Genes and chromosomes – chromatin, euchromatin, heterochromatin, giant chromosomes - One Line Questions
1.
Heterochromatin is often characterized by: —
Enriched repetitive DNA sequences
2.
Lampbrush chromosomes are typically found during which stage of meiosis? —
Prophase I (specifically diplotene stage)
3.
What is the fundamental unit of heredity? —
Gene
4.
The differential condensation of chromatin into euchromatin and heterochromatin is a key mechanism for: —
Cellular differentiation and development
5.
Polytene chromosomes are an example of which phenomenon? —
Endopolyploidy
6.
The process of 'chromosome puffing' in polytene chromosomes indicates: —
Active gene expression
7.
The chromomeres, visible as bead-like structures in chromosomes, are more prominent in: —
Lampbrush chromosomes
8.
The specific banding pattern of chromosomes, observable in both polytene and mitotic chromosomes, is often used for: —
Identifying chromosomal abnormalities
9.
Which of the following is NOT a component of a chromosome? —
RNA
10.
The term 'chromatin' refers to the complex of: —
DNA and proteins
11.
The 'puffs' in polytene chromosomes are regions where: —
Transcription is occurring
12.
Lampbrush chromosomes are characterized by extensive looping, which facilitates: —
Transcription of specific genes
13.
The loops extending from the central axis of lampbrush chromosomes are sites of: —
RNA synthesis (transcription)
14.
Histones are a class of proteins that are primarily involved in: —
Packaging and condensing DNA
15.
In lampbrush chromosomes, the lateral loops are extensions of the axial fiber that are actively engaged in: —
mRNA synthesis
16.
The centromere region of a chromosome is typically rich in: —
Heterochromatin
17.
The Barr body, found in the nuclei of female mammals, is an example of: —
Facultative heterochromatin
18.
The telomeres, regions at the ends of eukaryotic chromosomes, are typically composed of: —
Heterochromatin
19.
Which of the following is a type of heterochromatin that is present in all cells of an organism and is replicated late? —
Constitutive heterochromatin
20.
Giant chromosomes, such as polytene chromosomes, are formed by: —
Repeated rounds of DNA replication without cell division
21.
The transformation of euchromatin to heterochromatin can lead to: —
Transcriptional silencing
22.
Which type of chromatin is generally transcriptionally active and loosely packed? —
Euchromatin
23.
Which type of chromatin is more sensitive to DNase I digestion, indicating a more open structure? —
Euchromatin
24.
Which of the following is a key feature of heterochromatin? —
Late replication timing
25.
The transition from a decondensed euchromatic state to a condensed heterochromatic state is often mediated by: —
Histone deacetylases
26.
Which component of chromatin is primarily responsible for the basic structure of the nucleosome? —
Core histones (H2A, H2B, H3, H4)
27.
Which histone modification is generally associated with active transcription in euchromatin? —
Histone acetylation
28.
Which of the following is a consequence of the tightly packed nature of heterochromatin? —
Reduced accessibility to DNA repair enzymes
29.
Euchromatin is generally associated with: —
Open chromatin structure
30.
Which of the following is NOT a characteristic of heterochromatin? —
Early replication
31.
Heterochromatin is characterized by: —
Dense DNA packing and low gene activity
32.
Polytene chromosomes are commonly found in: —
Salivary glands of Drosophila larvae
33.
The functional significance of the lampbrush structure is to: —
Increase the surface area for gene transcription
34.
The study of giant chromosomes has been instrumental in understanding: —
The relationship between chromosome structure and gene activity
35.
The formation of polytene chromosomes involves multiple rounds of: —
Endoreduplication (DNA replication without cytokinesis)
36.
Which of the following is a characteristic of heterochromatin compared to euchromatin? —
Undergoes replication later in S phase
37.
The complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells is called: —
Chromatin
38.
Which of the following terms describes the DNA-protein complex that makes up chromosomes? —
Chromatin
39.
Constitutive heterochromatin is typically found: —
In regions that are always condensed
40.
Which type of giant chromosome exhibits a lampbrush appearance? —
Lampbrush chromosomes
41.
Which of the following is a function of euchromatin? —
Facilitating gene expression
42.
Heterochromatin plays a role in maintaining genome stability by: —
Preventing the formation of aberrant DNA structures
43.
The structural organization of chromatin, including euchromatin and heterochromatin, is crucial for: —
Regulation of gene expression
44.
Giant chromosomes like polytene chromosomes allow for: —
Detailed observation of gene activity
45.
The characteristic 'puffs' or 'balbiani rings' observed in polytene chromosomes represent: —
Sites of active gene transcription
46.
Facultative heterochromatin: —
Can change its condensation state depending on cellular needs
47.
The euchromatic regions of a chromosome are typically: —
Deacetylated histones and accessible to transcription machinery
48.
In lampbrush chromosomes, the axial structure consists primarily of: —
Double-stranded DNA with associated proteins
49.
Polytene chromosomes are formed by endomitosis, which is a process where: —
DNA replicates but the cell does not divide
50.
The banding patterns observed in Giemsa-stained polytene chromosomes are related to: —
The distribution of euchromatin and heterochromatin