Prepare for NEET with Botany-specific practice questions. Covering all major Botany chapters, this is perfect for your NEET Biology needs.
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.
A dormant seed of a desert plant exhibits an extremely low metabolic rate. Which of the following biochemical changes contributes MOST significantly to this state?
Increased gibberellin biosynthesis and rapid cell division
High abscisic acid (ABA) levels and dehydration of cellular components
Elevated ethylene production and fruit ripening processes
Increased cytokinin concentration and enhanced protein synthesis
Certain seeds require a period of cold exposure before germination, a process known as stratification. This requirement primarily ensures:
Increased seed coat permeability to oxygen solely
Activation of enzymes responsible for nutrient mobilization only
Leaching of germination inhibitors and promotion of gibberellin biosynthesis
Vernalization of the embryo and subsequent flowering
The aleurone layer in a monocot seed plays a crucial role in:
Protecting the embryo from mechanical damage
Storing starch and other reserve materials
Synthesizing and secreting hydrolytic enzymes for endosperm breakdown
Absorbing water and initiating germination
Which of these combinations correctly matches the seed type with its corresponding post-fertilization structure?
Monocot seed - Fruit with one cotyledon and endosperm; Dicot seed - Fruit with two cotyledons and reduced/no endosperm
Monocot seed - Fruit with two cotyledons and no endosperm; Dicot seed - Fruit with one cotyledon and endosperm
Monocot seed - Fruit with one cotyledon and no endosperm; Dicot seed - Fruit with two cotyledons and endosperm
Monocot seed - Fruit with two cotyledons and endosperm; Dicot seed - Fruit with one cotyledon and no endosperm
In a recalcitrant seed, which physiological factor is PRIMARILY responsible for its inability to withstand desiccation?
Presence of germination inhibitors that prevent metabolic slowdown
Lack of protective proteins that stabilize cellular components during drying
High sensitivity of cellular membranes to dehydration damage
Rapid depletion of stored reserves during the early stages of desiccation
The suspensor in a developing dicot embryo plays a critical role in:
Protecting the embryo from pathogens and environmental stress
Synthesizing growth hormones and regulating embryo development
Forming the root apical meristem and initiating root development
Pushing the embryo into the endosperm and facilitating nutrient absorption
