleotide?
Phosphodiester bond
66
What is the chain of phosphates and sugars known as?
A sugar-phosphate backbone
67
What is the structure of DNA?
Double helix structure, two strands, long, coiled up very tightly, compact
68
What is the specific sugar for a DNA nucleotide?
Deoxyribose sugar
69
What are the four possible bases in DNA?
``` Adenine Thymine Guanine Cytosine (ATGC) ```
70
The two polynucleotide strands are said to be...............
antiparallel - run in opposite directions
71
What is the specific sugar for a RNA nucleotide?
Ribose sugar
72
What are the four possible bases in RNA?
Adenine Uracil Guanine Cytosine
73
What are the differences between DNA and RNA?
DNA = Thymine, RNA = Uracil RNA strands are much SHORTER than DNA RNA = ribose, DNA = deoxyribose sugars RNA = single nucleotides, DNA = double nucleotides
74
Describe the stages of DNA replication:
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
What is the full name for ATP?
Adenosine Triphosphate
76
ATP is a ........ of energy
store
77
Give some main functions of water:
1, Important in metabolic reactions 2. Solvent so substances need to dissolve in it 3. Aids temperature control because it has a high latent heat of vaporisation 4. Cohesive molecules which helps transportation in plants - xylem
78
What charge does water have?
Polar molecules - it has a partial negative charge on one side and a slight positive charge on the other
79
What is latent heat?
The heat energy needed to change a substance from one state to another (e.g. from a liquid to a gas/evaporation)
80
Name four important inorganic ions
Hydrogen ions = water, enzymes Phosphate ions = DNA, RNA and ATP Sodium ions = synapses/co-transport Iron ions = in haemoglobin

Biology Paper 1 (4 decks)

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