Cell membrane Structure It is the outermost structure

� Cell membrane • Structure: It is the outermost structure in cells that lack a cell wall. Contains two layers of phospholipids. The phospholipid has a hydrophilic head and a hydrophobic tail. • Function: It is a protective barrier that encloses a cell. It separates the cell’s contents from the cell’s environment. It controls what comes into and out of the cell (semipermeable). � Cell wall • Structure: A rigid structure made of cellulose that surrounds the cell membrane. • Function: It provides support and protection to the cell. � � Chloroplasts • Structure: It has two membranes. They are green because they contain the green pigment chlorophyll. Chlorophyll is found in the inside the inner membrane. • Function: Performs photosynthesis, which is the process by which plants use sunlight, CO 2, and water to make sugar (food) and oxygen. Chlorophyll traps the energy of the sunlight to make sugar. Chromatin • Structure: It is a combination of DNA and protein. It is located in the nucleus. • Function: It packages the DNA into a smaller volume so it fits in the nucleus

� � Cytoplasm • Structure: It is a gel-like fluid found throughout the entire cell where the organelles are found. • Function: It constantly is moving, which moves the cell. It also helps move materials inside of the cell. ER • Structure: It is a system of folded membranes that is found in the cytoplasm. It is either rough or smooth. Rough ER is covered in ribosomes, and is found near the nucleus. Smooth ER lacks ribosomes. • Function: It is the “delivery system” of the cell. Materials/substances move through the ER to different places in the cell. It assists in the production, processing, and transport of proteins and in the production of lipids. � � Golgi Bodies • Structure: It looks like the smooth ER, folded membrane. • Function: It is the cell’s “mailroom”. Lipids and proteins from the ER are delivered here. The lipids and proteins may be modified to do different jobs. Final products are enclosed in a piece of Golgi bodies’ membrane. Is transported to other parts of the cell or outside of the cell. Forms vesicle Lysosome • Structure: Vesicle that contains proteins and enzymes. • Function: t is the cell’s “clean-up crew”. They destroy worn-out or damaged organelles, get rid of waste material, and protect the cell from foreign invaders.

� � Nucleus • Structure: Large organelle that has two membranes. There are pores in the membranes that allow materials to pass in and out of the cell. • Function: DNA is found in the nucleus. It is the “brain” of the cell. It directs all of the cells activities. Nucleolus • Structure: It is the dark region in the nucleus. • Function: The location where the cell begins to make ribosomes. Nuclear membrane • Structure: It is two membranes that surround the nucleus. It has pores. • Function: It allows materials to pass in and out of the nucleus. � � Ribosome • Structure: The smallest organelle made of RNA and protein. • Function: They synthesize protein. They are little factories that make protein. Vacuole • Structure: It is a membranous sac. Large central vacuole is in plant cells and takes up a large region of space in the cell. • Function: It acts as the cell “storage unit”. It stores water and other materials that the cell needs. Central vacuoles help support the cell. Mitochondrion • Structure: Organelle that has two membranes. The outer membrane surrounds the organelle and the inner membrane is a folded membrane. • Function: It is the “powerhouse” of the cell. It takes sugar and makes ATP.

1. 2. 3. 4. What cell parts do animal cells have that plant cells do not have? What cell parts do plant cells have that animal cells do not have? Why do plant cells have cell walls and animal cells do not? Why do you think plant cells have bigger vacuoles than animal cells? 2. 3. 4. Animal cells have lysosomes, but plant cells do not. Plant cells have cell walls and chloroplasts, but animal cells do not. Cell walls are supporting structures that help the plant to have a fixed shape, and protect it from injury. Animal cells, on the other hand, do not need the supporting structure of a cell wall because animals have a skeletal system. When you water a plant, the water collects in the vacuole and makes it stiff. This is why plants wilt if they don't get enough water.