ASU 181- Unit 2- Module 4b-Nucleus

nuclear envelope

A double membrane that surrounds the nucleus in the cell

Nucleus

A part of the cell containing DNA and RNA and responsible for growth and reproduction

minor groove

A smaller groove that spirals around the DNA double helix.

DNA bases

Adenine, Thymine, Guanine, Cytosine

Chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

Naked DNA

DNA not associated with histones or histone-like proteins.

Heterochromatin

Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed.

Nuclear Lamins

Intermediate filaments that make up the nuclear lamina layer—a lattice-like layer inside the nuclear envelope that stiffens the structure.

nuclear cage (nuclear lamina)

Network of fibrils which protrude from nuclear pore proteins into the nucleus and cytosol.

Euchromatin

The less condensed form of eukaryotic chromatin that is available for transcription.

Centrioles

a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.

nuclear pore

a protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm

•Using your knowledge of membrane flow and co-translational insertion of protein, can you design a path that explains how the nuclear envelope (shown on the previous slide) obtains new lipids and transmembrane proteins?

draw this path, will be on exam

Lighter area on nucleus is

euchromatin

Darker area on nucleus is

heterochromatin

the _____________ envelope below is contiguous with the RER.

nuclear

Cytoplasmic Fibril

of nuclear pore complex. filamentous proteins attached to the cytoplasmic ring of nuclear pore complex. They function in recognizing nuclear localization signals and initiating the transport of proteins from the cytoplasm into the nucleus.

Histone

protein molecule around which DNA is tightly coiled in chromatin

•Naked DNA does not exist in nature. But scientists can make naked DNA by stripping of the associated protein using technology. One such technology is referred to as "_________________". Scientist can make the DNA in this state in a test tube (in vitro)

salt washing

In a living cell the nucleus is like a vault, it take a combination (i.e., ________________) to get in or out of the nucleus.

signal sequence

Nucleolous

small, dense region within most nuclei in which the assembly of proteins begins

Major groove

the larger of the two grooves in the DNA double helix

A limitation of all studies on Isolated nuclei is that the nucleus becomes leaky

this is a limitation of the technology!!

There are 8 subunits in a nuclear pore complex. Only 4 of the 8 are shown here as this is a cross section of the pore.

this is on the quiz

Nucleoplasm

viscous fluid enclosed by the nuclear envelope

nucleosomal core

•composed of 8 histones: -Two H2A -Two H2B -Two H3 -Two H4 And with each nucleosomal core unit there is one H1 that is acting, sort of, like a staple.