Cell Cycle and Chromatin Structure Quiz

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Questions and Answers

Which process converts DNA into mRNA?

Translation

RNA replication from RNA

Transcription (correct)

Reverse transcriptase

What is the first level of folding for DNA?

Around histones (correct)

Wrapping around 8 histone proteins

Negatively charged due to phosphate groups

Double helix structure

Which components are involved in the transfer of information according to Crick's central dogma?

DNA, RNA, proteins (correct)

Lipids, carbohydrates, vitamins

Histones, ribosomes, enzymes

mRNA, tRNA, rRNA

Which transfer process is known to occur in specific conditions like some viruses or laboratory?

RNA replication from RNA Signup and view all the answers

What experimental instrument is used for single DNA imaging and manipulation to detect nucleosome distribution in chromatin?

Atomic force microscope Signup and view all the answers

According to Carter, what combination of factors stimulates tissue differentiation based on Pauwels theory?

Specific mechanical invariants and different times of loading Signup and view all the answers

What is the dependency of the diffusion coefficient in tissues according to the text?

Dependent on tissue phenotype Signup and view all the answers

Which histones form an octamer around which DNA wraps 1.7 times?

H2A, H2B, H3, H4 Signup and view all the answers

Which histone binds to DNA at the edge of each nucleosome, acting as a stabilizer?

H1 Signup and view all the answers

What is the role of post-translational modifications to histones?

Affect gene expression and regulation Signup and view all the answers

What leads to the formation of chromatin fiber?

Nucleosome coiling Signup and view all the answers

What is the purpose of G0 phase in the cell cycle?

For non-dividing cells Signup and view all the answers

What occurs during S phase of the cell cycle?

DNA replication and the formation of sister chromatids Signup and view all the answers

What regulates the cell cycle by controlling cell progression and division?

Cyclins, cyclin dependent kinases, and tumor suppressors Signup and view all the answers

What is the role of histones in relation to DNA?

Attracted to DNA due to high basicity Signup and view all the answers

What do nucleosome coiling lead to?

Formation of chromatin fiber Signup and view all the answers

What is the role of H1 histone in the nucleosome?

Acts as a stabilizer Signup and view all the answers

What is the purpose of interphase in the cell cycle?

Includes checkpoints for DNA synthesis, microtubule assembly, and programmed cell death Signup and view all the answers

What are the major histones involved in forming an octamer?

H2A, H2B, H3, H4 Signup and view all the answers

What is the role of p53 in the cell cycle?

Stimulates p21, which inhibits CDK and stimulates Rb Signup and view all the answers

Which factor can stimulate the cell cycle to progress to S phase?

Growth factors (GF) binding to tyrosine kinases Signup and view all the answers

What is the main function of DNA methylation?

Inactivate genes and regulate gene expression Signup and view all the answers

Which modification of histones leads to increased gene activation?

Acetylation Signup and view all the answers

What is the main characteristic of mitosis regarding chromosome number?

Constant chromosome number after replication Signup and view all the answers

What is the role of stem cells in cell differentiation?

Undifferentiated cells that can specialize into specific cell types Signup and view all the answers

What is the main focus of mechanobiology?

Mechanisms by which mechanical loads regulate biological processes Signup and view all the answers

Which stimuli is essential for the formation and maintenance of bone?

Compression Signup and view all the answers

What occurs when a sperm fertilizes an egg?

A zygote is created Signup and view all the answers

What is the primary function of epigenetics?

Modifications that alter DNA activity without changing the nucleotide structure Signup and view all the answers

What is the consequence of hyper-methylation of a promoter region?

Inactivation of a tumor suppressor gene Signup and view all the answers

What is the main difference between mitosis and meiosis?

Meiosis results in a halving of chromosome number Signup and view all the answers

What inhibits cyclin E production, halting progression to S phase?

Inhibition of E2F Signup and view all the answers

What stimulates p21, inhibiting CDK and stimulating Rb, both tumor suppressors?

p53 Signup and view all the answers

What stimulates cell cycle progression to S phase?

Growth factors like insulin and EPO Signup and view all the answers

What leads to apoptosis when DNA damage is not repairable?

DNA damage Signup and view all the answers

What prevents progression at G2 phase?

p53 and ATM Signup and view all the answers

What stimulates entry into the mitotic phase?

Cyclin B and CDK1 Signup and view all the answers

What replicates somatic cells?

Mitosis Signup and view all the answers

Where do epigenetic modifications occur?

Somatic cells Signup and view all the answers

What does DNA methylation involve?

Adding methyl groups to inactive genes Signup and view all the answers

What alters gene activation based on DNA wrapping and tail modifications?

Histone modification Signup and view all the answers

What does embryo development start with?

Zygote formation Signup and view all the answers

How does cell differentiation occur?

Through genome modification Signup and view all the answers

Study Notes

Cell Cycle and Chromatin Structure

Histones are positively charged due to high basicity, causing them to be attracted to DNA
There are 5 major histones: H2A, H2B, H3, H4, and H1
The first four histones form an octamer, around which DNA wraps 1.7 times, called a nucleosome
H1 binds to DNA at the edge of each nucleosome, acting as a stabilizer
Post-translational modifications to histones affect gene expression and regulation
Nucleosome coiling leads to the formation of chromatin fiber
Chromatin fibers further condense to form metaphase chromosomes
The cell cycle consists of interphase (G0, G1, S, G2) and mitosis (Prophase, Metaphase, Anaphase, Telophase)
Interphase includes checkpoints for DNA synthesis, microtubule assembly, and programmed cell death
G0 phase is for non-dividing cells, while growth factors and mitogens allow progression to G1 phase
S phase involves DNA replication and the formation of sister chromatids
The cell cycle is regulated by cyclins, cyclin dependent kinases, and tumor suppressors, controlling cell progression and division

Cell Cycle and Developmental Biology

Inhibition of E2F prevents cyclin E production, halting progression to S phase
p53 stimulates p21, inhibiting CDK and stimulating Rb, both tumor suppressors
Growth factors like insulin and EPO stimulate cell cycle progression to S phase
DNA damage not repairable leads to apoptosis
p53 and ATM prevent progression at G2 phase
Cyclin B and CDK1 stimulate entry into the mitotic phase
Mitosis replicates somatic cells, meiosis replicates germ cells with halved chromosome number
Epigenetics modifications occur in somatic cells, reversible and caused by personal behaviors and environment
DNA methylation involves adding methyl groups to inactive genes
Histone modification alters gene activation based on DNA wrapping and tail modifications
Embryo development starts with zygote formation, leading to blastocyst and embryo
Cell differentiation occurs through genome modification, stem cells can differentiate into specific cell types
Mechanobiology studies mechanical loads' effects on biological processes, including bone and tissue formation, cell competition, and specialization after fractures

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Description

Test your knowledge of the cell cycle and chromatin structure with this quiz. Explore the roles of histones, nucleosomes, and chromatin fibers in gene regulation, as well as the phases of the cell cycle and the regulatory mechanisms involved.