Topic 4 Flashcards
Metabolic strategies; Prokaryotic metabolism & growth
How is energy supplied in anabolic (biosynthetic) reactions?
- reaction require an input of energy
- via form of ATP hydrolysis
What is gluconeogenesis?
- 2x pyruvate => glucose
- synthesis of glucose from precursors (aa, glycerol or lactate)
- pathway reverse of glycolysis
Why does gluconeogenesis occur?
create glucose from other molecules (pyruvate) => use elsewhere
What are the four unique reactions of gluconeogenesis?
Including, tissues where this occurs, most common precursors, overall energy requirements to synthesise glucose from pyruvate
- 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)
What is the difference between prokaryote and eukaryotes?
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
What is the growth and reproduction in prokaryotes?
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)
What is the bacterial growth curve?
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
How is bacterial growth measured?
- turbidity - absorbance @ 600nm
- dry weight of cells
- counting of viable cells
- direct cell count
- protein measurement
How does water affects growth of bacteria?
- 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++
How does temperature affect growth of bacteria?
- dramatic effect on growth + survival
- bacteria = same temp as enviro
- extremes => bacteria die
- too hot: bacteria die
- too cold : inhibit growth
How does pH affect growth of bacteria?
only grow in aqueous enviro. effects: - disruption of membranes - inhibition of enzymes - inhibition of transport/uptake - alter nutrient availability
How does oxygen affect growth of bacteria?
vary in requirements
What is the difference between a strict anaerobe, a strict aerobe, a facultative anaerobe and aerotolerant anaerobe?
- 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
What is the overall reaction for photosynthesis?
6CO2 + 6H2O => C6H12O6 + 6O2
What does energy transduction (light dependent) reactions involve?
NADPH + ATP => used in C assimilation reaction (anabolic)
- oxidation of O2
- reduction of NADP+ => NADPH
- production of ATP from ADP + Pi
What does carbon assimilation (dark => light independent) reaction involve?
- use of NADPH + ATP to fix CO2 => sugars + carbs
- occurs in TCA cycle
- operates in stroma matrix of chloroplast
- then Calvin cycle
What is the importance of chlorophyll in photosynthesis?
green pigment in plants soaks up and absorbs energy from sunlight
What are the components produced by light reactions that are used in dark reactions?
NADPH + ATP
What is the importance of photosynthesis to life on Earth?
- essential to life on Earth
- conversion of solar energy => chemical energy
- responsible for removal of carbon from atmosphere
Where is the location of energy transduction (light dependent) reactions?
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
What is the location of carbon assimilation (dark => light independent) reactions?
Stroma matrix of chloroplast
What is the function of carbon assimilation (dark => light independent) reactions?
CO2 incorporated into organic molecules producing sugars
- NADH provide some energy as e
- ATP provide chemical energy same steps
What enzymes are involved in gluconeogenesis?
- glucose-6-phosphatase
- fructose-1, 6-biphosphatase
- pyruvate carboxylase
- phosphoenolpyruvate carboxylase
