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- Cells that enclose their DNA in nuclei. The nucleus seperates the genetic material from the rest of the cell.
- Examples: Plants, animals, and fungi
What is a cell mebrane?
A thin flexible barrier that ALL cells are surrounded by.
Cell theory is...
- 1. All living things are made up of cells
- 2. Cells are the basic units of structure and function in living things
- 3. New cells are produced from existing cells
What are cells?
The basic units of life
What is a vacuole?
- Vacuoles store material like water, salts, proteins, and carbohydrates.
- Eukaryotic cell
Explain the "fluid mosaic model"...
Most biological cell membranes are selectively permeable, meaning that some substances can pass across them and others cannot.
Describe the cell membrane...
- Regulates what eneters and leaves the cell and also protects and supports the cell
- Lipid bilayers give cells a flexible structure that forms a strong barrier
- All cells contain cell membranes
- Support, shape, and protect the cell
- Many are porous enough to allow water, oxygen, carbon diovide, and other substances to pass through easily.
- In non-animal eukaryotic and prokaryotic cells
What's a mitochondria?
- Mitochondria convert the chemical energy stored in food into compounds that are more convenient for the cell to use.
- Only in eukaryotic cells
Describe a chloroplast...
- Chloroplasts capture the energy from sunlight and convert it into food that contains chemical energy in a process called photosynthesis.
- Only in eukaryotic plant cells
What is the Golgi Apparatus?
- Modifies, sorts, and packages proteins and other materials from the ER for storage in the cell or release.
- Proteins produced in the Rough ER go here
- Only in Eukaryotic Cells
Endoplasmic reticulum (ER) &
Rough Endoplasmic reticulum (Rough ER)...
- An internal membrane system that is only present in Eukaryotic cells.
- Where lipid components of the cell membrane are assembled.
- The Rough ER is involved in the synthesis of proteins. Proteins made on the rough ER include those that will be released.
Proteins are assembled on ribosomes.
Describe microfilaments and microtubules...
- Microfilaments are threadlike structures made up of a protein called actin. They help cells move.
- Microtubules are hollow structure made up of a protein called tubulins. They help to maintain the cell's shape. Centrioles are also formed from tubulins. They help to organize cell division (not found in plant cells).
- Eukaryotic cells only
What is the cytoskeleton?
- A network of protein filaments that helps the cell to maintain it's shape and it also is involved in movement.
- Only in eukaryotic cells
- Small organelles filled with enyzmes. They break down lipids, 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.
- Eukaryotic cells only
- Contains nearly all of the cell's DNA and, with it, the coded instructions for making proteins and other important molecules.
- Prokaryotic cells have no nucleus but they have DNA that floats in the cytoplasm containing the same instructions.
What are organelles?
- Specialized componets of cells.
- In eukaryotic and some prokaryotic cells.
What is a cytoplasm?
- Fluid portion of the cell outside of the nucleus.
- Prokaryote and Eukaryote
- Do not seperate their genetic material within a nucleus.
- Examples: Bacteria
- The process by which particles move from an area of high concentration to an area of lower concentration.
- Passive transport is the movement of materials across the cell membrane without using cellular energy
- The process in which molecules cannot directly diffuse across the membrane pass through special protein channels
What is osmosis?
- The diffusion of water through a selectively permeable membrane
- Aquaporins are the water-channel protein
Describe istonic, hypertonic, hypotonic solutions...
- Isotonic means equilibrium
- Hypertonic means that the solution has a higher solute concentration
- Hypotonic has a lower solute concentration
What is osmotic pressure?
- Driven by differences in solute concentrationn, it is the net movement of water out of or into a cell
- Causes a hypertonic solution to shrink
- The movement of materials against a concentration difference
- Requires energy
Small molecules and ions are carried across membranes by protein pumps
What is endocytosis and exocytosis?
- Endocytosis is the process of taking material into the cell membrane by the means of infoldings of the cell membrane. The pocket breaks loose from the mebrane and forms a vesicle/vacuole.
- Exocytosis is the way cells release large amounts of material. The membrane of the vacuole fuses with the cell membrane, forcing the contents out of the cell.
- Maintaining homeostasis, unicellular organisms grow, respond to the enviroment, transform energy, and reproduce.
- Cells of multicellular organisms are specilized for multiple tasks.
What are the levels of organization?
- Tissue -> A group of similar cells that perform a particular function
- Organ -> Group of tissues working together
- Organ System -> A group of organs working together to perform specialized tasks
Describe cellular communication...
- Cells in large organisms communicate with each other by the means of chemical signals that can speed up or slow down the cells activites
- Receptors enable the cell to respond to chemical signals by allowing the signaling molecule to bind to it