Homework 1 is due now Bonus 1 is
Homework #1 is due now Bonus #1 is posted and due 10/24
Fig 8. 11 DNA contains the information to make RNA and/or proteins. Protein
General model of Ca++ signaling
Ca++ is involved in signal transduction for responses of: • • • in Plants in Animals Development • Neurons Cold • Muscle movement Guard cell closing • Wounding Osmotic shock • Development Light • Fertilization Fungal infection • Hormones Touch • … Pollen tube growth Wounding… How can there be specificity?
Everything has its place…
2 hypotheses about how Ca++ signals are transduced: Signatures vs. Switches Fig 1. Scrase-Field and Knight, Current Opinion in Plant Biology 2003, 6: 500– 506
Stomata regulate gas exchange: CO 2 in, O 2 and water out H 2 O
Stomata open closed
Ca++ fluxes in guard cells in response to hormone or stress that cause stomatal closing. Wildtype vs. det 3 and gca 2: mutants that fail to close stomata following treatment Fig 5. Sanders et al. , The Plant Cell, S 401–S 417, Supplement 2002
Stomata aperture in response to Ca++ spikes: More spikes= more closing Fig 1. Allen et al. , Nature, Vol 411: 10531057, 28 June 2001
Spike timing is critical for response Fig 2. Allen et al. , Nature, Vol 411: 1053 -1057, 28 June 2001
Duration of spikes for stomata closing Fig 2. Allen et al. , Nature, Vol 411: 1053 -1057, 28 June 2001
2 hypotheses about how Ca++ signals are transduced: Signatures vs. Switches Fig 1. Scrase-Field and Knight, Current Opinion in Plant Biology 2003, 6: 500– 506
Signal transduction – such as changes in cellular components or production of new cellular components
Fig 8. 11 How do cells express genes?
Fig 8. 3 The relationship between DNA and genes a gene promoter coding region terminator non-gene DNA
Combinations of 3 nucleotides code for each 1 amino acid in a protein.
• Overview of transcription Figure 8 -4 Fig 8. 4
Fig 7. 5 +8. 2 Each nucleotide carbon is numbered
Fig 7. 8 Each nucleotide is connected from the 5’ carbon through the phosphate to the next 3’ carbon.
Each nucleotide is connected from the 5’ carbon through the phosphate to the next 3’ carbon. Fig 7. 8
The relationship between DNA and RNA Fig 8. 6
Fig 8. 4 What is so magic about adding nucleotides to the 3’ end?
How does the RNA polymerase know which strand to transcribe? Fig 8. 8
Reverse promoter, reverse direction and strand transcribed. RNA 5’ 3’ 5’
Why do polymerases only add nucleotides to the 3’ end? RNA DNA U U
Incoming nucleotide Hypothetically, nucleotides could be added at the 5’ end. 5’ 3’
Error P-P P
Error P U P P-P-P The 5’ tri-P’s can supply energy for repair
Incoming nucleotide Error repair on 5’ end not possible. 5’ 3’
Need for error repair limits nucleotide additions to 3’ end. RNA DNA U U
Fig 8. 11 DNA contains the information to make RNA and/or proteins. Protein
Homework #1 is due now Bonus #1 is posted and due 10/24
- Slides: 33