Week 9 Lecture 2 - The nucleus

Explain the organizing of DNA

DNA is located in chromosomes. They get packed into cells by supercoiling, and histone proteins are used in this process. Chromatin is about 50% DNA and 50% protein. Histone proteins also open DNA so genes can be read.

What is the nuclear envelope?

The nuclear envelope is a lipid membrane that surrounds the nucleus. It is a double membrane.

What are nuclear pores?

Ring shaped protein structures that go through both membranes of nuclear envelope. It allows things to pass through the nucleus to the cytoplasm and vice versa such as RNA and proteins.

What is the nucleolus?

A region of the nucleus that contains very little DNA. It is the site where ribosomes are made. Ribosomes are made of protein and RNA, and they travel to the nucleolus where they are assembled and then leave through pores.

What is the function of the nucleus?

Storage of DNA, ribosomal production, transcription and replication.

Describe bacteria chromosomes and plastids

Chromosomes are circular, and plasmids are independent circles of DNA that can be gained or lost by bacteria.