The Nucleus and its Role in the Cell Flashcards
What is the main function of the nucleus in a cell?
The nucleus is the control center of the cell, containing most of the cell’s genetic material (DNA) and regulating gene expression.
What is the nuclear envelope?
The nuclear envelope is a double membrane that encloses the nucleus and separates it from the cytoplasm.
How many nuclei does a typical eukaryotic cell have?
A typical eukaryotic cell has one nucleus, though some specialized cells may have multiple nuclei.
What role do nuclear pores play?
Nuclear pores control the movement of molecules in and out of the nucleus, including mRNA, tRNA, ribosomal subunits, and transcription factors.
What is the nuclear lamina?
The nuclear lamina is a structural layer inside the nuclear envelope made of lamin proteins, maintaining the nucleus’s shape and integrity.
What is the nucleolus responsible for?
The nucleolus is responsible for producing ribosomal RNA (rRNA) and assembling ribosomal subunits.
How much DNA does the human nucleus contain?
The human nucleus contains approximately 2.5 meters of DNA, which is compacted to fit inside a structure 250,000 times smaller in diameter.
What is chromatin?
Chromatin is DNA packed with histone proteins, forming a highly organized structure in the nucleus.
What are nucleosomes?
Nucleosomes are formed when DNA wraps around histone proteins (H2-H4), resembling “beads on a string
What are the two types of chromatin?
Euchromatin (loosely packed, active) and heterochromatin (densely packed, inactive).
What happens during cell division in relation to chromatin?
During cell division, chromatin condenses into metaphase chromosomes for accurate genetic material distribution.
What are ribosomes made of?
Ribosomes are composed of ribosomal RNA (rRNA) and proteins, with two subunits (large and small).
What is the role of the small ribosomal subunit?
The small ribosomal subunit reads mRNA sequences during protein synthesis.
How does the nucleus contribute to ribosome production?
The nucleolus assembles ribosomal subunits, which exit through nuclear pores to participate in protein synthesis.
How does the nucleus interact with other organelles?
The nucleus works with ribosomes, the ER, and the Golgi apparatus to regulate gene expression, protein production, and metabolic processes.
