Lecture 7 Nucleus

Question 1

The outer membrane of the nucleus is often surrounded by a mesh of ____ _____

Answer 1

intermediate filaments

Question 2

The nuclear lamina supports the inner membrane of the nucleus and is primarily composed of _____ A, B, and C

Answer 2

Laminin

Question 3

Nuclear pores are formed by fusion of the inner and outer nuclear membrane and are associated with the _____ _____ complex

Answer 3

nuclear pore

Question 4

The nuclear pore complex is a cylindrical aqueous opening that allows passage of small ____ _____ molecoules

Answer 4

water soluble

Question 5

The nuclear pore complex consists of proteins arranged in _____ symmetry

Answer 5

octagonal

Question 6

Ions, small molecoules, and proteins less than 60 kDa can diffuse into the nucleus via NPCs. Transport of larger molecules requires nuclear pore _____ proteins

Answer 6

receptor

Question 7

Nuclear pore receptor proteins are ____ associated and recognize nuclear recognize signals, which are ____ ____ sequences on the protein.

Answer 7

fibril

amino acid

Question 8

Large proteins recognized by nuclear localization signals are transported into the nucleus via ____ transport

Answer 8

active

Question 9

Nuclear import-export requires energy in the form of ______ –> _____

Answer 9

GTP

GDP

Question 10

Specialized proteins called ____ and ____ are needed to move materials across the nuclear pore

Answer 10

importin

exportin

Question 11

Nucleoplasm is protoplasm surrounded by the nuclear envelope that consits of a ____ ____ and various particles

Answer 11

nuclear matrix

Question 12

The nuclear matrix acts as a _____ to organize the nucleplasm.

Answer 12

scaffold

Question 13

The nuclear matrix contains ___ components: including fibrillar elements, the nuclear pore-nuclear lamina complex, and the RNP network. The matrix also contains ____ components involved in transcription and process of mRNA and rRNA

Answer 13

structural

functional

Question 14

Chromatin resides within the nucleus in 2 forms: ____ and _____

Answer 14

heterochromatin

euchromatin

Question 15

Heterochromatin appears _____ under TEM and is concentrated at the nucleus periphery and around the nucleolus

Answer 15

darker

Question 16

Heterochromatin is transcriptionally _____

Answer 16

inactive

Question 17

Euchromain is lightly stained and dispersed throughout the nucleus and is transcriptionally _____

Answer 17

active

Question 18

Chromatin consists of double stranded DNA complexed with histones and non-histone acidic proteins that are responsible for _____ synthesis

Answer 18

RNA

Question 19

Histones contain _____ and ____ that bind to DNA

Answer 19

lys

arg

Question 20

the _____ is the fundamental packing unit of chromatin

Answer 20

nucleosome

Question 21

Chromatin resembels beads on a string at the TEM level, with the beads being nucleosomes and the string being ____ DNA

Answer 21

linker

Question 22

____ chromatin contains an additional histone (H1), which wraps around groups of nucleosomes forming 30-nm fibers, the strutural unit of the chromosome

Answer 22

condensed

Question 23

Chromosomes become visible during ____ and _____

Answer 23

mitosis

meiosis

Question 24

Barr bodies are present in nearly all somatic cells of ____ mammals

Answer 24

female

Question 25

Barr bodies are inactive ____ chromosomes and appear during interphase

Answer 25

X

Question 26

the _____ is a non-membrane bound, nuclear inclusion of the nucleus

Answer 26

nucleolus

Question 27

Cancer cells may have large or multiple _____

Answer 27

nucleoli

Question 28

The nucleolus is generally detectable only when the cell is in _____

Answer 28

interphase

Question 29

The _____ is protoplasm surrounded by the nuclear envelope. It contains nuclear matrix

Answer 29

nuceloplasm

Question 30

Nucleosomal histones include H2A, ____, H3, H4, and H1 histones

Answer 30

H2B