What are the functions of the major cell structures?

Cell Wall Found in plants, algae, fungi and nearly all prokaryotes Lie outside the cell membrane Made up of fibers of carbohydrate and protein Plant cell walls made of cellulose MAIN FUNCTION: provide support and protection for the cell

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Plant Cell Wall Structure Image from: http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/cellwall.htm

Bacterial cell walls Made up of peptidoglycan Different structures for different types of bacteria

Fungal and Algal cell walls Fungal cell walls Composed of chitin and cellulose Algal Cell Walls Composed of polysaccharides Which polysaccharides depends on the algae

Nucleus Controls most of the cell processes and contains the hereditary information (DNA) Parts of the nucleus Chromatin and chromosomes Nucleolus Nuclear envelope

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Image from: http://www.daviddarling.info/encyclopedia/N/nucleusc.html                                                                            Image from: http://www.daviddarling.info/encyclopedia/N/nucleusc.html

Image from: http://cellbio.utmb.edu/cellbio/nucleus.htm

Chromatin and Chromosomes The granular material visible within the nucleus Consists of DNA bound to proteins Chromosomes Chromatin condenses into chromosomes before cell division Contain genetic information

Nucleolus Assembly of ribosomes begins here

Nuclear envelope Double membrane layer surrounding the cell Has pores which allows material into and out of the cell

Cytoskeleton Network of protein filaments that help the cell maintain it’s shape Involved in many forms of cell movement

Parts of the Cytoskeleton Microtubules Hollow tubes of protein that maintain shape Serve as “tracks” for moving organelles Important in cell division Make up centrioles in animal cells Also make up flagella and cilia in some cells

Microtubules Images from: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Cytoskeleton.html

Parts of the Cytoskeleton Microfilaments Long, thin fibers that function in the movement and support of the cell Much smaller than microtubules

Microfilaments

Ribosomes Small particles of RNA and protein Function: assemble proteins Prokaryotic and Eukaryotic ribosomes have different structures

Ribosomes consist of a small subunit and a large subunit Image from: http://cellbio.utmb.edu/cellbio/ribosome.htm

Endoplasmic Reticulum Function: Components of the cell membrane are assembled and some proteins are modified Rough ER: Synthesis of proteins: chemical modification; Studded with ribosomes Smooth ER: synthesis of lipids

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Golgi Apparatus Function: enzymes in the Golgi attach carbohydrates and lipids to proteins From Golgi proteins are packaged and sent to their final destinations

Image from: http://cellbio.utmb.edu/cellbio/GOLGI.HTM

Image from: http://cellbio.utmb.edu/cellbio/GOLGI.HTM

Lysosomes Small organelles filled with enzymes Function: break down lipids, carbohydrates and proteins from food particles Break down old organelles and other cellular debris

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Vacuoles Function: Store materials such as water, salts, proteins, and carbohydrates In plants, a large central vacuole filled with fluid is used for support in the cell

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Chloroplasts Function: use energy from the sun to make energy-rich food molecules in photosynthesis Bound by two envelope membranes Stacks of photosynthetic membranes contain chlorophyll

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Mitochondria Function: use energy from food to make high energy compounds Powerhouse of the cell Bound by two envelope membranes Inner membrane is folded

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Organelle DNA Chloroplasts and mitochondria contain their own DNA Endosymbiotic theory:mitochondria and chloroplasts the result of endocytosis of bacteria and blue-green algae whichbecame symbiotic

Endosymbiotic theory

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Venn Diagram Use your notes and the venn diagram handout to compare and contrast prokaryotic and eukaryotic cells and plant and animal cells

Cell as a Factory See page 182