Prepare for NEET Biology Cell: The Unit of Life with MCQs & PYQs on NEET.GUIDE. Enjoy free practice, previous year questions, and expert solutions to understand cell structure and function.
A researcher observes a eukaryotic cell lacking functional peroxisomes. Which of the following metabolic processes would be MOST directly affected?
Glycolysis
Breakdown of long-chain fatty acids
Synthesis of proteins
Replication of DNA
Which statement BEST describes the relationship between the nuclear envelope and the endoplasmic reticulum?
The nuclear envelope is entirely separate from the endoplasmic reticulum.
The inner membrane of the nuclear envelope is continuous with the smooth ER membrane.
The outer membrane of the nuclear envelope is continuous with the rough ER membrane.
The nuclear envelope is formed by invaginations of the Golgi apparatus.
Histone H1 plays a crucial role in the structure of chromatin. Which of the following statements regarding its interaction and function is INCORRECT?
H1 binds to the linker DNA between nucleosomes.
H1 helps to compact chromatin structure.
H1 interacts with the core histones within the nucleosome octamer.
H1 stabilizes the interaction of DNA with the nucleosome.
Certain histone modifications are associated with actively transcribed genes. Which of the following combinations is MOST likely to be found in the nucleosomes of such genes?
Methylation of H3K9 and H3K27; Deacetylation of H3 and H4
Phosphorylation of H2AX; Trimethylation of H3K9
Acetylation of H3 and H4; Trimethylation of H3K4
Ubiquitination of H2A; Trimethylation of H3K27
A researcher isolates chromatin fibers and treats them with a nuclease that specifically cleaves linker DNA. Following this treatment, what would be the approximate size distribution of the DNA fragments observed?
Approximately 200 bp
Approximately 1000 bp
Approximately 50 bp
A wide range of sizes from 200 bp to several thousand bp
Polytene chromosomes, found in certain insect tissues, exhibit distinct banding patterns. These bands represent:
Individual genes arranged linearly along the chromosome.
Regions of heterochromatin exclusively.
Regions where DNA replication has been halted prematurely.
Regions of highly condensed chromatin corresponding to inactive genes interspersed with less condensed regions of active genes.
The 'histone code' hypothesis proposes that specific combinations of histone modifications influence gene expression. If a researcher discovered a novel histone modification, which experimental approach would be LEAST informative for initially investigating its potential role in gene regulation?
Analyzing the genome-wide distribution of the modification using ChIP-seq.
Correlating the presence of the modification with gene expression levels.
Assessing the binding of specific regulatory proteins to the modified histone.
Determining the crystal structure of the modified histone.
In an experiment, a researcher selectively removes histone H4 from chromatin. Which of the following is the MOST likely immediate consequence?
Increased condensation of the chromatin fiber.
Enhanced binding of RNA polymerase to promoter regions.
Specific activation of a subset of genes.
Significant destabilization of the nucleosome core and loss of DNA wrapping.
Which of the following statements regarding the chemical composition of the secondary cell wall is INCORRECT?
It may contain lignin, suberin, or cutin.
It often has multiple layers, denoted as S1, S2, and S3.
It predominantly contains pectin and hemicellulose.
Cellulose microfibrils are arranged in a more parallel fashion compared to the primary wall.
The orientation of cellulose microfibrils in the cell wall plays a crucial role in determining cell shape. If a plant cell has cellulose microfibrils arranged predominantly perpendicular to the direction of cell elongation, what shape is the cell most likely to adopt?
Spherical
Elongated/Rod-like
Cuboidal
Irregular
