Histone Quiz
How many base pairs is a core particle?
146 BP
Histones are the ___ level of DNA organization.
1st
How many times does the DNA nucleosome unwrap per second?
4
What is an operon?
A group of genes grouped together with related functions
A histone octamer consists of the proteins: A) 2H3, 2H2A, 2H2B, 2H4 B) 2H1, 2H2A, 2H2B, 2H4 C) 2H1, 2H2, 2H3, 2H4 D) 2H3, 2H2A, 2H2B, 2H4
A) 2H3, 2H2A, 2H2B, 2H4
Which one of these is not a class of histones? A) H1A B) H2A C) H3 D) H4
A) H1A
The catalytic subunit of the histone deacetylase (HDAC) complex is: A. Rpd3 B. Sin3 C. RD D. URS1 E. Ume6
A. Rpd3
Which of the following was the first well-characterized chromatin-remodeling complex? a. Swi/Snf b.Rpd3/Sin3 c. DBD/RD d.DBD/URS1
A. Swi/Snf
What type of physical change occurs when tryptophan binds to a repressor protein
Allosteric regulation of repressor protein
Which one of these is NOT paired up correctly? A) Nucleosome - Active transcription B) Metaphase Chromosome - Interphase C) 10 nm - Active Transcription D) 30 nm - Less Active Genes
B) Metaphase Chromosome - Interphase
Which type of chromatin is organized into the structure of nucleosomes? (a) Euchromatin (b) Heterochromatin (c) All of the above
B. Heterochromatin
Acetylation does which of the following to Lysine? a. Makes it more basic b.Neutralizes the charge c.Increases the acidity d.Causes Lysine to degrade
B. Neutralizes the charge
What of the following transcribes mRNA a. Pol III b. Pol II c. Pol I d. Pol IV
B. Pol II
What does the detachment of the H1 histone do to DNA in the nucleosomes? (a) degrades the DNA (b) unravels the DNA (c) causes unwinding of the helix (d) All of the above
B. Unravels the DNA
Which is NOT a way that cells introduce changes in protein structure/function? A) Post Translational Modifications B) Mutations C) Transposition D) Post Transcriptional Modifications
C) Transposition
_____ is the RNA polymerase binding site. A) operon B) operator C) promoter D) repressor protein
C. Promoter
What must happen before transcription can occur?
Chromatin remodeling - stretch of DNA containing the promoter must be released from the tight interactions with protein so that RNA polymerase can attach to the promoter
How is chromatin activated for transcription?
Covalently modified by acetylation
Which of the following is one of the ways that cells can introduce changes in protein structure and protein function? A) Mutations B) Acetylation C) Alternative Splicing D) All of the above are ways in which cells can introduce changes in proteins
D) All of the above are ways in which cells can introduce changes in proteins
A repressor protein: A) binds to DNA at operator site B) blocks RNA polymerase C) blocks transcription D) all of the above
D) all of the above
The catalytic subunit of the histone acetlytransferase (HAT) complex is: A. AD B. DBD C. UAS D. Gcn5 E. Gcn4
D. Gcn5
What inhibits transcription at multiple stages in condensed chromatin? A) Nucleus B) Proteins C) RNA D) Nucleosomes
D. Nucleosomes
DNA in a nucleosome unwraps rapidly for the processes _____ and _____
DNA replication and transciprtion
_____ digests nucleosomes to core particles
DNase 1
Give the order of chromatin condensation:
Double helix -> nucleosome core particle -> 10 nm -> 30 nm -> looped domain -> metaphase chromosome
True or False: Histones are NOT chaperones.
False
True or False: Histones are rich in Lysine and Arginine that are negatively charged.
False
True or False: acetylation decreases gene expression
False
True or False: The core histones (H1, H5) are conserved.
False, the core histones are H3 and H4 and the more peripheral core histones are H2A and H2B
Which class of histones is the biggest in size or has the greatest molecular weight? A) H1 B) H3 C) H4 D) H2A
H1
What are the five classes of histones?
H1, H2A, H2B, H3, H4
List the four core histones:
H2A, H2B, H3, H4
List histones from smallest to largest
H4<H3<H2B<H2A<H1
When stained, is heterochromatin or euchromatin darker?
Heterochromatin
What do nucleosomes consist of?
Histone H1, 2 of each histones H2A, H2B, H3, and H4, and a DNA fragment
_____ and ______ decondenses chromatin, and _______ and ________ condenses chromatin.
Histone acetyltransferase and histone lysine demethylase; histone deacetylase and histone methyltransferase
What two things are produced when nucleosomes undergo protein purification?
Histones and DNA
Is the lac operon induced or repressed?
Induced by the presence of allolactose and the promoter CAP-cAMP complex
What is the protein that trims nucleosomes to its core particle?
Micrococcal Nuclease
What is the DNA binding site of a repressor protein?
Operator
What level of organization is the octamer of core histones?
Quaternary structure
An octamer of proteins is ____ and on particular histone is ____.
Quaternary, Tertiary
______ chromatin structure allows transcription to occur, and _______ chromatin structure represses transcription.
Relaxed; dense
What are histones?
Special proteins that wrap around DNA which form chromatin networks.
What is the scientific name for jumping genes?
Transposons
True or False: Acetylated DNA means that the chromatin is less condensed and can be read by transcription factors.
True
True or False: DNA is complexed with proteins and organized as chromatin in the interphase nucleus.
True
True or False: Heterochromatin turns gene activity off and euchromatin turns gene activity on.
True
True or False: Heterochromatin is heavily condensed regions of DNA.
True
Deacetylation of histone N-terminus on nucleosomes in the vicinity of the ________ binding site inhibits binding of general transcription factors at the ____________ , thereby __________ transcription.
Ume6, TATA box, repessing
Why is heterochromatin more resistant to being degraded by DNase?
it is more condensed
The two formations made by the 30 nm fiber are:
solenoid and zig zag