Y12 MS - Biological Molecules (Excluding Proteins) (Complete) Flashcards
What is ATP an abbreviation for?
Adenosine triphosphate
What are the components of ATP?
Adenine
Ribose
Three phosphate groups
What is ATP?
An energy-carrying molecule which provides energy for various processes within living cells
What processes is ATP required for?
Metabolic processes
Active transport
Movement
Activation of molecules
Secretion
What is a hydrolysis reaction?
The break down of a chemical bond between two molecules with the use of a water molecule
What catalyses the hydrolysis of ATP?
ATP hydrolase
What is formed by the hydrolysis of ATP?
ATP + H20 —> ADP + Pi + E
Adenosine triphosphate + water —> adenosine diphosphate + inorganic phosphate + energy
How can ATP be resyntheised?
Through a condensation reaction
What is a condensation reaction?
Where two molecules are joined together with the formation of a chemical bond and the elimination of a molecule of water
What is used as a catalyst for the synthesis of ATP?
ATP synthesase
What can the inorganic phosphate formed from the hydrolysis of ATP be used for?
To phosphorylate other compounds, often making them more reactive
Why is ATP such a useful molecule?
Releases energy as it breaks down
Can move around but can’t leave the cell as the molecule is too large
Releases energy quickly
Releases energy in small amounts, suitable for cellular reactions
What is adenosine made up of?
Adenine and ribose
What is the name of the molecule with adenine, ribose and one phosphate group?
Adenosine monophosphate (AMP)
What is a metabolite?
Any substance produced by or involved in metabolic processes
How is water a metabolite?
Water is involved in many metabolic reactions such as being used in hydrolysis reactions and condensation reactions
What is the cohesion in water molecules?
Water molecules have strong cohesion between them (which supports columns of water in tube-like transport cells of plants)
This also produces surface tension where water meets the air
Does water have a high or low specific heat capacity?
High
What is the result of water having a high specific heat capacity?
It acts as a buffer for changes in temperature (advantageous for enzyme action and body temperature in organisms)
What does the density of water allow to occur?
Solid water is less dense than liquid water which means that ice can float and form land masses
What is a solvent?
A liquid in which a solute can be dissolved to form a solution
What are the two major properties of water?
Water is a polar molecule
Water is bonded together with hydrogen bonds
What is the effect of water having a large latent heat of vapourisation?
Loss of water through evaporation produces a cooling effect
What does it mean that monosaccharides are isomers?
Isomers are molecules with the same molecular formula but a different arrangement of atoms
Name three monosaccharides
Glucose
Fructose
Galactose
What are the two isomers of glucose?
Alpha glucose and beta glucose
What is the structure of alpha glucose?
What is the structure of beta glucose?
How many bonds can carbon make?
4
What is the formula for glucose?
C6H1206
Draw the structure of glucose (alpha)
What bond is formed through a condensation reaction between two sugars?
A glycosidic bond
What is a disaccharide?
Two monosaccharides joined together with a glycosidic bond
Glucose + glucose —>
Maltose
Glucose + fructose —>
Sucrose
Glucose + galactose —>
Lactose
How are the carbons numbered in a molecule?
Name some polysaccharides
Starch
Cellulose
Glycogen
What is a monosaccharide?
Monomers from which larger carbohydrates are made
What are polymers?
Molecules made from a large number of monomers joined together
How many bonds can oxygen make?
2
How many bonds can hydrogen make?
1
Starch is a ——— polysaccharide in ———
Storage
Plants
What two different polysaccharides make up starch?
Amylose and amylopectin
What are the features of amylose?
Amylose is an unbranched, helix-shaped chain with 1,4 glycosidic bonds between alpha-glucose molecules
What are the features of amylopectin?
Amylopectin is a branched molecule with 1,4 and 1,6 glycosidic bonds between alpha-glucose molecules
How is starch suitable for its function?
The helix shape allows it to be compact so only requires small space for storage
The molecule is large so cannot pass through membranes
It is insoluble so no osmotic effect
The many branches can be easily hydrolysed to release glucose
Cellulose is a ——— polysaccharide in ———
Structural
Plants
What is the structure of cellulose?
Cellulose consists of straight, unbranched chains with 1,4 glycosidic bonds between beta-glucose molecules. Many hydrogen bonds form between the long, parallel chains
How is cellulose suitable to its function?
Cellulose fibres are permeable so allow water and solutes to pass through
Cellulose fibres are insoluble so there is no osmoic effect
The parallel molecular chains are cross linked with hydrogen bonds, forming collective strength (microfibrils)
Glycogen is a ——— polysaccharide in ———
Storage
Animals
What is the structure of glycogen?
Glycogen consists of shorter, branched chains with 1,4 and 1,6 glycosidic bonds between alpha-glucose molecules
How is glycogen suitable for its function?
The many branches can be easily hydrolysed to release glucose
The molecules are too big to pass through membranes
It is insoluble so there is no osmoic effect
Compact so a lot can be stored in a small space
All monosaccharides are ———
Reducing sugars
Will reducing sugars give a positive or negative result from the Benedict’s test?
Positive
What is the only non-reducing sugar you will come across?
Sucrose
Describe the Benedict’s test?
Place 2cm3 of the test solution into a test tube
Add 2cm3 of Benedict’s solution
Heat in a water bath at 80°C for five minutes
Positive result - Colour change to brick red
Negative result - No colour change, remains blue
Describe the test for non-reducing sugars
Obtain a negative result from the Benedict’s test
Place 2cm3 of the test solution in a test tube
Add 2cm3 of dilute hydrochloric acid
Heat in a water bath at 80°C for two minutes
Add small amounts of solid sodium hydrocarbonate until it stops fizzing
Add 2cm3 of of Benedict’s solution
Heat in a water bath at 80°C for five minutes
Positive result - Colour change to a brick red colour
Negative result - No colour change, remains blue
What is the test for starch?
Place 2cm3 of test solution into the test tube
Add two drops of iodine solution
Positive result - Colour change to a blue/black
Negative result - No colour change, remains orange/brown
What can lipids exist as?
Fats, oils and waxes
Fats and oils are ————
Triglycerides
Are lipids soluble or insoluble in water?
Insoluble
What is a monounsaturated fatty acid?
A fatty acid which has one double bond between the carbon atoms
What is a polyunsaturated fatty acid?
A fatty acid which has two or more double bonds between the carbon atoms
What is a saturated fatty acid?
A fatty acid which doesn’t have any double bonds between the carbon atoms
What are the monomers of lipids?
Fatty acid and glycerol
What occurs when there is a condensation reaction between a fatty acid and glycerol?
A lipid is formed with the elimination of a water molecule and the formation of an ester bond
What are the main groups of lipids?
Triglycerides and phospholipids
What is a triglyceride?
A triglyceride is made up of three fatty acids and glycerol. Each fatty acid forms an ester bond with glycerol in a condensation reaction
What are the properties of lipids?
- Insoluble in water
- Source of energy (provided when oxidised)
- Slow conductor of heat -> good insulator
- Can provide protection (fat is stored near organs to protect them)
What are the properties of triglycerides (related to their function)?
- Able to release water (especially vital to organisms in dry environments) when oxidised due to the high ratio of hydrogen to oxygen atoms
- Insoluble in water as they are large and non-polar molecules so are good for storage as do not disrupt water potential
- Source of energy due to the energy-storing carbon-hydrogen bonds
What are microfibrils and how does it affect the properties of cellulose?
Microfibrils are structures of long, cellulose chains running parallel to each other and joined by hydrogen bonds, forming strong cross linkages. This makes cellulose good for structural purposes due to its strength
Do triglycerides and phospholipids have similar structures?
Yes. If you replace a fatty acid within a triglyceride with a polar phosphate group, a phospholipid is formed
What is the structure of a phospholipid?
Phospholipids are made up of hydrophilic phosphate heads and hydrophobic fatty acid tails
- Phosphate
- Glycerol
- Two fatty acids
Are phospholipids polar or non-polar?
Polar
What are the properties of phospholipids (related to their structure)?
- In an aqueous environment, a bilayer is formed within cell-surface membranes due to them being polar molecules, so a hydrophobic barrier is created
- Phospholipids can form glycolipids by combining with carbohydrates in the cell-surface membrane which are very important for cell recognition
- The hydrophobic phosphate heads can be used to hold at the surface of the cell membrane
Describe the test for lipids (the emulsion test)
- Take a completely dry and grease-free test tube
- Add 2cm3 of the sample being tested and 5cm3 of ethanol
- Shake the tube thoroughly to dissolve any lipids in the sample
- Add 5cm3 of water and shake gently
- If a lipid is present, a milky-white emulsion is produced
What is the importance of H+ ions
Maintenance of pH for metabolic processes
Maintenance of pH for optimum conditions for enzymes
What is the importance of iron ions (Fe3+ or Fe2+)
They bind to oxygen in haemoglobin in the blood so oxygen can be transported around the body
What is the importance of Na+ sodium ions
For the co-transport of amino acids and glucose
Transmission of nerve impulses
What is the importance of PO4 3- phosphate ions
Attaches to other molecules to form phosphate groups, an essential component of DNA, RNA and ATP
Found in phospholipids and form key components of the phospholipid bilayer
What is the importance of Ca2+ calcium ions
Stimulates muscle contraction
Regulates the transmission of impulses from neurone to neurone in synapses
Formation of blood clots
