Chapter 10 Primer Questions

Describe four different ways that Eubacteria and Eukaryotes differ in their mechanisms of protein synthesis.

1. Eubacteria- Transcribed mRNA often codes for multiple proteins Eukaryote- mRNA translate into a single protein 2. Eubacteria- Transcription and translation occur next to each other Eukaryote- Transcription and translation occur in different parts of the cell 3. Eubacteria- Control transcription by protein repressors, which binds to sections of DNA called operators to turn off transcription. Eukaryote- Use operators and activators, which bind to the enhancers, thereby activating transcription. 4. Eubacteria- No splicing, no protein cap, no poly A-tail Eukaryote- "mRNA processing"

Please distinguish the control of transcription between the Eubacteria and the Eukaryota

CONTROL: eukaryotes: - activators (proteins that bind to part of the DNA called the enhancer) are used to activate transcription - activators exert their influence at a further proximity from transcription initiation site of RNA polymerase - transcription factors bind to activators, influencing the same promoter region's inclination to bind RNA polymerase, the gene can be regulated in a continuous, graded fashion bacteria (prokaryotes): - proteins called repressors bind to sections of DNA to turn off transcription - no transcription factors

What is a repressor in Bacteria and what does it do?

a protein that stops transcription

What is a transcription factor, and what does it do?

a small molecule or protein used in eukaryotic transcription control to bind to activators and speed up initiation of transcription

What are exons and introns? What is their fate?

exons are remaining segments of the gene splicing process that produce the mature mRNA transcript and introns are sections of mRNA that are removed and recycled for nucleotides during gene splicing. Both destined for export out of the nucleus.

Where in the cell do transcription and translation occur in prokaryotes? In eukaryotes?

in prokaryotes transcription and translation both occur in the cytoplasm. in eukaryotes translation occurs in the ribosomes of the rough ER and transcription occurs in the nucleus.

Use the example of the lac operon to explain how transcription is regulated in Bacteria.

lac operon metabolizes lactose. If there is lactose, it wants to run but if no lactose it doesn't want to run to use ATP because there is nothing to metabolize. If repressor is made, it will bind to operator and stop transcription. If there is lactose will stop repressor from being made and let RNA polymer transcribe the rest of the strand.

Describe how eukaryotes package their gene products. Use the words, ribosome, rough endoplasmic reticulum, smooth endoplasmic reticulum, transport vesicle, golgi apparatus, cis face, trans face.

mRNA docks to ribosome which is transported to the rough ER where it is translated into proteins. these proteins get packages into transport vesicles. the transported tot he Golgi body where it enters though the cis face. exits via the trans face of the Golgi body

What is a lysosome, and why doesn't it consume itself?

vesicles that fuse with and break down 2 kinds of structures, activating the proton pump, which makes the internal environment more acidic, allowing the digestive enzymes in lysosomes to function without consuming itself