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1. Visible in this figure is a structure resembling tubes and flattened sacs (wh

ID: 275798 • Letter: 1

Question

1. Visible in this figure is a structure resembling tubes and flattened sacs (which synthesizes proteins) that surrounds the spherical organelle, with which it appears to share a membrane. The spherical organelle is the and the structure resembling tubes and flattened sacs is the nucleoid; rough ER nucleus; Golgi apparatus. nucleus; rough ER. nucleolus; rough ER. nucleoid; Golgi apparatus. 2. Which of the following would you expect to have a nuclear localization signal? mRNA. tRNA. DNA rRNA. DNA polymerase. 3. If the DNA sequence encoding the amino acid sequence Pro-Pro-Lys-Lys-Lys-Arg-Lys-Val was placed in the gene for a cytoplasmic protein, the resultant protein would stay in the endoplasmic reticulum. be modified in the Golgi. be directed to the nucleus. be directed to the cytoplasm. be directed to the lysosomes

Explanation / Answer

1 - Nucleus and the Rough ER

nucleus is enclosed by an envelope composed of two membranes perforated by pores and contains a nucleolus and chromosomes.Rough ER is a system of interconnected membrane bound flattend sacs where ribosomes are attached to the surface to give it a rough look.Proteins made by these ribosomes are treansported through the ER to the other parts of the cell.

2- m RNA

During translation nuclear localized signal is generated to direct the polypeptides to the specific parts of the cell .

3 - would be directed to nucleus

this gene sequence acts as asignal to translocate peptides to nucleus.

4 - a - Nuclear lamina ,helps to organise chromosomes

Nuclear lamina is a dense fibrilar network inside nucleus and provides mechanical support .

5 - golgi apparatus

Proteins are secreted by secretrory path way through rough ER --->Golgi---->cisternae of golgi--->transport vesicles---->cell surface by exocytosis.