First Chapter Flashcards
Is oxygen electronegative or electropositive
Electronegative
Is hydrogen electronegative or positive
ElectroPositive
Water is a polar molecule. What does this mean
It can form hydrogen bonds with other water molecules
What is cohesion
It is an important part of transpiration
Water molecules stay close together when in liquid form
Enables of column of water to move through a plant
What is the word for the attraction of water molecules to other substances
Adhesion
Is water more or less dense in its solid form
Less dense (solid water floats!)
Why is the fact that water is less dense in its solid form important
When water freezes in a river life can continue under it - even in an ice age
What is a universal solvent
Due to the polarity of water molecules, liquid water can dissolve a wide range of polar solutes
——- is a component of metabolic reactions
Water
Reactions that produce water as a byproduct are called
Condensation reactions
Reactions that take in water as a reactant are called
Hydrolysis reactions
What is specific heat capacity
It takes 4.2J to heat up 1g of water by 1degree
Why is it important that water has a high specific heat capacity
The water effectively buffers the temperature changes so organisms living in the water have a more stable environment in which they can operate
Over the whole planet water absorbs energy from the sun keeping the global temperature relatively constant
How does the latent heat of vaporisation help in removing excess heat form the body
Water can absorb a lot of energy before turning from a liquid into a gas. Therefore when someone is sweating the evaporation removes some heat without requiring an excessive quantity of water
What is hydrolysis
The chemical process by which water is used to break a bond in a molecule
What type of bonding takes place between molecules in liquid water
Hydrogen bonding
What is a glycosidic bond
A bond in a polysaccharide
What elements are present in a carbohydrate
C, H and O
What property of carbon enables it to form chains
It can form up to four covalent bonds with other atoms
What sugars comprise the disaccharide sucrose
Alpha glucose and fructose
What are the two structure types of starch
Amylopectin and amylose
How does the structure of cellulose make it useful as a structural polysaccharide
It is an unbranched, straight, molecule with hydrogen bonding between the cellulose molecules. This makes it very strong
What is the name of the bond between a fatty acid and glycerol
Ester bond
What state will a fat and an oil be at 20 degrees C
Fats are solid whilst oils are liquid
Why are lipids insoluable in water
They are hydrophobic
How can a triglyceride be broken down into its constituent fatty acids and glycerol
Hydrolysis
What is a saturated fat
A saturated fat has no double or triple bonds between carbon atoms in the fatty acid chains
What is an unsaturated fat
An unsaturated fat has at least one double or triple bond between carbon atoms in the fatty acid chains
Why is an unsaturated fat more likely to be an oil
The double or triple bonds in an unsaturated fat cause a “kink” to appear in the fatty acid chain. This makes unsaturated fats less able to form solids
Give three reasons why triglycerides are useful to an organism
Temperature insulation
electrical insulation around neurones
support around organs
energy store
What is the name of the bond between two amino acids in a polypeptide
Peptide bond
What groups are present in an amino acid
An amine group, NH2
A carboxylic acid group COOH
An R group
How many naturally occurring amino acids are there
20
Where do animals obtain the essential amino acids
Animals have to eat other animals and plants
What is meant by the primary structure of a polypeptide
The primary structure is the order of amino acids in the polypeptide
Give four ways the three dimensional shape is maintained in the tertiary structure of a protein
Disulphides bridges
Hydrogen bonding
Ionic bonds
Hydrophobic and hydrophilic interaction
How does the quaternary structure of a protein differ from the tertiary
structure
The quaternary structure includes more than one subunit
Name the two types of protein and state if they are insoluble or soluble
Fibrous (insoluble) and globular (soluble)
What is an enzyme
Enzymes are globular proteins that catalyse metabolic reactions
Describe how a competitive inhibitor works
It attaches to the active site of an enzyme so that the actual substrate can not fit
Describe how a non competitive inhibitor works
A non competitive inhibitor alters the shape of the active site from a distance
Why is an enzyme denatured at high temperatures
High temperatures cause the disulphides bridges and hydrogen bonds to permanently break, causing the shape of the enzyme to be irreversibly altered
How does pH affect the active site
Ph affects the active site by altering its shape. Unlike with temperature the change is not permanent
How do enzymes affect activation energy
They reduce it
Give an example of a coenzyme
Vitamin C (ascorbic acid)
