The Nucleus Flashcards
What is the ultra structure?
A cells internal structure revealed at high magnification.
What does the nucleus contain?
The organisms hereditary material.
What does the nucleus control?
The cells activities.
What shape is the nucleus?
Usually spherical.
What is the size of the nucleus?
Between 10-20 micrometers in diameter.
What are the features of a nucleus?
The nuclear envelope, nuclear pores, nucleoplasm, chromosomes and the nucleolus.
What is the nuclear envelope?
A double membrane that surrounds the nucleus.
What is the outer nuclear envelope membrane continuous with?
The endoplasmic reticulum.
What does the outer nuclear envelope membrane often have on its surface?
Ribosomes.
What does the nuclear envelope control?
The entry and exit of materials in and out of the nucleus.
What does the nuclear envelope contain?
The reactions taking place with in the nucleus.
What do nuclear pores allow?
The passage of large molecules, such as messenger RNA, out of the nucleus.
How many pores are in each nucleus?
Around 3000.
What size is a nuclear pore?
40-100 nanometers in diameter.
What is the nucleoplasm?
The granular, jelly-like material that makes up the bulk of the nucleus.
What do chromosomes consist of?
Protein-bound, linear DNA.
What is the nucleolus?
A small spherical region within the nucleoplasm.
What does the nucleolus do?
Manufactures ribosomal RNA and assembles the ribosomes.
How many nucleolus’ are there in a nucleus?
More than one.
What are the functions of the nucleus?
Act as a control centre of the cell through the production of mRNA and tRNA and hence protein synthesis, retain the genetic material of the cell in the form of DNA and chromosomes, and manufacture ribosomal RNA and ribosomes.
