Cell Structure and Function Chapter Seven www.nerdscience.com

The Discovery of the Cell Robert Hooke – first to see and identify cork “cells.” 7-1 www.nerdscience.com

Robert Hooke – first to see and identify cork “cells.”

The Cell Theory Cell Theory: All living things are composed of cells. Cells are the basic units of structure and function in living things. New cells are produced from existing cells. Schleiden Schwann Virchow 7-1 www.nerdscience.com

Cell Theory:

All living things are composed of cells.

Cells are the basic units of structure and function in living things.

New cells are produced from existing cells.

Prokaryotes and Eukaryotes Nucleus – large membrane-enclosed structure that contains the cell’s genetic information. Prokaryotes – cells that do not contain nuclei. (Bacteria) Eukaryotes – cells that contain nuclei. (All other organisms) 7-1 www.nerdscience.com

Nucleus – large membrane-enclosed structure that contains the cell’s genetic information.

Prokaryotes – cells that do not contain nuclei. (Bacteria)

Eukaryotes – cells that contain nuclei. (All other organisms)

Eukaryotic Cell Structure Organelles – structures in a cell that act like “little organs.” Cytoplasm – the jelly-like fluid where the organelles “float.” 7-2 www.nerdscience.com

Organelles – structures in a cell that act like “little organs.”

Cytoplasm – the jelly-like fluid where the organelles “float.”

Inside the Nucleus Nuclear Envelope – membrane that surrounds the nucleus. Chromatin – consists of DNA wrapped around proteins. “Ball of string” Chromosomes – condensed string-like structure that forms from DNA just before the cell divides. Nucleolus – structure within the nucleus that makes ribosomes. 7-2 www.nerdscience.com

Nuclear Envelope – membrane that surrounds the nucleus.

Chromatin – consists of DNA wrapped around proteins. “Ball of string”

Chromosomes – condensed string-like structure that forms from DNA just before the cell divides.

Nucleolus – structure within the nucleus that makes ribosomes.

Inside the Nucleus Nuclear Envelope Chromatin Nucleolus 7-2 www.nerdscience.com

Ribosomes Ribosomes – made of RNA and protein. Make Proteins! 7-2 www.nerdscience.com

Ribosomes – made of RNA and protein. Make Proteins!

Ribosomes Ribosome 7-2 www.nerdscience.com

Endoplasmic Reticulum (ER) Endoplasmic reticulum – internal membrane system of the cell. Lipids, proteins, and other products are made here. Rough ER – has ribosomes Smooth ER – no ribosomes 7-2 www.nerdscience.com

Endoplasmic reticulum – internal membrane system of the cell.

Lipids, proteins, and other products are made here.

Rough ER – has ribosomes

Smooth ER – no ribosomes

Endoplasmic Reticulum (ER) Rough ER Smooth ER 7-2 www.nerdscience.com

Golgi Apparatus Golgi Apparatus – modifies, sorts, and packages proteins. 7-2 www.nerdscience.com

Golgi Apparatus – modifies, sorts, and packages proteins.

Golgi Apparatus Golgi Apparatus 7-2 www.nerdscience.com

Lysosomes Lysosomes – small organelles filled with enzymes. Digest molecules to be used by the cell. 7-2 www.nerdscience.com

Lysosomes – small organelles filled with enzymes.

Digest molecules to be used by the cell.

Vacuoles Vacuoles – store materials. 7-2 www.nerdscience.com

Vacuoles – store materials.

Vacuoles Vacuoles 7-2 www.nerdscience.com

Mitochondria Mitochondria – organelle that converts chemical energy stored in food into compounds that are more convenient for the cell to use. “ Powerhouse of the Cell!” 7-2 www.nerdscience.com

Mitochondria – organelle that converts chemical energy stored in food into compounds that are more convenient for the cell to use.

“ Powerhouse of the Cell!”

Mitochondria Mitochondria 7-2 www.nerdscience.com

Chloroplasts Chloroplasts – organelles that capture energy from sunlight and convert it into chemical energy. ( Photosynthesis ) Found only in plants. 7-2 www.nerdscience.com

Chloroplasts – organelles that capture energy from sunlight and convert it into chemical energy. ( Photosynthesis )

Found only in plants.

Chloroplasts Chloroplast 7-2 www.nerdscience.com

Cytoskeleton Cytoskeleton – helps cell to maintain shape, move, and move organelles. Centrioles – help organize cell division. Not found in plants. 7-2 www.nerdscience.com

Cytoskeleton – helps cell to maintain shape, move, and move organelles.

Centrioles – help organize cell division. Not found in plants.

Cytoskeleton 7-2 www.nerdscience.com

Cell Boundaries Cell membrane – thin, flexible membrane that surrounds the cell. Cell walls – rigid layer around the membrane found only in bacteria, fungi and plants. 7-3 www.nerdscience.com

Cell membrane – thin, flexible membrane that surrounds the cell.

Cell walls – rigid layer around the membrane found only in bacteria, fungi and plants.

Cell Membrane Controls what enters/leaves cell, provides support/protection. Lipid Bilayer – double-layered sheet of phospholipids. Two layers! 7-3 www.nerdscience.com

Controls what enters/leaves cell, provides support/protection.

Lipid Bilayer – double-layered sheet of phospholipids.

Diffusion and Osmosis Diffusion – movement of particles from an area of high to low concentration. Osmosis – the diffusion of water through a selectively permeable membrane. Water will move into/out of a cell to equalize concentrations. 7-3 www.nerdscience.com

Diffusion – movement of particles from an area of high to low concentration.

Osmosis – the diffusion of water through a selectively permeable membrane.

Water will move into/out of a cell to equalize concentrations.

Osmosis Practice Cell 90% H2O 10% NaCl 90% H2O 10% NaCl 7-3 www.nerdscience.com Concentrations are equal, so no net movement of water!

Osmosis Practice Cell 90% H2O 10% NaCl 80% H2O 20% NaCl 7-3 www.nerdscience.com www.nerdscience.com Concentration of water is greater in the cell than out, so water will move out!

Osmosis Practice Cell 80% H2O 20% NaCl 90% H2O 10% NaCl 7-3 www.nerdscience.com Concentration of water is greater outside the cell than in, so water will move In!

Facilitated Diffusion and Active Transport Facilitated diffusion – when the plasma membrane “helps” particles pass through protein channels. No energy used. Active transport – when the plasma membrane uses energy to move particles against a concentration gradient. Uses Transport Proteins 7-3 www.nerdscience.com

Facilitated diffusion – when the plasma membrane “helps” particles pass through protein channels.

No energy used.

Active transport – when the plasma membrane uses energy to move particles against a concentration gradient.

Uses Transport Proteins

Facilitated Diffusion and Active Transport 7-3 www.nerdscience.com

Organization in Multicellular Organisms Tissues Organs Organ System Organism Cells 7-4 www.nerdscience.com