Bio Unit 1.1 Flashcards
4 Main Elements
Carbon, Hydrogen, Oxygen, Nitrogen
Organic chemistry is the study of…
carbon chemistry
Carbon forms strong covalent bonds because…
It has 4 electrons in the outer shell
Monomer and Polymers
Single molecule and lots of molecule joined together (larger molecule)
Valency
Number of electrons until full outer shell (e.g Carbon 4)
Ionic Bonding
Atoms gain or lose electrons to achieve full outer shell of electrons
Atoms giving away electrons become
Positively charged
Atoms receiving electrons become
Negatively charged
Hydrogen bonding
Attractive force/interaction between positive hydrogen atom (already bonded to another negative atom) and a negative atom.
Covalent bonding
Atoms share electrons so both have full outer shell (can have single or double bonds)
Hydrogen bonds are weak because…
No sharing of electrons, just attractive but large numbers of them within atom of polymer help stabilise molecule
Iron (Fe2+)
constituent of haemoglobin (transports o2 in red blood cells), lack of iron leads to anaemia
Importance of Inorganic Ions
cellular processes (muscle contraction, nerve coordination, maintaining water potential in cells and blood)
Magnesium (Mg2+)
constituent for chlorophyll, essential for photosynthesis, plants without Mg cannot make chlorophyll (yellow leaves),bone strength in mammals
Phosphate Ions (PO4^3)
used for making nucleotides, constituent of phospholipids found in biological membranes
Calcium (Ca2+)
important structural component of bones and teeth, component of plant cell walls (provides strength.)
Water Importance
Metabolic reactions, constituent of cells (70% each human is water)
Inorganic Meaning
A molecule/ion that has no more than one carbon atom
Dipole (Water Molecule)
Positively charged (H2) and negatively charged (o2) with no overall charge
Hydrogen bonds are weak but large number of them present in water makes the molecules difficult to…
separate and gives water many properties
Hydrogen bonds usually form between
Hydrogen atom and oxygen atom of different molecules
Molecule with separate charges is…
polar
High Specific Heat Capacity (raise temp by 1 degrees/1g)
H2 bonds between H20 molecules restrict movement, prevents large fluctuation in water temoerature, large amount of heat needed to raise temp
Useful: keeps aquatic habitats stable, animals don’t have to adapt to extreme conditions, enzymes in cells can work efficiently
Metabolite
Used in biochemical reactions as a reactant, reactions in body involve hydrolysis (water splits into a molecule)
E.g. maltose+water = glucose+glucose
Universal Solvent
Water molecules are dipoles and attract charged particles (ions) and other polar molecules like glucose.
Useful: transport medium (animals, plants, xylem, phloem)
High Latent Heat Of Vaporisation
Lots of heat needed to change from liquid to vapour, important in temperature control
Useful: Sweat evaporation, cooling body temp
Cohesion
Water molecules attract each other forming H2 bonds, bonds stick together in a lattice
Useful: Allows water to travel up in capillaries, xylem, etc.
High Surface Tension
cohesion between water provides surface tension, at ordinary temperatures water has highest tension excluding mercury
Useful: ‘skin’ layer created, insects can live on top of surface
High Density
Water is denser than air, ice denser than water (H2 bonds hold molecules further apart than they are in liquid)
Useful: ice floats, good insulator, prevents large bodies of water to lose heat, freezes completely (organisms survive underneath)
Transparency
Photosynthesis for aquatic plants (light passes through)
Basic Unit of Carbohydrates
Monosaccharide
General Formula for a monosaccharide
(CH20)n - names determined on number of carbons in molecule
glucose is a … sugar
hexose
how many isomers does glucose have
2 (beta and alpha)
Structure based on ‘OH’ and ‘H’ positions
Alpha, H on top
Beta, OH on top and alternating
Hexose sugar formula
C6H12o6
2 Monosaccharides is…
Disaccharide
Multiple monosaccharides are…
Polysaccharides
What determines the names of monosaccharides
Number of carbon atoms in the molecule
How are monosaccharides a source of energy for respiration?
C-H and C-C bonds are broken to release energy, transferred to make ATP
How are monosaccharides building blocks for larger molecules?
Glucose used to make polysaccharides like starch, cellulose and chitin
How are monosaccharides intermediates in reactions?
E.g. triodes are intermediates in reactions of respiration and photosynthesis
Monosaccharides in deoxyribose in DNA and ribose in RNA is a …
constituent of nucleotides
How are disaccharides composed with two monosaccharides?
Formation of a glycosidic bond and elimination of water (condensation reaction)
What carbons is a glycosidic bond between?
C1 and C4 (1-4 glycosidic bond)
Opposite of glycosidic bond that makes water?
Hydrolysis Bond
Glucose + Glucose =
Maltose (germination of seeds)
Glucose + Galactose =
Lactose (mammalian milk)
Glucose + Fructose =
Sucrose (transport in phloem of flowering plants)
What are reducing sugars?
Sugars that can donate an electron
What detects reducing sugars in a solution? How does it do this?
Benedict’s Solution. Donated electron reduces copper ions in copper sulphate solution (blue.) Copper(11) ions are reduced to Copper (1) ions in red copper oxide.
Test for Sugars Instructions:
Equal volumes heated to at least 70 degrees. Solution change from blue through green, yellow, orange and finally brick red. Qualitative test - does not tell you concentration of reducing sugar.
How do you use sucrase to detect sglucose?
Enzyme that hydrolyses sucrose into glucose and fructose - Benedicsts test positive
Quantitative Measurement for Glucose?
Biosensor (monitoring diabetes useful)
Why are the polysaccharides starch and glycogen more suitable than glucose in storage in plants?
Insoluble so they have no osmotic effect, cannot diffuse out of cell, compact molecules (stored in small space), carry a lot of energy in C-H and C-C bonds
What is starch made out of?
Alpha glucose molecules bonded together in 2 different ways forming amylose and amylopectin
What is amylose?
Linear, unbranched molecule with 1-4 glycosidic alpha bonds. Coils into helix
What is amylopectin?
Chains of alpha glucose monomers (glycosidic 1-4 and 1-6 bonds) and first inside amylose.
Individual cellulose molecule
Long chain of beta glucose units joined by 1-4 glycosidic bonds to make straight, unbranched chain ( rotates adjacent glucose molecules 180 degrees)
Main storage product in humans?
Glycogen (very similar to amylopectin) - 1-4 and 1-6 bonds but shorter chains so more branched
Hydrogen bonds in cellulose
Forms between OH groups of adjacent parallel chains (contributing to cellulose structural ability) Tightly linked H2 bonds form bundle called microfibril.
Where is chitin found?
Exoskeletons of insects and fungal cell walls
Bonds in Triglycerides
Fatty acids to glycerol by condensation reactions forming ester bonds
Monomers in chitin?
Rotated 180 degrees and long parallel chains are cross linked to each other by H2 bonds forming microfibrils. Beta glucose 1-4 glycosidic bonds
Lipids Solubility
Non polar compounds and are insoluble in water but dissolve in organic solvents, such as propane and alcohols
Triglycerides
one glyercyol and three fatty acids
If one C C double bond is present
Mono saturated
Phospholipid Molecules Properties
One end is soluble and the other is not (phosphate is hydrophilic and fatty acids are hydrophobic)
If hydrocarbon chain has single carbon bonds
Fatty acid is saturated
Many C C double bonds present
Polyunsaturated
Triglycerides Functions
Energy reserves, thermal insulation, protection, metabolic water
Phospholipids Function
Structural and electrical insulation
Waxes Function
Waterproofing (waxes reduces water loss e.g cuticle)
Test for Fats and Oils
Ethanol, Dissolves any lipids present, Shaken with equal volume of water, Dissolved lipids form emulsion and sample becomes cloudy white
High levels of unsaturated fats…
More HDL, carries harmful fats away to liver for disposal, lower risk of CVD or coronary heart disease
High levels of saturated fats in diet can…
LDL build up, atheroma deposited in coronary arteries, restricting blood flow and o2 delivered to heart, heart attack
Proteins contain
Carbon, Hydrogen, Oxygen AND Nitrogen
Proteins are made of monomers called….
amino acids
Attached to central carbon in each amino acid are:
amino group, carboxyl group, hydrogen atom, R group
Chains of amino acids are called
polypeptides
Amino group reacts with carboxyl group which eliminates water in…
A condensation reaction forming a peptide bond (resulting compound dipeptide.)
Primary Structure
Order of amino acids in a polypeptide chain. Polypeptides have up to 20 different amino acids, joined together in any number, order. Primary structure determined by base sequence on one strand of DNA molecule.
Secondary Structure
Hydrogen bonding between =O on OH groups and -H on -NH groups in peptide bonds along the chain, twisted 3D shape, spiral shape is alpha helix, beta pleated sheet
Quaternary Structure
Not functional, may combine with polypeptide chain or join to form complex molecules like haemoglobin.
Tertiary Structure
Hydrogen bonds, ionic bonds, disulphide bridges, hydrophobic interactions, complex and compact 3D structure
Testing for starch presence
Iodine solution (iodine dissolved in potassium iodid) turns solution orange-brown to blue-black
How is glycogen similar but different to amylopectin?
Same structure but shorter 1-4 lengths, branches more often
Where are starch and glycogen found as storage?
Plants and animals
Microfibres held in bundles are called…
Fibres
Why is cellulose freely permeable?
Spaces between fibres allow water and its solutes to penetrate cell wall to cell membrane
How is chitin different from cellulose?
groups derived from amino acids are added (heteropolysaccharide) making it strong, waterproof and lightweight
What bonds are microfibrils bonded by?
Hydrogen Bonds
Fibrous Proteins Shape
Long, thin molecule and insoluble in water
What does the role of proteins depend on?
Molecule shape
What is the function of fibrous proteins?
Structural (e.g in bone)
Why are fibrous proteins tough?
Polypeptides in parallel chains, cross linkages from long fibres (keratin in hair)
Collagen Structure
3 polypeptide chains twisted around each other like a rope and linked by hydrogen bonds (very stable)
Globular Protein Shape
compact, folded into spherical molecules
Why do globular proteins have so many different functions?
Soluble in water (enzymes, antibodies, hormones)
Haemoglobin Structure
4 folded polypeptide chains and ham (iron containing group ) in centre of each molecule
Test For Protein using Biuret
Add drops of biuret reagent (sodium hydroxide and copper(11) sulphate)
Why does positive Biuret Solution turn purple?
Makes copper hydroxide which is blue, copper hydroxide interacts with peptide bonds in protein which are purple. Blue to purple.
What kind of test in Biuret testing?
Qualititative (can be semi-quantitative if you use colorimeter with yellow filter - gives you estimated concentration of protein?
How can you make Biuret Test quantitative?
Biosensor
