2.2 Biologial Molecules Flashcards

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1
Q

How does the formation of a dipeptide occur?

Two amino acids joining

A

A condensation reaction occurs between the O-H and the H to form H2O and a bond between last carbon of one NCC amino acid and the first N from the other NCC amino acid.

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2
Q

Draw the formation of a dipeptide.

A

https://www.ecosia.org/images?q=formation+of+a+dipeptide#id=C0CE21F3D6A63B85DB9495CDCA9279B549DFC922

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3
Q

How are peptide bonds broken between two amino acids?

A

A hydrolysis reaction occurs because water is used to split them. H2O is added so that the last carbon of the NCC amino acid gains an O-H and the first N from the other NCC amino acid gains a H.

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4
Q

Draw the hydrolysis of a peptide bond breakage.

A

https://www.ecosia.org/images?q=hydrolysis+of+peptide+bond+breakage#id=9E25968166637C0FA0CE45ED232744ECB47FE088

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5
Q

What is the primary structure of a protein?

A

The sequence of amino acids found in a molecule.

-changing just one amino acids can alter the function of the protein

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6
Q

What is the secondary structure of a protein?

A

The coiling or folding of an amino acid chain, which is held into either a alpha-helix or beta-pleated sheet by bonds such as hydrogen bonds.
-Some chains do not adopt any regular structure and some chains have more than one secondary structure at different ends of the chain.

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7
Q

What is the tertiary structure of a protein?

A

The overall 3-D shape of a protein molecule. Its shape arises due to interactions including hydrogen bonding, disulphide bridges, ionic bonds and hydrophobic interactions.

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8
Q

What is the quaternary structure?

A

The protein structure that consists of more than one polypeptide chain.

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9
Q

What is a globular protein?

A

One which has spherical molecules which are soluble in water and often have metabolic roles in the organism.

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10
Q

What are disulfide bridges?

A

Bonds which form between two cysteine proteins (cysteine proteins are a type of amino acid).

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11
Q

What is a phosphodiester bond?

A

The bond between a sugar a phosphate group in a polynucleotide or dinucleotide.

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12
Q

How does a phosphodiester bond join together two nucleotides to create a dinucleotide?

A

A condensation reaction occurs between the phosphate group and the sugar.

This involves the hydrogen being removed from the hydroxyl (OH) group on the carbon 3 of the ribose sugar. And the other hydroxyl group being removed from the phosphate group.

https://goo.gl/images/yixX71

This leaves a covalent (phosphodiester) bond between carbon 3 of the ribose sugar and the oxygen of the phosphate group.

H20 is left as a waste product.

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13
Q

What are ionic bonds in the context of protein folding?

A

The electrostatic attraction of oppositely charged atoms where electrons are transferred.

Some amino acids have an extra carboxylic (-COOH) group and some have an extra amine group (NH2).
An ionic bond forms between these as the carboxylic group and the amine group are oppositely charged.

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14
Q

What are hydrophilic/hydrophobic interactions which assist in protein folding?

A

The hydrophobic molecules arrange in the centre of the helix, whereas the hydrophilic arrange on the outside.

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15
Q

How do hydrogen bonds join atoms in water molecules?

A

The oxygen is more electronegative, meaning electrons are more attracted to the oxygen.

The hydrogen atoms are more electropositive meaning electrons are less attracted to the hydrogen.

This creates forces of attraction keeping the atoms together, and creates the polarity of the molecule.

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16
Q

What are lipids?

A

A group of substances that are solubule in alcohol but not water.
They are a major component of every living cell and:
-act as a source of fuel
-are macromolecules (not polymers)

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17
Q

What is a macromolecule?

A

A very large, organic molecule

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18
Q

What is meant by a saturated molecule?

A

It has no double bonds, so cannot take on any more atoms.

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19
Q

What is meant by a unsaturated molecule?

A

It has avaible double bonds, so can bond more atoms

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20
Q

How does a molecules saturation affect melting points?

A

If a molecule is more unsaturated (more double bonds), there are more ‘kinks’ in the chain so cant pack together so closely, and are therefore more fluid with a LOWER MELTING POINT.

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21
Q

What is a triglyceride?

A

A lipid molecule which is broken down in respiration to generate ATP. It consists of three fatty acid chains and a glycerol. It is the main component of fat in our bodies.

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22
Q

How is a triglyceride formed?

A

Glycerol and fatty acid chains undergo a condensation reaction to produce ester bonds between the two.

Each fatty acid chain joins to a carbon from the glycerol. The -COOH group from the fatty acid and the -OH from the glycerol react to form water, and an ester bond forms in there place, between the carbon and the oxygen.

https://www.ecosia.org/images/?q=formation%20of%20a%20triglyceride#id=7FFE6C7B7B107724ED40B1B97BB3FB21B33FF72C

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23
Q

What are the biological uses of triglyceride?

A
  • store of energy
  • insulation
  • buoyancy
  • protection
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24
Q

Why are triglycerides and effective store of energy?

A
  • triglycerides are insoluble in water, so can be stored without affecting the water potential of the cell
  • contains twice the energy of glucose
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25
Q

How are triglycerides used as insulators?

A
  • lipids stored as adipose in mammals such as whale blubber, acting as a heat insulator
  • lipids make up the myelin sheath around nerve cells, acting as electrical insulators
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26
Q

How are triglycerides used as protection?

A
  • we have fat surrounding our delicate organs, acting as a shock absorber
  • in bacteria, the cell wall is sometimes covered in a lipid rich outer coat.
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27
Q

what is the structure of a phospholipid?

A

It has the same structure as triglycerides but one fatty acid is replaced by a phosphate group.
They consist of a glyceryl, two fatty acid chains and a phosphoric acid.

28
Q

How is a phospholipid formed?

A

A condensation reaction occurs between the H from the phosphoric acid molecule and of the -OH groups on the glycerol molecule.

https://www.ecosia.org/images?q=formation+of+phospholipids#id=E4244118C6CDEF0678977AE142C295F4B31A5EC0

29
Q

Why are the properties of cholesterol important to its function?

A

It is a small and hydrophobic molecule which means it can stay in the hydrophobic part of the membrane bilayer.

Some steroid hormones are also made from cholesterol, so being hydrophobic means they can easily pass through the hydrophobic channels in the membrane.

30
Q

What is a substrate?

A

A molecule which fits to the active site of an enzyme.

31
Q

What is the name of an enzyme binded to a substrate?

A

A enzyme-substrate complex

32
Q

What is an enzyme-product complex?

A

An enzyme binded to the substrate which has been broken into down into the product.

33
Q

What is activation energy?

A

Energy required to start a reaction

34
Q

How do enzymes catalyse a reaction???

A

They reduce the required amount of activation energy

35
Q

What is the difference between intracellular and extracellular enzymes?

A

Intracellular: Enzymes which work inside the cell, catalysing metabolic reactions.

Extracellular: Enzymes which work out side of the cells. They are made and then secreted by the cells to perform a variety of task such as assisting in digestion.

36
Q

What is the induced fit theory?

A

1) The substrate come into contact with the enzyme
2) The substrate induces conformational change in the enzyme so that it can mould its active site to that of the substrate
3) Substrate bonds to the ‘R’ groups on the amino acid of the enzyme.

37
Q

What is the name of the change which takes place to the enzyme during the induced fit theory?

A

Conformational change

38
Q

What is a retetention factor and how do you calculate it?

A

It is the RF value, you calculate it through doing:

Distance moved by solute/distance moved by solvent front.

39
Q

What are monosaccharides?

A

They are simple sugars, such as

  • Glucose.
  • Galactose (found in milk).
  • Fructose (found in fruit).
40
Q

What is the chemical formula of glucose?

A

C(6)H(12)O(6)

41
Q

Alpha and beta glucose are isomers, what are isomers?

A

They have the same chemical formula, but a different arrangement of atoms?

42
Q

What is the difference between Alpha and Beta glucose?

A

Alpha Glucose: Both OH groups are at the bottom of the molecule.

Beta Glucose: the OH group on the right is flipped so that it is positioned on the top of the molecule.

https://www.google.co.uk/search?q=beta+glucose+molecule&source=lnms&tbm=isch&sa=X&ved=0ahUKEwji4IK0uN7fAhVcQxUIHUiVCYoQ_AUIDigB&biw=1360&bih=626&safe=active&ssui=on#imgrc=OGfBsDJh8mM41M:

43
Q

What are disaccharides?

A

When two monosaccharides are joined together. Such as:
Glucose + glucose → maltose.
Glucose + fructose → sucrose.
Glucose + galactose → lactose.

44
Q

What is a hexose sugar?

A

One which contains 6 carbon atoms.

45
Q

What type of reactions join together monosaccahrides to make polysaccharides?

A

Condensation reactions to create glycosidic bonds.

46
Q

What are Reducing sugars?

A

Reducing sugars:
-carbohydrates capable of being oxidised (reduction of electrons) and reducing other substances

  • They can be oxidised my a mild oxidising agent
  • all monosaccharides are reducing
47
Q

What are non-reducing sugars?

A

Non-reducing sugars:

  • carbohydrates not capable of being oxidised or reducing other substances
  • Wont show up through benedicts solution
  • cannot be oxidised by mild oxidising agent
  • disaccharides are non-reducing
48
Q

What do you need to do to test for non reducing sugars?

A

Boil in hydrochloric acid, neutralise and then test with benedicts solution.

This is because disaccharides cant bond to the copper, so the hydrochloric acid breaks the them into monosaccharides so that they can bond to the copper and turn it brick-red

49
Q

What monosaccharides make up maltose?

A

a-glucose + a-glucose

50
Q

What monosaccharides make up sucrose?

A

a-glucose + fructose

51
Q

What monosaccharides make up lactose?

A

b-galactose + a-glucose

52
Q

What monosaccharides make up cellobiose?

A

b-glucose + b-glucose

53
Q

What type of reaction and bond is formed when a dissaccharide is formed?

A

A condensation reaction occurs to from a glycosidic bond.

54
Q

How do you differenciate between alpha and beta glucose?

A

Alpha Glucose
-Both -OH groups are at the bottom

Beta Glucose
-The -OH group on the right side is flipped, so that it is at the top

55
Q

What is the molecular formula for a hexose sugar?

A

C6 H12 O6

56
Q

What is the molecular formula for a pentose sugar?

A

C5 H12 O5

57
Q

What is the difference between ribose and deoxyribose?

A

Ribose contains one more oxygen atom as part of a hydroxyl group

58
Q

What structural feature allows celluose chains to not spiral?

A

Each monosaccharide in the pollysaccharide is flipped (Hydrogen and hydroxyl groups on carbon 1 are inveted in b-glucose, as apose to a-glucose.

59
Q

What are beta 1-4 linkages?

A

When Carbon one is bonded to carbon 4.

60
Q

What does it mean when a pollysaccahrides have 1-6 linkages?

A

It means they are more branched so release energy quicker, as the enzymes can reach the bonds and break them quicker.

61
Q

What are the properties and functions of three fibrous proteins?

A

Collagen

  • mechanical strength in artery walls and tendons
  • in bones and cartilage

Keratin

  • rich is cystine so lots of disulfide bridges to make it very strong and tough to make finger nails, hooves horns etc.
  • waterproof

Elastin

  • crosslinking and coiling makes the structure of elastin strong and extensible.
  • found in skin, lungs bladder and blood vessels.
62
Q

What are the properites and functions of three globular proteins

A

Haemoglobin

  • Soluble in water
  • contains haem group essential for the function of the enzyme.

Insulin
-binds to glycoprotein receptors on the outside of muscles and fat cells to increase their uptake of glucose from the blood.

Pepsin
-digests protein
-can operate in acidic enviroments becuas eof number of amino acids which dont take on any more H+ ions
`

63
Q

What examples of fibrous proteins are there?

A
  • Keratin
  • Collagen
  • Elastin

These are all strong proteins used for structure but vary e.i keratin is waterproof, elastin is stretchy

64
Q

What are the properties of fibrous proteins?

A
  • long thin structure
  • insoluble in water
  • metabolically inactive
  • structural use
65
Q

what are the properties of globular proteins?

A
  • spherical shape
  • soluble in water
  • often have metabolic roles in an organism
66
Q

What is a prosthetic group?

A

a non-protein component that forms a permanent part of a functional protein.