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TLS Online TPP Program

#Id: 8105

Three glycolipids of chloroplast thylakoid membranes.

#Unit 1. Molecules and their Interaction Relevant to Biology #Lipid #Part B Pointers
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TLS Online TPP Program

#Id: 6777

#Unit 3. Fundamental Processes

Mutation of either the 5′ or the 3′ invariant splice-site bases at the ends of the intron resulted in pre-mRNAs that were bound by snRNPs to form spliceosomes; however, RNA splicing was blocked, and the pre-mRNA was retained in the nucleus. 
In contrast, mutation of both the 5′ and 3′ splice sites in the same pre-mRNA resulted in export of the unspliced pre-mRNA, although less efficiently than for the spliced mRNA, probably because of the absence of an exon-junction complex. When both splice sites were mutated, the pre-mRNAs were not efficiently bound by snRNPs, and consequently, their
export was not blocked.
TLS Online TPP Program

#Id: 6778

#Unit 3. Fundamental Processes

The estimate is that as much as 70% of human genes produce antisense RNA.
TLS Online TPP Program

#Id: 6779

#Unit 3. Fundamental Processes

Clustered Regularly Interspaced Short Palindromic Repeats CRISPR consist of repeated sequences (each 30 bp long and highly conserved within a given cluster) interleaved with spacer sequences of similar length but highly divergent sequence.
TLS Online TPP Program

#Id: 6780

#Unit 3. Fundamental Processes

The mechanism of spacer sequence acquisition is as 
Each new spacer sequence is inserted next to the leader sequence, with the consequence that the array is a temporal record of acquisitions past. The sequence destined to become spacer is, within the phage genome, known as a “proto-spacer” and lies adjacent to a PAM sequence
TLS Online TPP Program

#Id: 6781

#Unit 3. Fundamental Processes

A set of conserved protein-coding genes is tightly associated with the CRISPR sequences. The two most highly conserved members (cas1 and cas2, for “CRISPR associated”) are found in all cases
TLS Online TPP Program

#Id: 6782

#Unit 3. Fundamental Processes

The protospacer adjacent motif (or PAM for short) is a short DNA sequence (usually 2-6 base pairs in length) that follows the DNA region targeted for cleavage by the CRISPR system, such as CRISPR-Cas9. The PAM is required for a Cas nuclease to cut and is generally found 3-4 nucleotides downstream from the cut site