BIOLOGICAL MOLECULES
Monomers & Polymers
Monomers= Small basic units that form polymers (e.g. glucose, amino acids and nucleotides).
Polymers= Can be long, single strands or highly branched. Carbon forms the 'backbone' of many polymers as its atoms readily form bonds.
Condensation= Monomers undergo polymerisation to form polymers, releasing a water molecule.
Hydrolysis= Polymers split into shorter chains of monomers which uses a water molecule.
Carbohydrates
Carbohydrates consist only of Carbon, Hydrogen & Oxygen. They produce energy in respiration & act as structural polymers in plant cell walls.
Monosaccharides= Single sugars with the formula (CH O)n, including glucose, Disaccharides= Two monosaccharides joined via a condensation reaction. Two -glucose
galactose and fructose. molecules form a 1-4 glycosidic bond.
Glucose has an alpha ( ) and beta ( ) isomer.
Remember- The second hydrogen in
glucose is above in , below in .
All monosaccharides are reducing sugars
& have the chemical formula C6 H12O6.
Test for reducing sugars:
Add Benedict’s reagent
Heat in water bath (80℃ for 5 mins).
Positive result= Brick red
Multiple monosaccharides form a polysaccharide. Glucose polysaccharides:
Test for non-reducing sugars:
Glycogen Starch Cellulose
Do Benedict’s test (negative= continue testing)
Made from -glucose Made from -glucose Made from -glucose
Boil in Hydrochloric acid (5mins)
Found in animals Found in plants Found in plants
Neutralise with alkali
Highly branched Highly branched Long, parallel straight chains
Once neutral, re-do Benedict’s test
Used for storage Used for storage Hydrogen bond cross-linkages
Positive result= orange/red
Used for cell wall strength
Lipids Proteins Enzymes
Lipids are fats and oils, they: Proteins are made up of amino acids. Biological catalysts- required for a reaction
Combine with phosphate to form phospholipid bilayer They contain: Globular proteins
Provide an energy source when oxidised Hydrogen atom Lower activation energy of reactions
Are insoluble- used for waterproofing Amino group Induced fit model
Are slow heat conductors- used for insulation Carboxyl group
Form protective layers around organs (fat)
Dipeptides- Amino acids joined by peptide bonds.
Triglycerides Phospholipids
Glycerol+3 fatty acids 1 glycerol+2 fatty Protein Structure
acids+1 phosphate Primary structure= Sequence of amino acids held by
group peptide bonds. Factors affecting enzyme rate of reaction:
Phosphate head- Secondary structure= Folding of H bonds between the Temperature- Optimum= 40℃ more kinetic
polar/hydrophillic amino & carboxyl group.
Tertiary structure= Complex folding of polypeptide (H,
→
energy more successful collisions.
Fatty acid tail- non- pH- Too high/low= enzyme denatures.
polar/hydrophobic ionic & disulphide bonds) between alpha helices and Substrate conc- more substrate= increased rate of
Ester bond pleated sheets. reaction.
Quaternary structure= Protein consisting of more than
1 amino acid chain (polypeptide) held by H, ionic &
→
Enzyme conc- more available active sites more
Fatty acids enzyme substrate complexes.
disulphide bonds.
Saturated= no C-C double Competitive inhibitor- Molecule which competes with
bonds- solid at room temp. Protein test: Buiret reagent- positive= purple the substrate for the active site.
Unsaturated= C-C double Non-competative inhibitor- Binds in allosteric site
bonds- liquid at room temp. Most proteins=globular (compact, ball shape structure). changing active site shape.
DNA- Deoxyribonucleic acid DNA structure: Why is it suitable for its functions?
A polymer composed of nucleotides. Double stranded- 2 polynucleotide strands antiparallel. Stable= phosphodeister backbones protects
Nucleotides contain: Double helix- The 2 strands are wound around each bases and double helix.
Pentose sugar (deoxyribose) other (creates stability). Replication= the 2 strands can separate and be
Phosphate group Two strands are joined by H bonds used as template strands.
Nitrogenous base (Adenine, Guanine, Thymine or Cytosine) Compatible base pairs (G-C & A-T) Large= carries a lot of genetic info.
Helical & compact= large amounts of genetic
Adenine is complimentary to Thymine (double bond) Semi-conservative replication:
info in small amount of space.
Guanine is complimentary to Cytosine (triple bond) 1) DNA helicase unwinds/separates the 2 strands (breaks
H bonds between nitrogenous bases). Meselson-Stahl experiment:
Prokaryotic DNA: Eukaryotic DNA: 2) New DNA built up from free nucleotides. Found evidence of semi-conservative rep.
not wrapped around histone- wrapped around histone- 3) DNA polymerase joins new nucleotides together with →
DNA replicated in N15 (heavy) replicated again
proteins. proteins. strong covalent bonds. in N14 (light)= New DNA mix of heavy+light
DNA not in nucleus (cytoplasm) in nucleus (linear) 4) 2 new identical daughter stands are formed. proving each strand splits and reps itself.
RNA- Ribonucleic acid ATP- Adenosine triphosphate Water
A polymer composed of nucleotides. Nucleotide derivative consisting of: Molecule containing Oxygen and 2 Hydrogen atoms.
Nucleotides contain: Adenine
Pentose sugar (ribose) 3 phosphate groups Water has many key roles, including:
Phosphate group Ribose Metabolite- essential for metabolic reactions
Nitrogenous base (Adenine, Guanine, Uracil or ATP acts as an immediate source of energy and is such as condensation and hydrolysis reactions.
Cytosine) hydrolysed in a single step when 3 phosphate groups are Polar- acts as universal solvent (enables
removed by hydrolysis, catalysed by ATP hydrolase. efficient nutrient transport) and regulates
Each RNA polynucleotide strand is composed of a ATP hydrolysis occurs in: temperature.
sugar-phosphate backbone and unpaired bases. Muscle contraction High specific heat capacity- acts as a buffer
Active transport (minimises temperature fluctuations).
Messenger RNA (mRNA)= carries genetic code Metabolic processes Large latent heat of vaporisation-
from DNA to the ribosomes (protein synthesis). condensation of water creates a cooling effect
ATP synthase reconnects inorganic phosphate (Pi) with (e.g. sweating).
Transfer RNA (tRNA)= has a specific anticodon AMP & ADP through condensation. This process occurs: Cohesion- strong cohesion between molecules
complementary to a specific triplet of bases on during photosynthesis in plants (photophosphorylation) (created by H bonds) supports columns of
an mRNA molecule (protein synthesis). Respiration in animals (oxidative phosphorylation). water. This creates surface tension and allows
for effective transport of water (e.g. in the
Ribosomal RNA (rRNA)- primary structural and ATP isn’t stored in large quantities as it can easily be xylem).
catalytic component of Ribosomes. reformed by ADP in seconds.
Monomers & Polymers
Monomers= Small basic units that form polymers (e.g. glucose, amino acids and nucleotides).
Polymers= Can be long, single strands or highly branched. Carbon forms the 'backbone' of many polymers as its atoms readily form bonds.
Condensation= Monomers undergo polymerisation to form polymers, releasing a water molecule.
Hydrolysis= Polymers split into shorter chains of monomers which uses a water molecule.
Carbohydrates
Carbohydrates consist only of Carbon, Hydrogen & Oxygen. They produce energy in respiration & act as structural polymers in plant cell walls.
Monosaccharides= Single sugars with the formula (CH O)n, including glucose, Disaccharides= Two monosaccharides joined via a condensation reaction. Two -glucose
galactose and fructose. molecules form a 1-4 glycosidic bond.
Glucose has an alpha ( ) and beta ( ) isomer.
Remember- The second hydrogen in
glucose is above in , below in .
All monosaccharides are reducing sugars
& have the chemical formula C6 H12O6.
Test for reducing sugars:
Add Benedict’s reagent
Heat in water bath (80℃ for 5 mins).
Positive result= Brick red
Multiple monosaccharides form a polysaccharide. Glucose polysaccharides:
Test for non-reducing sugars:
Glycogen Starch Cellulose
Do Benedict’s test (negative= continue testing)
Made from -glucose Made from -glucose Made from -glucose
Boil in Hydrochloric acid (5mins)
Found in animals Found in plants Found in plants
Neutralise with alkali
Highly branched Highly branched Long, parallel straight chains
Once neutral, re-do Benedict’s test
Used for storage Used for storage Hydrogen bond cross-linkages
Positive result= orange/red
Used for cell wall strength
Lipids Proteins Enzymes
Lipids are fats and oils, they: Proteins are made up of amino acids. Biological catalysts- required for a reaction
Combine with phosphate to form phospholipid bilayer They contain: Globular proteins
Provide an energy source when oxidised Hydrogen atom Lower activation energy of reactions
Are insoluble- used for waterproofing Amino group Induced fit model
Are slow heat conductors- used for insulation Carboxyl group
Form protective layers around organs (fat)
Dipeptides- Amino acids joined by peptide bonds.
Triglycerides Phospholipids
Glycerol+3 fatty acids 1 glycerol+2 fatty Protein Structure
acids+1 phosphate Primary structure= Sequence of amino acids held by
group peptide bonds. Factors affecting enzyme rate of reaction:
Phosphate head- Secondary structure= Folding of H bonds between the Temperature- Optimum= 40℃ more kinetic
polar/hydrophillic amino & carboxyl group.
Tertiary structure= Complex folding of polypeptide (H,
→
energy more successful collisions.
Fatty acid tail- non- pH- Too high/low= enzyme denatures.
polar/hydrophobic ionic & disulphide bonds) between alpha helices and Substrate conc- more substrate= increased rate of
Ester bond pleated sheets. reaction.
Quaternary structure= Protein consisting of more than
1 amino acid chain (polypeptide) held by H, ionic &
→
Enzyme conc- more available active sites more
Fatty acids enzyme substrate complexes.
disulphide bonds.
Saturated= no C-C double Competitive inhibitor- Molecule which competes with
bonds- solid at room temp. Protein test: Buiret reagent- positive= purple the substrate for the active site.
Unsaturated= C-C double Non-competative inhibitor- Binds in allosteric site
bonds- liquid at room temp. Most proteins=globular (compact, ball shape structure). changing active site shape.
DNA- Deoxyribonucleic acid DNA structure: Why is it suitable for its functions?
A polymer composed of nucleotides. Double stranded- 2 polynucleotide strands antiparallel. Stable= phosphodeister backbones protects
Nucleotides contain: Double helix- The 2 strands are wound around each bases and double helix.
Pentose sugar (deoxyribose) other (creates stability). Replication= the 2 strands can separate and be
Phosphate group Two strands are joined by H bonds used as template strands.
Nitrogenous base (Adenine, Guanine, Thymine or Cytosine) Compatible base pairs (G-C & A-T) Large= carries a lot of genetic info.
Helical & compact= large amounts of genetic
Adenine is complimentary to Thymine (double bond) Semi-conservative replication:
info in small amount of space.
Guanine is complimentary to Cytosine (triple bond) 1) DNA helicase unwinds/separates the 2 strands (breaks
H bonds between nitrogenous bases). Meselson-Stahl experiment:
Prokaryotic DNA: Eukaryotic DNA: 2) New DNA built up from free nucleotides. Found evidence of semi-conservative rep.
not wrapped around histone- wrapped around histone- 3) DNA polymerase joins new nucleotides together with →
DNA replicated in N15 (heavy) replicated again
proteins. proteins. strong covalent bonds. in N14 (light)= New DNA mix of heavy+light
DNA not in nucleus (cytoplasm) in nucleus (linear) 4) 2 new identical daughter stands are formed. proving each strand splits and reps itself.
RNA- Ribonucleic acid ATP- Adenosine triphosphate Water
A polymer composed of nucleotides. Nucleotide derivative consisting of: Molecule containing Oxygen and 2 Hydrogen atoms.
Nucleotides contain: Adenine
Pentose sugar (ribose) 3 phosphate groups Water has many key roles, including:
Phosphate group Ribose Metabolite- essential for metabolic reactions
Nitrogenous base (Adenine, Guanine, Uracil or ATP acts as an immediate source of energy and is such as condensation and hydrolysis reactions.
Cytosine) hydrolysed in a single step when 3 phosphate groups are Polar- acts as universal solvent (enables
removed by hydrolysis, catalysed by ATP hydrolase. efficient nutrient transport) and regulates
Each RNA polynucleotide strand is composed of a ATP hydrolysis occurs in: temperature.
sugar-phosphate backbone and unpaired bases. Muscle contraction High specific heat capacity- acts as a buffer
Active transport (minimises temperature fluctuations).
Messenger RNA (mRNA)= carries genetic code Metabolic processes Large latent heat of vaporisation-
from DNA to the ribosomes (protein synthesis). condensation of water creates a cooling effect
ATP synthase reconnects inorganic phosphate (Pi) with (e.g. sweating).
Transfer RNA (tRNA)= has a specific anticodon AMP & ADP through condensation. This process occurs: Cohesion- strong cohesion between molecules
complementary to a specific triplet of bases on during photosynthesis in plants (photophosphorylation) (created by H bonds) supports columns of
an mRNA molecule (protein synthesis). Respiration in animals (oxidative phosphorylation). water. This creates surface tension and allows
for effective transport of water (e.g. in the
Ribosomal RNA (rRNA)- primary structural and ATP isn’t stored in large quantities as it can easily be xylem).
catalytic component of Ribosomes. reformed by ADP in seconds.
