Lesson 3 Everything Begins with Cells Objectives Define

Lesson 3 Everything Begins with Cells

Objectives: • Define the term cell • Describe the functions of cells • Identify the parts of a cell

Cells are the smallest structural unit of living things, which carry on all of the functions of life. Functions of life includes: ● Taking in food and oxygen ● Producing heat and energy ● Eliminating wastes ● Reproducing to create new cells. Different cells perform different tasks.

Part of a cell: Cell membrane – The cell membrane forms an outer boundary around the cell to separate it from its surrounding. This thin membrane is also known as the plasma membrane. Nucleus – The nucleus is a round structure within the cytoplasm. It may be referred to as the "brain" of the cell because it controls cell activities and directs cell reproduction. Cytoplasm – Cytoplasm is a jelly-like, semifluid material that transports substances within the cell.

Organelles – small structures with a specific job to help the cell function. Centrioles – play an important role in cell division. Golgi apparatus – a stack of membrane layers that produces, stores, and packages secretions to be sent out of the cell. Ribosomes help to create protein. Lysosomes contain enzymes used to digest food as well as other substances. Endoplasmic reticulum – a fine network of tubular structures that allows substances to be transported into and out of the nucleus. Mitochondria – breaks down nutrients to help make the major energy source for the cell, adenosine triphosphate (ATP).