Cell Structure and Function Chapter 7 Cell Structure and Function

7-1 Life is Cellular

7-1 Life is Cellular Objectives Explain what the cell theory is. Describe how researchers explore the living cell. Distinguish between eukaryotes and prokaryotes

7-1 Life is Cellular The Discovery of the cell The study of the cell was made possible by the invention of microscopes

7-1 Life is Cellular Robert Hooke was the first person to see cells through a compound microscope. All he saw was the cell wall

7-1 Life is Cellular German scientists Matthias Schleiden and Theodore Schwann developed the CELL THEORY.

7-1 Life is Cellular CELL THEORY: All living organisms are composed of one or more cells. Cells are the basic units of life. New cells come from pre-existing cells.

7-1 Life is Cellular Cell theory is significant! Why? All living things are made of cells. Differences in the structure and function of different life forms are reflected in differences in their cell structure.

7-1 Life is Cellular Prokaryotes and Eukaryotes – the 2 basic kinds of cells

7-1 Life is Cellular Prokaryotic Primitive cells that lack membrane bound organelles. Lack nucleus Most are single-celled. bacteria

7-1 Life is Cellular Prokaryotic Bacteria

7-1 Life is Cellular

7-1 Life is Cellular

7-1 Life is Cellular Eukaryotic More complex developed cells Have membrane bound organelles Distinct nucleus Both single and multiple-celled organisms

7-1 Life is Cellular

7-1 Life is Cellular A Stained Yeast Cell

Eukaryotic PLANT Cell (notice the cell wall) 7-1 Life is Cellular Eukaryotic PLANT Cell (notice the cell wall)

A comparison of Prokaryotic and Eukaryotic Cells 7-1 Life is Cellular A comparison of Prokaryotic and Eukaryotic Cells

A comparison of Prokaryotic and Eukaryotic Cell 7-1 Life is Cellular A comparison of Prokaryotic and Eukaryotic Cell

7-1 Life is Cellular Objectives Explain what the cell theory is. Describe how researchers explore the living cell. Distinguish between eukaryotes and prokaryotes End of Section 7-1

7-2 Eukaryotic Cell Structure Objectives Describe the function of the cell nucleus. Describe the functions of the major cell organelles. Identify the main roles of the cytoskeleton.

7-2 Eukaryotic Cell Structure Divided into two major parts that work together: Nucleus Cytoplasm – outside the nucleus

7-2 Eukaryotic Cell Structure Organelles (“little organs”) - Specialized Nucleus (Both) Ribosomes (Both) Endoplasmic Reticulum (Both) Golgi apparatus (Both) Lysosomes (Both) Vacuoles (Both, but mostly plants) Mitochondria (Both) and Chloroplasts (Plants) Cytoskeleton (Both) Cell membrane (Both) Cell wall (Plants)

7-2 Eukaryotic Cell Structure Nucleus Directs most of cell’s activities Contains information needed to make proteins Stores genetic material - DNA Chromatin chromosomes Surrounded by the nuclear envelope Nucleolus – small, dense region where assembly of ribosomes begins

7-2 Eukaryotic Cell Structure Ribosomes In cytoplasm Small particles of RNA and protein Make proteins following coded instructions from the nucleus

7-2 Eukaryotic Cell Structure Endoplasmic Reticulum Rough – ribosomes on surface Smooth – no ribosomes on surface

7-2 Eukaryotic Cell Structure Endoplasmic Reticulum Membrane system Lipid parts of cell, proteins and other materials that are exported are assembled Moves proteins & Carbohydrates to the Golgi Body.

7-2 Eukaryotic Cell Structure Golgi apparatus Stacks of flattened sacs Modify proteins made by the cells Package, sort & export proteins from the ER

7-2 Eukaryotic Cell Structure Lysosomes Break down compounds into small particles that the cell can use. Remove “junk” that clutter cell

7-2 Eukaryotic Cell Structure Vacuoles Saclike structures Store materials: Water proteins, Salts carbohydrates

7-2 Eukaryotic Cell Structure Mitochondria and Chloroplasts Sources of energy From food and/or from the sun

7-2 Eukaryotic Cell Structure Mitochondria Releases energy in the cell. (The powerhouse of the cell) Produce ATP (high energy compound) from food. Plants DO have these.

7-2 Eukaryotic Cell Structure Mitochondria The powerhouse of the cell.

7-2 Eukaryotic Cell Structure Chloroplasts Uses energy from sunlight to make food molecules (photosynthesis). Found in plants and some other microscopic organisms

7-2 Eukaryotic Cell Structure Cytoskeleton Network of protein filaments that helps the cell maintain shape. Involved in movement Made of two different structures: Microfilaments Microtubules

7-2 Eukaryotic Cell Structure

7-2 Eukaryotic Cell Structure

7-2 Eukaryotic Cell Structure

7-2 Eukaryotic Cell Structure

7-2 Eukaryotic Cell Structure Objectives Describe the function of the cell nucleus. Describe the functions of the major cell organelles. Identify the main roles of the cytoskeleton. End of Section 7-2

7-3 Cell Boundaries Objectives Identify the main functions of the cell membrane and the cell wall. Describe what happens during diffusion. Explain the processes of osmosis, facilitated diffusion, and active transport.

7-3 Cell Boundaries Cell Membrane Thin, flexible barrier Protection Support Regulates what enters/leaves the cell

The Cell Membrane is known as a “Lipid Bilayer” 7-3 Cell Boundaries The Cell Membrane is known as a “Lipid Bilayer” I wonder Why?

7-3 Cell Boundaries Cell Walls Support Protection Plant cellulose cell walls from the ragweed plant anther. The rigid cell wall of plants is made of fibrils of cellulose.

7-3 Cell Boundaries Diffusion Through Cell Boundaries Particles move from an area of high concentration to an area of low concentration. Concentration – the mass of solute in a given volume of solution. Equilibrium – concentration is the same throughout a solution.

A simple rule to remember: 7-3 Cell Boundaries Osmosis – diffusion of water through a selectively permeable membrane. hypertonic = more solute concentration hypotonic = less solute concentration isotonic = same solute concentration A simple rule to remember:

7-3 Cell Boundaries

It lets the water through but not the spaghetti. 7-3 Cell Boundaries selectively permeable What? It lets the water through but not the spaghetti.

7-3 Cell Boundaries Facilitated Diffusion facilitated diffusion - diffusion through a membrane with help from a transport protein. Because…some molecules just can’t get across that membrane on their own. Different proteins allow particular molecules. Does not require energy.

7-3 Cell Boundaries Facilitated Diffusion

7-3 Cell Boundaries Active Transport Transport proteins within the membrane must use energy (ATP) to move substances either to the inside or outside of the membrane. (Against a concentration gradient.) endocytosis Phagocytosis Pinocytosis exocytosis

7-3 Cell Boundaries Active Transport

7-3 Cell Boundaries Phagocytosis “CELL EATING” takes in large particles by engulfing them

pinch off to form vacuoles. 7-3 Cell Boundaries Tiny pockets form along cell membrane fill with liquid, pinch off to form vacuoles.

Vacuole fuses with membrane 7-3 Cell Boundaries Vacuole fuses with membrane forces contents out.

7-3 Cell Boundaries Objectives After this section, can you… Identify the main functions of the cell membrane and the cell wall. Describe what happens during diffusion. Explain the processes of osmosis, facilitated diffusion, and active transport. End of Section 7-3

7-4 The Diversity of Cellular Life Objectives Describe cell specialization Identify the organization levels in multicellular organisms.

7-4 The Diversity of Cellular Life Unicellular Organisms Single-celled Performs all of it’s necessary life functions. Ciliata (up to 3 mm long) are unicellular organisms most abundant in fine sandy sediments. Their body is covered by a felt of cilia which may be modified around the mouth opening

7-4 The Diversity of Cellular Life Unicellular Organisms Diatoms are a major group of eukaryotic algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular. Not only are there more than 100000 species of the cute little critters, they are found everywhere that there’s water including on and in soil.

7-4 The Diversity of Cellular Life Multicellular Organisms Cell specialization – Each specialized cell performs a specific life function.

7-4 The Diversity of Cellular Life Levels of Organization (Largest) (Smallest)

7-4 The Diversity of Cellular Life Levels of Organization Tissues – similar cells are grouped into units. Organs – Groups of tissues work together. Organ System – A group of organs that work together to perform a specific function.

7-4 The Diversity of Cellular Life Levels of Organization continued… ORGAN SYSTEM ORGAN CELL TISSUE

7-4 The Diversity of Cellular Life Levels of Organization What level of organization is a tongue??? Hmmm?

7-4 The Diversity of Cellular Life Objectives Describe cell specialization Identify the organization levels in multicellular organisms. End of 7-4