Topic 1 Biological Molecules Flashcards
What is a monomer?
Smaller units which create large molecules
What is a polymer?
Made of lots of monomers bonded together
Give 3 examples of monomers
Glucose, Amino acid & nucleotide
Give the 3 polymers glucose can create
Starch, Cellulose & glycogen
What polymer does amino acids make
Protein
What polymer do nucleotides make
DNA & RNA
What is a condensation reaction?
Joining 2 molecules together creating a chemical bond and removing water
What is a hydrolysis reaction?
Breaks a chemical bond between 2 molecules and involves use of water
What elements does a carbohydrate contain?
Carbon, hydrogen & oxygen
What is a monosaccharide?
One sugar unit
What is a disaccharide?
Two sugar units
What is a polysaccharide?
Many sugar units joined together
Give 3 examples of monosaccharides
Glucose, fructose & galactose
Give 3 examples of disaccharides
Sucrose, maltose & lactose
Give 3 examples of polysaccharides
Starch, cellulose & glycogen
What is the chemical formula for alpha glucose?
C6H12O6
What is an isomer?
Same molecular formula but different structure
Give the acronym for defining alpha and beta glucose
A - alpha
B - below
B - beta
A - above
When referring to the hydroxyl group (OH)
How is a disaccharide made?
Made by 2 monosaccharides joined by a glycosidic bond and formed by condensation reaction
Give the word equation for the creation of maltose
Glucose + glucose —> maltose + water
Give the word equation for lactose
Glucose + galactose —> lactose + water
Give the word equation for sucrose
Glucose + fructose —> sucrose + water
Where is starch found and what is it’s function?
Found in plants
Function is to store glucose
Where is cellulose found and what is it’s function?
Found in plants
Function is to provide structural strength
Where is glycogen found and what is it’s function?
Found in animals
Function is to store glucose
Which 2 polysaccharides are formed Fromm the alpha isomer of glucose?
Starch and glycogen
Which polysaccharide is formed from the beta isomer of glucose?
Cellulose
What are the bonds between monomers in starch?
1-4 glycosidic bonds in amylose
1-4 & 1-6 in amylopectin
What are the bonds between monomers in cellulose?
1-4 glycosidic bonds
What are the bonds between monomers in glycogen?
1-4 & 1-6 glycosidic bonds
What does a 1-4 glycosidic bond form?
A polysaccharide in a straight line
What do 1-6 glycosidic bonds form
Branched polysaccharides
What is the structure of amylose
An unbranched helix
What is the structure of amylopectin
A branched molecule
What is the structure of cellulose?
Long straight chains held in parallel lines by hydrogen bonds to form fibrils
What is the structure of glycogen?
A highly branched molecule
Name one common feature of polysaccharides
They are all large insolvable molecules meaning they won’t affect water potential and won’t be affected by osmosis
Explain how the structure of amylose leads to it’s function
Helix can compact to fit a lot of glucose in a small space
Explain how the structure of amylopectin leads to the function
Branched structure increases surface area for rapid hydrolysis back to glucose
Explain how the structure of cellulose leads to it’s function
Many hydrogen bonds provide strength
Explain how the structure of glycogen leads to it’s function
Beach bed structure increases surface area for rapid hydrolysis back to glucose
What is the difference between amylopectin and glycogen?
Glycogen contains more 1-6 glycosidic bonds so is even more highly branched
Give the structure of a triglyceride?
A glycerol molecule with 3 fatty acid chains
Give the structure of a phospholipid
Glycerol molecule with 2 fatty acid chains and a phosphate group attached to glycerol molecule
How are triglycerides formed?
Via condensation reaction between one molecule of glycerol and 3 molecules of fatty acid
How many condensation reaction must occur to create a triglyceride
3
What is the bond formed by a triglyceride and how many are formed when creating one triglyceride molecule
An ester bond 3 are formed
What is a saturated fatty acid?
The hydrocarbon chain only has SINGLE bonds between carbons
What is an unsaturated fatty acid?
Contains at least one DOUBLE BOND between carbons
What is the function of a triglyceride
Energy storage
Why is triglyceride used for energy storage?
(4)
Large ratio of energy storing carbon- hydrogen bonds
Large ratio of hydrogen - oxygen atoms act as a metabolic water source (can release water if oxidised)
Triglycerides do NOT affect water potential and osmosis as they are large & hydrophobic making them insoluble
Lipids have a low mass so can be sorted without increasing mass without increasing mass
How many condensation reactions would be needed to create a phospholipid
2
What are the 2 properties of phospholipids
- Hydrophilic head due to negative charge in phosphate group this means it attracts water and repels fat as it is charged
2.the fatty acid chain ‘tail’ is hydrophobic so will repel water and mix with fats
Give the structure of an amino group
Nitrogen with 2 hydrogen atoms
Give the basic chemical structure for a protein
One amine group ( a nitrogen and 2 hydrogens)
An R group (variable group 20 options)
Attached to one carbon
A carboxylate group (carbon with a double bonded oxygen and a single bonded OH
Give the basic structure of an amino acid
A central carbon atom with an R group attached (variable group with 20 options) and a hydrogen attached
An amine group which contains one nitrogen atom bonded to two hydrogen atoms
A carboxyl group which is a carbon double bonded to an oxygen atom and then a single bonded OH
How are dipeptides formed?
2 amino acids joined by a condensation reaction so water is removed and forms a peptide bond
How are polypeptides formed?
Multiple amino acids joined together and multiple condensation reactions joined by peptide bonds
What are the 4 structure levels for proteins
Primary, secondary, tertiary and quaternary
What is the primary structure of proteins? And when is it made?
Made straight after translation in protein sysnthesis
The order of amino acids in a polypeptide chain this is a polymer
What is the secondary structure of a protein?
The sequence of amino acids causes part of molecule to bend into alpha helix shape of fold into a beta pleated sheet many hydrogen bonds hold structure
What is the tertiary structure of proteins? What bonds are present
Further folding of the 2nd structure to form a unique 3D shape
Bonds present are iconic, hydrogen and disulphide bridges
What is the quaternary Structure?
Same bonds as tertiary (iconic, hydrogen and disulphide bonds) but it is made up of more than 1 polypeptide chain
What structure level are enzymes
Tertiary
What is the role of enzymes?
Lower activation energy if the reactions they catalyse
Why can each enzyme only catalyse one specific reaction?
The active site is a specific unique shape due to folding and bonding in the tertiary structure
What is the induced fit model? And how does it help lower the activation energy?
When the active site is slight induced (changes) to mould around the substrate
when the enzyme substrate comped occurs because of this moulding it puts a strain on the bonds lowering the activation energy
What is the activation energy?
The amount of energy required for a reaction to occur
What are the 5 factors affecting enzymes?
- Temperature
- PH
- Substrate concentration
- Enzyme concentration
- Inhibitors
How does temperature affect enzyme activity?
If temp too low not enough kinetic energy for successful collisions between enzyme and substrate
If the temp too high enzyme will denature and a cube site will change shape
How does PH affect enzyme activity?
Too high or too low PH will interfere with the charges in the amino acids active site so will break bonds holding tertiary structure causing active site to change shape
Enzyme will denature
How do both substrate and enzyme concentrations affect enzyme activity?
If there is not enough substrates the reaction will be slower as there will be fewer collisions
If there is not enough enzymes the active sites will become saturated with the substrate and unable to work any faster
What is a competitive inhibitor?
(3)
Same shape as the substrate
Binds to active site
Prevents enzyme substrate complex
What are non competitive inhibitors?
(3)
Bind to the allosteric site
Caused the active site to change shapes
No enzyme substrate complex
What is the allosteric site
Part of the enzyme that is away from the active site
What is the test for starch?
(2)
Add Iodine
Positive result solution turns orange - blue/black
What is the test for REDUCING sugars
(3)
- Add Benedict’s reagent
- Heat
- Positive test turns from blue to green to yellow or orange or brick red
The more red the higher the conc of reducing sugar
What is the test for NON-REDUCING sugar?
(5)
- Following a negative Benedict’s test where the reagent is still blue
- Add acid and boil
- Cool solution and add an alkali to neutralise
- Add Benedict’s reagent and heat
- Positive test solution turns from blue to brick red
What is the test for proteins?
(2)
Add biuret
Positive test turns from blue to purple
What is the test for lipids?
(3)
- Dissolve sample in ethanol and shake
- Add distilled water
- A positive test = a white emulsion forms
What does DNA stand for?
Deoxyribonucleic acid
What does DNA code for?
Codes for a sequence of amino acids in the primary structure of a protein which then determines the 3D structure and function of a protein
Why is DNA essential?
Cells contain a copy of this genetic code that can be passed on to new cells without being damaged
Give the structure of a monomer of DNA
Made up of deoxyribose (Penrose sugar) a nitrogenous vase and a phosphate group
What are the 4 possible options for the nitrogenous base for a nucleotide?
Guanine, Cytosine, adenine or thymine
How is the polynucleotide made?
Created by condensation reactions between deoxyribose sugar and the phosphate group
What bonds are formed when creating a polynucleotide?
Phosphodiester bonds
What bonds connect the 2 polymer chains in a polynucleotide
Hydrogen bonds are between the bases and creates a double helix
Give the structure of RNA
Constrains a Penrose sugar (ribose) nitrogenous base of adenine, uracil , guanine and cytosine and a phosphate group
Give 2 structural differences between RNA & DNA
RNA is a shorter polynucleotide
RNA is single stranded
What is the function of RNA
Transfer genetic code from DNA into nucleus to the ribosomes. rRNA Is combined with proteins to create ribosomes
What is the process of DNA replication?
Semi conservative replication
Give the steps of semi conservative replication
(4)
- The enzyme DNA helix add breaks down the hydrogen bonds between the complementary base pairs this causes the DNAs double helix to unwind
- Each of these strands will act as a template stands and free floating DNA nucleotides within the nucleus are attracted to their complementary base pair on the template strand
- The nucleotides are joined together to form a phosphodiester bond by a condensation reaction DNA polymerase catalysed this reaction
- The 2 sets of daughter DNA contains one strand of parental DNA and one newly synthesised strand
Give the name of the scientists to provide evidence for semi conservative replication
Watson and crick discovered the structure of DNA which was helped by Rosalind Franklins research on x ray diffraction
Meselson & Stahl conducted experiment proving DNA replication was semi conservative
Give the structure for ATP
A Penrose sugar (ribose)
The nitrogenous base (adenine)
3 phosphate groups
What does ATP stand for
Adenosine triphosphate
What is ATP
An immediate source of energy for biological processes
When is ATP made and what is the word equation
ATP made during respiration
ADP + Pi
Made by condensation reaction using the enzyme ATP Synthase
How does ATP release energy?
When hydrolysed into ADP + Pi using enzyme ATO hydrolase this releases a small amount of energy
How can ATP transfer energy to other compounds?
The inorganic phosphate release by hydrolysis of ATP can be bonded onto different compounds to make them more reactive this is called phosphorylation
What are the 5 key properties of water
- Water is a metabolite (involved in chemical reactions)
- Water is a solvent
- Water has a high heat capacity takes a lot of energy to raise the temp
- Has a large latent heat of vaporisation provides a cooling effect with loss of water through evaporation
- Water has strong cohesion between molecules this supports water columns and provides surface tension
What is the role of hydrogen ions?
Lower the PH of solutions and impact enzyme function
What is the role of Iron ions
A component of haemoglobin in the transport of oxygen
What is the role of sodium ions
Involved in co-transport of glucose and amino acids in absorption OR in role in generating action potentials
What is the role of phosphate ions
A component of DNA and ATP
