Intro to Biology – Lecture 42 Cell Energy and Storage
Chloroplasts The food producers of the cell. Found only in plant (producer) cells. In a factory, chloroplasts would be the cafeteria.
In the Chloroplasts Plants convert carbon dioxide and sunlight into sugar and oxygen in photosynthesis.
Chloroplasts Structure Two membranes surround it stroma - area inside where sugars are created Thylakoid stacks have chlorophyll on their surface
Photosynthesis in the Chloroplasts When the Sun hits a chloroplast, chlorophyll uses energy to combine carbon dioxide (CO 2 ) and water (H 2 O). The molecular reactions create sugar and oxygen (O 2 ).
Mitochondria Mitochondria work in the opposite direction of chloroplasts and break down the sugars and nutrients that the cell receives.
Mitochondria Mitochondria are known as the powerhouses of the cell. They would be the power-room (generator) of a factory
Mitochondria act like a digestive system takes in nutrients, breaks them down, and creates energy for the cell Very small organelles
Varying Numbers of Mitochondria cells can have several thousand mitochondria or only a few Muscle cells need a lot of mitochondria while nerve cells only need a few
Adapting with the Mitochondria If the cell feels it is not getting enough energy to survive, more mitochondria can be created. They can even grow, move, and combine with other mitochondria, depending on the cell's needs.
Mitochondria Structure 2 membranes – Outer, and inner (cristae) The cristae is folded many times to increase surface area for reactions. This allows the small organelle to do as much work as possible because there is more room. The fluid inside is called the matrix.
Mitochondria and Cellular Respiration The matrix is filled with water and proteins (enzymes). Those proteins combine food molecules with oxygen. This helps digest the food, giving the cell energy.
Lysosomes in every animal-like eukaryotic cell hold enzymes that were created by the cell. Purpose is to digest things Made from the Golgi apparatus float in the cytoplasm until they are needed
Making and Digesting Food When food is in the cell, lysosomes attach and release their enzymes which break down complex molecules (sugar/protein) When food is scarce, lysosomes digest the cell organelles for nutrients.
Peroxisomes Small vesicles found around the cell. single membrane that contains digestive enzymes for breaking down toxic materials in the cell. Requires oxygen Known for digesting fatty acids, amino acids, and ethanol
Where does the Oxygen Come From? Digestion makes hydrogen peroxide (H 2 O 2 ). Peroxisomes break it down into water (H 2 O) and oxygen (O 2 ). Water is released to the cell, oxygen is used in the digestive process.