Brief Summary
This video provides an overview of cell biology, explaining the basic components of cells, the differences between eukaryotic and prokaryotic cells, and the functions of various organelles within the cell. It also touches on unique cell structures like cilia and flagella.
- Cells are the smallest living units and have a cell membrane, cytoplasm, and DNA.
- Eukaryotic cells have organelles, including a nucleus, while prokaryotic cells do not.
- Organelles like ribosomes, endoplasmic reticulum, Golgi body, vacuoles, lysosomes, and mitochondria perform specific functions within the cell.
- Plant cells have chloroplasts for photosynthesis and a cell wall for support, while animal cells do not have a cell wall.
- Some cells have unique structures like cilia and flagella for movement and other specialized functions.
What is a cell?
Cells are the smallest living units of an organism. All cells, regardless of type, share three common features: a cell membrane that separates the cell's interior from its environment, cytoplasm, which is a jelly-like fluid within the cell, and DNA, the cell's genetic material. These components are essential for the cell's structure and function.
What are the 2 categories of cells?
There are two main categories of cells: eukaryotic and prokaryotic. Eukaryotic cells are more complex and contain organelles, including a nucleus, which houses the cell's DNA. These cells are found in plants and animals. Prokaryotic cells, on the other hand, lack a nucleus and membrane-enclosed organelles. Their genetic material is not contained within a nucleus. Prokaryotic cells are always unicellular organisms, such as bacteria.
What is an Organelle? DNA, Chromatin, Chromosomes
Organelles are specialized parts of a cell, each with unique functions. The nucleus, often called the control center, contains DNA, which dictates the cell's activities. Within the nucleus, DNA exists in two forms: chromatin, which is the tangled, spread-out form, and chromosomes, which are condensed structures formed when the cell is ready to divide. The nucleus also contains the nucleolus, where ribosomes are made.
Organelles: Ribosomes, Endoplasmic Reticulum
Ribosomes are responsible for synthesizing proteins. After leaving the nucleus, they either float freely in the cytoplasm or attach to the endoplasmic reticulum (ER). The ER is a network of membrane-enclosed passageways that transport materials within the cell. There are two types of ER: rough ER, which has ribosomes attached to it, and smooth ER, which does not.
Organelles: ER function, Vesicles, Golgi Body (Apparatus)
The endoplasmic reticulum (ER) transports materials, such as proteins synthesized by ribosomes, throughout the cell. Proteins and other materials exit the ER in small vesicles, which are then received by the Golgi apparatus (or Golgi body). As proteins move through the Golgi body, they are customized into usable forms through folding or by adding lipids or carbohydrates.
Organelles: Vacuole, Lysosome, Mitochondrion
Vacuoles are sac-like structures that store various materials. In plant cells, the central vacuole stores water. Lysosomes, found in animal cells, act as garbage collectors, taking in damaged or worn-out cell parts and breaking them down with enzymes. The mitochondrion is the powerhouse of the cell, present in both animal and plant cells. It produces ATP molecules through cellular respiration, providing energy for the cell's activities. Cells that require more energy have a higher number of mitochondria.
Organelles: Cytoskeleton
The cytoskeleton maintains the cell's shape. It consists of thread-like microfilaments made of protein and microtubules, which are thin, hollow tubes. These structures provide support and help maintain the cell's structure.
Plant Cell Chloroplast, Cell Wall
Plant cells, which are photoautotrophic (capture sunlight for energy), contain chloroplasts, organelles where photosynthesis occurs. Chloroplasts contain chlorophyll, a green pigment essential for photosynthesis. Plant cells also have a cell wall outside the cell membrane, providing shape, support, and protection. Animal cells do not have a cell wall.
Unique Cell Structures: Cilia
Some cells have unique structures like cilia and flagella. Cilia are microscopic, hair-like projections that move in waves, helping to trap and expel inhaled particles in the respiratory tract. Flagella are tail-like structures that aid in cell movement. For example, some bacteria have flagella to propel themselves, and in humans, the only cell with a flagellum is the sperm cell.
