Lecture 10 Photosynthesis, Anabolism and Genetics Flashcards
What are the two parts of Photosynthesis?
- Light energy trapped, converted to chemical (light reactions)
- Chemical used to reduce CO2 and synthesize cell material (dark reactions)
What are Chlorophylls and what reaction do they take part in?
- Light Reactions: Trapping Light
- Major light-absorbing pigments - eukaryotes cyanobacteria
What are bacteriochlorophylls
- Major light-absorbing pigments -purple, green bacteria
What do accessory pigments do?
- Transfer light energy to chlorophylls
- Absorb different wavelengths that chlorophylls
- Quench toxic forms of oxygen (photoprotection, antioxidants)
Beta - Carotene is what?
An accessory pigment that gives carrots there orange color.
Lycopene is what?
An accessory pigment that gives tomatoes there red color.
In cyanobacteria and Plant, chlorophylls and accessory pigments are assembled into light-harvesting arrays called ___ that are embedded in membranes called ___
Photosystem, Thylakoids
Describe how Photosystems work
- absorbs light energy from photons
- Energy transferred to rxn center
- Chlorophyll electrons excited and passed to the first acceptor in ETC
Describe cyclic photophosphorylation
PSI
ATP via ETC, PMF and FoF1 ATP synthase
REVIEW SLIDE
Describe Noncyclic Photophosphorylation
PSI and PSII
ATP and NADH
-Electrons lost to NADP in PSI
-Replenished by splitting water in PSII
Describe the light reactions for green and purple bacteria
- takes place in the plasma membrane
- Bacteriochlorophyll
- Anoxygenic (use H2, H2S or organic matter as electron donor)
- Only one photosystem (PSI)
- Generates ATP but no NADPH
How do green and purple bacteria generate NADPH?
- Reverse electron transport
- Use proton motive force to drive electrons backwards
- To reduce NADP to NADPH
Look at table 11.8
Look at table 11.8
Microbial Rhodopsin
- Pigment protein
- In plasma membrane
- 7 transmembrane helices
- Pigment = Retinal
- absorbs light
- causes conformational changes in rhodopsin
Rhodopsin, Retinal and Retinal
Rhodopsin is also found in the retina of the eye, where it functions as a light sensitive receptor protein, enabling vision in low light
its pigment Retinal is produced from retinal a form of vitamin A
What is Anabolism?
Synthesis of complex molecules from simpler ones with the input of energy
uses ATP and reducing power often in the form of NADPH
What is the Calvin Cycle?
Anabolic Pathway for Fixing CO2 into Carbohydrate
- Dark reactions of photosynthesis
- Energy demanding
- Chloroplasts - plants
- Cytoplasm - bacteria
- Crucial to life, provides organic matter for heterotrophs (use reduced organic molecules as C sources)
Review the Calvin Cycle Fig 12.4
Review the Calvin Cycle Fig 12.4
Review the Reductive TCA Cycle Fig 12.5
Review the Reductive TCA Cycle Fig 12.5
What is Gluconeogenesis?
- Glucose synthesis
- Animals, plants, fungi, bacteria
- humans use to
maintain blood
glucose levels
Requires ATP and GTP
- humans use to
- 6 enzymes also used in glycolysis but 4 unique to gluconeogenesis
What are the 3 processes of genetic information flow?
- ) DNA replication
- ) Transcription
- ) Translation
What is a Gene?
- Functional unit of genetic information
- deoxyribonucleic acid (DNA)
- Genes: pilA, lacZ
- Proteins: PilA, LacZ
What is a Genome?
- All genetic material in cell or virus
- Bacterial genomes consist of one (usually) or more DNA chromosomes
What is a Genotype?
- Specific set of genes carried in the genome
Describe the Promotor region in a gene
Where RNA polymerase binds to begin transcription
Describe the Operator Region
Where repressor proteins bind to block transcription
What are Inducers?
Molecules the bind repressors
What are the parts of a nucleotide?
- Sugar (Ribose)
- Nitrogenous Base (A,G,T,C)
- Phosphates group.
What is the size of DNA expressed as?
- base pairs (bp)
- bacterial genomes vary greatly: one of the smallest- Mycoplasma - 580kb encoding 480 proteins.
