MCB 2050 Nucleus Exam

Prokaryotes do not possess a nucleus that is ___________ but Eukaryotes do. - Correct Answer-Membrane bound The boundary between the cytosol and the nucleus is called the _____. - Correct Answer-Nuclear Envelope Where chromosomes are located in the prokaryotes... - Correct Answer-nucleoid Main functions of the nucleus: - Correct Answer-- DNA replication - transcription/RNA processing - protein synthesis - cell division (reproduction) - control of metabolism - translation components (ribosomes, mRNA, tRNA) synthesized - storage component The outer membrane of the nuclear envelope binds ________ and is continuous with the _______________. - Correct Answer-Ribosomes; RER Inter membrane space of the nuclear envelope can otherwise be referred to as .... - Correct Answer-Nuclear Envelope Lumen The intermembrane contains proteins that connect the nuclear _______. - Correct Answer-lamina The nuclear lamina provides what for the nucleus? - Correct Answer-structural framework (keeps ovular) Main functions of the nuclear envelope - Correct Answer-- separates nuclear content from cytoplasm - Selective Barrier - Regulates gene expression - Binds nuclear lamina Nuclear lamina provide _____ for chromatin. - Correct Answer-scaffold for attachment Mutations in either lamina genes can lead to diseases such as____ - Correct Answer-Progeria _________ are located in the nucleoplasm and do not contain membranes - Correct Answer-subdomains (specialized regions) Location of actively transcribed gene in the nucleus - Correct Answer-periphery of a chromosomal subdomain regions between domains that serve as barriers to prevent unwanted DNA-DNA or DNA-Protein interactions - Correct Answer-Interchromosomal channels Transcription factors are highly concentrated in _______________ - Correct Answer-Transcription factories Nucleoli are _________________ involved in __________________. - Correct Answer-Transcription factories; ribosome synthesis TF: In transcription factories, related genes are transcribed at the same time - Correct Answer-TRUE Subdomains where mRNA splicing factors are concentrated (where pre-mRNA processing occurs) - Correct Answer-Nuclear Speckles Initial stages of ribosomal subunit occur at _____________ and final assembly occurs in ______________. - Correct Answer-nucleolus; cytoplasm Size and number of nucleoli in the cell depend on the ______________ of the cell. - Correct Answer-metabolic activity Nuclear Pore Complex contains approx 40___________ - Correct Answer-Nucleoporins (NUPS) Y complexes are made of _____________ nucleoporins and connect to the _____________. - Correct Answer-structural; cytoplasmic filaments The hydrophobic mesh that limits the diffusion of molecules greater than 40kDa - Correct Answer-FG domains (nucleoporins) Membrane NUPS are connected to the _____________. - Correct Answer-nuclear basket Nuclear protein that is synthesized in the cytoplasm, associates with cytoplasmic filaments, and is translocated into the nucleus - Correct Answer-Nucleoplasmin Three things cytosol-nuclear transport requires - Correct Answer-- energy - specific protein receptors - unique targeting signals short stretch of positively charged amino acids (KKQRKK) - Correct Answer-Classic Nuclear Location Signal two short stretches of basic amino acids and a 7-10 spacer sequence; found in nucleoplasmin (KR________KKKK) - Correct Answer-Barpartite Nuclear Location Signal ____________ are known as importins and exportins - Correct Answer-Karyopherins (types of transport receptors) Mutation in the SRY gene or TDF causing mutation in NLS and cannot enter the nucleus to execute it's function - Correct Answer-Swyer Syndrome SRY acts on ____________ to suppress it's activity of transcribing female phenotypes - Correct Answer-Beta-cretinine Importin _____ subunit recognizes and binds to basic residues of the NLS of cargo protein - Correct Answer-Importin alpha Importin ____ subunit brings the cargo-protein complex to the cytoplasmic filaments of nuclear pores - Correct Answer-Importin Beta ______________ elements serve as highways for almost all types of intracellular transport - Correct Answer-cytoskeleton In the nucleus, Importin beta experiences confirmational chance from the binding of _________, causing subsiquential change in inportin alpha. - Correct Answer-Ran-GTP RAN - Correct Answer-Ras related nuclear protein Guanine exchange factor that converts RAN - GDP to RAN-GTP in the nucleus - Correct Answer-RCC1 Cystolic protein that promotes the hydrolysis of RAN-GTP to RAN-GDP - Correct Answer-RAN-GAP 1 Free RAN-GDP moves to the cytoplasm after being hydrolyzed by ________ due to the __________________ between the cytosol and nucleus. - Correct Answer-RAN-GAP1; concentration gradient Importin Alpha contains a _____________ with many _____________ residues, to move out of the nucleus - Correct Answer-Nuclear Export Signal; Leucine ___________ moves back into the nucleus once it dissociates from importin alpha - Correct Answer-Exportin The entire complex moved from the nucleus to the cytosol contains.... - Correct Answer-- Importin alpha - Ran-GTP - Exportin These two proteins direct the spliced mRNA to the central channel of the NPC - Correct Answer-NXF1/NXT1 This protein removes the transport proteins from the mRNA in an ATP manner - Correct Answer-Dbp5