Biomolecule Flashcards
Describe the structure of a water molecule
- one oxygen atom covelently bonded to two hydrogen atoms
- oxygen is more electronegative than hydrogen which leads to polar bonds and an uneven charge distribution
What is a hydrogen bond
Strong intermolecular forces
Hydrogen atoms which are directly covalently bonded to a highly electronegatively atom (NOF) are attracted to highly electronegative atoms in other molecule
What is a solvent
Any substance which solutes can dissolve in to form a solution
State 6 important properties of water
- act as a solvent
- act as a metabolite
- high surface tension
- high specific heat capacity
- high latent of vaporisation
- strong cohesion and adhesion forces
Why is cohesion useful in biological systems
Cohesion is the main force supporting columns of water as they are pulled up the xylem in plants. The water molecules stick together as a constant column
Why is adhesion useful in biological system
It allows water to move against the pull of gravity up the xylem
What are carbohydrates
Molecules that consists of carbon, hydrogen and oxygen only
What are monosaccharides
One sugar unit
What is a disaccharides
When two monosaccharides covalently linked by glycosidic bond by condensation reaction
What is a polysaccharides
A polymer made of many monosaccharides covalently linked by glycosidic bond
Properties of monosaccharides
Single sugar unit
Water soluble
Taste sweet
Reducing
Single-ring structure
No glycosidic
Osmotic effect
Disaccharides
Water soluble
Taste sweet
Reducing ( not sucrose)
Two ring structure
Glycosidic
No osmotic effect
Polysaccharides
Insoluble
Not sweet
Non-reducing
No osmotic effect
Define isomers
Same molecular formula but different structure formula
Describe what happens in a condensation reaction
Two molecules are joined togther and water is removed
What type of reaction breaks a glycosidic bond
Hydrolysis reaction
Describe what happens in a hydrolysis reaction
A molecule is broken apart using water
Describe the structure of glycogen
Made up of alpha glucose molecules joined by either alpha 1,4 or alpha 1,6 bonds
Highly branched
Compact
Large molecule - store lots of energy
Insoluble - no osmotic effect
Function of glycogen
Main energy storage material in animals
Describe the structure of starch
Made up amylose (joined by alpha 1,4 bomds)
- unbranched
- coiled
- compact -can fit more glucose molecules in a small space
Amylopectin (joined 1,4 and 1,6 alpha bonds)
-branched chain - can be rapidly hydrolysed by enzyme break down into glucose to be released
Starch is also insoluble in water - so it doesnt cause water to enter cells by osmosis
-good for storage
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Sucrose monosaccharides
Glucose + fructose
Stored in plants such as sugar cane
Lactose monosaccharides
Glucose + galactose
Milk sugar - main carbohydrates found in milk
Maltose monosaccharides
Glucose + glucose
Malt sugar - found in germinating seed such as barley
What 3 element are triglycerides made up of
Carbon hydrogen and oxygen
How is triglycerides made
Triglycerdies are formed by condensation of 1 glycerol molecule and 3 fatty acids forming an ester bond between the carboxyl and hydroxyl group releasing 3 molecules of water
Properties of saturated triglycerides
No Carbon- carbon double bond
Melting point high
State rtp solid
Example butter
Properties Unsaturated triglycerides
Have carbon carbon double bond
Low melting point
State rtp liquid
Example oil
How is a liquid triglycerides
The different state due to the presence of a double bond between carbon atoms in the fatty acids tail
—> double bond cause the bend pushes the unsaturated triglycerides molecule further apart than the saturated molecules
—> this weakens the intermolecular forces between the unsaturated triglycerides molecule so they form a liquid
Describe amino acid
Building blocks of protein consisting of an amino group (-NH2) and carboxyl group (-COOH) attached to a carbon atom and R group that varies between amino acid
Polypeptide
Two or more amino acid joined together
Dipeptide
Two amino acid joined by peptide bonds
Primary structure of protein
Sequence of amino acid in a protein held together by peptide bond
Secondary structure of protein
Is the folding of the polypeptide chain into alpha helices and beta-pleated sheets due to the formation of hydrogen bonding
-the hydrogen in NH2 is slightly positive and the oxygen in -C=O is slightly negative resulting hydrogen bond between amino acid
— alpha helix the polypeptide chain coils with hydrogen bond keeping rhe coil stable
-pleated betasheet chain form a zigzag and fold over themselves
Tertiary structure in protein structure
Further folding of the secondary structure to form a unique functional 3D shape held togther by ionic, hydrogen & disulphide bond
-alpha helices and beta pleated sheets also twist and turn to form a protein with unique 3D structure
Quaternary structure in protein
A specific 3D shape of a protein that is determined by multiple polypeptide chains held together by hydrogen , ionic, disulphide bonds
Globular proteins 3D structure
Complex tertiary and sometimes quanternary structure and fold into spherical (globular) shapes
Globular protein properties
Proteins soluble
Outer layer - R group is hydrophilic
Inner layer - R group is hydrophobic
Molecule is so big Forms a colloid
Carboxyl and amino acid ends give them ionic properties so might expect them to dissolve in water, form a solution
Haemoglobin
Consists of 4 polypeptide chains which are 2 alpha chains and 2 beta chains
- each polypeptide chain contains a iron - haem containing group (prothetics group) that bind with oxygen then released when required
- soluble, so it can be easily transported
- it is a quanternary structure
—> has 4 polypeptide
4 haem prothetic groups
—> conguagated protein
What is fibrous
Little or no tertiary structure
Long parallel polypeptide chains with occasional crosslinkage that forms them into fibre
Contain large proportion of amino acid with hydrophobic R groups
—> insoluble - too large to be dissolve in water
Triple helix - high tensile strength
Collagen structure and properties
The primary structure of these chain is repeating sequence of glycine with two others
Quanternary structure has 3 polypeptide chain
The 3 polypeptide alpha - chains are arranged/wrapped around into a unique triple held by hydrogen bond
—> help stabilise the quanternary structure
Collagen further strengthened by crosslinking between different triple helical molecule
Define Conjugated protein
Protein molecule joined with or conjugated to prothetic group
Define prosthetic group
A molecule incorporated in a conjugated protein
Lipoprotein
Proteins conjugated with lipids prosthetic group
—> help transport of cholesterol in blood
Glycoprotein
Proteins with a carbohydrates prosthetic group
-help in holding lots of water so harder for protein- digesting enzyme (proteases break them down)
Lubricants
-mucus -synovial fluid in joints
—> stomach produces mucus to protect enzyme attack the stomach wall
Principle of circulation
Transport in small organism
Very small distance
Surface area to volume ratio is large
Low metabolic demand need less nutrients O2 excrete less waste
Tranport in large organism
Small surface area to volume ratio is small
High metabolic rate
Diffusion alone isnt enough
Transport oxygen and heat using mass flow
Double circulation system advantages
Oxygenated and deoxygenated blood cannot be mixed are separated thus maintain a steep concentration gradient
Transport at high pressure
Transport oxygen at hih pressure using mass flow
Arteries
-smooth muscle
—> thicker change the diameter of the vessel to control blood flow
Elastic fibre
- maintain high blood pressure
- stretch and recoil
Collagen
-provides strengthen prevent from rupture
Smooth endothelium reduce friction
Narrow lumen maintain high blood pressure
Vein
Smooth muscle
- control /maintain blood flow
- contract pushing blood along
Capillaries
One cell thick
-short diffusion distance
Narrow lumen
-slow blood flow, red blood cell can only fig through and squeezed against the walls and this maximise diffusion
Pores
In walls between cells allow substances to escape
Red blood cell can only squeezed against the walls maximise diffusion
