Biological molecules Flashcards
What a polymers? Give an example
Large complex molecules composed of chains of monomers.
Starch
Name the polymer of each monomer... Glucose Amino acids Nucleic acid Fatty acid and glyerol
Starch/cellulose/glucagon
Protein
DNA/RNA
Lipids
How are monomers joined to make a polymer?
Through a condensation reaction where H2O is removed forming a bond.
What reaction separates polymers?
Hydrolysis, water is removed.
What is a polysaccharide and a monosaccharide?
Polysaccharide= more than two monosaccharides joined Monosaccharide= The monomers carbohydrates are made from
Finish what is made from... Glucose + fructose Glucose + galactose Alpha glucose + alpha glucose Beta glucose + beta glucose
Sucrose + H2O
Lactose + H20
Maltose + H20
Cellulose + H20
Properties of starch
Energy storage for plants
Insoluble, doesn’t affect water potential or swell
Branched, enzymes used to break it down can access quickly
Coiled, more room
Properties of glycogen
Energy storage for animals
Branched, glucose can be released quickly
Compact, allows for more room
Properties of cellulose
Major component of cell walls in plants
Long unbranched chains of beta glucose
H bonds form microfibrils, provides structural support
Properties and role of Lipids
Non-polar, insoluble in water, made up of C H O, soluble in organic solvents
Insulation, cell membranes, energy, protection
How are triglycerides formed? What bond?
Condensation reaction, ester bond
What are triglycerides made up of?
Glycerol and three fatty acid chains...
H O H H H H
H-C-O-H HO-C-C-C-C-C-H (x3)
H-C-O-H H H H H
H-C-O-H
HWhat s a phospholipid?
Special lipid that has phosphate molecules instead of one of the acid chains.
(Phosphate group)
R
O
O-P= O
OProperties of triglycerides
Long hydrocarbon tails contain chemical energy
Insoluble
Properties of phospholipids
Can make up a bilayer of cell membranes
Hydrophilic heads and hydrophobic tails, double layer
Water soluble molecules can’t pass
Role of protein
Enzymes, often have roles in metabolism
Antibodies, involved in the immune response
Transport, present in cell membranes transporting ions and molecules
Structure, strong proteins providing structure
What are amino acids joined by?
Peptide bonds
What is a proteins primary structure?
The sequence of amino acids controlling the properties of the polypeptide.
What is a proteins secondary structure?
The shape of the polypeptide as a result of being pulled by H bonds.
Either an alpha helix or a beta pleated sheet
What is a proteins tertiarty structure?
How other forces of attraction cause the polypeptide to form a complex and unique shape.
Eg, disulphide or ionic bonds
What is a proteins quaternary structure?
When polypeptide have more than one polypeptide.
Eg, haemoglobin have haem groups which aren’t part of the protein but enable it to carry O2.
What do enzymes do?
Lower the activation energy required in a reaction
Describe the lock and key model
Enzymes have a fixed active site complimentary to the structure of the substrate.
Describe the induced fit model
The enzyme has an active site which becomes complimentary to the substrate as they form an ES complex. The binding puts pressure on the H bonds of the substrate which makes the reaction occur more quickly.
Name the factors affecting enzyme activity
Heat
PH level
Enzyme concentration
Substrate concentration (to a point)
What is competitive inhibition?
Molecule which has a similar shape to the substrate blocks the active site, the enzyme and substrate cannot form an ES complex.
What is non-competitive inhibition?
Molecule which binds the the enzyme at another binding site, which changes the shape of the active site and the substrate can no longer bind to the enzyme.
What are the bases of DNA?
Adenosine, Thymine
Cytosine, Guanine
What are the bases of RNA?
Adenosine, Uracil
Cytosine, Guanine
What is DNA made up of?
A nucleotide (the monomer of DNA)
A phosphate group, a deoxyribose sugar, and a nitrogenous base
Bonds between the phosphate group and carbon 3 (making DNA stable, allows it to coil, protects from damage)
What is RNA made of?
A ribose sugar, phosphate group and nitrogenous base.
Shorter than DNA
How dos DNA replicate?
Semi conservatively
DNA helicase breaks H-bonds and unwinds the strands
The original strand acts as a template
DNA polymerase catalyses bonding of free floating DNA nucleotides
What does it mean that DNA strands are antiparallel?
Each end is slightly different in structure
One end is 3’ and one is 5’
DNA polymerase= complementary to 3’
DNA polymerase moves down template strand 3’ to 5’
Describe evidence for semi- conservative
Two samples of bacteria was grown (one light N one heavy N) Sample taken and spun in centrifuge Light N settled higher Heavy N was added to light N broth Then was spun again DNA settled in the middle
Name some properties of water
Used in important metabolic reactions eg. hydrolysis
Can be a solvent (most reactions take place in a solution)
High latent heat of vaporisation (good temperature control)
Cohesive (good transport molecule)
Polar molecule
Name the structure of water
One O joined to two H, shared electrons
The shared neg electron pulled towards O causing other side left with positive charge
unshared electrons give slight negative charge
Makes water a polar molecule
Describe the structure of ATP
An adenine base
Ribose sugar
Phosphate group (high energy bonds)
How is energy released from ATP?
ATP is broken down into ADP+ Pi
In a hydrolysis reaction
Catalysed by ATP hydrolase
How can the inorganic phosphate from the hydrolysing of ATP be used?
Added to another compound to make it more reactive
phosphorylation
How is ATP re-synthesised?
In a condensation reaction between ADP+ Pi
Happens during respiration and photosynthesis
Catalysed by ATP synthase
What is a cation?
An ion with positive charge
What is a anion?
An ion with a negative charge
What is an inorganic ion?
An atom that has an electric charge
An inorganic ion doesn’t contain carbon (with exceptions)
Inorganic ions in a solution (cytoplasm), each ion with a specific role
Talk about iron ions role in haemoglobin
Haemoglobin= carry oxygen in RBC
Made up of 4 polypeptides, iron ion in centre
The iron ion binds to the oxygen
When bound Fe2+ temporarily becomes Fe3+
Talk about hydrogen ions role in pH
pH is determined by the concentration of H ions in the environment
More H ions= lower pH
Talk about sodium ions role in co-transport
Glucose and amino acids need to be co-transported across membranes
They can be co-transported by Na ions
Talk about phosphate ions role in ATP and DNA
Both DNA and ATP contain phosphate groups
In ATP the phosphate groups store energy
In DNA phosphate groups allow nucleotides to join up
