Biological Molecules Flashcards
What monomers make up maltose?
Alpha glucose and alpha glucose
What monomers make up lactose
Alpha glucose and galactose
What monomers make up sucrose?
Alpha glucose and fructose
What bond joins monosaccharides?
Glycosidic
What is the monomer of cellulose?
Beta glucose
What is the monomer of glycogen?
Alpha glucose
What is the reaction that joins two molecules together?
Condensation reaction
What is the reaction that breaks a chemical bond between two molecules?
Hydrolysis reaction and involves the use of water
What is the monomer of a polypeptide?
Amino acids
What bond is formed between two amino acids?
Peptide bond
What is the monomer that makes up starch?
Alpha glucose
How does cellulose structure relate to its function?
Long straight chains parallel chains
Linked together by many hydrogen bonds to form fibrils
Provides strength to cell wall
What is the structure of glycogen? +why is it a good source of energy?
Polysaccharide of alpha glucose
Joined by glycosidic bonds
Branched structure
Hydrolysed to glucose and used in respiration
Describe the structure of starch and how it relates to its function?
Insoluble - doesn’t affect water potential
Coiled (alpha helix) - so compact molecule
Large molecule - so can’t leave the cell membrane
Polymer of alpha glucose - provides glucose for respiration
Branched - more ends for faster breakdown
What is the biochemical test for starch?
Iodine test
Add iodine to sample
Will turn blue/black
Biochemical test for reducing sugar?
Heat with Benedict’s reagent
Will change from blue to orange/red
Biochemical test for non-reducing sugar?
Heat with acid and neutralise
Heat with Benedict’s solution
Red precipitate
Biochemical test for lipids?
Emulsion test
Add ethanol to sample
Then distilled water and shake for 1minute
Will turn white emulsion
Biochemical test for proteins?
Biuret test
What is the structure of a triglyceride? + bonds formed?
Contains 1glycerol and 3fatty acids
Forms ester bond
What is the difference between a phospholipid and triglyceride?
Phospholipid contains 2 fatty acids and 1 phosphate group.
Phospholipid- condensation reaction between glycerol and fatty acid
What is the difference between saturated fatty acid and unsaturated?
Saturated - single carbon carbon bonds
Unsaturated - at least one double
What is the biochemical test for proteins?
Add biuret reagent
Purple colour
Describe how the structure of a protein depends on the amino acids it contains? 5marks
Structure is determined by the position of Rgroup
Primary structure is a sequence of amino acids
Secondary structure is formed by hydrogen bonding
Tertiary structure is formed by bonds between Rgroups
The tertiary structure creates specific shape (active site in enzymes)
Quaternary structure contains more than 1 polypeptide
Describe the induced fit model of enzyme action and how an enzyme acts as a catalyst
Enzyme lowers the activation energy needed
Substrate binds to active site forming enzyme-substrate complex
Active site changes shape slightly breaking bonds in the substrate
Describe how a non-competitive inhibitor can reduce the rate of an enzyme controlled reaction
Attaches the the enzyme at a site other than the active site
Changes the tertiary structure of the enzyme
So the active site is no longer complementary to the substrate so substrate can’t bind/less enzyme-substrate complexes formed
Describe how a competitive inhibitor reduces rate of reaction
Inhibitor similar shape to substrate
Binds to active site
Prevents enzyme-substrate complexes forming
Describe the structure of DNA
Polymer of nucleotides
Deoxyribose sugar, phosphate group and organic base
Phosphodiester bonds between nucleotides
Double helix held together by hydrogen bonds
DNA bases = adenine, thymine, cytosine and guanine.
Describe the process of semi-conservative replication
DNA helically breaks hydrogen bonds, unwinding alpha helix
One DNA strand is used as a template
Free nucleotides complementary base pair with exposed nucleotides
DNA polymerase joins adjacent nucleotides
Phosphodieste bond formed
What is the difference between RNA and DNA?
RNA contains ribose sugar
RNA contains uracil base instead of thymine
What are the components in ATP?
Adenine
Ribose sugar
3 phosphate groups
What makes ATP a good source of energy
Universal
Released in small manageable amounts
Explain five properties that make water important for organisms. 5marks
Cohesion- supports columns of water in plants
Large latent heat of vaporisation- provides a cooling effect through evaporation
High specific heat capacity- so buffers changes in temperature
Metabolite- in condensation reactions
Solvent- so metabolic reactions can occur
Describe the role of iron ions, sodium ions and phosphate ions in cells. 5marks.
Iron - haemoglobin associates with oxygen
Sodium - contra sport of glucose into cells because sodium moved out by active transport which creates a sodium concentration gradient
Phosphate ions - used in ATP + joins nucleotides in DNA
