Introduction to biochemistry

Question 1

What is biochemistry?

Answer 1

• Explains the biological processes, which involve the synthesis and decomposition of biological molecules

Question 2

What is a metabolic pathway?

Answer 2

• Chemical reactions that occur in a multi-step reaction mechanism instead of just one
• Biological molecules are made using complex metabolic pathways

Question 3

What is anabolism?

Answer 3

• When compounds are synthesised from many monomers
• Requires energy from chemical bonds between small compounds
• Endothermic process

Question 4

What is catabolism?

Answer 4

• When larger compounds are decomposed into smaller compounds (kaput machen)
• Energy released
• Exothermic process

Question 5

What do metabolic processes require?

Answer 5

• Chemical reactions require aqueous environment which is provided by a cytoplasm (90% water)
• Metabolic reactions take place in highly controlled aqueous environments: dissolved ion concentration
• The timing of various reactions depend on having an appropriately controlled environment

Question 6

What factors effect a metabolic process?

Answer 6

• Require narrow range of conditions to function optimally
• Biological molecules contain functional groups that undergo chemical changes, effects their shape and structure
• Conditions: pH, temperature, concentration of various components of the cell’s cytoplasm
• Concentration maintained by passive or active transport

Question 7

What condition must the pH be in a cell’s cytoplasm?

Answer 7

• pH is buffered to be within a limited range for the molecules involved
• Some cells require an aqueous environment of a particular pH for redox reactions
• The products of certain chemical reactions might include acids and bases, which could fluctuate the pH
• A buffer system minimises these pH fluctuations

Question 8

How does the temperature effect metabolic processes?

Answer 8

• Temperature can affect the spontaneity of chemical reactions, effect enzymes
• Humans 37°C, humans adjust with homeostasis
• Extremophiles can operate well outside a normal temperature range

Question 9

What is photosynthesis?

Answer 9

• The process when plants obtain light energy from the sun and convert that to form of energy into stored chemical potential energy in glucose
• Synthesis of energy-rich molecules from carbon dioxide and water using light energy
• Endothermic reaction ΔH = +2803 kJ mol-1
• Light energy —> chemical potential energy stored in bonds of glucose molecule
• Anabolic process

Question 10

What is respiration?

Answer 10

• When consumers digest the glucose to obtain the chemical potential energy to provide energy needed for biological functions
• Obtaining chemical potential energy stored in glucose for cellular functions
• Exothermic ΔH = –2803 kJ mol-1
• Releases energy to make water and CO2
• Catabolic process

Question 11

What is the difference between aerobic and anaerobic respiration?

Answer 11

• Anaerobic, limited or unavailable O2, extreme exercise, underwater ecosystems –> fermentation
• Humans: lactic acid
• Plants: ethanol and CO2

Question 12

What are condensation reactions?

Answer 12

• Removal of a hydrogen ion (H+) and hydroxyl functional group (OH-) forming H2O
• Involves two different molecules
• Requires heat and an acidic environment, help with removal and isolation of water molecule
• Occurs in formation of polymers, long chains of repeating units are joined
• Anabolic reaction, require energy
• Biopolymers made by condensation and broken by hydrolysis

Question 13

What are hydrolysis reactions?

Answer 13

• Where a water molecule is broken into H+ and OH- by heterolytic fission
• A covalent bind is broken and both electrons form the bond got to one species, forming two ions
• Involve heat and an acid catalyst or biological catalyst (enzyme)
• Catabolic reaction