topic 4 -final exam Flashcards
Summarise and explain the process of light-dependent reaction of photosynthesis including the importance of chlorophyll in photosynthesis and how light is absorbed by chlorophyll
Light dependent reaction also known as energy transduction
1. Chloroplasts captures light energy
2. Absorbed by chlorophyll molecules
3. Energy from photons f light trapped and transferred to form a high energy state (photoexcitation)
4. Oxidation of H2o to o2
5. Captured electrons transferred to compounds along an electron transport chain the form NADPH
6. ATP procued by ATP synthase enzyme complex from ADP and Pi
7. Reactions occur in the thylakoid membranes of chloroplasr in granum
8. NADHP and ATP used in carbon assimilation reactions
Chlorophyll is important as it allos this light to be converted into energy to which CO2 can be converted to O2 and glucose
LLO4.2 Summarise and explain the process of light-independent reaction of photosynthesis
Light independent reaction – carbon assimilation
1. Use of NADPH and ATP to fix CO2 into CH2O (sugars/carbohydrates)
2. Carbon incorporated into organic molecules to produce sugars
3. Via enzyme called rubisco -> occurs in calvin cycle
4. In stroma matrix of cholorplasts
5. ATP and NADPH provides energy
similarities and differences between light dependent and light independent
(light dependent ans first)
Location
- Thylakoid membrane of the chloroplasts
- Take place in the stroma of the chloroplast
process
- Mostly linear
- cyclic
Light requirement - Requires light energy - Can occur in the light or dark
products
- ATP and NADPH
- Uses light dependent products to produce glucose ATP
LLO4.3 Compare and contrast processes within photosynthesis and aerobic respiration
Similarities
- Uses specialized organelles (chlolorplasts vs mitochondria)
- Uses similar ETC
- Use chemiosmosis (Chemiomosis: process where electrochemical gradient (H+) is used to generate atp
- Both uses ATP synthase as the transport protein
- Produced atp in aerobic respiration and light dependent reactions of photosynthesis) and ATP synthase
differences
Reactants
Aerobic resp: glucose + O2
Photo: CO2 +H2O
Products
Aerobic resp: CO2 +H2o
Photo: O2 +glucose
LLO4.4 Identify and categorise bacteria according to their metabolic characteristics and requirements
- Energy source
Phototrophs – use light as energy source
Chemotrophs – obtain energy from oxidation of compounds - Electron source
Lithotrophs – use reduced inorganic substances as their electron source
Organotrophs – extract electrons from reduced organic compounds - Carbon source
Autotrophs – use carbon dioxide as their sole carbon source
Heterotrophs – use reduced, preformed organic molecules as their carbon source
Describe the growth and reproduction in prokaryotes
- Process: binary fission – single bacterial cell divides into two identical daughter cells
Dna replication
Cell elongation- cell wall and cell membrane enlarging
Cell division – septum (cross wall) formed, dividing cell into 2 daughter cells
desribe the 5 phases of growth of prokaryotes
lag phase- - Cells are alive but population is not increasing
- Cells are synthesizing new components such as ribosomes
- Period of djusting due to new conditions
Carbon source
Temp
pH
log (or exponential phase)
- cells are growing and diving at max rate possible
- growth is measured in this phase
- mean generation time (MGT): time required for one generation of bacteria to double
- increasing at a constant rate (exponential)
Stationary phase
- Population stops increase
Number of viable cells remain constant
Balance of cell dividion and cell death
- Growth stops due to environmental chang e
Nutrition depletion
Ph change
Lack of oxygen
Toxic compounds build up
Death phase
- Viable cells declines exponentially
- Cells dying at a constant rate
- Cell division < cell death
- Cells die due to environmental change
Nutrition depletion
Ph change
Lack of oxygen
Toxic compounds build up
calculate MGT
factors effectin growth of bacteria
water, temp, ph, oxygen,
Water
Essential for survival
Can be present in environemnt but not available to bacteria
Availability of water determined by amount and type of solutes dissolved in water
water moves from a place of low solute conc to a place of high solute concentration
Temperature
- no insulation or internal thermoregulation
same temperature as environment
affects temp- sensitive enzymatic reactions in bacteria
each enzyme has a temp where it functions optimally
affect membrane structure
very low temp: membrane solidifys
high temp: lipid bilayer melts and disintegrates
pH
- bacteria needs to maintain their pH for survival (normally neutral internal pH)
- eg if external pH is low H moves into cell and lower the cytoplasmic ph
- disrupt plasma membrane
- inhibit enxyme activites
- inhibit transport/uptake
oxygen
- vary in their requirement for oxygen
- most metabolic processes requires movement of e-
terminal e- acceptor: o2
- o2 can damage molecules – formation of reactive oxygen specie (ROS)
- 5 types of bacteria
Obligate aerobes : requires and use o2 for respiration
Microaerophiles: requires low levels of o2 (5-10%)
Facultative anaerobes: able to underfo both aerobic or anaerobic growth (prefer former)
Aerotolerant anaerobes: doesn’t use but able to tolerant presene of o2
Obligate anerobobes : anaerobic growth only
Light energy is absorbed by chlorophyll molecules inside the chloroplasts of photosynthetic organisms and converted into light energy in the form of carbohydrate.
false
Chemolithoheterotrophic bacteria:
Obtain energy, electrons from inorganic sources and carbon from CO2
Bacterial growth rate is measured during
log phase
In bacteria, anaerobic respiration mean
An electron acceptor other than O2 supports respiration
