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Biological molecules Flashcards

2.1.2

1
Q

How do hydrogen bonds form between water molecules ?

A

Water is a polar molecule meaning oxygen is more electronegative than hydrogen which therefore makes oxygen slightly negative and hydrogen slightly postive .
There are intermolecular forces of attaction between a lone pair of oxygen of one molecule and hydrogen on an adjancent molecule

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2
Q

State biological important properties of water

A
  • High specfic heat capacity
  • High latent heat of vaporisation
  • High surface tension
  • Reaches maximum density at 4 degrees
  • Cohesion between molecules
  • Incompressible
  • Good solvent
  • Transport medium
  • Medium for chemical reactions
  • Habitat for organisms
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3
Q

Why is it important that ice is less dense then water?

A

Ice is less dense then water because the hydrogen bonds are held in fixed postions further away.
The ice floats which insulates the water underneath from freezing protecting habitats underneath

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4
Q

Why is it important that water has a high surface tension?

A
  • Slows water loss due to transpiration in plants
  • Water rises unusually high in narrow tubes, lowering demand on root pressure
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5
Q

Why is it important that water is a good solvent ?

A

Polar universal solvent dissolves and transports charged particles.
This is because waters charge is unevenly distrubted so it is able to dissolve charged particles

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6
Q

1.Why is high specific heat capacity important?
2. Why is latent heat of vapourisation important?

A
  1. Acts as a temperature buffer which helps to resist fluctuations in core temperatures to maintain optimum enzyme activity
  2. Colling effect when water evaporates from skin surface as sweat
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7
Q

What is a:
1. Monomer
2. Polymer

A
  1. Monomers - smaller units that join together to form molecules (monosaccharides, amino acids, nucleotides)
  2. Polymer - molecules formed when many monomers join together (polysaccharides, proteins, DNA / RNA
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8
Q

What happens in a:
1. Condensation reaction
2. Hydrolysis reaction

A
  1. Chemical bond forms between 2 molecules and a molecule of water is produced
  2. A water molecule is used to break a chemical bond between 2 molecules with the help of a enzymes
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9
Q

Carbohydrates + lipds : C,H,O
Proteins : C,H,O,N,S
Nucleic acids : C,H,O,N, P

A
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10
Q

Alpha glucose

Properties of a alpha glucose ( monosaccharides + diasaccharides)
* small + water solube = easily transported in the blood
* sweet
* forms crystals

A

Structure of an alpha glucose
* triose - 3 carbons
* pentose - 5 carbons
* hexose - 6 carbons

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11
Q

What is a diaccharides ?

A

Two monosaccharides join to form a diaccharides

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12
Q
  1. alpha glucose + alpha glucose =?
  2. alpha glucose + fructose =?
  3. alpha glucose + galactose =?
  4. beta glucose + beta glucose =?
A
  1. maltose
  2. sucrose
  3. lactose
  4. cellulose
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13
Q

What are the properties of polysaccharides?

A
  • Insolube in water
  • Not sweet
  • Cant be crystalisised
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14
Q

What is the function of starch ?

A
  • Insolube in water - doesnt affect the water potential ( glucose lowers the water potential)
  • Brached - main energy storage in plants ( branched structure in amylopectin means lots of glucose can be released and used quickly for respiration
  • Compact - doesnt take up of space + good energy storage molecule
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15
Q

What is the structure of starch:

A
  1. amylose - **1,4 glycosidic bonds **with a helix and intermolecular H bonds = compact ( alpha glucose) coiled
  2. amylopectin - 1,4 + 1,6 glycosidc bonds , branched to access glucose to be accessed more easily (roots in plants) colied but has branches
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16
Q

What is the structure and function of glycogen?

A
  • Function : **main energy storage **of alpha glucose in animal cells (liver +muscles)
  • Structure :** 1,4 + 1,6 glycosidic bonds** , branched,less coiled , compact , more ends at the end of the branches
    insolube in water - doesnt affect water potential
17
Q

What is the function and strucutre of cellulose ?

A
  • Structure: Polymer of beta glucose molecules joined together by hydrogen bonds forming strong fibres called mircofibrils - straight chains
  • Function: high tensile strength because of the glycosidic bonds and hydrogen bonds between the chains preventing bursting when turgid , fibres go in all directions so gives it extre strength
  • ** fully permeable**
  • turgid to help protect the strucure of the whole plant
  • Fibre - Helps maintain a healthy digestive system
18
Q

How is a glycosidic bond formed with two beta glucose?

A

the alternate b glucose is rotated through 180 forming strain chains . Forms hydrogen bonds with adjancent molecules

19
Q

What is the function of :
1. amylose
2. amylopectin
3. glycogen
4. cellulose

A
  1. respiration in plants, store of energy
  2. respiration in plants, store of energy
  3. used to store glucose in the liver + muscles , aerobic respiration
  4. cell wall and fibre
20
Q

How does a triglycerides form?

A

A condensation reaction between 1 molecule of glycerol and **3 fatty acids **with form a ester bonds

21
Q

What is the function of lipids ?

A
  • Energy source
  • structure
  • thermal insulation
  • electrical insulation
  • protection + cushioning
  • waterproofing
  • hormones
22
Q

what are :
1. saturated acids
2. unsaturated fatty acids

A
  1. Saturated
    * all carbon atoms have formed the maximum number of bonds
    * no double bonds = no kinks
    * high melting point = solid at room temp.
  2. unsaturated
    * contain atleast one double bond
    * double bonds = liquid at room temperature
    * monounsaturated - one double bond
    * polyunsaturated- two or more double bond
23
Q

What is the function of triglycerides ?

A
  • energy store
  • release high amounts of energy
  • non-polar so insolube and doesnt affect water potential waterproofing
  • respiration which releases water for desert animals
    * thermal insulation
24
Q

What is the structure of phospholipids ?

A
  • glycerol backbone attached to 2 hydrophobic fatty acid tails and 1 hydrophilic polor phosphate head
25
Q

What is the function of phosolipids?

A
  • Forms phosolipid bilayers - tails inwards , heads outwards
  • Forms micelles - tiny balls with the tails pointing in and heads out
  • water proofing
26
Q

What is the structure and function of cholesterol ?

A

Structure: Steriod structure of 4 hyrdocarbons with a hydrocarbon tail and a hydroxyl group on the other side
Function : adds stability to cell surface phospholipid bilayer by reducing fluidity

27
Q

How do polypeptides form?

A

A condensation reaction between amino acids to form a peptide bond

28
Q

What are the primary structure of a protein?

A
  • primary structure - a specific sequence of amino acids
29
Q

What is the secondary structure of a protein?

A
  • alpha helix - spiral shape and hydrogen bonds parallel to helical axis
  • b- pleated sheets - a flat sheet where the polypeptide that folds back on itself
    stablised by hydrogen bonds
30
Q

W

What is the tertiary structure of proteins ?
What are the bonds present as well ?

A
  • A 3d structure formed by futher folding
  • Disulfide bonds - Strong covalent s-s bonds between molecules of the amino acid cysteine (very strong)
  • Ionic bonds - relatively stron bonds between charded R-groups (quite strong)
  • Hydrogen bonds - numerous and easily broken (very weak)
  • Hydrophobic/hydrophilic interactions - whether the R group faces inwards or outwards away from the water or towards the water ( weak)
  • Peptide Bonds - Stong covalent bonds between amino acids ( very , very strong )
31
Q

What is a conjugated protein?

A

Proteins that contain a non protein part which is known as the prosthetic group which may be attached to any of the bonds

32
Q

Describe the structure of a globular proteins

A
  • Spherical and compact
  • precise primary structure with a non repeating amino acid sequence
  • complex secondary and tertiary structure
  • solube in water
33
Q

What is the function of globular proteins ?

A
  • Hydrophilic R groups face outwards and hydrophobic r groups face inwards = usually water soluble
  • Involved in metabolic processes e.g enzymes , amylase. insulin
34
Q

What is the structure of haemoglobin?

A
  • Globulat conjugated proteins with a prosthetic group ( haem)
  • 2 alpha chains and 2 beta chains
  • Water soluble so dissovles in plasma
  • Fe2+ haem group forms a bond with o2 to transport oxygen around the blood
35
Q

what is the structure of fibrous proteins?

A
  • long narrow fibres
  • simple primary structure with repeating amino acid sequence
  • simple secondary and tertiary structure
  • insolube in water
36
Q

What is the function of :
1. Collagen
2. elastin
3. keratin

A
  1. component of bones, cartilage, connective tissue , tendons
  2. elasticity to connective tissue , arteries , skin , lungs, cartilage and ligaments
  3. structural component of hair , nails , hooves
37
Q
A

Biology (13 decks)

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