Exercise 4-1 Organelles and Cell Structures MATERIALS O Cell models and diagrams
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Exercise 4-1 Organelles and Cell Structures MATERIALS O Cell models and diagrams a Five colors of modeling clay O Fetal pigs or other preserved small mammal a Wooden applicator sticks O Colored pencils O Methylene blue dye O Glass slide (blank) O Distilled water O Coverslip O Light microscope O Cell slides (with red blood cells, skeletal muscle, and sperm cells) name of the model and the structures that you were able to identify on the model inventory in Table 4.2. When you have completed this activity, answer Unit Quiz questions 1 and 2 (p. 47). 1 Plasma membrane 6 Rough endoplasmic reticulum a Phospholipid bilayer b Integral proteins 7 Golgi apparatus c Peripheral proteins 8 Lysosomes d Carbohydrates 9 Peroxisomes 2 Nucleus 10 Mitochondria a Nuclear membrane 11 Centrioles b Nuclear pores c Chromatin and 12 Microtubules and chromosomes microfilaments d Nucleolus 13 Vesicle 3 Cytoplasm 14 Microvilli 4 Ribosomes 15 Cilia 5 Smooth endoplasmic 16 Flagella reticulum Most cells in the body are composed of three basic parts the plasma membrane, cytoplasm, and nucleus. 1. Plasma membrane. The plasma membrane is the outer boundary of the cell. It is composed of a phospholipid bilayer (FOSS-foh-lip-id) with multiple components interspersed throughout. It is a dynamic, fluid structure that acts as a selectively permeable barrier. 2. Cytoplasm. The cytoplasm (SY-toh-plazm) is the mate- rial inside the cell. It consists of three parts: cytosol, the cytoskeleton, and organelles. Cytosol (SY-toh-sahl) is the fluid portion of the cytoplasm and contains water, sol- utes, enzymes, and other proteins. The cytoskeleton is a collection of protein filaments including microtubules, actin filaments, and intermediate filaments. Organelles (ohr-gan-ELLZ) are specialized cellular compartments that carry out a variety of functions. 3. Nucleus. The third component in nearly all cells, the large nucleus (NO0-klee-us), is the cell's biosynthetic center. Within the nucleus we find chromatin (KROH- mah-tin; Figure 2.22 in your atlas), a ball-like mass of tightly coiled DNA and proteins, RNA, and a dark- staining region called the nucleolus (noo-klee-OH-luss). TABLE 4.2 ° Cellular Structures Model Inventory Model/Diagram Structures Identified phospholipid bilayer, fluid mosaic model of integral and periheral plasma embrane proteins, carbohydrates Typical structures found in a eukaryotic cells All the other structures from 2-16 PROCEDURE 1 Model Inventory Identify the following structures of the cell on models and diagrams, using your textbook and Figures 2.1-2.12 in your lab atlas for reference. As you examine the anatomical models and diagrams, record theExplanation / Answer
Ans: Plasma Membrane is a bilayer of phospholipids, with hydrophilic phosphate heads on the ends and hydrophobic fatty acid tails in the middle. Hydrophilic ends are compatible with the water within the cytosol and outside the cell, while the hydrophobic middle acts as a protective barrier for uncontrolled flow of water. Both plants and animals have plasma membrane.
Cell Wall is only found in plant cells, and prokaryotic cells. It is a rigid, protective wall made out of cellulose around the plasma membrane. Provides a rigid and strong shape for the plant cells.
Nucleus is enclosed in the nuclear envelope, the nucleus holds DNA, which provides the cell with its code. The nucleus contains chromatin, which holds DNA and protein. The nucleus also has the nucleolus located inside of it, which synthesizes ribosomes. Found in both plant and animal cells
Nucleolus is a darker region in the nucleus, produces ribosomes, which move out of the nucleus and take position on the rough ER - used as proteins for secretion. Found in both plant and animal cells
Centrioles is a ring of nine groups of fused microtubules, with three microtubules in each group. Centrioles are part of the cytoskeleton, and they enable chromosomal movement during cell division. Only found in animal cells
Ribosomes is a packets of RNA and protein that can be found in both prokaryotic and eukaryotic cells. Ribosomes are the site of protein synthesis. Ribosomes can be found in the cytosol, which means that the proteins they synthesize are used inside the cell or they can be found on the rough ER, which indicates that the proteins these synthesize are meant for exocytosis. Found in both animal and plant cells.
Golgi Apparatus is a membrane-bound structure. It is the post office of the cell as it packages and prepares proteins for secretion or use inside the cell. Has a cis face, which faces the rough ER, and a trans face, which faces the plasma membrane. Uses transport vesicles and docking molecules as a mean of transportation for the proteins. Found in both animal and plant cells
Endoplasmic Reticulum (Rough): The rough ER appears to be pebbled on the outside due to the embedded ribosomes on its surface. Proteins that are synthesized in those ribosomes are collected in the ER, processed, and modified a little so they can go on to the next step of protein transport throughout the cell. The smooth ER has no ribosomes on its surface. Responsible for hormones and steroids. It also is another processing center for the proteins, modifying them so they can keep going through the process. The smooth ER breaks down toxins in liver cells, making the toxins soluble.
Mitochondria is the powerhouse of the cell as they provide the cell with energy needed to move, divide, and produce products. Its outer membrane is really smooth but its inner membrane has many folds called cristae where food (sugar) is combined with oxygen to produce ATP.
Chloroplasts is found only in plant cells. Contain the plant cell's chlorophyll, which is responsible for the plant green color and its ability to absorb energy from sunlight. Needed in the process of photosynthesis. Contains thylakoids.
Lysosomes is common in animal cells but not very common in plant cells. Contain digestive enzymes necessary for digestion. Lysosomes are carefully released into closed vacuoles because the uncontrolled release of lysosomes into the cytoplasm can cause cell death
Peroxisomes are basically cellular structures that hold the enzyme peroxidase. Many cell reactions yield the by product of hydrogen peroxide, which can be harmful and toxic to the cell as it is used to kill bacteria. Peroxidase just breaks down the hydrogen peroxide to make it less harmful.
Vacuole is a membrane-bound sac that plays roles in cellular digestion and release of cellular waste products. Quite large in plant cells as it holds water and proteins. Can even act as lysosomes in animal cells. Regulates turgor pressure.
Cytoskeleton helps maintain the cell shape but also allows for the cell's movement as the cytoskeleton is crucial in locomotion and muscle fiber connection in the cell. There are 3 primary filaments: microtubules, intermediate and microfilaments.
Vesicles are used as transport vehicles for proteins from the ER to the Golgi and from the Golgi to the protein specific place.
Microfilaments: Maintenance of cell shape (tensionbearing elements); changes in cell shape; muscle contraction; cytoplasmic streaming in plant cells, cell motility (as in amoeboid movement); division of animal cells
Intermediate Filaments: Maintenance of cell shape (tensionbearing elements); anchorage of nucleus and certain other organelles; formation of nuclear lamina
Microtubules: Maintenance of cell shape (compression-resisting girders), cell motility (as in cilia or flagella); chromosome movements in cell division; organelle movements
Cytoskeleton is a network of microtubules, microfilaments, and intermediate filaments that extend throughout the cytoplasm and serve a variety of mechanical, transport, and signaling functions
Centrosome is a structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division.
Flagellum is a long cellular appendage specialized for locomotion.
Ans: Glycocalyx is a substance that prokaryotes secrete on their surface. Sugar coat that surrounds the cells. Composed of Carbohydrates moieties of membrane glycolipids and glycoproteins. It is made is made inside the cell and secreted to the cell surface, when glycocalyx is organized an firmly attached to the cell wall called as a capsule. It acts as an I.D tag that enables the body to determine self or foreign (diseased cells) i.e., it function as protection, immunity to infection, defense against cancer, transport compatibility, cell adhesion, fertilization and embryonic development.
Ans: 3 Principle parts of cell are the plasma membrane, cytoplasm, nucleus
Cells is the smallest living things; structural and functional sub-units of all our body systems
Plasma membrane is the flexible outer surface of the cell, separating the cell's internal environment for the external environment. Regulates the flow of materials into and out of a cell. It also plays a key role in communication among cells
Cytoplasm consists of all the cellular contents between the plasma membrane and the nucleus. It consists of cytosol, the fluid portion of cytoplasm that contains water, dissolved solutes, and suspended particles. It also consists of organelles within the cytosol.
Nucleus is a large organelle that houses most of the cells DNA. Control Center of the Cell. A double walled nuclear envelope separates the nucleus from the cytoplasm
the nucleolus is a site within the nucleus that produces new ribosomes
Chromosomes contain our genes - the source of information for building and running cells
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