Biological Molecules Flashcards
What is the biological significance of water?
- Water Molecules are POLAR(hydrogen bonding)
- Ice is less dense than liquid water( acts as an insulating layer)
- Extremely good solvent( allow for the dissolving of substances)
- HIGH SPECIFIC Heat capacity (THERMO STABLE)
- Low viscosity (easier blood flow)
- Surface tension(capillary action)
- Aquatic animals can be larger in water since the water can support their weight
How does Hydrogen bonding occur between water?
•The 2 lone pairs of the water are attracted to 2 positive dipoles of the hydrogen
How does water work as a coolant?
•The heat is transferred into the water molecules and they evaporate taking the energy with them
What is the difference between alpha/beta glucose?
- alpha has both hydrogens on the same side
* Beta has the two hydrogens on opposite sides
What makes Maltose?
2x Alpha glucose
What makes Sucrose?
•a Glucose and fructose
What makes Lactose?
•b Glucose and galactose
What makes Cellulose?
•Long unbranched chains of b-glucose
What makes Glycogen?
•Alpha Glucose
What makes Amylose, Amylopectin(Starch)?
•Alpha Glucose
Properties of Cellulose?
•Strong
•Insoluble
•Forms microfibres, macro fibrils
- used in plant cell walls
What is the structure of Cellulose?
- Long chains of β glucose that are upside down so 2 OH face each other
- Singular chain/ Straight chain polymer
Structure of Starch?
•Alpha glucose joined by glycosidic bonds
•Amylose 1-4 Glyclosidic bonds ( Forms a HELIX)#
•Branched Amylopectin
-These are both present-
Properties of Starch?
- More compact than glucose
* Less soluble than glucose
Structure of Glycogen?
- Branched (1,6 glycosidic bonds)
- More Branches than amylopectin
- Both 1,4 and 1,6 glycosidic bonds
- (a-glucose only)
Properties of Glycogen?
- More compact than Amylopectin(COMPACT)
- Insoluble
- Branched
- Compact
- Free end which allows for easy addition onto the glycogen
Function of cellulose?
- Used in plants to make the CELL WALL
- Hard to Break down
- Fibre for a healthy digestive system
Function of Starch?
•Used as an energy store in plants
Function of Glycogen?
- Used as an energy store in fungi and animals
* More glucose chains can be added to the store as there is a free end
What are the two types of lipids?
saturated unsaturated
What are enzymes? (2 marks)
- Enzymes are Globular proteins that act as a BIOLOGICAL CATALYST (1)
- This lowers the Activation energy for metabolic reactions (1)
What are intracellular and extracellular enzymes?
-enzymes that can catalyse reaction inside cells and outside cells
What is the name of the current model of enzyme action?
-Induces fit hypothesis
Some amino acids that are not part of an enzymes active site are changed. Explain how this might affect the functioning of an enzyme
- It would affect the enzyme
- This will cause a change to the whole structure
- So the active site can change
- so the substrate can no longer form an enzyme-substrate complex
What is activation energy?
-energy needed for a reaction to occur
What elements form carbohydrates?
C, H, O
What elements form lipids?
C, H, O (same as carbs)
What elements form proteins?
C, H, O, N, S
What elements form Nucleic acids?
C, H, O, N, P
How are polysaccharides formed?
Polysaccharides are formed by many monosaccharides joined together
Why is the ability of water to act as a solvent important for the survival of organisms?
medium for (metabolic) reactions ;
(because) allows (named) ionic compound(s) to
separate ;
transport ;
two named transport, systems / media
OR
one example of a transport, medium / system, with a
named example of what is transported ;
(organisms can) absorb / take in , (named) minerals /
ions / (named) gas / food ;
able to dilute toxic substances ;
State the name given to the sequence of amino acids in a protein molecule.
Primary structure
properties of Globular Proteins
- compact
- water soluble
- roughly spherical shape
- have metabolic roles
Fibrous proteins
- Long and insoluble
- Have structural roles
Conjugated Proteins
- globular proteins that contains a non protein group
What is Catalase?
Catalase
•Globular protein (Conjugated)
- A quaternary protein that contains 4 haem prosthetic groups. The presence of Fe2+ ions allows it to speed up the reaction between Hydrogen peroxide in the cells. Catalase makes sure the H2O2 does not harm the body as catalase breaks it down
Primary Protein Structure (1°)
- Sequence of amino acids
* Bonds - PEPTIDE BONDS ONLY
Secondary Protein Structure (2°)
- alpha - helix & Beta pleated sheets
* This is due to hydrogen bonds forming in regions along the protein molecule depending on the amino acid sequences
Tertiary Protein Structure (3°)
- Folding of a protein into its final shape
- More interaction can occur (a-helix & b-pleated sheets)
- Hydrophobic/phillic interactions
- Disulphide bridges
- Ionic bonds
- Hydrogen bonds
- Vander walls forces
Quaternary Protein Structure (4°)
- From the association of of two or more individual proteins called (subunits)
- Haemoglobin globular protein that has 4 subunits (two sets of identical subunits)
How is a peptide bond broken?
- add H2O in a hydrolysis reaction
* Reforming the amine and carboxyl group
Explain how hydrogen bonds are formed in the secondary structure.
- H,O,N atoms of the basic repeating structure interact
* hydrogen bonds may form within the amino acid chain pulling it into a a-helix or beta pleated sheet structure
What is Collagen?
- Fibrous Protein
- Is the connective tissue found in skin ,tendons, ligaments and the nervous system
- Made up of 3 poly peptides wound together into a strong long rope-like structure
What is Keratin?
- Fibrous Protein
- Found in Nails, Hair, Skin
- Large proportion of sulfur containing amino acid CYSTEINE
- Degree of sulfide bonds determine the flexibility
- (Hair contains fewer sulfide bonds than nails)
What is Elastin?
- Fibrous Protein
- Quaternary protein made from many stretchy molecules called tropoelastin
- Found in the walls of blood vessels and the alveoli
- Give the structures flexibility to expand and recoil
What is Insulin?
- Globular Protein
- Hormone involved in the regulation of blood glucose concentrations
- Soluble
What is Haemoglobin?
- Globular protein (Conjugated)
- Red oxygen carrying pigment found in erythrocytes
- Fe2+ able to combine reversibly with oxygen
What is a globular protein?
- Compact
- Water soluble
- Rough Spherical Shape
- Formed when The Hydrophobic R groups fold away from the aqueous environment (making it soluble in water)
What is a conjugated Protein?
- Globular proteins
* That contains a Prosthetic group (e.g. Fe2+)
What is a Fibrous protien?
- Long Insoluble Molecules
* Because of large proportion of amino acids with a hydrophobic R-Groups in their structure
What are pyrimidines ?
- Smaller bases that contain a single carbon ring structure
* C, T
What are Purines?
- Larger bases that contain a double carbon ring structure
* A, G
What is a Nucleotide?
- Pentose monosaccharide
- Contains a Phosphate group
- And a Nitrogenous Base (A,C,T,G)
What are the Bonds between nucleotides called?
• Phosphodiester bonds
What is the difference between DNA and RNA
•Deoxy ribose has one less oxygen atom than Ribose
What are the inorganic Cations you need to know?
cations: calcium ions (Ca2+), sodium ions (Na+),
potassium ions (K+), hydrogen ions (H+), ammonium
ions (NH4+)
What are the inorganic Anions you need to know?
anions: nitrate (NO3(–0), hydrogen carbonate(HCO3(–)), chloride (Cl (–)), phosphate (PO4(3–)), hydroxide(OH(–)).
Structure of DNA?
- Two strands of polynucleotides
- Forms into a DNA double helix
- The two parallel strands run in opposite directions (ANTIPARALLEL)
How do the properties of DNA allow it to be transcribed easily?
•Hydrogen bonds
•Complementary Base pairing (nucleotide pairing is easier)
A-T
C-G
What are the base pairing rules?
- A-T (Adenine and Thymine) form 2 Hydrogen Bonds
- C-G (Cytosine and Guanine) from 3 Hydrogen Bonds and so they only form bonds with each other
- This is known Complementary Base Pairing
What is the function of mRNA?
- To transport copied section of the DNA
* T is replaced with U (uracil)
How is a phosphodiester bond formed?
A phosphodiester bond is formed between two nucleotides when the phosphate group of one nucleotide reacts with the hydroxyl group present at the third carbon of another nucleotide. A water molecule is released in the process of bond formation.-condensation reaction
