C1 Biological Molecules Flashcards
Condensation reaction
A reaction in which water molecules are formed when monomers are joined together
Hydrolysis
(Inverse of condensation reaction) - Adding water to a polymer to split it
Polymer
Large molecules made by bonding single repeating units
Monomer
Repeating unit that joins to form polymers
Disacchardies
Formed when monosaccharides join via condensation reaction (Glycosidic bonds in between)
Glycosidic Bonds
Bonds between monosaccharides in a di/polysaccharide
Types of Monosaccharides
Fructose, Galactose, Glucose
Types of Disaccharides
Sucrose, Lactose, Maltose
Glucose + Fructose
Sucrose
Galactose + Glucose
Lactose
Glucose + Glucose
Maltose
Test for REDUCING sugar
Benedict’s;
1. Benedict’s solution in a tube with water
2. Grind the solution with mortar and pestle and distilled water
3. Put the sample in a test tube
4. Heat with a water bath
5. If positive, the solution with turn BRICK RED (from blue)
Test for NON-REDUCING sugars
If negative for reducing sugars: 1. Add dilute HCl 2.Add sodium carbonate to neutralise 3. Add Benedict’s solution & gently heat
Reducing sugar
Sugars that acts as a reducing agent in chemical reactions (donate electrons to other molecules)
Non - reducing sugar
Does not donate electrons
Polysaccharides
A molecule made up of more than 2 monosaccharides
Types of Polysaccharides
Starch, Glycogen, Cellulose
Properties of Starch
- Insoluble; doesn’t affect water potential (water isn’t drawn into the cell via osmosis
- Large; doesn’t diffuse out of cells
- Compact; can fit large amounts into small spaces
- Breaks down into alpha glucose when hydrolysed; stored in small spaces & transported to be ready for use in respiration
- Branched form(many ends); each can have an enzyme attached to the end to be acted on rapidly to release glucose -(1,4) & (1,6) bonds; more branches
Properties of Glycogen
- Insoluble; doesn’t affect water potential (water isn’t drawn into the cell via osmosis
- Large; doesn’t diffuse out of cells
- Compact; can fit large amounts into small spaces
- MORE branched than starch; more enzymes > more rapid release of glucose for respiration (animals have higher metabolic rates than plants (starch))
- (1,4) & (1,6) bonds; more branches
Properties of Cellulose
- made of BETA glucose; forms long straight unbranched chains
- chain run parallel + CROSSLINK via H BONDS; making the structure stronger
- molecules are grouped to form MICROFIBRES which then group to form FIBRES; which adds to the strength of the polymer
Triglyceride
3 fatty acids with ester bonds between glycerol (hence glyceride)
Saturated
Fatty acid with no carbon-carbon double bond; bonded to max number of hydrogen atoms (monounsaturated if 1 double bond)
Unsaturated
Fatty acid with carbon-carbon double bond; bonded to max number of hydrogen atoms (polyunsaturated if multiple double bond)
Phospholipid
Similar to triglyceride
- 2 fatty acids instead of 3; one replaced by a phosphate molecule
Phospholipid structure
-Have 2 parts:
-Hydrophilic ‘head’ > attracted to water
-Hydrophobic tail > orients away from water -2 ends are POLAR (behave differently)
-when placed in water, they orient themselves so that the hydrophilic head is closer to the water
Roles of lipids
- Cell membrane - flexibility of membrane
- Source of Energy - releases more than 2x the energy the same mass of carbohydrates do when oxidised
- Waterproofing - insoluble in water = waterproofing eg: plants w/ waxy cuticles, mammals w/ oily secretion from sebaceous glands in the skin
- Insulation - slow conductors of heat; help retain heat when stored beneath body surface
- Protection - fat is stored around the delicate organs
Polypeptide
molecule made up of MORE THAN 2 amino acids
Peptide bond
Bond betweeen the 2 amino acids
Primary Structure
Peptide bonds between amino acids
Secondary Structure
- Alpha = helix
- Beta = pleated sheet; with H bonds between amino group H+ and Carboxyl group H
Tertiary Structure
-H bonds
-Disulfide bridges, and ionic bonds between R groups(makes it into a globular protein)
Quaternary Structure
Consists of many different polypeptides
Activation energy
The minimum amount of energy required for a reaction to take place
Active site
The area of the enzyme where the reaction with the substrate takes place
Substrate
The chemical reactant that enzymes bind to
Induced Fit Model
The idea that the active site of the enzyme changes shape slightly due to bonds distorting as the substrate binds to it to better fit the shape of the active site
Competitive Inhibitors
Compete with the substrate for the active site > binds to the active site to prevent the substrate
Non-competitive Inhibitors
Binds to a different site on the enzyme, changing the shape of the enzyme preventing the enzyme from binding to the substrate effectively
Factors affecting enzyme activity
-Temperature; when the temp gets too high, H bonds & others begin to break in the enzyme, therefore enzyme (and its active site with it) changes shape (DENATURATION)
-pH; changes the charge on the amino acid that makes up the active site, causes the bonds maintaining the tertiary structure to break, changing the shape of the active site
-Enzyme concentration
LOW enzyme concentration
Too few enzymes to allow substrates to be broken down
What will the rate of reaction be like with an INTERMEDIATE enzyme concentration?
- DOUBLES as there are enough enzymes for the substrates
HIGH enzyme concentration
No effect; substrates become limiting factor
Roles of Proteins
- collagen; skin elasticity
- keratin; protection of hair, nails, etc
- insulin
- haemoglobin; binds to oxygen
Reproducable
If the investigation is repeated by ANOTHER person and the same results are obtained
Repeatable
If the original experimenter repeats the same investigation with the same method and equipment obtains the same results
Validity
Suitability of the investigative procedure to answer the question being asked (eg investigation is only affected by the independent variable and all other variables must be controlled
Control Variable
Variable which must be kept constant/ monitored
Dependent Variable
Variable of which the value is measured for each change in the independent variable
Indepenent Variable
the variable for which values are changed by investigator
Accuracy
Measurement that is judged to be close to the true value
Precision
Results in which there is very little spread about the mean value
Fair Test
In which only the independent variable has been allowed to affect the dependent variable
Inorganic ions
Sodium, Phosphate, Hydrogen, Iron
Sodium ions
Involved in nerve impulse transmission, the control of cell osmotic pressure and the absorption of molecules such as glucose into the cell. Actively transported outside of a cell across the plasma membrane using ATP. As it is now at a higher concentration gradient outside of the cell, it diffuses back in via a channel protein, along with a glucose molecule against the concentration gradient. Ensures that all available glucose produced during digestion is utilised.
Phosphate Ions
Phosphorus is chemically bonded to other atoms, in this case, 3 oxygen atoms. Forms the phosphodiester backbone of DNA and RNA. In ATP 3 phosphate ions are linked to ribose and Adenine. These bonds are unstable and, therefore only require a small amount of activation energy which releases a lot of energy.
Hydrogen ions
Responsible for the pH of a cell. This is a critical role as a significant change would result in the denaturation of enzymes in the cytoplasm. In reality, the pH fluctuations are only slight, which would more likely affect the activity of the enzyme. Hydrogen results in a buffering effect of haemoglobin. During the transport of carbon dioxide, it forms hydrogen carbonate in the blood.
Iron ions
involved in the transport of oxygen. They form the prosthetic group, haem. There are 4 haem groups per haemoglobin molecule which can reversibly bind molecules of oxygen each.
