Compare and Contrast Specialised Cells

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CELL ULTRASTRUCTURE
CELL ULTRASTRUCTURE

Cells are the smallest functional units of the body, (Waugh, A. and Grant, A.2010). Most cells are microscopic. The largest cell in the body is the female ovum. The erythrocyte is the smallest cell. The longest cell is the neuron. Cells group together to form tissues, each of which has specialised function. Different tissues group together to form organs. Organs are group together to form organ systems, each of which performs a particular function that maintains the homeostasis and contribute to the health of the individual, (Waugh, A. and Grant, A.2010). Animal cell consists of a plasma membrane, separating the cells internal components from the extra cellular materials and external environment. Inside which are a number of organelles suspended in a watery fluid called cytoplasm. Cytoplasm includes the organelles and the inclusions. Organelles are highly specialized structures and often enclosed in their own membrane within the cytoplasm, specialised for specific activities. They include nucleus, mitochondria, endoplasmic reticulum, ribosomes, Golgi apparatus, lysosomes and cytoskeleton. The organelle with the largest volume is the nucleus, which contains the genetic material. (See Figure 1). Cell Inclusions are secretory and storage chemical substances without membranes. They include melanin, glycogen and triglycerides. Melanin is a pigment stored in the skin. Glycogen is a polysaccharide stored in the liver, skeletal muscle. Triglycerides which are stored in the adipocytes, (Tortora and Grabowski, 1996).

Figure 1-1 Cell ultrastructure
Source-www.biologia.com
Figure 1-1 Cell ultrastructure
Source-www.biologia.com
Mitochondria: Spherical/rod shaped structures, enclosed by double membrane carries enzymes for respiration - Production of ATP Mitochondria: Spherical/rod shaped structures, enclosed by double membrane carries enzymes for respiration - Production of ATP Plasma membrane: Lipid bilayer composed of phospholipids and cholesterol with proteins that embedded in either surface of lipid bilayer - Selective barrier that retains cell content and enables cells to recognise one another. Plasma membrane: Lipid bilayer composed of phospholipids and cholesterol with proteins that embedded in either surface of lipid bilayer - Selective barrier that retains cell content and enables cells to recognise one another. Secretory vesicle: Membrane bound bag pinched off Golgi apparatus - Carries proteins and lipids to cell surface for secretion. Secretory vesicle: Membrane bound bag pinched off Golgi apparatus - Carries proteins and lipids to cell surface for secretion. Lysosome: Spherical vesicle containing digestive enzymes -Intracellular digestion, Autolysis. Lysosome: Spherical vesicle containing digestive enzymes -Intracellular digestion, Autolysis. Rough endoplasmic reticulum: Intracellular membrane system with ribosomes on the cytoplasmic surface - site for protein synthesis and transports to Golgi apparatus. Rough endoplasmic reticulum: Intracellular membrane system with ribosomes on the cytoplasmic surface - site for protein synthesis and transports to Golgi apparatus. Nucleus: Major cell organelle containing chromatin. (DNA & Histones)-Regulates the metabolism/carries hereditary information. Nucleus: Major cell organelle containing chromatin. (DNA & Histones)-Regulates the metabolism/carries hereditary information. Ribosomes: Ribosomal RNA and proteins form large and small subunits, attached to ER or free ribosomes distributed in the cytoplasm – Site of Protein Synthesis. Ribosomes: Ribosomal RNA and proteins form large and small subunits, attached to ER or free ribosomes distributed in the cytoplasm – Site of Protein Synthesis. Nucleolus: A dense body in the nucleus consists of ribosomal RNA and proteins-Synthesis of ribosomes and RNA. Nucleolus: A dense body in the nucleus consists of ribosomal RNA and proteins-Synthesis of ribosomes and RNA. Nuclear envelope:...
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