1.1 Chemical elements joined together to form biological compounds Flashcards
Definition of Molecules
A group of atoms bonded together
C6H12O6
Definition of Ions
Atom or molecules with a net electric charge (+ or -) due to the loss or gain of electron
Compounds
Formed from 2 or more elements H2O
Function of magnesium
Constituent of chlorophyll needed for photosynthesis
Function of Iron
Constituent of hemoglobin
Function of Phosphate
Making nucleotides e.g ATP, DNA, RNA. Constituent of phospholipids
Function of Calcium
Structural component of bones and teeth, component of cell walls
Structure of water
Covalent bonds
Polar
Molecule
Polar - water
Oxygen is slightly negatively charged
Hydrogen atoms are slightly positively charged
Hydrogen bonding
Hydrogen bonds exist between water molecules.
The slightly negative oxygen of one water molecule attracts the slightly positive hydrogen atoms of other water molecules
High specific heat capacity
is the measure of the amount of energy needed to raise the temperature of a fixed amount of that substance by 1ᵒC
A large amount of energy is needed to cause a small rise in the temperature of water - aquatic environments stay stable
Universal solvent
- unequal distribution electrical charge makes water a good solvent
- polar molecules e.g amino acid, sugar readily dissolve in water
- non polar molecules such as lipids will not dissolve in water
Ice is less dense than water
- forms an insulating when frozen
- ponds and aquatic habitats do not freeze solid so animals can still swim
-Water expands when frozen
-Ice floats on water
High latent heat of vaporisation
A lot of energy is needed to evaporate water so organisms use water to cool down (e.g Sweating) and aquatic habitats don’t disappear easily by evaporation
- Transpiration in plants also has a cooling effect on leaves
Water is transparent
Light can pass through aquatic plants to photosynthesise
Light can pass through the cytoplasm of plant cells to reach the chloroplast
High surface tension
Cohesion is the tendency of molecules of a substance to attract one another
Cohesion between the water molecules on the surface of the water forms a skin that covers the water
Cohesion
Water to water
Adhesion
Water to object
Water is a metabolite
Water is used in many biochemical reaction e.g as a reactant in photosynthesis
Water is a liquid at most temperatures
can be used as a transport medium e.g in blood, xylem in plants
What compounds are in carbohydrates?
Carbon, Hydrogen, Oxygen
Functions of carbohydrates
- Source of energy
- Store of energy
- Structural support
3 main types of carbohydrates
- Monosaccharides
- Disaccharides
- Polysaccharides
General formula of carbohydrates
n(CnH2nOn)
Name the 2 glucose monomers
Alpha glucose
Beta glucose
ABBA
Definition of isomer
They have the same chemical formula but different structural formulas
Functions of monosaccharides
Sweet, soluble
- When C-H and C-C bond are broken - energy released - transferred to make ATP
- As building blocks to make larger molecules
- Intermediates in reactions e.g triose intermediates in respiration and photosynthesis reactions
Hydrolysis
Chemical addition of water to break a bond
How are disaccharide formed
Formed when 2 monosaccharides join together
What is released during a condensation reaction?
Water
What’s the name of the reaction when 2 monosaccharides join together?
Condensation reaction
What’s the name of the bond when 2 monosaccharides bond together?
Glycosidic bond
What 2 monosaccharides form Sucrose?
glucose and fructose
What is the name of the disaccharide formed from glucose and fructose?
Sucrose
What’s the source of sucrose?
Stored in plants such as sugar beet and sugar canes
What is the name of the disaccharide formed from glucose and galactose?
Lactose
What 2 monosaccharides form Lactose?
Glucose and galactose
What is the source of Lactose?
Milk sugar - main carbohydrate found in milk
What 2 monosaccharides form Maltose?
glucose and glucose
What is the source of Maltose?
Malt sugar found in seeds such as barley
What is the name of the disaccharide formed from glucose and glucose?
Maltose
What test detects sugars in solutions?
Benedict’s test
Benedict’s test
Need to heat solution
- Colour changes from blue, green, yellow to a brick read if sugar is present
Polymer
A large molecule comprising of repeated monomers, bonded together
Monomer
are the individual monosaccharides which join to form the polysaccharide
Polymerisation
The process of bonding many monomers by condensation reactions to form one large molecules
2 examples of alpha glucose polysaccharides
Starch
Glycogen
2 examples of beta glucose polysaccharides
Cellulose
Chitin
Polymer made up of alpha glucose molecules bonded together in 2 different ways, forming what 2 polymers?
amylose and amylopectin
Startch facts
it is a polysaccharide
insoluble
store of glucose in plants
How to test for starch?
Iodine test
What colour does iodine change if starch is present?
Brown- orange to blue-black
Amylose
-unbranched polymer
-α glucose
-C1-C4 glycosidic bonds
-twists on it’s self
Amylopectin
-chains of glucose monomers joined with
-C1-C4 glycosidic bonds crosslinked with C1-C6 glycosidic bonds
-α glucose
Glycogen
-Main storage product in animals in muscle and liver
-Similar to amylopectin but glycogens C1-C4 bond is shorter than amylopectin so its more branched
-C1-C4 and C1-C6 glycosidic bonds
-α glucose
Cellulose
-a structural polysaccharide - cell wall of plants
-β glucose
-C1-C4 glycosidic bonds
-unbranched
-Hydrogen crosslinked bonds
-adjacent glucose molecules rotated 180*
Chitin
-a structural polysaccharide
-β glucose
-C1-C4
-Amino acid side chains
-Rotated 180*
-cross linked by hydrogen bonds
*Strong
*Waterproof
*Lightweight
What are the compounds of lipids?
Carbon, oxygen, hydrogen
Examples of lipids
- Triglycerides
- Phospholipids
- Waxes
- Steroids
Lipids are ……
Non-polar
Insoluble in water
Fats and oils
Triglycerides consists of……
One molecule of glycerol
Three molecules of fatty acids
What group joined to the long hydrocarbon chain at the end of the fatty acid?
Carboxyl group (-COOH)
Saturated fatty acid contains
only C-C single bonds
Unsaturated fatty acid contains
at least one C=C double bond
Triglycerides are formed as a result of what reaction and which groups of the fatty acid are involved?
condensation reaction
-OH of the glycerol and the -COOH of each fatty acid
How many water molecules are removed in the formation of triglycerides?
3
3 condensation reactions
For each condensation reaction in a triglyceride what bond is formed?
Ester bond
Triglycerides contain
Glycerol
3 fatty acids
NO phosphate
Phospholipids contain
Glycerol
2 fatty acids
Phosphate
Phosphate head is …..
water loving
polar
hydrophilic
soluble in water
lots of oxygen
Fatty acid tail is…..
water hating
non polar
hydrophobic
insoluble in water
no oxygen
Waxes are….
Long-chained fatty acids are linked to a long-chained alcohol
Insoluble waxy cuticle
Roles of lipids - triglycerides
Energy reserves - Plant (seed), animal (adipose tissue)
Thermal insulation -stored under the skin - insulate against heat loss or heat gain
Protection - stored around delicate organs - kidney
Metabolic water - released during chemical reactions in the body
Roles of lipids - phospholipids
Biological - cell membrane
Electrical insulation - myelin sheath surrounding axons of nerve cells
Cause of heart disease
-fatty deposit sin the coronary arteries
- high blood pressure
High density lipoproteins
when food has been absorbed at the small intestine
-Diet in high saturated fats
-Increase in low density lipoproteins
-Atheroma deposited in coronary
-Angina, myocardial infarction
What 2 compounds combine to make lipoprotein?
Protein and lipids
The higher the ratio of high density lipoproteins : low density lipoproteins in a persons blood, the lower the risk of…….
cardio-vascular and coronary heart disease
What compounds are in proteins?
Carbon, Hydrogen, Oxygen and NITROGEN
some sulphur contains phosphorus
What is a monomer of protein called?
Amino acid
What is a polymer of protein called?
Polypeptide
(chain of amino acids)
What 3 groups form amino acid?
- Variable R group
- Carboxyl group (-COOH)
- Amino acid (-NH2)
What’s the name of the bond that joins 2 amino acids (dipeptide) And what’s the reaction?
Peptide bond
Condensation reaction
Primary structure of a protein
Simple
-20 different amino acids
-Peptide bonds join the amino acids
Secondary structure of a protein
Hydrogen bonds
-long polypeptide chain twists into a 3D shape
1. Alpha helix
2. Beta pleated sheet
Tertiary structure of a protein
alpha helix of a secondary protein can be folded and twisted to give a MORE complex 3D structure
-Hydrogen bonds
-Ionic bonds
-Disulphide bonds
-Peptide bonds
Hydrophobic interaction
Quaternary structure of a protein
2 or more tertiary bonded together
-Hydrogen bonds
-Ionic bonds
-Disulphide bonds
-Peptide bonds
Hydrophobic interaction
e.g red blood cells
Globular proteins - hemoglobin
-hemoglobin consists of 4 polypeptide chains
-spherical
-own specific shape
-soluble
-easily changed chemically- unstable
-Metabolic functions
Fibrous proteins - collagen
-consists of polypeptides laid down in parallel chains
-very stable, insoluble, strong
- a single collagen fiber consists of 3 polypeptide chains that’s twisted in a alpha helix form
-Hydrogen bonds
-similar shapes
-Structural functions
What iron containing group is in a globular protein? And what does it do?
- center of each polypeptide chain is an iron-containing group called haem
-Heam contains an iron ion - each iron ion can bond with one molecule of oxygen - each hemoglobin can pick up four oxygen molecules
What’s the food test of proteins?
Biuret changes from blue to purple
Qualitative
result indicates whether food group is present or not
don’t know how much is present
Semi-quantitative
different colour changes can indicate different concentration
Quantitative
actual value for the concentration of food group present
colorimeter
