nuclear structure

• What is the function of the nuclear envelope?

  Separates nucleus from cytoplasm
• What type of membrane is the nuclear envelope?

  Double membrane
• What is the perinuclear space?

  Space between layers of the nuclear envelope
• What is the role of nuclear pores?

  Allow passage of small molecules and ions
• What is nucleoplasm?

  Fluid contents of the nucleus
• What components are found in nucleoplasm?

  Fine filaments, ions, enzymes, RNA, DNA
• What are nucleoli?

  Transient, clear nuclear organelles
• What is the composition of nucleoli?

  rRNA, enzymes, proteins (histones)
• How do nucleoli function in protein synthesis?

  Form around DNA instructions for proteins/RNA
• Where are many nucleoli found?

  In large, protein-producing cells
• Which types of cells commonly have many nucleoli?

  Liver, nerve, muscle cells
• What is the primary function of DNA?

  Instructions for protein synthesis
• How is DNA structured in terms of coiling?

  Strands coiled around histone molecules
• What is chromatin?

  Loosely coiled DNA in nondividing cells
• What are chromosomes?

  Tightly coiled DNA in dividing cells
• What holds two copies of each chromosome together?

  Centromere
• How many paired chromosomes are in somatic cells?

  23 paired chromosomes
• Where do the chromosomes in somatic cells come from?

  One from mother and one from father
• What functions do chromosomes carry out?

  Carry instructions for proteins and RNA
• What additional functions do chromosomes have?

  Some regulatory and unknown functions