and their organelles Discovery Video: Cells
REVIEW!!!! The Cell Theory 1. Every living organism is made of one or more cells. 2. The cell is the basic unit of structure and function. It is the smallest unit that can perform life functions. 3. All cells arise from pre-existing cells. *Why is the Cell Theory called a Theory and not a Fact? Cell Features ALL cell have these parts Ribosomes make protein for use by the organism Cytoplasm fluid material within cell DNA genetic material Cytoskeleton internal framework of cell Cell Membrane outer boundary, some things can cross the cell membrane
Comprehension Checkpoint Answer true or false 1.Bacteria cells have a cell membrane. 2.The Cell Theory was developed by a single scientist. 3.Plant cells have cytoplasm. 4.Cells taken from fungi do not have DNA. 5.Cells can only come from pre-existing cells. 6.It only took five years to develop the Cell Theory. REVIEW!!!! Prokaryote Cells The first cells to inhabit the earth Simple cells Bacteria These cells do NOT have a nucleus, their DNA is circular and floats in the cytoplasm Some bacteria have a tail-like structure called a flagella, that helps it to move. A capsule surrounds some bacteria and helps them avoid the body s immune system
REVIEW!!!! Eukaryotic Cells Cells found in plants, animals, protists, and fungi The cell is composed of 4 main parts: 1.Cell membrane 2. Cytoplasm 3.Nucleus control center of cell, houses DNA 4.Organelles small structures inside cells that carry out specific functions ( little organs ) Nucleus Function: the brain of the cell it contains the DNA, which directs all cell functions Has a nuclear membrane & nuclear pores Contains cell s DNA in one of 2 forms o chromatin - DNA bound to protein (non-dividing cells) o chromosomes - condensed structures seen in dividing cells Also contains an organelle called nucleolus - which makes the cell s ribosomes
Cell Organelles Endoplasmic Reticulum Transport, "intracellular highway". -Rough ER contains many ribosomes & is involved in protein synthesis -Smooth ER ribosomes not found on surface. Used for lipid production and storage of ions.
As seen through a Transmission Electron Microscope Cell Organelles Golgi Apparatus processes, packages and secretes proteins. It is comparable to a factory or a post office. *A vesicle forms with Golgi to transport substances outside cell.
unprocessed proteins enter the Golgi apparatus from ER proteins are packaged and exported near membrane Figure 4.13
Cell Organelles Ribosomes function: protein synthesis (protein manufacturing). Ribosomes read messenger RNA sent out of the nucleus and put amino acids together to make proteins. Ribosomes are manufactured inside the nucleolus, inside the nucleus Lysosomes Contain digestive enzymes, break things down; "suicide sac Digest particles taken in by phagocytosis. Only in animal cells Protein Production The cell is like a factory. Its product is protein which goes to body to serve different functions. 1.DNA has instructions to build protein 2.These instructions are sent to ribosomes 3.The ribosomes build protein and send it through ER 4.The proteins are delivered to the Golgi where they are completed and tagged for export outside cell
Cell Organelles Mitochondria this is the cell s energy center. It turns food into a chemical energy called ATP The mitochondria is sometimes called the powerhouse of the cell Has 2 membranes, one smooth outer membrane, and an inner membrane folded into layers called cristae Figure 4.17
Cell Organelles Cytoskeleton Helps cell maintain support & shape; movement a. microtubules-hollow structures; also help build cilia and flagella b. microfilaments-threadlike Cell Organelles Centrioles part of cytoskeleton used during cell division to move and separate chromosomes Only found in animal cells
Cell Organelles Flagella long, whiplike extension of the cell. Cilia short, hairlike extensions of the cell. Only found in animal cells Both are used in different ways for locomotion (moving). Made of microtubules Cell Organelles Vacuole mainly used for storage of water but can also contain other molecules Plant cells have larger and fewer vacuoles that also function in maintaining hydrostatic pressure that keeps the plant rigid.
Cell Organelles Chloroplasts where photosynthesis takes place function: to convert light energy into carbohydrates. Carbohydrates are then broken down in mitochondria to produce ATP only found in plant cells Elodea Cells Viewed With a Microscope This is what you saw in the lab
REVIEW!!!! CELL MEMBRANE Selectively permeable ; it regulates what comes into the cell and what leaves the cell It is composed of a double layer of phospholipids with proteins embedded throughout Watch the video. Can you name the cell parts and processes shown?