4. Ribosomes- site in which we have protein synthesis- functional in the cytoplasm (4 RNA, 70 proteins)1. **not an organelle- it is not membrane-bound, very important macromolecule2. ½ RNA ½ protein3. typical eukaryote has 10 million of these in cytoplasm4. 80s Ribosome (name refers to size (sedimentation coeff.)) has 2 subunits 40s and 60s, making a large and small ribosomal subunit in a Eukaryotea. relative size – message will go through the two subunits and will cover about 25 nucleotides of the message5. rRNA is negatively charged and will be attracted to the positively charged proteinsa. rRNA is the most abundant kind of RNA in the cellb. RNA in ribosome is largely structural, provides ‘scaffolding’ for it some RNA has a catalytic abilityc. Some cases where proteins work as enzymes and do their job but others fill in around RNAd. 4 Types or sizes of rRNA- names for their size and where and how they are madei. 28s – RNA polymerase 1 transcribes this, in 60s ribosomal subunitii. 18s – RNA polymerase 1 transcribes this, in 40s ribosomal subunitiii. 5.8 s - RNA polymerase 1 transcribes this, in 60s ribosomal subunitiv. 5 s – RNA polymerase III transcribes this, in 60s ribosomal subunit6. Once you have the RNA for ribosome, it self assembles for no additional charge of energy7. 1930s Barbera McClintock found a sub-structure within the nucleus called the nucleolus, which inside there were fibrillan and outside the nucleolus there was a granular regiona. during mitosis in realized that the fibrilla region originated from specific parts of certain chromosomes. Realized there were certain regions on several specific chromosomes that had secondary regions (constrictions that stayed together) – that secondary region formed the fibrilla region of the nucleolus- this was called the nucleolar organizer from then onb. 1950s more assays and radio isotopes were used to study the nucleolus- and found huge amounts of RNA were produced in the fibrilla region, more than anywhere else in the cellc. from the radio tracers, knew there was a linkage between chromosomes, nucleolus and ribosomes because the amount of RNA that tracked through eachi. the tracer began in the fibrilla region, then traveled to the granular region and then to the ribosomes, suggesting their linkaged. Fibrilla – that primary fiber was DNA, and when they looked at it closely, they found there were regions on the DNA that looked like circles with extensions from those circles, looking like sideways Christmas trees, looking like fuzzy DNA at first. It turned out the string that made the ‘trunk of the tree’ was DNA, the circles were RNA polymerase Is and the fuzzy extensions were RNA, looking like the Christmas trees in tandem repeatse. The area that represents the ‘trunk’ of the Christmas tree is the gene RNA polymerase I moves all the way up the ‘trunk’ of the tree and gets off like an escalator would work.i. RNA polymerase will get off at right time because RNA polymerase I recognizes the TTTT end sequence like prokaryotesf. There were some cells that needed to make many proteins and they had very large nucleoli, there were other cells that didn’t make many proteins (neurons, Sperm) had a very small nucleolus8. On the gene, the 18s RNA molecules are made first, then 5.8s then 28sa. there are spaces in between them that have extra RNA, but these are NOT introns or exons, those are only in mRNA9. Promoter region from 140 nucleotides upstream to the start of the genea. important sequences that need to be conserved to be recognized from 114 nucleotides upstream to 72b. the sequences will attract transcription factors that will help the RNA polymerase bindc. You can regulate how much RNA is made byi. limiting the number of transcription factorsii. or limiting RNA polymerases presentd. Above the promoter that is effecting how often the RNA polymerases were binding aside from the transcription factors,  found there was a region of 60-80 nucleotides that were upstream of the promoter that looked very close to the central sequence of the promoter, they looked so similar to the promoter that they were called “promoter-like” sequences (90% homologous)i. these promoter-like regions were enhancing the chance for the transcription factor to hit the promoter region by attracting more transcription factor to that areaii. other function of these- bind to transcription factors and make sure they stay during mitosise. 5s genes are NOT made in nucleolus, and rather in the nucleoplasm- are about 20,000 5s genesi. small- only about 120 nucleotides in length in some areas where they could be tandem arranged as wellii. 2 types of 5s genes – o-type and s-typef. Cell type with 5s genesi. germcell (oocyte) = 20000 5s genes; 19,000 o-type (95% RNA) and 1,000 s-type (5% RNA) **makes senseii. somatic = 20,000 5s genes; 19,000 o-type (about O% of RNA) and 1,000 s-type (100% of RNA) **doesn’t make sense1. the different distribution of RNA gives differential gene expressionBY 330 1st Edition Lecture 11 Outline of Last Lecture D. Post TranscriptionE. Translation1. Translation begins2. Coding region3. Promoter regionOutline of Current Lecture 4. RibosomeCurrent Lecture4. Ribosomes- site in which we have protein synthesis- functional in the cytoplasm (4 RNA, 70 proteins)1. **not an organelle- it is not membrane-bound, very important macromolecule2. ½ RNA ½ protein 3. typical eukaryote has 10 million of these in cytoplasm4. 80s Ribosome (name refers to size (sedimentation coeff.)) has 2 subunits 40s and 60s, making a large and small ribosomal subunit in a Eukaryotea. relative size – message will go through the two subunits and will cover about 25 nucleotides of the message5. rRNA is negatively charged and will be attracted to the positivelycharged proteins a. rRNA is the most abundant kind of RNA in the cellb. RNA in ribosome is largely structural, provides ‘scaffolding’ for it some RNA has a catalytic abilityThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.c. Some cases where proteins work as enzymes and do their job but others fill in around RNAd. 4 Types or sizes of rRNA- names for their size and where and how they are madei. 28s – RNA polymerase 1 transcribes this, in 60s ribosomal subunitii. 18s – RNA polymerase 1 transcribes this, in 40s ribosomal subunitiii. 5.8 s - RNA polymerase 1