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A Level Biology - Eduqas (Year 1) > Chapter 1 - Chemical Elements and Biological Compounds > Flashcards

Chapter 1 - Chemical Elements and Biological Compounds Flashcards

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1
Q

What are the 4 main organic ions organisms need to survive?

A

Magnesium (Mg)
Iron (Fe)
Phosphate (PO4)
Calcium (Ca)

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2
Q

What are the 4 organic ions used for?

A

Mg - Importants constituent of chlorophyll and for bones
Fe - Constituent of haemoglobin
PO4 - Used for making nucleotides (ATP) and are constituents of phospholipids.
Ca - Structural component of bones and teeth and is a component of plant cell walls.

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3
Q

What does it mean to be a dipole and which end is which on a water molecule?

A

A molecule has a positively charged end and a negatively charged end.
Positive - Hydrogen
Negative - Oxygen

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4
Q

What bonds do water form between each other and what property does this make water have?

A

Hydrogen bonds form between water molecules and this shows cohesion due to the huge number of hydrogen bonds. This allows columns of water to be drawn up xylem vessels.

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5
Q

What properties does water show that make it essential for life?

A

Its a solvent (they attract charged particles e.g. ions)
Its a metabolite (hydrolysis or condensation reactions)
It has a high specific heat capacity ( due to H bonds)
High latent heat of vaporisation - temp control
High surface tension
High density - anomalous expansion 4c
Transparent - lets aquatic plants photosynthesise

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6
Q

What is the basic unit of a carbohydrate, what do two of them form and what does a long chain of them form?

A

Monosaccharide
Disaccharide
Polysaccaride

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7
Q

Whats a common example of a hexose monosaccharide and how many carbon atoms does a hexose sugar have?

A

Glucose

6 carbon atoms

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8
Q

What are the two isomers of glucose and how do they differ?

A

Alpha and Beta

The OH and O swap on the 3rd Carbon

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9
Q

What are the functions of monosaccharides?

A
  • Source of energy in respiration.
  • Building block for larger molecules
  • Constituents of nucleotides
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10
Q

How are disaccarides formed and what bond is formed between the two molecules?

A

A condensation reaction

A glycosidic bond is formed

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11
Q

What is maltose, sucrose and lactose made up of?

A

Maltose - Glucose + Glucose
Sucrose - Glucose + Fructose
Lactose - Glucose + Galactose

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12
Q

How do you test for the presence of a reducing sugar?

A

Heat (to at least 70c) equal amounts of benedicts solution with the solution your testing. The solution will turn from a light blue colour to a brick red precipitate.

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13
Q

How to you test for the presence of a non reducing sugar?

A

Boil the solution in Hydrochloric acid and then add an alkali solution. Then test for the presence of a reducing sugar. If a non-reducing sugar was initially present, the solution will form a brick red precipitate.

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14
Q

How do you test for the presence of a protein?

A

Add a biuret reagent to the solution. If a protein is present, the solution will turn from a light blue colour to purple.

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15
Q

How do you test for the presence of fats/lipids?

A

Emulsion test - solution is mixed with absolute ethanol. An equal volume of distilled water is then added. If present, the solution with turns from clear to a milky white precipitate.

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16
Q

How do you test for the presence of starch?

A

Add iodine - if the solution turns to black starch is present.

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17
Q

What polymer do monosaccharides form and what is the definition of a polymer?

A

Polysaccharides

A polymer is a large molecule compromising of repeated units (monomers) bonded together.

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18
Q

Why is starch a good form of glucose to use for storage?

A
  • It is insoluble so it has no osmotic effect
  • It can’t diffuse out of the cell
  • It is a compact molecule so can be stored in a small space
  • It carries a lot of energy
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19
Q

What is starch used for and what and the two components it’s made up of?

A

It is the main store of glucose for plants and it is made up of amylose and amylopectin.

20
Q

What structural polysaccharide is present in cell walls and what type of glucose does it consist of?

A

Cellulose

Long parallel chains of Beta glucose units.

21
Q

What bonds can form that add to celluloses stuctural stabilty and what are the bundles called that it forms?

A

Hydrogen bonds between the chains.
They form microfibrills and these are held in bundles called fibres. (Has a laminated structure which contributes to the strength of the cell wall. They’re freely permeable).

22
Q

What structural polysaccharide is found in the exoseleton of insects and in fungal cell walls and what makes it different from cellulose?

A

Chitin

It has groups derived from amino acids (Acetyl amide group).

23
Q

What 3 features does chitin have that make it important in insects exoskeletons?

A

Strong
Lightweight
Waterproof - to prevent dehydration

24
Q

Why are lipids insoluble in water?

A

Because they’re non-polar compounds.

25
Q

What are triglyerides comprised of and what are the bonds called that hold these components together?

A

One glycerol molecule and 3 fatty acids.

All joined together with ester bonds.

26
Q

In a phospholipid, which end is hydrophobic and which end is hydrophyllic?

A

Glycerol end is polar so is hydrophyllic.

Fatty acids are non-polar so are hydrophobic.

27
Q

What is the difference between a saturated and and unsaturated lipid?

A

All the carbon atoms in a saturated are single bonded whereas an unsaturated molecule has at least 1 double bond between C atoms.

28
Q

What consequence does having a double bond in a lipids have and what kind of lipids have double bonds?

A

It means the molecules cannot align uniformly and the lipid doesn’t solidify readily.
Oils

29
Q

Where does the synthesis and transport of lipids occur?

A

In the smooth endoplasmic reticulum.

30
Q

What is the role of phospholipids?

A
  • In biological membranes (Phospholipid Bilayer).

- In electrical insulation (Mylein Sheath that surrounds the axons of nerve cells).

31
Q

What is the role of triglyerides?

A
  • Energy reserves (both plants and animals).
  • Thermal insulation- when stored underneath the skin
  • Protection - it’s often stored around delicate organs.
  • Metabolic water -releases a lot of water when hyrolysed
32
Q

What is the role of waxes?

A

Waterproofing - in terrestrial orgaisms (insect exoskeleton and plant cuticles).

33
Q

What factors can lead to high blood pressure and a risk of heart disease?

A

Diet high in saturated fats.
Smoking
Lack of exercise
Ageing

34
Q

In the small intestine, what do lipids and proteins join to form and what two types are there?

A

Lipoproteins -high density lipoproteins and Low-density lipoproteins.

35
Q

What causes Low-density Lipoproteins to build up and whats the fatty material that builds up called?

A

A diet high in saturated fats

Atheroma (gets deposited in the coronary artery and restricts blood flow.

36
Q

What causes the body to make more High-density Lipoproteins and why are they good?

A

A diet in unsaturated fats.

They carry harmful fats away to the liver for disposal.

37
Q

What monomers are proteins made of and what is a long chain of them called?

A

Amino acids

Polypeptide

38
Q

How many different amino acids and what is their basic structure?

A

20 different amino acids

All have an amino group (NH2), a carboxyl group (COOH), a hydrogen atom and an R group all attached to a central C atom.

39
Q

What is the bond that holds two amino acids together called?

A

Peptide bond

40
Q

What is the primary structure of a protein?

A

The order of the amino acids in a polypeptide chain. This is determined by he base sequence on one strand of a DNA molecule.

41
Q

What is the secondary structure of a protein?

A

The shape the polypeptide chain forms as a result of hydrogen bonding (twisted into a 3D shape). Either an alpha helix or a Beta pleated sheet.

42
Q

What is the tertiary structure of a protein?

A

The Alpha helix can be folded further to give a more complex shape. This is maintained by

  • Hydrogen bonding
  • Ionic bonds
  • Disulphide bonds
  • Hydrophobic interactions.
43
Q

What is the quaternary structure of a protein?

A

Dome polypeptide chains can’t function unless they’re in combination (they may be associated with other polypeptide chains or with non-protein groups E.g. Haemoglobin).

44
Q

What is the role of fibrous proteins?

A

Long thin molecules (insoluble in water) so they have structural functions (bone). They’re strong and tough.
E.g. collagen- 3 chains linked with hydrogen bonds.

45
Q

What is the role of Globular proteins?

A

Compact and folded into spherical molecules (soluble in water). For example, enzymes, hormones, antibodies Haemoglobin (Four polypeptide chains with an iron-containing group -Haem).

A Level Biology - Eduqas (Year 1) (11 decks)

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