The correct answers are:
- Methylation of histone tails in chromatin can promote condensation of the chromatin.
- DNA is not transcribed when chromatin is packaged tightly in a condensed form.
- Acetylation of histone tails is a reversible process.
- Some forms of chromatin modification can be passed on to future generations of cells.
- Acetylation of histone tails in chromatin allows access to DNA for transcription.
Histone modifications are post-translational modifications of histone protein that can affect gene expression by altering chromatin structure or recruiting histone modifiers.The most common modifications are methylation, phosphorylation, acetylation and ubiquitylation. All of them affect the binding affinity between histones and DNA and thus loosening (gene activation) or tightening (gene repression) the condensed DNA.
Histone methylation is a transfer of methyl group by histone methyltransferases to lysine or arginine amino acid of protein. Effect of methylation depends on the type of protein that is modified. Demethylation is the reverse process.
Histone acetylation is the process of adding of an acetyl group(by histone acetyltransferases) to histone proteins and it can also activate or inhibit the gene expression. Deacetilation is reverse process.
Answer:
c. mitochondrion, virus, hemoglobin, glucose, water molecule
Explanation:
The mitochondrion is a membrane which is found in cytoplasm of eukaryotic cells. It is also known as power house of cells. This is largest from virus, hemoglobin, water molecule and glucose.
Virus is second largest and is small infectious agent. It has capability to infect many organisms and living cells. Hemoglobin is protein which is present in red blood cells. Glucose is a type of sugar presence in the blood. Water molecule is composed of hydrogen and oxygen and is smallest among the others.
Answer:
D is rhe answer of rhis question.
Explanation:
collection of cells make tissue, collection of tissues form organ, similarly group of organs combine to form a system and when these systems combine it forms a whole body of organism.
Answer and Explanation:
Red Rock Canyon is an area of universal geologic interest, located a few miles west of Las Vegas within the Mojave Desert. Many experienced geologists visit the Red Rock; they are surprised by the vivid colors of rocks, natural beauty, and rock formations. A visual display takes million years to make the masterpiece known as the Red Rock Canyon National Conservation area. About 500 million years ago, Red Rock Canyon was found at the bottom of an ocean basin. Limestone accumulated in this ocean basin, which contains the fossils of sea life. The tracks of two-footed meat-eating dinosaurs have been found in the Aztec Sandstone. The tracks of small animals such as spiders, scorpions, early mammals, and proto-mammals were also found. The fossils and rock layers that are found in Red Rock Canyon provide evidence for Earth’s geologic history. Paleontologists are still searching these areas.
