4.1 THE FUNCTION OF THE NUCLEUS WITHIN THE CELL. : no true nucleus or membrane-bound. (Refer to pp in BC Science 9)

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1 4.1 THE FUNCTION OF THE NUCLEUS WITHIN THE CELL Review from last year: Name: Date: Block: There are 2 types of cells: : no true nucleus or membrane-bound organelles : have a true nucleus and membrane-bound organelles Animal and plant cells are both. (Refer to pp in BC Science 9) Scientists use technologies, such as, to see the within cells more clearly and to learn about how cell parts and messages to the nucleus. A SURVEY OF ANIMAL AND PLANT CELLS Both plant and animal cells are equipped with many structures that allow the cell to perform a variety of. Cell parts and organelles found in BOTH animal and plant cells: A. : thin covering that controls the flow of materials in and out of the cell. B. : jelly-like substance contains the organelles (specialized cell parts). C. : provide energy for cells. D. : manufacturing plants for proteins.

2 E. : membrane-covered channels that act as a transport system for materials made in the cell. F. : membrane-covered sacs formed by the endoplasmic reticulum. Vesicles transport new proteins to the. G. : sorts and packages proteins for transport. H. : controls all cell activities. I. :membrane-free organelle that makes ribosomes. J. : protects the contents of the nucleus. K. : openings in the nuclear membrane that allow only certain materials to pass. L. : membrane-bound storage containers. PLANT CELLS Plant cells are equipped with some structures that animal cells do have. A. : trap energy from Sun to make glucose, food for the plant. B. :tough, rigid structure that surrounds cell membrane, provides protection and structural support. C. : plant cells are equipped with a large vacuole for storing water.

3 THE NUCLEUS: CONTROL CENTRE OF THE CELL The nucleus contains DNA. DNA is the molecule has the master set of for: what a cell will, how it will, what it will and when it will. DNA carries the master set of instructions for cell function instructions in the nucleus are carried in long, two-stranded molecules called (DNA). DNA looks like a twisted - two strands wrap around each other in a spiral shape. The sides of the DNA ladder are made of and. The steps of the ladder are made of four : (A), (G), (C), and (T).

4 The arrangement of bases in DNA directs all cell activities Everything that occurs within a cell is the result of how bases on the DNA molecule are (the ). The bases join in a specific way: always joins with always joins with the and of bases can vary greatly within the DNA molecule. In humans, a single DNA molecule can be several base pairs in length. DNA in stored in chromatin chromatin: Within each strand of chromatin is molecule of DNA. When a cell is growing, the DNA is and helps in the manufacture of the cell requires. When a cell is ready to divide, chromatin coils tightly into X-shaped. chromosome:

5 Every organism has a specific number of chromosomes Chromosomes in the nucleus are found in. Most human cells have chromosomes arranged in pairs The pair determines sex: for females and, for males Genes are found on chromosomes Gene: Genes store the information needed to produce. Arrangement of in a gene will usually code to produce a protein. Each chromosome can carry thousands of genes, which contain the information to make thousands of proteins. Proteins determine what body cells will become & how they will function All your body cells have the genes (same amount of genetic information in the 46 chromosomes), but only specific genes are in each cell to produce specific proteins. This produces. Specialized Two types of specialized proteins: 1. enzymes: Ex. digestive enzymes like pepsin. 2. hormones: Ex. hormones for growth

6 HOW PROTEINS ARE PRODUCED Protein production in the cell involves several important steps (p. 131): 1. The nucleus receives a to make a specific protein. 2. The DNA message for the protein is copied into a small molecule called 3. RNA leaves the nucleus through a. 4. The RNA message is delivered to a, the ribosome makes the. 5. The manufactured protein enters the (ER). 6. A forms at the end of the ER, and carries the protein to the. 7. The Golgi body the protein for transport out of the cell. 8. A forms off the end of the Golgi body to carry the protein to the. 9. The vesicle attaches to the cell membrane, and its protein contents are released of the cell. A NEW TASK FOR SCIENTISTS Scientists used to think that one gene coded for protein. But, there are at least different proteins in the human genome, but only genes in the human body. Scientists are currently researching how one gene can code for more than one protein? SUMMARY: