Dr Harran Module 2 Flashcards
What are macromolecules?
Large organic molecules that are not polymer’s but have bonded components
What is Glycerol made of?
3 carbon chain with 3 hydroxyl (-OH) groups, hence tri-glyceride
What does glycerol look like?
H
|
H-C-OH
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H-C-OH
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H-C-OH
|
H
What does a triglyceride look like?
3 chains of fatty acids and glycerol
What is an unsaturated or kinky fatty acid?
A fatty acid carbon chain that contains a C=C
What is the bond in a triglyceride called?
An ester bond
Why do saturated an unsaturated fats look physically different?
Because, due to their regular structure, saturated fats can pack up tightly, so often are solid like butter or lard whereas unsaturated fatty acids, due to the kink of the C=C bond, cannot pack as tightly so are more likely to be liquid like vegetable oil
What are the functions of a triglyceride?
- Energy Source - Can be broken down in respiration by hydrolysing the ester bond, and then glycerol and fatty acids can broken into CO2 and H2O. This produces more H2O than the respiration of sugar
- Energy Store - Because of their insolubility and high proportion of H atoms, triglycerides can produce x2 more energy than glucose and can be stored without affecting a cells water potential
- Insulation - Adipose tissue can act as an insulator and in nerve cells acts as a heat insulator
- Buoyancy - Fat < dense than H2O so used by aquatic mammals to keep afloat
- Protection - Humans have fat around delicate organs to absorb shock
What is glucose used for in plants? (crops)
Cellulose cell walls
Respiration (aerobic)
Oils and fats
Proteins (actually amino acids+nitrate ions)
Starch (Amylose+Amylopectin)
What is a phosolipid?
A glycerol molecule with 2 fatty acid carbon chains and one hydrophilic phosphate group
What does mono-unsaturated mean?
A fatty acid one C=C double bond. Poly-unsaturated is therefore where there are many C=C double bonds
What is a bacterial cell wall made of?
A phospholipid bi-layer with peptidoglycan within the hydrophobic centre, so bacteria are described as having a lipid rich outer layer
What can phospholipids form in water?
Due to the fatty acid tails being hydrophobic, and the phosphate group (containing a number of hydroxyl groups, so being polar and attracted to water) being hydrophilic, phospholipids form structures like micelles, lysosomes and phospholipid bi layers when exposed to water
What is a phospholipid bi layer?
The structure that allows the membrane to form boundaries between two watery environments as phospholipids arrange themselves with their hydrophobic tails facing in and their hydrophilic heads pointing outwards. The membrane is fluid, meaning that the lipids flow around each other to allow certain molecules past the membrane, e.g. CO2 or O2. This type of membrane makes up 20-80% of membranes in organelles
What is cholesterol?
It is a steroid alcohol that is based around a 4 carbon ring, making it a lipid that is not based upon fatty acids or glycerol. It is a hydrophobic and philic molecule allowing it to sit in the hydrophobic middle of a phospholipid bi layer. From there it regulates the fluidity of the membrane, allowing certain needed molecules through
What does HDL and LDL mean?
HDL: Means that a consumed cholesterol contains a high density of lipoproteins and is better for the body LDL: Means a cholesterol consumed contains a low density of lipoproteins, so in high quantities is worse for the body than HDL cholesterol
What is a condensation reaction?
When two molecules bond through the loss of a water molecule.
What is hydrolysis?
Hydrolysis is the separation of two molecules by the addition of a water molecule.
Why is water a liquid at room temperature?
Know this script: -Hydrogen is bound to oxygen via a covalent bond -Oxygen has more protons in its nucleus than Hydrogen, so attracts the shared pair of electrons more strongly -This is because O is more electronegative -This leaves H with a δ+ charge and O with a δ- charge -This makes water a polar molecule -Hydrogen bonds are weak electrostatic interactions between the δ+ H and the δ- O of 2 water molecules
What are some features of water?
-High latent heat of vaporization, large amount of energy needed to from a liquid to a gas, e.g. sweat cools you without dehydrating you
-High specific heat capacity, large amount of energy needed to raise the temperature by 1*C, so aquatic animals have a thermally stable habitat
-Ice is less dense than water, so can float creating a habitat for organisms like penguins
-Ice insulates the water below it keeping it a liquid so aquatic organisms do not freeze
-It is an effective solvent due to its polarity. This makes it a good reaction and transport medium, e.g. the blood
-The H bonds allow adhesion and cohesion amongst H2O molecules, e.g. water travelling up the xylem vessel in a plant
-Because of adhesion, water has a high surface tension creating a habitat for some organisms like the pond skater
-Water is transparent so allows underwater plants to photosynthesise
-Water has a high density so allows objects to float providing support for aquatic organisms
What does an amino acid look like?
Amino acids have an amine group on one side and a carboxylic acid group on the other. There is also an R group attached to the central carbon.
How many amino acids are there?
Over 200, but 20 in proteins. Animals can make some, but have to ingest others, essential aa’s, whereas plants can make all of them if they have a steady supply of nitrates.
Why are amino acids amphoteric?
Amino acids are amphoteric because they contain both acidic and basic groups in the same molecule, so at low pH’s they accept H^+ ions as bases and at high pH’s they release H^+ ions as acids.
What is the primary structure of a protein?
It is the sequence of amino acids in a polypeptide chain. It is held together by peptide bonds that are created through a condensation reaction.
What is the secondary structure of a protein?
It is where the polypeptide folds into either an α helix structure or a β pleated sheet. This is held together with hydrogen bonds, the α helix between the -NH and the -CO 4 places ahead in the chain, and the β pleated between the -NH and the -CO much further ahead in the strand.
What is the tertiary structure of a protein?
It is the 3D shape of the protein, including bending, that shows whether or not the protein is fibrous or globular. It is maintained by hydrogen bonds, ionic bonds between R groups and disulphide bridges between cysteine sulphur R groups. It also contains hydrophobic/philic interactions.
What is the quaternary structure of a protein?
The quaternary structure appears when two or more polypeptide chains are joined together, and form a different and final 3D shape, like haemoglobin. Not all proteins have this. It is held together with Ionic, Hydrogen and disulphide bonds as well as hydrophobic or philic interactions.
What are fibrous proteins?
Fibrous proteins usually contain a repetitive sequence of amino acids. Because of this it forms insoluble fibre-like polypeptide chains that take on a structural function in the body such as collagen, elastin and keratin.
What are globular proteins?
Proteins with a specific 3D shape. They are soluble as the hydrophilic R groups arrange themselves so that they are on the outside of the protein. Because of their solubility they usually take on a more functional role, e.g. haemoglobin, Insulin/hormones, enzymes….
What are carbohydrates?
A group of molecules containing C, H and O.
How do you draw β glucose?
- draw the hexose back-bone, with 5 C’s and an O
- follow the up down rule for the placement of the hydroxyl groups
- add the H’s at the other ends of the hydroxyl groups
- to draw α glucose, reverse the first hydroxyl group
What is a glycosidic bond?
When two monosaccharide rings are bonded via a condensation reaction.
What are the 3 different uses of carbohydrates?
- Energy storage- polysaccharides are an energy store as monosaccharides can be hydrolysed off the main chain
- Energy source- for instance glucose is used in aerobic respiration and the production of ATP
- Structural support- the polysaccharide cellulose is used in cell walls to keep the cell turgid and strong
What are some examples of disaccharides?
α glucose + α glucose - maltose, α glucose + fructose - sucrose, α glucose + β glucose - lactose, β glucose + β glucose - cellobiose (component of cellulose)
What are the 2 types of polysaccharides?
- Homopolysaccharide, made of only one type of monosaccharide
- Heteropolysaccharide, made of more than one type of monosaccharide
Why are polysaccharides good energy stores?
-They are stored as densely packed granules, so don’t take up much space in the cell
-They hold monosaccharides in chains, so that they can be hydrolysed and used when needed for respiration
-Some are branched meaning that they are more compact and have more ends, so more monosaccharides can be removed at once
-Polysaccharides are less soluble than their monomers, and so do not affect the cells water potential and disrupt normal cell functions
What enzymes are responsible for hydrolysing polysaccharide chains?
Amylase is responsible for hydrolysing 1-4 glycosidic bonds and glucosidase for 1-6 glycosidic bonds.
What is amylose? (plants)
A long polysaccharide of α glucose monosaccharides, bonded with 1-4 glycosidic bonds, found in starch. It coils in a helix shape, held together by hydrogen bonds on the inside of the molecule, so it is less soluble.
What is amylopectin? (plants)
A long, branched chain of alpha glucose found in starch containing 1-4 and 1-6 alpha glycosidic bonds. It is therefore more compact than amylose, and because of the branches is less helical.
What is glycogen? (animals)
It is a branched polysaccharide of α glucose, like amylopectin, but containing many more branches. This makes glycogen very compact and useful for animals when lots of glucose is needed for respiration due to intensive movement, as the branches allow lots of glucose to be removed as there a many ends. The 1-4 bonded chains are also smaller than the equivalent in starch, so glycogen is less likely to form a helix.
What does amphipathic mean?
A molecule that contains both hydrophilic and hydrophobic parts.
