Section 6.4 The Structure and Function of the Nucleus The nucleus contains DNA The information contained in the nucleus directs all of the activities of the cell A pair of membranes of membranes called the nuclear envelope surrounds the nucleus – Substances that are made in the nucleus move into the cytoplasm through little holes, or pores in the nuclear envelope Nucleolus: ball like mass of fibers and granules contained in the nucleus

Section 6.4 Structure and Function of the Nucleus

Section 6.4 Ribosomes Where proteins are created Work as protein assembly lines Ribosomes are clusters or proteins and nucleic acids assembled from components made in the nucleolous Some ribosomes are bound to the outer surface of a membrane network within the cytoplasm Other ribosomes are suspended in the cytoplasm

Section 6.4 The Endoplasmic Reticulum Within the cell there is an extensive network of membranes called the endoplasmic reticulum The main place where manufacturing and transportation occur – Produces an enormous variety of molecules

Section 6.4 The Endoplasmic Reticulum Rough ER – Gets its name from the ribosomes that are attached to the outside – Ribosomes created proteins the the rough ER “packages” them and export them Smooth ER – Lacks ribosomes – Builds lipids

Section 6.4 The Endoplasmic Reticulum

Section 6.4 The Golgi Apparatus Products that are made in the ER are sent to the golgi apparatus stored inside vesicles The golgi apparatus modifies, stores and routes proteins and other chemical products to their next destinations It is like a factories processing and shipping center

Section 6.4 The Golgi Apparatus

Section 6.4 Vacuoles Large membrane bound sac Many store un digested nutrients Plant cells have a very large vacuole that stores salts a contributes to plant growth

Section 6.4 Lysosomes Membrane bound sacs that contain digestive enzymes that can break down the macromolecules They have several functions – Fuse with incoming food vacuoles and expose the nutrients to enzymes to digest them – They also help destroy harmful bacteria – Serve as recycling centers for damaged organelles Lysosomes can engulf entire organelles Makes molecules available to create new organelles

6.4 Lysosomes

Section 6.4 Membrane Pathways in a cell

Section 6.5 Chloroplasts We know that plants and algae capture light energy through the process of photosynthesis Chloroplasts are the photosynthetic organelles found in the cells of plants and algae An envelope made of two membranes enclose the chloroplasts We will learn more about chloroplasts in chapter 8

Section 6.5 Chloroplasts

Section 6.5 Mitochondria Place where cellular respiration occurs – Process by which some organisms get their energy Releases sugars and other organic molecules then use it in the formation of ATP (Adenosine Triphosphate) – ATP is the main energy source that cells use for most of their work Found in nearly all cells (including plants)

Section 6.5 Mitochondria A mitochondria’s structure is related to its function – An envelope of two membranes surrounds a mitochondrion The inner membrane has many folds The folds increase the surface area, which increases the the rate of cellular respiration – Maximize the number of ATP produced We will learn more about mitochondria in chapter 7

Section 6.5 Mitochondria