Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
47 Cards in this Set
- Front
- Back
The contents of the nucleus are enclosed by the _______.
|
Nuclear Envelope
|
|
What size solutes can easily pass through the nuclear pores?
|
<40kD
|
|
The inner surface of the nuclear envelope is lined by the _______.
|
Nuclear Lamina
|
|
The _______ is composed of lamins and supports the nuclear envelope.
|
Nuclear Lamina
|
|
The integrity of the nuclear lamina is regulated by _______ and _______.
|
phosphorylation and dephosphorylation
|
|
Nuclear pores contain the _______ that appears to fill the pore like a stopper.
|
Nuclear pore complex (NPC)
|
|
The NPC is composed of about _______ proteins called _______.
|
30
nucleoporins |
|
Proteins synthesized in the cytoplasm are targeted for the nucleus by _______.
|
Nuclear Localization Signal (NLS)
|
|
What is the basic residues of the NLS?
|
P-K-K-K-R-K-V
|
|
What is the first step in importing proteins from the cytoplasm to the nucleus?
|
The protein with NLS binds to importin alpha/beta.
|
|
What is the second step in importing proteins from the cytoplasm to the nucleus?
|
The importin alpha/beta and protein form a complex with the cytoplasmic filament.
|
|
What is the third step in importing proteins from the cytoplasm to the nucleus?
|
The protein complex is moved through the nuclear pore.
|
|
What is the fourth step in importing proteins from the cytoplasm to the nucleus?
|
The protein complex moves into the nucleoplasm and interacts with Ran-GTP and dissociates.
|
|
What is the fifth step in importing proteins from the cytoplasm to the nucleus?
|
Importin beta is transported back to the cytoplasm, along with Ran-GTP.
|
|
What is the role of guanine exchange factors (GEF)?
|
GDP to GTP
|
|
What is the role of GTPase activating protein (GAP)?
|
GTP to GDP
|
|
Chromosomes consist of _______ fibers, composed of DNA and associated proteins.
|
chromatin
|
|
What amino acids do histones have a large content of?
|
Arginine and Lysine
|
|
What are the five different groups of histones?
|
H1
H2A H2B H3 H4 |
|
Why are histones so highly conserved?
|
Their positive charge is associated with the negative charges on the backbone of DNA.
|
|
What is the %Arg and %Lys in H1? What is its UEP?
|
%Arg - 1
%Lys - 29 UEP - 8 |
|
What is the %Arg and %Lys in H2A? What is its UEP?
|
%Arg - 9
%Lys - 11 UEP - 60 |
|
What is the %Arg and %Lys in H2B? What is its UEP?
|
%Arg - 6
%Lys - 16 UEP - 60 |
|
What is the %Arg and %Lys in H3? What is its UEP?
|
%Arg - 13
%Lys - 10 UEP - 330 |
|
What is the %Arg and %Lys in H4? What is its UEP?
|
%Arg - 14
%Lys - 11 UEP - 600 |
|
DNA and histones are organized into repeating subunits called _______.
|
nucleosomes
|
|
The histone core complex consists of two molecules each of _______, _______, _______, and _______ forming an octamer.
|
H2A
H2B H3 H4 |
|
What is the preferred organizational model of chromatin structure?
|
Zig-zag (solenoid is the other)
|
|
_______ returns to a dispersed state after mitosis.
|
Euchromatin
|
|
_______ is condensed during interphase.
|
Heterochromatin
|
|
What kind of heterochromatin is found around centromeres and telomeres, remains condensed all the time (no gene expression), and consists of highly repeated sequences?
|
Constituative Heterochromatin
|
|
What kind of heterochromatin is inactivated during certain phases of an organism's life and found on one of the X chromosomes as a Barr body?
|
Facultative Heterochromatin
|
|
What are two ways that histone tail modifications influence chromatin?
|
-serve as docking sites to recruit non-histone proteins
-alter the way in which histones of neighboring nucleosomes interact with one another |
|
Histone _______ leads to DNA inactivation.
|
methylation
|
|
Histone _______ leads to DNA activiation.
|
acetylation
|
|
Chromatin of a _______ cell exists in its most highly condensed state.
|
mitotic
|
|
A preparation of homologous pairs ordered according to size.
|
Karyotype
|
|
The end of each chromosome is called a _______ and is distinguished by a set of repeated sequences.
|
telomere
|
|
The _______ is located at the site markedly indented on a chromosome.
|
centromere
|
|
_______ contain constituative heterochromatin.
|
centromeres
|
|
_______ DNA is the site of microtubule attachment during mitosis.
|
Centromeric
|
|
_______ inheritance depends on factors other than DNA sequences.
|
epigenetic
|
|
The _______ is a network of protein-containing fibrils.
|
nuclear matrix
|
|
_______ involve the breakage of a chromosome and resealing of the segment in a reverse order.
|
inversions
A B C D -> D C B A |
|
_______ are the result of the attachment of all or one piece of one chromosome to another chromosome.
|
translocations
|
|
_______ result when there is a loss of a portion of a chromosome.
|
deletion
|
|
_______ occur when a portion of a chromosome is repeated.
|
duplication
|