The Nucleus By Meredith Derecho, Elizabeth Eyermann, and Hannah Woolf Source 3.

The Nucleus

By Meredith Derecho, Elizabeth Eyermann, and

Hannah Woolf Source 3

Key Facts About Nuclei•“The nucleus is the genetic control center of a eukaryotic cell” (Source 5)•Only eukaryotic cells have a nucleus—prokaryotic cells do not•The word “nucleus” comes from the Latin word

“nucula” meaning “little nut” (Source 6)•Some eukaryotic cells have multiple nuclei or none at all•The nucleus is near the center of the cell, and it takes up about 10% of a cell’s mass

Source 5

Structure of the Nucleus

The nucleus has three main components:

1.The Nuclear Envelope

2.The Chromatin

3.The Nucleolus

Source 4

The Nuclear Envelope

•Space between the layers is called the perinuclear space•This space connects with the rough endoplasmic reticulum•The inner layer of the double membrane, the nuclear lamina, is made of protein•The entire nuclear envelope disintegrates during mitosis and reforms as the new cells are created

•Double membrane structure made of phospholipids•Nuclear pores control the flow of materials•They allow building blocks of RNA and DNA molecules and energy sources to enter the nucleus

Source 2

Chromatin and Chromosomes•Chromatin is made up of strings of DNA and

histones•The strands come together to form chromosomes during mitosis•Heterochromatin and euchromatin are two classifications of chromatin•Heterochromatin is more condensed while euchromatin is delicate and less tightly packed•The six feet of DNA within the cell are stored as chromatin

An artist’s depiction of chromatin!

Source 7

The Nucleolus

For more information about the nucleolus, see Josh, Callie, and Garrett’s project

•The nucleolus is spherical, dense, and located in the middle of the nucleus•It produces ribosomal subunits, thus indirectly helping to synthesize proteins•GEMs (gemini of coiled bodies) are made by the nucleolus•Interchromatin granule clusters are also made by the nucleolus•It is visible when the cell is not being divided•The nucleolus may affect the senescence, or aging, of an organism

Source 5

Major Functions of the Nucleus1. Gene expression2. Managing cellular reproduction

Source 8

DNA, RNA, and Gene ExpressionThe Nucleus:

1. Stores and regulates the DNA

2. Uses transcription DNA to make the mRNA

3. Processes the pre-mRNA through post-transcriptional modification

4. Exports the mRNA to the ribosomes, where the mRNA becomes protein

DNA RNA

Consequently, controlling gene expression allows the nucleus to manage cellular activities such as:• Intermediary metabolism• Protein synthesis• Growth• Cell

compartmentalization • Mitosis• Nuclear transport

Source 12

Source 11

The Nucleus’s Role in Cellular Reproduction•Mitosis is the process of cells dividing to create new cells•The nucleus must replicate all the cell’s genomic DNA•The DNA divides into two identical sets for mitosis to occur •The nucleus splits and forms two nuclei around each new set of DNA •That allows the cell to divide into two new identical cells

The process of mitosis:

Source 13

Work

s C

ited:

Th

anks

to a

ll ou

r so

urc

es!

1. http://www.buzzle.com/articles/cell-nucleus-structure-and-functions.html

14. Our lovely textbook! Campbell, et al. Biology: Concepts and Connections.

12. http://www.shutterstock.com/pic-1449081.html

11. http://www.ichromatography.com

10. micro.magnet.fsu.edu/cells/nucleus/nucleus.html

9. ibiblio.org/virtualcell/textbook/chapter3/nucf.htm

8. glogster.com

7. http://www.philipp-diesinger.de

6. http://www.etymonline.com/index.php?term=nucleus

5. http://library.thinkquest.org/

4. http://micro.magnet.fsu.edu/cells/nucleus/nucleus.html

3. http://www.biologie.uni-hamburg.de/b-online/library/onlinebio/

2. http://micro.magnet.fsu.edu/cells/animals/nucleus.html

13. http://allstrangledup.wordpress.com/

Thanks for watching our slideshow about the

nucleus!