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aqa biology > 3.1 Biological Molecules | COMPLETE > Flashcards

3.1 Biological Molecules | COMPLETE Flashcards

1
Q

3.1.1
what are monomers?

two examples

A

smaller units from which larger molecules are made from

glucose and amino acids

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2
Q

3.1.1
what are polymers?

two examples

A

molecules made from a large number of monomers joined together

polypeptides and cellulose

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3
Q

3.1.1
define monosaccharides

one example

A

single sugars which are monomers

glucose

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4
Q

3.1.1
name three monomers

A

monosaccharides
amino acids
nucleotides

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5
Q

3.1.1
what is a condensation reaction?

A

a reaction which joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water

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6
Q

3.1.1
what is a hydrolysis reaction?

A

a reaction which breaks a chemical bond between two molecules and involves the use of a water molecule

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7
Q

3.1.2
what are monosaccharides?

give three examples

A

the monomers from which larger carbohydrates are made

glucose, galactose and fructose

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8
Q

3.1.2
what bond forms when two monosaccharides undergo a condensation reaction?

A

glycosidic bond

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9
Q

3.1.2
when are disaccharides formed?

A

in a condensation reaction between two monosaccharides

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10
Q

3.1.2
glucose + glucose = …

A

maltose

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11
Q

3.1.2
glucose + fructose = …

A

sucrose

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12
Q

3.1.2
glucose + galactose = …

A

lactose

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13
Q

3.1.2
what are the two isomers of glucose?

A

α-glucose

β-glucose

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14
Q

3.1.2
what is an isomer?

A

each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties

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15
Q

3.1.2
TRUE OR FALSE
α-glucose has the H atoms above the OH atoms

A

true

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16
Q

3.1.2
TRUE OR FALSE
β-glucose has the H atoms above the OH atoms

A

false
left H is above and right H is below

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17
Q

3.1.2
what is a polysaccharide and how are they formed?

two examples

A

a chain of monosaccharides

formed by the condensation reaction of many glucose units

glycogen and cellulose

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18
Q

3.1.2
what is the basic structure of glycogen?

A

bonds between carbons 1-4 and 1-6
branches
α-glucose
glycosidic bonds

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19
Q

3.1.2
what is the structure of cellulose?

A

β-glucose
every other molecule is inverted
glycosidic bond
hydrogen bonds
chains run parallel to each other

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20
Q

3.1.2
what is the biological test for reducing sugars?

A

add benedict’s solution
add to water bath for five minutes
brick red = positive

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21
Q

3.1.2
what is the biological test for non-reducing sugars?

A

failed benedict’s test
add hydrochloric acid and boil for five minutes
add equal parts sodium hydroxide to neutralise the solution
add benedict’s and add to a water bath for five minutes
brick red = positive

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22
Q

3.1.2
what is the biological test for starch?

A

add iodine
black = positive

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23
Q

3.1.2
what is the biological test for lipids?

A

add ethanol to sample
shake
add water to sample
shake
white emulsion = positive

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24
Q

3.1.3
what are the components of triglycerides?

A

one glycerol
three fatty acids

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25
3.1.3 what elements are in triglycerides?
carbon hydrogen oxygen
26
3.1.3 describe a glycerol molecule
glycerol molecule: ''' H H H ' | | | H - C - C - C - H '''' | | | '''' OH OH OH
27
3.1.3 what group do all fatty acids contain?
COOH
28
3.1.3 what type of reaction occurs to form a triglyceride?
condensation
29
3.1.3 what are the bonds in a triglyceride?
three ester bonds
30
3.1.3 TRUE OR FALSE the R-group of a fatty acid is always saturated
FALSE it can be both saturated or unsaturated
31
3.1.3 what does a phospholipid contain?
two fatty acids one glycerol one phosphate group
32
3.1.3 what are four similarities between triglycerides and phospholipids?
contain glycerol both have fatty acids made with carbon, hydrogen and oxygen ester bonds
33
3.1.3 what are three differences between triglycerides and phospholipids?
tri = 3 fatty acids, phos = two fatty acids tri = no phosphate group, phos = one phosphate group tri = three ester bonds, phos = two ester bonds
34
3.1.3 what are the properties of a polar head of a phospholipid?
hydrophilic glycerol and phosphate group
35
3.1.3 what are the properties of the fatty acid tails of a phospholipid?
hydrophobic two fatty acid tails
36
3.1.4 what are amino acids?
monomers which proteins are made from
37
3.1.4 what is the general structure of an amino acid?
general structure : R | H₂N -- C -- COOH | H
38
3.1.4 what is NH₂?
amine group
39
3.1.4 what is COOH?
carboxylic group
40
3.1.4 what is R?
varied part of the amino acid
41
3.1.4 what reaction between amino acids creates a polypeptide?
condensation
42
3.1.4 TRUE OR FALSE a functional protein may only contain one or more polypeptides
TRUE
43
3.1.4 what bonds form between R-groups in amino acids?
disulphide ionic
44
3.1.4 how many different amino acids are there?
20
45
3.1.4 what do the bonds in between the R-groups determine?
how the protein will fold
46
3.1.4 how many stages/structures are there a protein can go through?
4
47
3.1.4 what happens in the primary structure?
the sequence of amino acids in a polypeptide chain is the primary structure peptide bonds between amino acids o-0-o-o-o-0-0-o-0-o-o-0-o-o-0
48
3.1.4 what happens in the secondary structure?
the polypeptide chain coils to produce an alpha helix or fold to produce a beta pleated sheet hydrogen bonds between amine group and carboxylic group of two amino acids
49
3.1.4 what happens in the tertiary structure?
further folding produces a unique 3D shape the shape is held in place by hydrogen, ionic and disulphide bonds between R-groups
50
3.1.4 what happens in the quaternary structure?
NOT ALL PROTEINS HAVE THIS LEVEL made of more than one polypeptide chain it is folded into an unique 3D shape held by hydrogen, ionic and disulphide bonds
51
3.1.4 name two examples of proteins with a quaternary structure?
collagen haemoglobin
52
3.1.4 what are the two types of proteins?
fibrous globular
53
3.1.4 what are the shape, function, solubility of fibrous proteins? give two examples
long and thin structural function insoluble keratin and collagen
54
3.1.4 what are the shape, function, solubility of globular proteins? give two examples
spherical biochemical function soluble haemoglobin and enzymes
55
3.1.5 what does DNA stand for?
deoxyribonucleic acid
56
3.1.5 what does RNA stand for?
ribonucleic acid
57
3.1.5 what is the difference between roles of DNA and RNA?
DNA holds genetic information RNA transfers genetic information from DNA to the ribosomes
58
3.1.5 what are ribosomes formed from?
RNA and proteins
59
3.1.5 what monomer makes up DNA and RNA?
nucleotides
60
3.1.5 what is a nucleotide made up of?
pentose sugar phosphate group nitrogen-containing base
61
3.1.5 what are the bases for DNA?
adenine cytosine guanine thymine
62
3.1.5 what are the bases for RNA?
adenine cytosine guanine uracil
63
3.1.5 what reaction produces DNA?
condensation reaction
64
3.1.5 what bond is between two nucleotides?
phosphodiester bond
65
3.1.5 what part does phosphodiester bonds form between?
phosphate group base
66
3.1.5 what are the differences between DNA and RNA?
DNA > double helix/strands > complimentary base pairs > A,T,C,G > longer > stores genetic information RNA > single helix/strand > nucleobases > A,U,C,G > shorter > carries small parts of genetic info to ribosomes
67
3.1.5.2 describe the process of semi-conservative replication?
> DNA helicase hydrolyses the hydrogen bonds between the base pairs in the two strands within a double helix > the double helix unwinds and separates > each of the separated parental DNA strands acts as a template > free floating nucleotides within the nucleus are attracted by the complementary base pairs on the template strands > the adjacent nucleotides are joined together to form a phosphodiester bond by a condensation reaction > DNA polymerase catalyses the joining together of adjacent nucleotides > the two sets of daughter DNA contains one newly synthesised strand and one strand from the parental DNA
68
3.1.5.2 describe the Meselson-Stahl study?
> grew E-coli on a 15N medium > then placed the E-coli on a 14N medium > in each generation they collected a sample and measured the density using a centrifuge > 15N would go to the bottom and 14N would go to the top after centrifugation > after generation one: conservative replication was dismissed because there was NOT two lines after centrifugation > after generation two: dispersive replication was dismissed because there was two lines and not one big chunk
69
3.1.5.2 what were the three theories of how DNA replicates and what they formed?
semi-conservative - half old, half new DNA strand conservative - entirely new DNA helix dispersive - patchworks of old and new DNA
70
3.1.5.2 who theorised how DNA replicates?
Watson and Crick
71
3.1.5.2 what is the name of how DNA replicates?
semi-conservative replication
72
3.1.6 what does ATP stand for?
adenosine triphosphate
73
3.1.6 TRUE OR FALSE ATP is a nucleotide derivative
TRUE
74
3.1.6 what makes up ATP?
ribose sugar three inorganic phosphates adenine
75
3.1.6 what makes a molecule inorganic?
if no carbon is present
76
3.1.6 how is energy stored in ATP?
in the bonds between the second and third phosphate ions
77
3.1.6 what is the ATP cycle?
the last phosphate ion of ATP is hydrolysed by ATP-Hydrolase energy is released this produces ADP+Pi ATP-Synthase then joins them back together
78
3.1.7 list the five properties of water and why they are important
metabolite -> used in chemical reactions high specific heat capacity -> buffers temperature changes to keep temperature stable solvent -> reactions can occur and substances can dissolve to be transported large latent heat of vaporisation -> provides a cooling effect (sweating) cohesion -> transport water in a continuous column (in xylem)
79
3.1.7 TRUE OR FALSE water is a metabolite in many metabolic reactions, including condensation and hydrolysis reactions
TRUE
80
3.1.7 FILL IN THE GAPS water has a relatively ____ heat capacity, buffering changes in ___________
high temperature
81
3.1.7 where do the hydrogen bonds form between water molecules?
O--H
82
3.1.7 name the charges of a water molecule
O = delta minus H2 = delta positive
83
3.1.7 why is it a good thing water has strong cohesion between water molecules?
supports columns of water in the tube-like transport cells of plants produces surface tension where water meets air
84
3.1.7 water makes up around ___% of a cell’s contents
80%
85
3.1.7 does water have strong or weak cohesion between water molecules?
strong
86
3.1.8 where do inorganic ions occur?
in solutions (in the cytoplasm and body fluids)
87
3.1.8 name four inorganic ions
Iron ions Fe2+​ Sodium ions Na+​ Phosphate ions PO4 3-​ Hydrogen ions H+
88
3.1.8 what are phosphate ions used in? (four)
DNA and RNA ATP Phosphorylates other molecules making them more reactive​ Hydrophilic part of phospholipid bilayer
89
3.1.8 what are iron ions used in? (one)
haemoglobin
90
3.1.8 what are hydrogen ions used in? (two)
affect on pH and enzymes​ chemiosmosis in respiration and photosynthesis​
91
3.1.8 what are sodium ions used in? (three)
Co-transport​ Affect osmosis​ Role in action potentials in neurones.​

aqa biology (9 decks)

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