Topic 4

Question 1

How is energy supplied in anabolic (biosynthetic) reactions?

Answer 1

• reaction require an input of energy

- via form of ATP hydrolysis

Question 2

What is gluconeogenesis?

Answer 2

• 2x pyruvate => glucose
• synthesis of glucose from precursors (aa, glycerol or lactate)
• pathway reverse of glycolysis

Question 3

Why does gluconeogenesis occur?

Answer 3

create glucose from other molecules (pyruvate) => use elsewhere

Question 4

What are the four unique reactions of gluconeogenesis?
Including, tissues where this occurs, most common precursors, overall energy requirements to synthesise glucose from pyruvate

Answer 4

• pyruvate carboxylase, in mitochondrial matrix
• phosphoenolpyruate (PEP) carboxykinase in mitochondrial matrix + cytosol
• fructose-1, 6-bisphosphatase in cytosol
• glucose-6-phosphatase located in the endoplasmic reticulum (ER)

Question 5

What is the difference between prokaryote and eukaryotes?

Answer 5

PRO
nucleus: no
membrane-bound organelles: no
cell division: cell fusion
ribosomes: 
- smaller
- 3 RNAs
- 55 proteins
EUK
nucleus: yes
membrane-bound organelles: yes
cell division: mitosis + meiosis
ribosomes: 
- larger
- 4 RNAs
- 78 proteins

Question 6

What is the growth and reproduction in prokaryotes?

Answer 6

Binary fission
a. DNA rep
b. cell elongation
c. cell division
1 cell => 2 genetically identical daughter cells
1 -> 2 (2^1) -> 4 (2^2) -> 8 (2^3) -> 16 (2^4) -> 32 (2^5)

Question 7

What is the bacterial growth curve?

Answer 7

LAG
- cells alive but do not double
- period of adjustment to new conditions
EXPO
- cells growing + dividing at constant rate
- rate of growth measured - mean generation time (MGT)
- time taken for population to double
STATIONARY
- population stops increasing
- stop due to environmental change
DEATH
- cells die due to nutrient depletion, pH change, lack O2, toxic compounds

Question 8

How is bacterial growth measured?

Answer 8

• turbidity - absorbance @ 600nm
• dry weight of cells
• counting of viable cells
• direct cell count
• protein measurement

Question 9

How does water affects growth of bacteria?

Answer 9

• liquid H2O allows for cell metabolism
• essential for bacterial growth
• H2O availability determined by amounts + types of solutes dissolved in water
  organic and inorganic solutes
• sugars, aa
• NaCl, K+, Mg++

Question 10

How does temperature affect growth of bacteria?

Answer 10

• dramatic effect on growth + survival
• bacteria = same temp as enviro
• extremes => bacteria die
• too hot: bacteria die
• too cold : inhibit growth

Question 11

How does pH affect growth of bacteria?

Answer 11

only grow in aqueous enviro.
effects:
- disruption of membranes
- inhibition of enzymes 
- inhibition of transport/uptake 
- alter nutrient availability

Question 12

How does oxygen affect growth of bacteria?

Answer 12

vary in requirements

Question 13

What is the difference between a strict anaerobe, a strict aerobe, a facultative anaerobe and aerotolerant anaerobe?

Answer 13

• strict anaerobe: anaerobic growth only, no O2
• strict aerobe: O2 for respiration
• facultative anaerobe: both aerobic/anaerobic respiration
• aerotolerant anaerobe: don’t use but tolerate O2

Question 14

What is the overall reaction for photosynthesis?

Answer 14

6CO2 + 6H2O => C6H12O6 + 6O2

Question 15

What does energy transduction (light dependent) reactions involve?

Answer 15

NADPH + ATP => used in C assimilation reaction (anabolic)

• oxidation of O2
• reduction of NADP+ => NADPH
• production of ATP from ADP + Pi

Question 16

What does carbon assimilation (dark => light independent) reaction involve?

Answer 16

• use of NADPH + ATP to fix CO2 => sugars + carbs
• occurs in TCA cycle
• operates in stroma matrix of chloroplast
• then Calvin cycle

Question 17

What is the importance of chlorophyll in photosynthesis?

Answer 17

green pigment in plants soaks up and absorbs energy from sunlight

Question 18

What are the components produced by light reactions that are used in dark reactions?

Answer 18

NADPH + ATP

Question 19

What is the importance of photosynthesis to life on Earth?

Answer 19

• essential to life on Earth
• conversion of solar energy => chemical energy
• responsible for removal of carbon from atmosphere

Question 20

Where is the location of energy transduction (light dependent) reactions?

Answer 20

Occur in THYLAKOID MEMBRANE of CHLOROPLAST

• chloroplasts capture light energy
• energy from photon light trapped + absorbed by chlorophyll molecules
• captured e transferred to other compounds along ETC to form NADPH
• ATP produced by ATP SYNTHASE enzyme complex
• CO2 flow of e coupled transfer H+ across thylakoid membrane
• Similar to mitochondria e gradient drives proton pump through ATP SYNTHASE to produce ATP by phosphorylation

Question 21

What is the location of carbon assimilation (dark => light independent) reactions?

Answer 21

Stroma matrix of chloroplast

Question 22

What is the function of carbon assimilation (dark => light independent) reactions?

Answer 22

CO2 incorporated into organic molecules producing sugars

• NADH provide some energy as e
• ATP provide chemical energy same steps

Question 23

What enzymes are involved in gluconeogenesis?

Answer 23

• glucose-6-phosphatase
• fructose-1, 6-biphosphatase
• pyruvate carboxylase
• phosphoenolpyruvate carboxylase