homework #1 is due now bonus #1 is posted and due 10/24
DESCRIPTION
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. in Plants Development Cold Guard cell closing Osmotic shock Light Fungal infection Touch Pollen tube growth - PowerPoint PPT PresentationTRANSCRIPT
Homework #1 is due nowBonus #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• Development• Cold• Guard cell closing• Osmotic shock• Light• Fungal infection• Touch• Pollen tube growth• Wounding…
in Animals• Neurons• Muscle movement• Wounding• Development• Fertilization• Hormones• …
How can there be specificity?
Everything has its place…
Fig 1. Scrase-Field and Knight, Current Opinion in Plant Biology 2003, 6:500–506
2 hypotheses about how Ca++ signals are transduced:Signatures vs. Switches
Stomata regulate gas exchange: CO2 in, O2 and
water out
H2OH2O
Stomata
closedopen
Fig 5. Sanders et al., The Plant Cell, S401–S417, Supplement 2002
Ca++ fluxes in guard cells in response to hormone or stress that cause stomatal closing.
Wildtype vs. det3 and gca2: mutants that fail to close stomata following treatment
Fig 1. Allen et al., Nature, Vol 411:1053-1057, 28 June 2001
Stomata aperture in response to Ca++ spikes:More spikes= more closing
Fig 2. Allen et al., Nature, Vol 411:1053-1057, 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 1. Scrase-Field and Knight, Current Opinion in Plant Biology 2003, 6:500–506
2 hypotheses about how Ca++ signals are transduced:Signatures vs. Switches
Signal transduction
– such as changes in
cellular components
or production of new cellular components
Fig 8.11
How do cells express genes?
a gene
The relationship between DNA and genes
promoter coding region terminator non-geneDNA
Fig 8.3
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.
Fig 7.8
Each nucleotide is connected from the 5’ carbon through the phosphate to the next 3’ carbon.
The relationship between DNA and RNA
Fig 8.6
Fig 8.4
What is so magic about adding nucleotides to the 3’ end?
Fig 8.8
How does the RNA polymerase know which strand to transcribe?
5’5’3’
3’5’
Reverse promoter, reverse direction and strand transcribed.
RNA
DNARNA RNA
DNA
UU
Why do polymerases only add nucleotides to the 3’ end?
3’
5’Hypothetically, nucleotides could be added at the 5’ end.
Incoming nucleotide
P
Error
P-P
The 5’ tri-P’s can supply energy for repair
Error
P
P-P-PP
U
3’
5’
Error repair on 5’ end not possible.
Incoming nucleotide
DNARNA RNA
DNA
UU
Need for error repair limits nucleotide additions to 3’ end.
Fig 8.11
DNA contains the information to make RNA and/or proteins.
Protein
Homework #1 is due nowBonus #1 is posted and due 10/24