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Biological Molecules Flashcards

1
Q

What are monomers?

A

small molecules that form basic units of polymers

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2
Q

What are polymers?

A

molecules made from a large number of monomers joined together.

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3
Q

What is condensation?

A

joins monomers together to create polymers by joining two molecules together with the formation of a chemical bond and involves the elimination of a water molecule.

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4
Q

What is hydrolysis?

A

breaks down polymers into their monomers by breaking down a chemical bond between two molecules and involves the use of a water molecule.

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5
Q

What are examples of monomers?

A

monosaccharides, amino acids, nucleotides

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6
Q

What are examples of polymers?

A

glycogen, DNA, proteins

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7
Q

What is a monosaccharide?

A

a sugar made up of one unit of carbohydrate

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8
Q

What is a disaccharide?

A

a sugar made up of two units of carbohydrate

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9
Q

What is a polysaccharide?

A

a sugar made up of more than two units of carbohydrate.

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10
Q

What is an isomer?

A

a molecule that has the same formula but atoms are arranged differently.

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11
Q

What are glucose’s isomers?

A

alpha glucose and beta glucose

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12
Q

How are disaccharides formed?

A

the condensation of two monosaccharides forming a glycosidic bond.

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13
Q

What is a glycosidic bond?

A

a covalent bond formed when two carbohydrate molecules are joined together by a condensation reaction.

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14
Q

How is maltose formed?

A

the condensation reaction between 2 alpha glucose molecules and joined by alpha 1-4 glycosidic bonds.

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15
Q

How is sucrose(table sugar) formed?

A

condensation reaction between alpha glucose and beta fructose and joined by alpha 1-4 glycosidic bonds.

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16
Q

How is lactose(milk sugar) formed?

A

condensation reaction between alpha glucose and beta galactose and joined by beta 1-4 glycosidic bonds.

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17
Q

What is glycogen?

A

made up of alpha glucose and is used as a storage molecule in animals and bacteria.

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18
Q

What are the adaptations of glycogen?

A

helical shape- lots of storage space and compact
lots of branches- lots of ends for enzymes to make hydrolysis faster.
made up of lots of glucose- glucose molecules obtained through hydrolysis to be used for respiration.
large molecules- insoluble, unable to leave the cell freely, won’t affect water potential
less dense than starch- broken down rapidly

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19
Q

What is starch?

A

made up of alpha glucose and used as a storage molecule in plants.

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20
Q

How is starch adapted?

A

wound into a tight coil- makes it compact

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21
Q

What is cellulose?

A

made up of beta glucose and found in cell walls.

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22
Q

How is cellulose adapted?

A

long straight chains- allows hydrogen bonds to form between -OH groups resulting in collective strength.
microfibrils- chains of cellulose are grouped together into these and fibres resulting in more strength.

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23
Q

What are lipids?

A

molecules that contain carbon, hydrogen and oxygen. Non-polar and insoluble in water. (hydrophobic)

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24
Q

What bond is formed between glycerol and fatty acids?

A

ester bond

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25
What is an unsaturated fatty acid?
contains at least one double bond between C atoms
26
What is a saturated fatty acid?
contains only single bonds between C atoms
27
How would you test for lipids?
1. add a few drops of ethanol to sample and shake 2. add distilled water and shake 3. if lipids are present colour will change to milky white.
28
What are triglycerides?
made up of on glycerol molecule and three fatty acids. a condensation reaction occurs between the carboxyl group and hydroxyl group of the glycerol.
29
What is the role of triglycerides?
energy storage, insulation, buoyancy(ability to float), protection
30
What are phospholipids?
made up of two fatty acids bonded to a glycerol molecule as well as a phosphate ion. phosphate is polar and soluble in water (hydrophillic). fatty acid tails are non-polar and insoluble in water (hydrophobic).
31
What is the role of phospholipids?
main component of cell membranes: stops water-soluble molecules, enables cells to organise specific roles into organelles, control membrane protein orientation.
32
What does amphipathic mean?
both hydrophobic and hydrophillic phospholipids form monolayers or bilayers in water.
33
How do amino acids differ?
they each have a different side group
34
How are peptides formed?
condensation reaction between the carboxyl group of one amino acid and the amine group of another amino acid.
35
What is a dipeptide?
formed by the reaction of two amino acids.
36
What is a polypeptide?
formed by the reaction of multiple amino acids.
37
How do you test for proteins?
sample is treated with sodium hydroxide to make it alkaline, use buiret reagent- if proteins are present colour will change from blue to purple.
38
What are the monomers present in proteins?
amino acids
39
Describe the primary structure of proteins
sequence of amino acids linked together with a peptide bond- it determines the overall structure and shape of the protein.
40
Describe the secondary structure of proteins
alpha helix or beta sheet- hydrogen bonds between the NH group and the C=O group of two different amino acids form.
41
Describe the tertiary structure of proteins
3D arrangement of polypeptide chains formed by the combination of disulfide, ionic and hydrogen bonds. Its shape allows it to be recognised by other molecules and to recognise.
42
Describe the Quaternary structure of proteins
contains more than 1 polypeptide chain and formed by the interaction between the different polypeptides and is held together by disulfide bridges.
43
Describe the test for reducing sugars
add benedicts reagent to a sample in a test tube and heat it in a water bath. If a reducing sugar is present, there will be a colour change.
44
Describe the test for non-reducing sugars
add dilute hydrochloric acid to the sample and heat in a water bath, neutralise the solution with sodium hydrogen-carbonate(use a suitable ph indicator to identify when it has been neutralised), then carry out benedicts test.
45
Describe the test for starch
add a few drops of iodine in potassium iodide solution to the sample, if starch is present, colour will change to blue-black.
46
What are enzymes?
enzymes are biological catalysts made of proteins, they speed up reactions without being used up.
47
What is an enzyme-substrate complex?
when a substrate attaches to the active site of an enzyme it forms an enzyme-substrate complex.
48
What is the activation energy?
a certain amount of energy required for reactions to occur.
49
Describe the lock and key model
the enzyme active site is a fixed shape and during a collision, the substrate can collide and attach to the enzyme forming an enzyme-substrate complex.
50
Describe the induced fit model
the enzyme active site is induced or slightly changes shape to mold around the substrate. when the enzyme-substrate complex occurs, the change of the shape puts a strain on the bonds and lowers the activation energy.
51
What is the effect of temperature on enzymes?
if the temperature is too low, there won't be enough kinetic energy for successful collisions. if the temperature is too high, the enzyme will denature meaning the active site will change shape and enzyme-substrate complexes cannot form.
52
What is the effect of pH on enzymes?
if the pH is too high or too low, the enzyme will denature.
53
What is the effect of enzyme-substrate concentration on enzymes?
if there is not enough substrate added, the reaction will be slower. if there are not enough enzymes, the active sites will become saturated with substrate and unable to work quicker.
54
What are competitive inhibitors?
they are the same shape as the substrate and can bind to the active site.
55
What are non-competitive inhibitors?
they bind to the enzyme away from the active site, the allosteric site.
56
What is the role of competitive inhibitors?
prevent the substrate from binding and the reaction occurring. if you add more substrates, this will out-compete the inhibitor, knocking them out of the active site.
57
What is the role of non-competitive inhibitors?
cause the active site to change shape and therefore the substrate can no longer bind.
58
What is the role of DNA?
holds genetic information
59
What are the components of a DNA
deoxyribose, a phosphate group and one of the organic bases (adenine, cytosine, thymine, guanine)
60
What is the role of RNA?
transfers genetic information from DNA to the ribosomes
61
What are the components of RNA?
ribose, a phosphate group and one of the organic bases (adenine, cytosine, uracil, guanine)
62
What bond is formed between nucleotides?
during a condensation reaction between nucleotides a phosphodiester bond is formed.
63
What is the structure of DNA?
a double helix with two polynucleotide chains(anti parallel) held together by hydrogen bonds between specific complementary base pairs.
64
What is the structure of RNA?
a short polynucleotide chain
65
Describe the semi-conservative replication of DNA
- DNA helicase unwinds DNA and breaks hydrogen bonds - both strands of DNA act as a template - nucleotides line up in complimentary pairs (A-T, G-C) - DNA polymerase joins nucleotides together forming phosphodiester bonds - the hydrogen bonds between complimentary base pairs reform - each new DNA molecule consists of one original strand and one new strand
66
What is ATP?
adenine triphosphate- a nucleotide derivative
67
How is ATP formed?
formed from a molecule of adenine, a molecule of ribose and three phosphate groups
68
What is the role of ATP?
used as an immediate energy source by organisms
69
What is the equation showing the hydrolysis of ATP?
ATP + H2O ---------> ADP + Pi + energy
70
What is ATP broken down into?
ADP and an inorganic phosphate group
71
How can ATP be resynthesised?
during respiration and photosynthesis, it is resynthesised in a condensation reaction and is catalysed by ATP synthase.
72
What is the role of the inorganic phosphate ion formed?
can be used to phosphorylate other compounds and this often makes the compounds more reactive
73
What are the advantages of ATP?
-releases small, manageable amounts of energy so little is lost as heat - releases energy instantaneously - can rapidly be resynthesised - it is unable to leave cells
74
Why do we need to make lots of ATP?
- it cannot be stored and only lasts for a couple of seconds - only small amounts of energy is released at a time
75
What are inorganic ions?
occur in a solution of cytoplasm and body fluids of organisms, each ion has a specific role
76
What are examples of inorganic ions?
hydrogen ions, iron ions, sodium ions, phosphate ions
77
What is the role of hydrogen ions?
determine pH of a substance, lowers the pH affecting enzyme activity and the tertiary structure and denature it
78
What is the role of iron ions?
component of haemoglobin, charged, binds with oxygen forming oxyhaemoglobin and oxygen is then transported.
79
What is the role of sodium ions?
co-transport of glucose and amino acids, moved out of the cell by active transport- creating a concentration gradient, affecting the water potential
80
What is the role of phosphate ions?
component of DNA and ATP, found in the backbone in DNA and used to make ATP during the condensation of ADP.
81
What are polar molecules?
a molecule that is slightly positively charged at one end and slightly negative at the other end
82
Why is water important for organisms?
-needed for hydrolysis - its a solvent - keeps organisms in shape - metabolic rates - photosynthesis and respiration
83
What is the structure of water?
a negative charge on the oxygen pole, a positive charge on the hydrogen pole, a water molecule is electrically dipolar
84
What are the properties of water?
- it is a metabolite - has a high specific heat capacity - it is dipolar - large latent heat of vaporisation - strong cohesion between water molecules - density
85
Define cohesion
the attraction of molecules for other molecules of the same kind
86
Define metabolite
a small molecule (non-polymeric compound) that participates in metabolic reactions and is required for the maintenance, growth, and normal function of cells.
87
What is the difference between the hydrogen bonds in ice and liquid water?
in ice hydrogen bonds are stable, in water hydrogen bonds constantly break and reform.
88
What does hydrophobic mean?
does not interact with water(insoluble in water)
89
What does hydrophilic mean?
interacts with water(soluble in water)
90
What does semi conservative replication mean?
ensures genetic continuity between generations of cells. every new DNA molecule has one original strand and one new strand

Biology (8 decks)

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