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A LEVEL BIOLOGY > Module 2: Section 2 - Biological Molecules > Flashcards

Module 2: Section 2 - Biological Molecules Flashcards

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1
Q

What does water being di polar result in

A

Attracts positively and negatively charged ions towards it

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2
Q

How do hydrogen bonds form

A

Hydrogen is slightly positively charged and oxygen slightly negatively charged so these opposite charges attract to each-other forming hydrogenbonds

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3
Q

What does hydrophilic mean

A

It attracts water (water loving)

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4
Q

Do charges / polar molecules dissolve readily in water and if they do what are they called

A

Yes and are called hydrophilic

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5
Q

Do charges/ non polar molecules dissolve readily in water and if not what are they called

A

No and are called hydrophobic

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6
Q

What does hydrophobic mean

A

It repels water (water hating)

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7
Q

How can water resist changes in temperature

A

Hydrogen bonds between water molecules can absorb a lot of energy. This means they have a high specific heat capacity so it doesn’t change temperature very easily and remains at constant temperature

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8
Q

Why is water having a high specific heat capacity good for organisms

A

The constant temperature is good for organisms because it means water doesn’t experience rapid temperature changes so it’s a good habitat for them. And water inside organisms is stable which helps them maintain a constant internal body temperature

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9
Q

Why is water having a high specific heat capacity good for organisms

A

The constant temperature is good for organisms because it means water doesn’t experience rapid temperature changes so it’s a good habitat for them. And water inside organisms is stable which helps them maintain a constant internal body temperature

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10
Q

What is cohesion

A

It’s the tendency for molecules within a substance to stick together

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11
Q

Why are water molecules very cohesive

A

They are polar hydrogen bonds so can stick together

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12
Q

What does waters strong cohesion do

A

Helps water to flow which is useful for transporting substances
Gives the water a high surface tension, allowing small organisms to walk/ move on the surface of things like a pond

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13
Q

Is waters solid or liquid form more dense

A

Liquid

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14
Q

How are water’s density and freezing properties beneficial for organisms

A

Ice floats on water and insulates the water below it reducing the chances of organisms completely freezing and increasing chances of life

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15
Q

What are monomers

A

Small, identical or similar molecules,that can be joined together to make large molecules called polymers

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16
Q

What are polymers

A

Large molecules which are formed by joining many identical or very similar monomers together

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17
Q

What is a hexose sugar

A

A monosaccharide which has six carbon atoms in each molecule

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18
Q

What are the types of glucose

A

Alpha and beta

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19
Q

What is an isomer

A

Same molecular but the atoms are connected in a different way

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20
Q

Is glucose a hexose or Pentose sugar

A

Hexose

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21
Q

What is the difference between alpha and beta glucose

A

Alpha have a H on top and OH on the bottom and beta has a OH on top and H on bottom

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22
Q

What bonds are carbohydrates joined by

A

Glycosidic bonds

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23
Q

What bonds are proteins joined by

A

Peptide bonds

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24
Q

What bonds are lipids joined by

A

Ester bonds

25
Q

What elements do carbohydrates contain

A

Carbon, hydrogen and oxygen

26
Q

How are disaccharides formed

A

Two monosaccharides are joined by a glycosidic bond (condensation reaction) and a water molecule is released

27
Q

What is glucose +glucose

A

Maltrose

28
Q

What is glucose and fructose

A

Sucrose

29
Q

What is glucose and galactose

A

Lactose

30
Q

What is cellulose structure

A

-Polymer of beta glucose
-Made of long unbranched chains of beta glucose
- 2nd glucose is inverted so cellulose molecule is straight rather than curved
- cellulose chains linked together by hydrogen bonds to form cellulose micro fibrils and as these fibres are so strong it supports the cell

31
Q

What is starch a mixture of

A

Two polysaccharides of alpha glucose amylose and amylopectin

32
Q

What is amylose structure

A

-Long
- unbranched chain of alpha glucose
- 1-4 glycosidic bonds
- coiled, cylinder like structure due to the angle of glycosidic bonds

33
Q

Amylopectin structure

A

-Long
- branched chain of alpha glucose
- side branches
-1-6 glycosidic bonds
-compact

34
Q

Glycogen structure

A

-long branched chain
-1-4 and 1-6 glycosidic bonds
- side branches
-compact

35
Q

Why are compact branches good

A

Good for Energy storage

36
Q

What is glycogens function

A

Energy storage in animals, bacteria and fungi

37
Q

What are triglycerides soluble in and insoluble in

A

Soluble in alcohol
Insoluble in water as not polar

38
Q

How are triglycerides formed

A

1 glycerol esterified with three fatty acid

39
Q

Triglycerides function

A

Storing energy

40
Q

What are phospholipids structures

A

-1 glycerol esterified with two fatty acid groups and 1 phosphate group
- phosphate head is hydrophilic and polar(water soluble) and the tails are non polar and hydrophobic

41
Q

What happens when phospholipids are mixed with water

A

Form droplet spheres with the hydrophilic heads facing the water and the hydrophobic tails facing eachother

42
Q

What is amino acids general structure

A

-central carbon
-amino group
-carboxyl group
-hydrogen atom
-an R group

43
Q

How are polypeptides formed

A

Condensation reactions between the amine group of one amino acid and the carboxyl group of another

44
Q

What are the 4 levels of the protein structure

A

Primary structure, secondary structure,tertiary structure and the quaternary

45
Q

What is the primary structure

A

The unique sequence of amino acids in the polypeptide chain

46
Q

What are the bonds that hold the secondary structure of proteins together

A

Hydrogen bonds which cause the protein to fold into specific structures

47
Q

What are two secondary structures of proteins

A

Alpha helix
Beta pleated sheet

48
Q

Why are the secondary structure of proteins stable

A

Many hydrogen bonds

49
Q

How does the secondary structure form

A

Primary polypeptide chain folds to form a secondary structure ( result of protein folding)

50
Q

How does the tertiary structure form

A

Further foldings in the secondary structure

51
Q

What are the bonds in the tertiary structure

A

Hydrogen bonds-which are weak
Ionic bonds- which are strong
Sulphur bridges -which are strong

52
Q

How is the quaternary structure formed

A

The interaction between many polypeptides

53
Q

Examples on quaternary structure of proteins

A

-collagen(protein in skin)has 3 polypeptide chains
-haemoglobin( globular proteins 4 polypeptide chains)
-insulin(2 polypeptide chains held together by disulphide bonds)

54
Q

what is meant by a conjugated protein

A
  1. contains non-protein
    groups
  2. has prosthetic group
  3. (prosthetic group) is , iron
    / Fe , ion
  4. (prosthetic group) is
    attached by , covalent
    bonds / ionic interactions
    / hydrogen bonds
55
Q

what are fibrous proteins properties

A

-insoluble in water
-strong
-stable (unreactive)structure
-polypeptide chains form long twisted strands
-form hydrogen bonds with adjacent chains

56
Q

what are globular proteins properties

A

-unstable (reactive) structures
-soluble
-Hydrophobic R group on the inside and hydrophilic on the outside
-Polypeptide chains roll up into spherical shape

57
Q

what are 3 roles of lipids

A

-energy storage
-thermal insulation
-protection

58
Q

What are the examples of globular proteins and what do they do

A
  • Haemoglobin has 4 polypeptide chains and a prosthetic group called a haem, it carries oxygen around the red blood cells
  • insulin is a hormone secreted in the pancreases and consists of 2 polypeptide chains
    -amylase is an enzyme that catalyses the breakdown of starch
59
Q

what are the examples of fibrous proteins and what do they do

A

-collagen is found in animal connective tissues e.g skin and is very strong
-keratin is found in skin hair nails.it can be flexible or tough
-elastin- found in elastic connective tissues such as skin . As its elastic it allows the tissue to return to its original shape

A LEVEL BIOLOGY (28 decks)

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