Module 2.1.2 Biological Molecules Brewer Flashcards
What is a monomer?
A small molecule that is one of the units bonded to form a polymer
What is a polymer?
A large molecule made up of many repeating molecules covalently bonded together
What is a polar molecule?
A molecule with regions of negative charge and positive charge
What is hydrogen bonding ?
Relatively weak interaction which break and reform between the constantly moving water molecules
Details of water being a liquid
-Hydrogen bonds continually break and reform
-hydrogen bonds make it difficult for molecules to escape and become a gas so more energy is required to do so
- low viscosity so can flow easily
Why does ice float ?
1) water becomes more dense as it cools until 4C-0C
2)At this temp the polar nature causes the molecules to align themselves
3) due to less kinetic energy hydrogen bonds form up and expand forming a lattice structure with empty space making ice low density.
What is the arrangement of ice ?
Tetrahedral arrangement
Why is water a good solvent?
-polar so attracts to another polar substance
- the water molecules rearrange around the positive ion so that the partially negative region on the oxygen atom is fully surrounding the ion as opposites attract then making the ion saturated and fully dissolved.
-opposite for - ions . partially + regions in hydrogen
What is cohesion?
Hydrogen bonds between the molecules pull them towards eachother so they stick together
What is surface tension ?
Between the air and the water the cohesion between the molecules provide surface tension as the hydrogen bonds pull the molecules towards the surface
Why does water have a ^ SHC
-hydrogen bonds absorb alot of energy
- water doesn’t experience rapid temperature change
Why does water have high specific latent heat if vaporisation?
-a lot of energy is needed to break hydrogen bonds
- when water evaporates latent heat of vaporisation helps the molecules to break away and become gas
- a lot of energy needed = high SLHOV
Water as a reactant
-photosynthesis
- hydrolysis
-doesn’t draw on its polarity
What are lipids made of ?
-Carbon
-hydrogen
-oxygen
What are carbohydrates made of?
-carbon
-hydrogen
-oxygen
What are proteins made of ?
-carbon
-hydrogen
-oxygen
-nitrogen
-sulphur
What are nucleic acids made of?
-carbon
-hydrogen
-oxygen
-nitrogen
-phosphorus
Mass number
The MASSive number
How many bonds can carbon form ?
4
How many bonds can nitrogen form ?
3
How many bonds can oxygen form ?
2
How many bonds can hydrogen form ?
1
What is calcium required for (cation)?
-nerve impulses
-muscle contractions
What is sodium required for (cation)?
-nerve impulses
-kidney function
What is potassium required for? (cation)
-nerve impulses
-stomata
How many amino acids are need to create a protein?
20
What is a condensation reaction?
MAKING polymers
A chemical reaction where two molecules are joined together through covalent bonding forming a larger molecule and a molecule of water
What is hydrolysis?
BREAKING polymers
A chemical reaction where the covalent bond is broken when you add a water molecule, separating the two molecules
Where do hydrolysis reaction occur?
-maltose
-sucrose
-lacyose
What is covalent bonding?
-between two non metals
-share electrons
What is ionic bonding ?
-atoms are gained or lost
-metal and non metal
Properties of a covalent bond
1) strong
2) don’t break and reform easily
3) useful to make polymers
4) attraction WITHIN the molecule
Properties of hydrogen bond
1) relatively weak
2) break and reform easily
3) always invoked hydrogen
4) attraction BETWEEN molecules
What are the 2 carb groups?
Sugars
Starch
Describe sugars
-one or two units
1 unit -> monosaccharide
2 unit -> disaccharide
Describe starch
-long , large storage
-many units
-polysaccharide
General formula of monosaccharides
(CH2O)n
What are carbs for?
-act as an energy source and support
-function is related to structure
-contain carbon, oxygen, hydrogen
General formula of carbohydrates?
Cx(H2O)y
What’s an isomer ?
Molecules that have the same molecular formulas, but different arrangement of atoms
How is glucose related to its function of energy ?
-it makes it soluble -> can easily be transported
-it’s chemical bonds contain a lot of energy
What type of saccharide is glucose m?
Hexose monosaccharide
What do the hydrogen bonds between the hydroxyl groups and water molecules allow glucose to be ?
Insoluble I’m non polar solvents
How are disaccharides formed ?
-condensation reaction
What’s the bond formed between 2 monosaccharides to form a disaccharide?
-glycosidic bond
What is a glycosidic bond ?
A covalent bond formed when 2 carbohydrates are joined by a condensation reactionn
How is maltose formed?
- 2 alpha glucose molecules are joined by an alpha 1-4 glycosidic bond
How is sucrose formed ?
Isomer of glucose
Glucose and fructose join by an alpha 1-4 glycosidic bond
-alpha and beta
What are polysaccharides made of one kind of monomer called ?
Homopolysaccharides
What are polysaccharides made of more than one type of monomer called?
Heteropolysaccharides
What is starch ?
-a polymer of alpha glucose molecules with glycosidic bonds linking the molecules together
What is the formation of starch like?
-coiled up into a spring
-the shape of the monomer and angle the glycosidic bonds joking forms a 1-4 glycosidic bond
What are the 2 molecules of starch?
-Amylose
-amylopectin
Key features of amylose
-un branched chain of alpha glucose
-angles of glycosidic bonds give it a coiled structure ->compact hood for storage
Key features of amylopectin
-long, branched chasing of alpha glucose-> allows enzymes to break down the molecule to get at the glycosidic bonds so glucose can be released quickly
-better
What are plastids in starch ?
The way starch is stored -> as intracellular starch grains in organelles (plastids)
-membrane bound
-plant cells
Is starch soluble ?
No
-insoluble ->non polar
Why is starch insoluble?
-so it doesn’t cause water to enter cells by osmosis causing them to swell
What is glycogen ?
-main energy store in animals
-animals store excess glucose as glycogen
Structure of glycogen
-lots of side branches -> stored glucose can be released quickly
-compact -> storage
-alpha 1-6 glycosidic bonds
Glycogen vs starch
-Glycogen is less dense and more soluble than starch
-glycogen is broken down more rapidly -> shows animals have a higher metabolic requirements than plant
Structure of cellulose
-beta glucose joined by glycosidic bonds
-unbranched chains (straight cellulose chains)
-molecules flip in an alternating pattern due to the position of the -OH and -H group at C1
How are cellulose chains linked together?
-by hydrogen bonds
-form strong fibres (microfibrils) due to high number of -OH on the outside chains
How are macrofibres formed (cellulose)
Bundles of microfibrils are cross linked by hydrogen bonds
Why is cellulose used in cell walls?
-strong fibres provide structural support that’s stable
What are lipids?
-Macromolecules
-contain: carbon, hydrogen and oxygen
Are lipids soluble ?
No
-insoluble in water as they are not polar and don’t attract water molecules (hydrophobic )
-DO dissolve in alcohol
What are the three types of lipids ?
1) triglycerides
2)phospholipids
3)cholesterol
What’s a macromolecule?
-very large , organic molecule
What is a fatty acid ?
-a molecule with a hydrocarbon chain and a carboxylic acid
What is glycerol?
-a 3 carbon alcohol molecule
-joins to fatty acid to form a triglyceride
What is an ester bond ?
Bond formed when an organic acid joins an alcohol by a CONDENSATION reaction
In LIPIDS
What does R stand for in structures ?
-hydrocarbon tail
How long is a hydrocarbon tail?
2-20 carbons
What does an unsaturated tail have that a saturated one doesn’t ?
A carbon DOUBLE bond
Saturated only has one SINGLE bond
Where can you find phospholipids ?
-In all biological membranes
What do phospholipids contain that triglyceride’s don’t ?
A phosphate group
How many fatty acids do phospholipids have ?
2
-1 SATURATED and 1 UNSATURATED
How long are phospholipids fatty acids hydrocarbon chains ?
16-18 carbons
EVEN number
Where are phosphate ions found?
-in cytoplasm
-negatively charged (soluble in water)
Why is the phosphate molecule hydroPHILIC?
-ATTRACTS water
Why are the hydrocarbons in phospholipids hydroPHOBIC?
-non polar
-REPEL water
What are the properties of proteins?
-structural
-catalytic
-carriers and pores
How are proteins structural?
They’re the main component body tissue in animals such as muscle,skin ligament and hair
How are proteins catalytic?
They make enzymes, antibodies and some hormones due to the specificity of their shape mr
How are proteins carriers and pores ?
Membranes have protein constituents that act as carriers and pores for active transport across the membrane and facilitated diffusion
What are proteins
Long chains of amino acids
What are amino acids ?
Monomers of all proteins and all have the same basic structure
What are the elements in amino acids ?
-carbon
-hydrogen
-oxygen
-nitrogen
-some sulfur
How many amino acids are there and how many are in proteins?
-500+ typed
-only 20 are proteinogenic
How many of the 20 amino acids are non-essential?
5
Our bodies can be made from other amino acids
How many of the 20 amino acids are essential?
9
Only obtained by food
How many of the 20 amino acids are conditionally essential?
6
Only needed in infants and growing children
Structure of an amino acid
-an amino group -NH3
-a carboxyl group -COOH
-a central carbon atom that carried a hydrogen atom on one side and an R group on the other
What is an R group?
-A side chain that acts as a functional group
-helps determine the internal bonds and the shape of the polypeptide and hence it’s final function
-called residual groupb
Examples of amino acids
Glycines
Arginines
End in ines except those with acidic R groups
How can R grounds vary?
In
-size
-by charge
-by polarity
-some are hydrophobic
-some are hydrophilic
How are amino acids linked together ?
-By peptide bonds
-To from dipeptides or polypeptides
What is the shape of protein determined by ?
-the amino acids and their arrangements in the chain
What are the 4 levels of protein structure ?
1) primary
2) secondary
3) tertiary
4)quaternary
What is the primary structure of proteins?
-the sequence
-type
-number of amino acids in the polypeptide chain
Bonds involved in primary structure?
-peptide bonds between the carboxyl and amine groups
What is the primary structure of a protein directed by?
-information carried within DNA
- change in a single amino acid alters it’s function
What is the secondary structure ?
-the twisting chain of amino acids
Bonds involved in the secondary structure?
Hydrogen bonds between the NH group of amino acid and CO group of another down the chain
What are the 2 main forms of secondary folding ?
1) alpha helix
2)beta pleated sheets
How is the alpha helix of the secondary structure held together ?
-by the hydrogen bonds between the NH group of one amino acidand the CO group of another four places ahead in its chainn
How is the secondary beta pleated structure held together ?
By hydrogen bonds between the NH group of one amino acid and the CO group of another further down the strand hold the sheet together
What is the tertiary structure ?
-when the coils and pleats start to fold along with areas of straight chains of amino acids
-folding the protein into its 3D shape
Bonds involved in tertiary structure
-ionic bonds
-disulfide bonds
-hydrophobic and hydrophilic interactions
-hydrogen bonds
What is the quaternary structure ?
Results from the association of two or more individuals proteins called subunits
Bonds invoked in quaternary structure
-ionic bonds
-disulfide bonds
-hydrophobic and hydrophilic interactions
-hydrogen bonds
Definition of ionic bonds
-stronger than hydrogen bonds
-forms between oppositely charged R groups
Define disulfide bonds
-strongest bonds
-covalent bonds
-only form between R groups that contain sulfur atoms
Define hydrogen bonds
-Weakest bonds formed
Define Hydrophilic and hydrophobic interactions
Weak interactions between polar and non polar R groups
Where are proteins assembled?
-in the cytoplasm (aqueous environment)
-affects the way the protein folds and depends on the polarity of the R groups
Where are hydrophilic and hydrophobic found in the protein ?
-hydrophilic groups are found outside the proteins
-hydrophobic groups would be shielded on the inside of the molecule away from the water in the cytoplasm
How are peptides broken down
-heating the protein to a high temperature breaks it ionic bonds, hydrophobic/Phillic interactions and hydrogen bonds cause the 3D protein shape to change
-the protein will unfold, become denatured and stop working
What can cause proteins to denature ?
-change in:
1) temperature
2) Ph
3) salt concentration
What happens to proteins when their denatured?
-fibrous proteins lose their structural strength
-globular proteins become insoluble and inactive
Function of starch?
Store of glucose
Location of starch ?
Plants
Structure of starch?
2->
Amylose : unbranched helix
Amylopectin: branched molecule
How does structure of starch lead to its function ?
-helix can compact to fit a lot of glucose in small space
-branches increases surface area for rapid hydrolysis back to glucose
-insoluble so doesn’t effect water potential
Monomers is cellulose?
Beta glucose
1-4 glycosidic bonds
Function of cellulose?
Structural strength in cell wall
Location of cellulose?
Plants-> cell wall
Structure of cellulose ?
-long straight polymer chains
-held parallel by many hydrogen bonds to form fibrils
-microfibrils combine to form cellulose fibre
How does cellulose structure helps its function ?
-many hydrogen bonds provide collective strength
-insoluble so won’t affect water potential
Monomers involved in glycogen?
Alpha glucose
1-4 and 1-6 glycosidic bonds
Function of glycogen?
Store of glucose
Location of glycogen?
Animals -> muscle and liver cells
Structure of glycogen?
-highly branched
How structure of glycogen helps function?
Highly branched increases surface area for rapid hydrolysis back to glucose
-insoluble so doesn’t affect water potential
What are lipids made of ?
Fatty acids and glycerol
How are triglycerides formed ?
Via condensation reaction between one molecule of glycerol and 3 molecules of fatty acid
Why can triglycerides transfer energy well ?
-large ratio of energy-storing Carbon to hydrogen bonds compared to number of carbon atoms
-a lot of energy when broken doen
How are triglycerides good metabolic water sources?
-high hydrogen to oxygen atom ratio
-can release water is they’re oxidised
Why are triglycerides insoluble?
-hydrophobic
-don’t affect water potential
What are phospholipids made of ?
-glycerol
-2 fatty acids
-a phosphate
-2 ester bonds -> condensation reaction between fatty acid and phosphate
Property of the head and tail of a phospholipid?
Head ->Hydrophilic
Tail -> Hydrophobic
How is the phospholipid bilayer formed?
Hydrophilic heads spin facing the water and hydroponic tails spin inwards facing each other making the membrane structure .
What is the structure of cholesterol?
-4 carbon rings and a hydroxyl group
-hydrophobic and hydrophilic regions
Where is Cholesterol found ?
Embedded within cell membranes to impact fluidity
How does cholesterol impact fluidity?
-REDUCE -> HIGH temp
-INCREASE-> LOW temp
What shape are globular proteins?
-round and compact
Are globular proteins stable or unstable?
Unstable
Why are globular proteins soluble?
-hydrophilic R group on amino acids is pushed to outside of molecule in tertiary structure
Why is it good fibulas proteins are soluble?
Easily transported in fluids eg haemoglobin in blood
What’s the shape of fibrous proteins?
Tough and rope shaped
Are fibrous proteins soluble or insoluble?
Stable or unstable
-insoluble
-stable
Examples of fibrous proteins ?
Collagen-> connective tissue
Keratin->hair
Elastin-> elastic connective tissue
What is an inorganic ion?
One that doesn’t contain carbon s
Role of calcium (cation) Ca2+
-Transmission of nerve impulses
-release of insulin in pancreas
Role of sodium (cation) Na+
-generates nerve impulses
-regulates body fluid balance
Role of potassium (cation) K+
-generates nerve impulses
-activated essential enzymes in photosynthesis
Role of hydrogen (cation) H+
-affects ph of substances
-important in respiration in inner membrane of mitochondria
Role of ammonium (cation) NH4+
-absorbed from soil by plants to source nitrogen
Role of nitrate (anion) NO3-
-absorbed from soil by plants to source nitrogen
Role of hydro carbonate (anions) HCO3-
-maintain ph of blood
Role of chloride (anion) Cl-
-maintain ph of blood during gas exchange
-cofactor of enzyme amylase
Role of phosphate (anion) PO43-
-photosynthesis and respiration
Role of hydroxide (anion) OH-
-Affects ph of substances
Test for starch
-add iodine
-present : Blue/ black
Test for reducing sugar
-Benedict’s and HEAT
-if present: green/yellow and orange/ brick red
Test for non reducing sugars
-following negative Benedict’s
-add acid and boil
-cool and add alkali to neutralise
- add Benedict’s and heat
- present: yellow/ green or orange/ brick red
Test for protein
-biuret
-present: purple
Test for lipid
-dissolve sample in ethanol
-add distilled water
-present: white emulsion
What is a biosensor?
-device that uses a biological molecule to detect a chemical.
Rf value
Distance moved by solute
————————————
Distance moved by solvent
What is mobile stage ?
Liquid solvent such as ethanol or water
What is the stationary phase ?
The chromatography paper
