Cells are the fundamental building blocks of all living organisms, encompassing a wide variety of shapes and structures. They can either be prokaryotic—lacking a nucleus and simpler in structure—or eukaryotic, which contain a nucleus and can be unicellular or multicellular. A cell's various organelles, such as mitochondria, ribosomes, and the nucleus, play key roles in processes like energy production, protein synthesis, and genetic information management. Understanding these cellular components is essential in fields like biotechnology.
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Cells • Basic building blocks of life • Understanding of cell morphology is critical to the study of biotechnology
Cell • Smallest living unit of an organism • Grow, reproduce, use energy, adapt, respond to their environment
Cell • Many cannot be seen with the naked eye • A cell may be an entire organism or it may be one of billions of cells that make up the organism
Cells • Divided and classified in many ways • One common classification method is the presence or absence of a cell nucleus
Nucleus • Relatively large structure within a cell • Directs cell activities • Some simple single-celled organisms lack a nucleus
Nucleus • Prokaryotes – have no nucleus • Eukaryotes – have a nucleus
Prokaryotes • Single celled organism • Kingdom Monera • Lacks a cell nucleus • Internal structure is less organized than other cells
Prokaryotes • Genetic info needed is within the cell • Two most common – blue green bacteria and true bacteria
Blue green bacteria • Have ability to produce their own food like plants • Most bacteria get their food from other sources
Prokaryotes • Less complex than eukaryotes • Still have many of the basic internal characteristics
Common prokaryote structures • Cytoplasm • Chromosomal material • Cell membrane and wall • Ribosomes • Some have flagellum for mobility
Eukaryotes • Organism made up of cells that have a nucleus • May be single celled – Kingdom Protista • May have billions of cells like plant and animal kingdoms
Eukaryotes • Single celled eukaryotes include paramecia, euglena, and diatoms
Eukaryotes • Typically are highly organized • Infinite number of shapes and purposes
Eukaryotes • Human body has at least 85 different cell types • All eukaryotes have a number of structures in common
Common structures • Organelles – smaller parts of the cell with specific functions • Cell membrane – acts as a gatekeeper
Cell membrane • Controls what enters and leaves the cell • Plants, algae, and bacteria typically have a tough outer structure known as a cell wall
Cell wall • Provides additional structure and protects the cell from pressure caused by movement of water • Animal cells do not have walls
Cytoplasm • Organelles are surrounded by a jelly-like substance • Primary component is water
Nucleus • Largest and most identifiable part of the cell
Other organelles • Lysosomes • Vacuoles • Chloroplasts in plants
Nucleus • Brain of the cell • Site of much of the manipulation done in biotechnology
Nucleus • Controls activity of the cell • Round or oval structure • Typically found in the middle of the cell • Appears darker than surrounding material
Nucleus • Surrounded by a membrane that controls passage of materials in and out of the area
Nucleus • Contains DNA • DNA is located on chromosomes • Most organisms are diploid – have tow chromosomes for each trait
Cytoplasmic Organelles • Organelles are required for proper cell function • Ribosome – make proteins for cellular use and communication • May be attached to endoplasmic reticulum
Fission • Prokaryotes • Cell grows larger and makes a second copy of its DNA • At some point the cell membrane divides the cell by the growth of a transverse septum
Fission • Two new cells are formed as the division grows inward from either side of the cell • Two cells now called “daughter cells” • Sometimes known as “binary fission”
