STANDARD SC.912.L.14.3
- Compare and contrast the general structures of plant and animal cells.
- Compare and contrast the general structures of prokaryotic and eukaryotic cells.
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Interactive Activities
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All cells, no matter which type, have the following structures:
- DNA (because all cells need a set of instruction to make proteins important for life)
- Ribosomes ( because those proteins are not going to get done by themselves, ribosomes make them)
- Cytoplasm (because all cells need and environment were chemical reactions take place)
- Cell Membrane (because all cells need a barrier between in and out spaces, and to control who gets in or out)
Cell Types
Eukaryotic Animal & Plant Cells |
Prokaryotic Cells |
Eukaryotic vs. Prokaryotic
Eukaryotic Cells
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Both
All cells have basic structures such as:
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Prokaryotic Cells
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Cell Organization
- Nuclear Envelope or Nuclear Membrane: Phospholipid bilayer that surrounds the DNA. The layer is punctured by nuclear pores (like holes) or transport proteins, that allow the active transport of ribosomes
- Cytoplasm or Protoplasm: It is the jelly-like substance that fills a cell and composed mostly of water, salts, and important enzymes that speed up chemical reactions. The cytosol refers to the part of the cytoplasm that does not contain any organelles.
- Nucleus: Found only in Eukaryotic cells. The nucleus encompasses the DNA(in the form of chromatin) enclosed by a nuclear membrane, also called nuclear envelop. This membrane has pores that allow the active transport of messenger RNA (mRNA) and ribosomes (which are proteins) produced by the nucleolus housed inside the nucleus.
- DNA or Deoxyribonucleic Acid: Genetic material that directs protein synthesis (dictates what the cell is going to do, and how it going to do it) All cells have DNA.
- Nucleolus: Region of the nucleus containing DNA that only codes for the production of Ribosomes. Site of ribosome synthesis.
- Chromatin: Tangled, spread out form of DNA found inside the nuclear membrane.
- Chromosomes: Condensed formed of DNA only visible when the cell is ready to divide.
Organelles That Build Proteins
- Ribosomes: Protein synthesis. Make proteins following the DNA's instructions. Ribosomes are made of 2 ribosomal subunits. They exit the nucleus through nuclear pores and attach to the nuclear envelop, the rER, or float freely in the cytoplasm of the cell.
- Rough Endoplasmic Reticulum (rER): Membrane-enclosed pathways (tube-like) that is continues from the nuclear envelop and extends to the cytoplasm of the cell. It has ribosomes attached to its surface. Like a system of highways it functions in the transport and modification of proteins made by the ribosomes.
- Smooth Endoplasmic Reticulum (sER): Similar to the rER, but it does NOT have ribosomes attached to it. It functions in the production of lipids (fats), steroid-type hormones, and detoxification of the cell.
- Golgi apparatus or Golgi Body: A complex of vesicles and folded membranes within the cytoplasm of most eukaryotic cells, helps process and package proteins and lipid molecules, especially proteins destined to be exported from the cell.
Organelles That Store, Clean up, and Support:
- Vacuoles and Vesicles: A vacuole is a membrane-bound cell organelle. In animal cells, vacuoles are generally small and help sequester waste products.
- Large Central Vacuole: In plant cells, vacuoles help maintain water balance. Sometimes a single vacuole can take up most of the interior space of the plant cell.
- Lysosomes: A lysosome is a membrane-bound cell organelle that contains digestive enzymes. Lysosomes are involved with various cell processes. They break down excess or worn-out cell parts. They may be used to destroy invading viruses and bacteria.
- Peroxisomes: Peroxisomes are organelles that sequester diverse oxidative reactions and play important roles in metabolism, reactive oxygen species detoxification, and signaling.
- Centrioles: The main function of centriole is to help with cell division in animal cells. Centrioles also help in the formation of the spindle fibers that separate the chromosomes during cell division (mitosis).
- Cytoskeleton: give shape to cells lacking a cell wall; allow for cell movement,e.g. , the crawling movement of white blood cells and amoebas or the contraction of muscle cells; and movement of organelles within the cell and endocytosis;
Organelles That Capture and Release Energy
- Chloroplast: CAPTURE Energy: Chloroplast is an organelle found in the leaves of green plants. They are found in a plant cell. What are the two main functions of chloroplasts? The two main functions of chloroplasts are to produce food (glucose) during photosynthesis, and to store food energy.
- Mitochondria: RELEASE Energy: They make most of the cell's supply of adenosine triphosphate (ATP), a molecule that cells use as a source of energy. This means mitochondria are known as "the powerhouse of the cell".
Cellular Boundaries
- Cell Membrane or Plasma Membrane: Is a selectively-permeable barrier that separates the interior of the cell from its external environment, and regulates that movements of molecules in and out of the cell. Composed of a double layer of phospholipids.
- Cell Wall: Is a rigid layer composed of polysaccharides (carbohydrates). The type of carbohydrate changes depending upon the type of cell. In plants is made of cellulose, in fungi is made of chitin, in bacteria of peptidoglycan, in archaea the wall lacks peptidoglycan. And animal cells do not have cell wall. It provides protection, shape and support to the cell.
- Flagella or Flagellum (singular): Specialized structure that propels the cell in the environment. Present in some bacterium (see image below). The sperm is the only human cell that contains flagella.
- Cilia: Hair-like projections located on the surface of the cell, that moves single-celled organisms in their environment (locomotion). Cilia in the human respiratory tract move in a sweeping motion allowing pathogens trapped in mucus out of the body. Cilia in the Fallopian Tubes help the ovum move towards the uterus.