Topic 2 Flashcards
What does molecular biology explain?
Living processes in terms of the chemical substances involved
The structures of molecular biology are what?
Diverse and complex
What is urea?
A component of urine that is produced when there is excess amino acids in the body and the nitrogen is then excreted
What is vitalism?
The belief that organic molecules can only be synthesised by living systems
What disproves vitalism?
-Wohler heated ammonium nitrate and produced urea and urea is an organic molecule so vitalism is not correct
Draw the structure for Ribose
Draw the structure for glucose
Draw the structure for saturated fatty acid
Draw the structure for an amino acid
What is metabolism?
The sum of all the enzyme catalysed reactions in a cell or organism
Where does metabolism mostly happen?
In the cytoplasm
What does metabolism consist of?
Pathways in by which one type of molecule is transformed to another in a series of steps
How many bonds can carbon form?
4
What kind of bonds do carbon make with other atoms?
Covalent bonds ( sharing of electrons)
How do you classify carbohydrates?
C,H,O ( 2 H atoms to 1 O)
How do you classify lipids?
- Insoluble in water
- Triglycerides are fats at room temp and oils in liquids
What is anabolism?
The synthesis of complex molecules from smaller ones including the formation of macromolecules from monomers
How do you classify proteins?
C,H,O,N with one or more amino acid chains
How do you classify nucleic acids?
C,H,O,N,P. Found in DNA and RNA
What does anabolism require?
Energy from ATP
What is an example of anabolism?
Protein synthesis using ribosomes
Why is water polar?
Unequal sharing of electrons ( O is slightly negative but H is slightly positive)
What kind of bonding forms between water molecules?
Hydrogen
What does hydrogen bonding and polarity explain?
The cohesive, adhesive and solvent, thermal properites of water
What do enzymes have?
An active site that specific substrates bind to
What is an enzyme?
A globular protein that speeds up the rate of reaction
What is enzyme catalysis?
The collisions of substrate to the active site
What happens when a substrate binds to an enzyme’s active site?
- Enzyme substrate complex is formed
- The enzyme then catalyses the reaction converting the substrate into a product creating an enzyme- product complex
- the enzyme and product then dissociate
What increases the frequency of collisions?
- Increase concentration of particles
- increasing the molecular motion of particles
What is the shape of the active site dependent on?
The tertiary structure
What is denaturation?
Any change to the enzyme’s active site
What can cause denaturation?
- pH
- High temperatures
What is the effect of temperature on enzyme activity?
What type of enzymes are widely used in industry?
Immobilised enzymes
What are examples of the uses of immobilised enzymes?
- Biofuels
- Medicine
- Food production
How is lactose free milk produced?
- Lactase is purified from yeast then bound to an inert substance
- milk is then repeateadly passed over the enzyme becoming lactose free
n an experiment the effect of changing pH on an enzymatic reaction is tested. Which could be a dependent variable in this kind of experiment?
A. Changing substrate concentration
B. Rate of formation of product
C. Variation in temperature
D. Change in pH
B
Explain the production of lactose-free milk.
-Lactase is added to the milk which causes the break down of lactose into glucose and galactose
Distinguish between globular and fibrous proteins.
Globular = soluble in water and are round structures Fibruous = not soluble in water and are long/narrow
What is meant by cohesive and adhesive properties of water?
Cohesive / adhesive properties – Water will ‘stick’ to other water molecules (cohesion) and charged substances (adhesion)
What is meant by the solvent properties of water?
Solvent properties – Water dissolves polar and ionic substances (forms competing polar associations to draw materials apart)
What is meant by the thermal properties of water?
Thermal properties – Water can absorb much heat before changing state (requires breaking of hydrogen bonds)
Why does hydrogen bonding explain the thermal properties of water?
- This is due to the extensive hydrogen bonding between water molecules – the H-bonds need to be broken before a change in state can occur and this requires the absorption of energy (heat)
- water is an excellent medium for living organisms as it is relatively slow to change temperature and thus supports the maintenance of constant conditions (internal and external)
What are the similarities between water and methane?
- they both have similar size and atomic weight
- both have tetrahedral orbital formations
Why are water and methane so different?
- water is polar and forms hydrogen bonds whereas methane is non polar and can only form weaker intermolecular forces between the molecules
What are the key differences between water and methane?
- Water has a higher SHC
- Water has a higher boiling point and melting point
- Water has a higher heat of vaporisation
Why can water be used as a coolant in sweat?
- The change of water from liquid to vapour (evaporation) requires an input of energy
- This energy comes from the surface of the skin when it is hot, therefore when the sweat evaporates the skin is cooled
- Because water has a high specific heat capacity, it absorbs a lot of thermal energy before it evaporates
- Thus water functions as a highly effective coolant, making it the principal component of sweat
Describe what is meant by the solvent properties of water?
- Water can dissolve any substance that contains charged particles (ions) or electronegative atoms (polarity)
- This occurs because the polar attraction of large quantities of water molecules can sufficiently weaken intramolecular forces (such as ionic bonds) and result in the dissociation of the atoms
- The slightly charged regions of the water molecule surround atoms of opposing charge, forming dispersive hydration shells
What are the modes of transport of substances in the blood
How are monosaccarides linked together?
By condensation reaction to form disaccharides and polysaccharides
What are monosaccharides?
Monosaccharides (one sugar unit) are typically sweet-tasting and function as an immediate energy source for cells
What are disaccharides?
Disaccharides (two sugar units) are small enough to be soluble in water and commonly function as a transport form
What are cellulose and starch both?
Polysaccarides
Describe the structure of cellulose
- Beta glucose in a 1,4 arrangement
- indigestable for most animals as they lack the enzyme to break it down
- no branches
- found in plant cell wall
What are the two forms of starch?
Amylose and amylopectin
Describe the structure of amylose
- found in plants
- alpha glucose
- 1 -4 arrangment
- not branched
- helical
Describe the structure of amylopectin
- alpha glucose
-1-4 and 1-6 linkages
branched
What can fatty acids be?
Monounsaturated, polyunsaturated and saturated
Outline the role of proteins in active and passive transport of molecules through membranes.
channel proteins allow diffusion/osmosis/passive transport;
b. large/polar molecules cannot cross the (hydrophobic) membrane freely;
c. facilitated diffusion involves moving molecules through proteins down their concentration gradient/without requiring ATP;
d. aquaporins (specific integral membrane proteins) facilitate the movement of water molecules/osmosis;
e. some proteins (for facilitated diffusion) are specific to molecule/ions;
f. active transport involves moving molecules through proteins against their concentration gradient/requiring ATP;
g. (some) proteins in the membrane are pumps / pumps perform active transport / sodium potassium pump;
State the function of energy storage
TO provide energy
Explain the production of lactose free milk
- lactase is added to the milk and then immobilised
- lactose is broken down into glucose and galactose
- for people who are lactose intolerant
