Cell Structure and Function Eukaryotic Cell Structure Plant

Cell Structure and Function Eukaryotic Cell Structure Plant Cells vs. Animal Cells

What are we learning today? Benchmark: ü SC. 912. L. 14. 3 – Compare and contrast the general structures of plant and animal cells. ü SC. 912. L. 14. 2 – Relate structure to function for the components of plant and animal cells. Objectives: ü Relate the success of eukaryotes to the presence of organelles ü Describe the function the major cell organelles ü Distinguish between plant and animal cells

What is the essential question? How have organelles enabled eukaryotic cells to become successful?

What is the cell membrane? Thin double-layered (bilayer) sheet surrounding the cell q Flexible structure that forms a barrier between the cell and its environment (fluid mosaic model) q Regulates what enters or leaves the cell (Selectively or semi-permeable) q Provides protection and support q

Question �Cell membranes are primarily composed of a double layer of phospholipids. Why are phospholipids particularly well suited to serving as membranes? A. They can be used to metabolize starches B. They create a selectively permeable membrane C. They are only hydrophobic causing them to form a bilayer D. They form a membrane that is impermeable to chemicals

What is the nucleus? Controls most cell processes. q Contains the hereditary information of the cell (DNA in the form of chromatin) q Surrounded by a nuclear membrane q q q Provides support Controls movement of substance through the nuclear pores

What is the nucleolus? q Small, dense region inside the nucleus q DNA that produces r. RNA which later joins with proteins to form the small and large subunits of ribosomes

Question � Which of the following statements best describes the nucleus of a cell? A. The nucleus has a membrane that allows for active transport of RNA and proteins B. The nucleus exports lysosomes which direct amino acid production within the cell C. The nucleus is responsible for supplying the cell with chemical energy in the form of ATP D. The nucleus contains some of the genetic material in a cell; the majority is contained in the cytoplasm

What is the cytoplasm or cytosol? Fluid made of mostly of water, salts, some proteins, and many organelles q Found outside the nucleus and inside the cell membrane q Site of many of the cell’s chemical reactions (metabolism) q

What is the cytoskeleton? Network of proteins q There are two principal proteins q Microfilament q Microtubules q Helps the cell to maintain its shape. q Involved in movement. q Help organelles stay in place q

What are mitochondria? q Transforms Energy q Use oxygen (O 2) to breakdown food (glucose, C 6 H 12 O 6) and releases energy in chemical bonds to form ATP, Carbon Dioxide (CO 2) and water (H 2 O). q In humans, all or nearly all of our mitochondria come from the cytoplasm of the ovum. q Has it’s own small circular DNA. Why? DNA Folding of the Membrane: increases surface area, in the mitochondria it’s called cristae

What are chloroplasts? q Captures energy from sunlight (solar energy) and converts it into chemical energy (bonds of glucose) in a process called photosynthesis q Chloroplasts contain the green pigment chlorophyll Notice it has a small circular piece of DNA and its own ribosomes. Why? DNA

What is the cell wall? q Extra layer found on the outside of the cell membrane. q Gives additional support, shape and strength to the cell. q In plants, the cell wall is made of cellulose. q What about fungi? q Who else has a cell

What are ribosomes? q q q Made from small particles of r. RNA and proteins. Where is it made? Ribosomes are found q throughout the cytoplasm (free floating) q attached to the endoplasmic reticulum. Proteins are assembled from amino acids on ribosomes by reading the m. RNA. Cells active in protein synthesis are often packed with ribosomes. They are made of two parts: small subunit and large subunit

reticulum? Rough ER is an extensively folded network of membranes. It is the site of protein synthesis. The proteins go to the golgi body and are sometime secreted from the cell q The portion of the ER involved in the synthesis of proteins is called rough ER because it has q Smooth ER is involved in ribosomes attached. q making more lipids for the cell membrane q q it detoxifies poisons from the cells.

What is the Golgi apparatus? q q Stacked of apposed membranes 2) Secreted Modifies, sorts, and packages proteins and other materials from the ER (vesicles are used 1) Lysosome 3) Membrane to transport materials from the ER to the Golgi) q It sends proteins to 1. 2. 3. Make lysosomes (enzymes) To be Secreted outside the cell (secretory proteins). Part of the membrane (membrane proteins) Transport Vesicle

�What are the mitochondria, nucleus, endoplasmic reticulum, and Golgi apparatus all made out of? WHY? 17

Question �Which of the following statements correctly explains the function of the Golgi apparatus within a cell? A. It uses oxygen to convert sugar into chemical energy and also controls the metabolism of the cell B. It contains most of the genetic material within the cell and is responsible for gene expression and DNA replication when the cell divides C. It prepares new macromolecules such as lipids by sorting and encasing them before sending them to the correct destination within a cell D. It breaks down molecules that are not needed within the cell, and returns some of the products of digestion to the cell for use in building new cell parts

lysosomes Formed by the Golgi apparatus. q Small organelle filled with enzymes. q Food Vacuole or Bacteria Digest macromolecules such as lipids, carbohydrates, nucleic acids and Food or proteins into small bacteria are taken molecules. q Break down organellesin by that have outlived their endocyto Lysoso sis usefulness. me q q Are used by white bloods cells to destroy bacteria Damaged Mitochondria in a vacuole Useful stuff is recycled and used by cell Waste is expelled by exocytosi s

What are vacuoles? q Sac-like structures q Store materials such as water, salts, proteins, and carbohydrates q Plant cells have a single, large central vacuole filled with liquid.

Question � Which of the following statements correctly explains the role of lysosomes within a cell? A. The lysosome prepares fats and lipids for transport throughout the cell by sorting and encasing them B. The lysosome uses oxygen to convert sugar into chemical energy and also controls the metabolism of the cell C. The lysosome breaks down molecules that are not needed within the cell and returns some of the products of digestion to the cell for later use D. The lysosome isolates water and other molecular compounds and stores them so they can be used later by the cell, or expels them as waste products

Flagella and Cilia • Used for movement • Usually one flagellum • Usually many cilia • They are made of microtubules • Flagellum and cilium are plural forms of the word.

Question �Which of the following structures would be present in a plant cell, but not in an animal cell? A. Nucleus, mitochondria, chloroplasts B. Chloroplasts, cell wall, central vacuole C. Cell wall, mitochondria, Golgi apparatus D. Central vacuole, Golgi apparatus, nucleus

Question �Which of the following is a structure that is present in both eukaryotic and prokaryotic cells? A. Golgi complex B. Plasma membrane C. Nucleus D. Vacuole

Centrosome and Centrioles �Centrosomes are in plants and animals. They are used in cell division. �Centrioles are found only in animals. 25

When they analyzed the results of the experiment, they found that simple organic molecules were formed. What kind of molecules did they find? A. B. C. D. Lipids Proteins Amino Acids Nucleic Acids

What are the two types of eukaryotes? Plant Cell Animal Cell

How are plant and animal cells similar? � Have cell membranes that enclose the cell � Have cells filled with cytoplasm � Have ribosomes � Have a nucleus � Have mitochondria � Have vacuoles � Have endoplasmic reticulum � Have Golgi apparatus � Have a cytoskeleton (microfilaments and microtubules) � Centrosome

How are plant and animal cells different? Plant Cell q q q q Rectangular shape Have cell walls Have chloroplasts for photosynthesis Have only one large central vacuole Use both chloroplasts and mitochondria to convert energy No lysosomes No centrioles Animal Cell q Circular shape q No cell walls q No chloroplasts. q Have many small vacuoles q Use only mitochondria to convert energy q Have lysosomes q Have Centrioles

Organelle Plant Cell Animal Cell Size Large Smaller than plant cells Cell Shape Rectangular/cubical Circular/spherical Vacuoles Present (one large central vacuole) Present (small vacuoles) Cell Wall Present Absent Chloroplasts Present Absent Mitochondria Present Absent? Lysosomes (some have vacuoles with enzymes that function like lysosomes) Present Golgi Bodies Present Nucleus Present ER Present Centrioles Absent Present Ribosomes Present