Cells are the basic units of life.
Cell theory states:
-All living things are made up of cells.
-Cells are the basic units of structure and function in living things.
-New cells are produced from existing cells.
Microscopes help explore the cells. They produce an enlarged image of something very small. Most microscopes use lenses to magnify the image of an object by focusing light or electrons.
All cells are surrounded by a thin flexible barrier called a cell membrane. Cells fall into two broad categories, depending on whether they contain nucleus. The nucleus is a large membrane-enclosed structure that contains genetic material in a form of DNA, and controls many of the cell's activities. Eukaryotes are cells that enclose their DNA in nuclei. Prokaryotes are cells that do not enclose DNA in nuclei.
Prokaryotes:
-They are smaller and simpler than the eukaryotic cells.
-Prokaryotic cells do not separate their genetic material within a nucleus.
-Prokaryotes grow, reproduce, respond to the environment, and sometimes swim through liquids.
-Bacteria are prokaryotes.
Cell theory states:
-All living things are made up of cells.
-Cells are the basic units of structure and function in living things.
-New cells are produced from existing cells.
Microscopes help explore the cells. They produce an enlarged image of something very small. Most microscopes use lenses to magnify the image of an object by focusing light or electrons.
All cells are surrounded by a thin flexible barrier called a cell membrane. Cells fall into two broad categories, depending on whether they contain nucleus. The nucleus is a large membrane-enclosed structure that contains genetic material in a form of DNA, and controls many of the cell's activities. Eukaryotes are cells that enclose their DNA in nuclei. Prokaryotes are cells that do not enclose DNA in nuclei.
Prokaryotes:
-They are smaller and simpler than the eukaryotic cells.
-Prokaryotic cells do not separate their genetic material within a nucleus.
-Prokaryotes grow, reproduce, respond to the environment, and sometimes swim through liquids.
-Bacteria are prokaryotes.
Prokaryotic Cell
Eukaryotes:
-They are larger and more complex than prokaryotic cells.
-Most of eukaryotic cells contain dozens of structures and internal membranes.
-In eukaryotic cells, the nucleus separates the genetic material from the rest of the cell.
-They are larger and more complex than prokaryotic cells.
-Most of eukaryotic cells contain dozens of structures and internal membranes.
-In eukaryotic cells, the nucleus separates the genetic material from the rest of the cell.
Eukaryotic Animal Cell
Eukaryotic Plant Cell
- The cytoplasm is the portion of the cell outside the nucleus.
- The nucleus contains nearly all the cell's DNA and, with it, the coded instructions for making proteins and other important molecules.
- Vacuoles are large, saclike, membrane-enclosed structures. They store materials like water, salts, proteins, and carbohydrates.
- Lysosomes are small organelles filled withe enzymes. Lysosomes break down lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell. They are also involved in breaking down organelles that have outlived their usefulness.
- Cytoskeleton is a protein filaments. It helps the cell maintain its shape and is also involved in movement. Microfilaments and microtubules are two of the principal protein filaments that make up the cytoskeleton.
- Microfilaments are threadlike structures made up of a protein called actin. They form extensive networks in some cells and produce a tough flexible framework that supports the cell. They also help cells move.
- Microtubules are hollow structures made up of proteins known as tubulins. They help maintain cell shape. They are also important in cell division, where they form a structure known as the mitotic spindle, which helps to separate chromosomes. In animal cells, organelles called centrioles are also formed from tubulins. Centrioles are located near the nucleus and help organize cell division. Centrioles are not found in plant cells.
- Proteins are assembled on ribosomes. Ribosomes are small particles of RNA and protein found throughout the cytoplasm in all cells.