Unit 3 AOS 1: Photosynthesis and Cellular Respiration Flashcards
Chloroplasts
An organelle that uses light energy, carbon dioxide and water to produce glucose.
Photosynthesis Equation
Water + Carbon Dioxide = Glucose + Oxygen
Light Dependent Inputs, Outputs, Location
Inputs: Water, ADP+Pi, NADP
Outputs: Oxygen, ATP, NADPH
Location: Thylakoid/Granum
Light Independent Inputs, Outputs, Location
Inputs: Carbon Dioxide, ATP, NADPH
Outputs: Glucose, ADP+Pi, NADP
Location: Stroma
Evidence for chloroplasts having bacterial origin
- they possess DNA that consists of circular double-stranded DNA (not nuclear DNA)
- they divide via binary fission
- they contain their own ribosomes
- joined by eukaryotic cells after mitochondria because all eukaryotic cells have mitochondria, but not all have chloroplasts.
Relationship between light-dependent and light-independent reactions
The products or outputs of each reaction, becomes the inputs for the opposite reaction
Role of NADP+ in photosynthesis
Collects hydrogen ions for the transport to the light-independent stage
Role of ATP in photosynthesis
Energy carrier when charged with Pi. Energy is used in the light-independent stage
Factors affecting the rate of photosynthesis
Temperature Light availability CO2 availability O2 availability Chlorophyll availability
Main purpose of photosynthesis
The main purpose of photosynthesis is to convert radiant energy from the sun into chemical energy that can be used for food
Factors affecting ROP
Temp
- Photosynthetic enzymes and reactant molecules move more rapidly with increasing temperature
- With more collisions between enzymes and substrate a greater rate of photosynthetic reactions occur
- When temp is too hot and fine stage and rate of photosynthesis plummets
Factors affecting ROP
Light availability
- Chlorophyll requires light to conduct the light-dependent reactions of photosynthesis
- Thus as light intensity increases so does the rate of photosynthesis until a light saturation point is achieved
Factors affecting ROP
CO2 availability
- Carbon dioxide is a reactant for the light-independent stage of photosynthesis
- As carbon dioxide rises, the rate of photosynthesis will increase until the active sites of enzymes involved in photosynthetic reactions are saturated and an optimum rate is achieved
Factors affecting ROP
O2 availability
- More oxygen means a higher rate of photosynthesis, as it’s a result of the light-dependent action
Factors affecting ROP
Chlorophyll availability
- Chlorophyll absorbs the light energy required to convert carbon dioxide and water into glucose
- The more chlorophyll the higher the rate of photosynthesis
An increase in atmospheric CO2 level increases the rate of photosynthesis
The rate of photosynthesis increases because
The rate of the light-independent reactions in the stroma increases with the increase in CO2 levels.
Endosymbiotic theory of chloroplast and mitochondrial evolution
The endosymbiotic theory states that some of the organelles in eukaryotic cells were once prokaryotic microbes.
Mitochondria and chloroplasts of the same size as prokaryotic cells and divided by binary fission. Chloroplasts have their own DNA which is circular, not linear
In this theory the first eukaryotic cells probably amoeba-like so they got nutrients by phagocytosing and contained a nucleus that formed when a piece of the cytoplasmic membrane pinched off around the chromosomes.
The amoeba ate the prokaryotic cell the mitochondria formed when the bacteria are capable of aerobic respiration was ingested and chloroplast formed when photosynthetic bacteria was ingested
Evidence for the endosymbiotic theory
- Mitochondria and chloroplasts of the same size as prokaryotic cells and divided by binary fission
- Mitochondria and chloroplasts have their own DNA which is circular, not linear
- Mitochondria and chloroplasts have their own ribosomes which have 30S and 50S of subunits, not 40 and 60
Cofactors and Coenzymes
Coenzymes are small, non-protein organic molecules that carry chemical groups between enzymes e.g. NAD and FAD. Forms easily remove loose binds
A cofactor is a non-protein chemical compound that tightly and loosely bonds with an enzyme or other protein molecules.
What is the difference between anaerobic respiration in animals compared to anaerobic respiration in plants, yeast, and bacteria?
Anaerobic bacteria can sustain itself without the presence of oxygen.
Almost all animals and humans are obligate aerobes that require oxygen for respiration, whereas anaerobic yeast is an example of facilitative anaerobe bacteria. Individual human cells are also facilitative anaerobes: They switch to lactic acid fermentation if oxygen is not available.
Mitochondria
Membrane-bound organelles that generate most of the chemical energy needed to power the cell’s biochemical reactions. Chemical energy is produced by the mitochondria is stored in a small molecule called ATP.
Cellular respiration equation
Glucose + Oxygen = Carbon Dioxide + Water + ATP
Cellular respiration
The complete breakdown of glucose to provide energy for cells. Specifically, it refers to the second aerobic stage that occurs in the mitochondria and produces 36-38 ATP per molecule of glucose.
Glycolysis
Location: Cytosol
Inputs: Glucose, ADP+Pi, NAD+
Outputs: Pyruvate, ATP, NADH
ATP yield: 2
