Nucleous
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The document discusses the cell nucleus, providing details on its history, characteristics, structure, and functions. It describes how the nucleus was discovered in 1831 and named by Robert Brown. The nucleus is a membrane-bound organelle found at the center of eukaryotic cells that can vary in shape and size depending on the cell. It houses genetic material in the form of chromatin and chromosomes and directs protein synthesis, cell growth and regulation, and transportation between the nucleus and cytoplasm. The nucleus contains a nuclear membrane, nucleolus, chromatin, and DNA and serves as the command center of the cell.
Nucleous
- 1. INTRODUCTION • TOPIC : CELL NUCLEUS • DEPARTMENT: ZOOLOGY • UNIVERSITY OF PESHAWAR
- 2. TOPIC OVERVIEW • HISTORY • CHARACTERS • SHAPEANDSIZE • STRUCTURE • FUNCTION
- 3. History Robert Brown 1773-1858 -Discovered in 1831 by Scottish botanist Robert Brown -Suggested the nucleus played a key role in fertilization and development of the embryo in plants -Name (nucleus) derived from the Latin word for kernel/nut
- 4. Main Characteristics • Membrane-enclosed organelle found in eukaryotic cells • Generally found in the central region of the cell (in animal cells) • Roughly spherically shaped • Largest and most easily seen organelle
- 5. SHAPE AND SIZE • SPERICAL OR OVAL SHAPE ; • PARAMISIUM HAVE BEAN SHAPE , • SMOTH MUSCLES HAVE ELONGTED • LOCATED AT THE CENTRE OF CELL • EXIST IN VERITY OF SHAPES AND SIZES • DEPEND ON CELL SIZE
- 6. STRUCTURE • CONSIST OF : • NUCLEAUR MEMBRANCES . NUCLEUR PORES • NUCLEOPLASM • NUCLEOLUS • CHROMATIN .CHROMOSOME .DNA .PROTEIN
- 7. Structure
- 8. NUCLEAR MEMBRANE • DOUBLE LAYERED COVERING OF NUCLEUS • SPACE BETWEEN MEMBRANE IS PERINUCLEUR SPACE (LIPOPROTEIN) • MAINTAIN SHAPE OF NUCLEUS
- 9. Nuclear Envelope Consists of: • Phospholipid bi- layer membrane • Nuclear Pores • Ribosomes
- 10. Nuclear Pores • Allow small molecules to diffuse easily between nucleoplasm & cytoplasm • Control passage of proteins & RNA protein complexes – Import: proteins moving in to be incorporated into nuclear structure or to catalyze nuclear activities – Export: RNA / RNA-protein complexes to the cytoplasm
- 11. Nucleoplasm A jelly-like (made mostly of water) matrix within the nucleus All the other materials “float” inside Also term as “karyolamp” Helps the nucleus keep its shape and serves as the median for the transportation of important molecules within the nucleus
- 12. Nucleolus • Largest structure present inside the boundaries of the nucleus • Dark staining zone in center of nucleus • Where intensive synthesis of ribosomal RNA takes place • Main components are ribonucleic acid (RNA), deoxyribonucleic acid (DNA) and proteins
- 13. CHROMATIN • THIN THREAD LIKE STRUCTURE EMBEDED IN NUCLEOPLASM CONSISTS OF: • DNA • RNA • HISTONE AND NON HISTONE PROTEIN • HISTONE ARE BASIC PROTEIN PACKED DNA TO STRUCTURAL UNIT • IT CONDENSE TO FORM CHROMOSOME
- 14. Chromatin & Chromosomes Chromosomes contain DNA in a condensed form attached to a histone protein. Chromatin is comprised of DNA. There are two types based on function. Heterochromatin: highly condensed, transcriptionally inactive mostly located adjacent to the nuclear membrane Eurochromatin: delicate, less condensed organization of chromatin, located in a transcribing cell * Transcribing means equivalent RNA copies are being made from the DNA to create proteins.
- 15. DNA DNA, or deoxyribonucleic acid, contains the information needed for the creation of proteins (which include enzymes and hormones) and is stored in the nucleus, as already said, in the form of chromatin or chromosomes. The nucleus is the site of DNA duplication, which is needed for cell division (mitosis) and organism reproduction and growth.
- 16. Proteins and Cell Regulation The nucleus oversees cells’ functions and regulatory mechanisms for keeping the cell healthy and alive. The nucleus controls growth of the cell through the synthesis of structural proteins, energy and nutrient metabolism. The nucleus regulates the secretion of ribosomes, which are made in the nucleolus and are the sites of gene transcription.
- 17. Primary Functions within the Cell • Repository of genetic information (DNA & RNA) • Enables the synthesis of nearly all proteins • Houses the nucleolus • Responsible for production of ribosomes • Selective transportation of regulatory factors and energy molecules through nuclear pores
- 18. Functions The nucleus is often compared to the “command center,” as it controls all functions of the cell. It is important in regulating the actions of the cells. It plays an important part in creating the cell’s proteins. It is involved in important processes dealing with DNA and other genetic molecules.