Cell Structure and Function Chapter 7 Cell Structure and Function

Anton van Leeuwenhoek Father of the microscope - 1600’s used lens technology fabric quality telescope same time 1st to see life in a drop of water (“animalcules”)

Robert Hooke 1665 1st to examine plant tissue Resembled monastery’s tiny rooms “Cells”

Matthias Schleiden 1838 - all plants are made of cells

Theodor Schwann 1839 - All animals are made of cells

Rudolf Virchow 1855 - Cells come from other preexisting cells

The 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

What do all cells have in common? Cell membrane thin, flexible barrier surrounding the cell (protection) Cytoplasm fluid within the cell Genetic Material (DNA/RNA)

Major Groups of Organisms Bacteria Protists (amoeba, algae, seaweed) Fungi Plants Animals

Basic Cell Types Prokaryotic Cells cell membrane cytoplasm genetic material (lack a nucleus) bacteria Genetic Material Cell membrane

Eukaryotic Cells Cell membrane Cytoplasm Nucleus Membrane-bound organelles animals, plants, fungi and protists

Prokaryotic Cell Eukaryotic Cell Cell membrane Cytoplasm Nucleus Section 7-1 Cell membrane Cytoplasm Prokaryotic Cell Nucleus Eukaryotic Cell Organelles Go to Section:

7-2 A Closer Look at the Cell Your objective is to… Describe the main functions of each cell structure

Cell Wall Plants, bacteria (prokaryotes), fungi, algae (protists) Provides structure and protection Gas and water exchange Plants - made of polysaccharide cellulose

Nucleus Controls cell processes Contains DNA deoxyribose nucleic acid codes for protein and other molecules

Chromatin Chromosomes Nucleolus Nuclear Envelope DNA bound to protein chromatin condenses during cell division Nucleolus make ribosomes Nuclear Envelope 2 layers with pores that allow for the passage of material

Nucleus The Nucleus Chromatin Nuclear envelope Nucleolus Nuclear pores

Cytoskeleton Network of protein filaments (microtubules and microfilaments) Maintains cell shape Cell Movement Intracellular Movement moves organelles important during cell division

Tracks for organelle movement

Figure 7-7 Cytoskeleton Cell membrane Endoplasmic reticulum Microtubule Microfilament Ribosomes Mitochondrion

Structures for Movement: Flagella-tail-like structures to propel cell in whipping motion Cilia- hair-like projections that beat together to move the cell

Transportation

The Organelles Specialized structures within the cytoplasm of the cell that perform specific jobs

Ribosomes Use genetic information to make protein found free in cytoplasm or on RER

Endoplasmic Reticulum 2 types Rough and Smooth Cell membrane assembly Rough contain ribosomes certain proteins are modified Smooth synthesis of lipids

Endoplasmic Reticulum Ribosomes

Golgi Apparatus Receive proteins from RER Use enzymes to attach carbohydrates and lipids to proteins Sent to final destination

Lysosomes Contain enzymes that breakdown large molecules into smaller molecules Recycle old organelles and debris

Enzyme

Recycling

Vacuoles Storage units for water, salts, proteins and carbohydrates Provide support for plants “water” Central water vacuole

Vacuole

Chloroplasts Found in plants and algae (some bacteria) photosynthesis 2 membranes Contains DNA

Chloroplast

Mitochondria Convert food into high-energy compounds (ATP) that the cell uses to power growth, development and movement ATP = Energy 2 membranes Contains DNA

Mitochondrion

Animal vs. Plant Cells Plant Cells have the following (Animal Cells do not): Cell Wall Chloroplasts Central Water Vacuole

Venn Diagrams Prokaryotes Eukaryotes Animal Cells Plant Cells Section 7-2 Prokaryotes Eukaryotes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell membrane Ribosomes Cell wall Animal Cells Plant Cells Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Vacuoles Mitochondria Cytoskeleton Cell Wall Chloroplasts Lysosomes Go to Section:

Animal vs. Plant Cells Figure 7-5 Plant and Animal Cells Plant Cell Nuclear envelope Ribosome (attached) (free) Smooth endoplasmic reticulum Nucleus Rough endoplasmic reticulum Nucleolus Golgi apparatus Mitochondrion Cell wall Cell Membrane Chloroplast Vacuole Plant Cell

Figure 7-5 Plant and Animal Cells Centrioles Nucleolus Nucleus Nuclear envelope Rough endoplasmic reticulum Golgi apparatus Smooth Mitochondrion Cell Membrane Ribosome (free) (attached) Animal Cell

7-3 The Cell Membrane Objectives: Describe the structure of the cell membrane Describe how substances move through the cell

Cell Membrane Structure: Lipids, Proteins, Carbohydrates Lipid bilayer Functions: Regulates entry and exit of materials Protection and support Carbohydrate chains act as identification cards

Fluids ICF = Intracellular Fluid (inside cell/cytoplasm) ECF = Extracellular Fluid (outside cell) Always dissolved particles in both of these fluids Dissolved particles = solutes Concentration of solutes can vary High = more solute Low = less solute

Figure 7-15 The Structure of the Cell Membrane Outside of cell Inside (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains

Diffusion Movement of materials from a high concentration to a lower concentration until equilibrium is reached requires no energy = passive What materials diffuse across a cell membrane?

Permeability Ability of membrane to allow substances to penetrate/pass through Levels of permeability: Permeable- any solutes can pass through Semi-permeable/Selectively Permeable- certain solutes are selected to pass through Impermeable- nothing is able to pass through All cell membranes are selective = picky/choosy Impermeability is not an optioncell would die! Why???

Osmosis Diffusion of water across a selectively permeable membrane Types of Solutions hypertonic - higher concentration of dissolved particles (solute) hypotonic - lower concentration of dissolved particles (solute) isotonic - identical concentration

Osmosis occurs b/c the solute is unable to pass through the membrane Osmosis occurs b/c the solute is unable to pass through the membrane. Water can always pass through the membrane.

Hydrophobic Lipid Tails Nonpolar Hydrophilic Lipid Heads Polar

Continues until the concentrations are equal

Solutions outside of the cell…..

Problems in Organisms (Maintaining Homeostasis) Plants turgor pressure rigid vs. wilting Antibiotic effects on bacteria Single Celled Organisms contractile vacuole homeostasis Animals cells bathed in isotonic fluids “blood”

Facilitated Diffusion specific protein channels for specific substances that cannot diffuse on their own glucose channel

Facilitated Diffusion Glucose molecules Facilitated Diffusion Protein channel

Active Transport movement of materials from lower concentration to higher concentration requires energy = ATP

Molecule to be carried Active Transport

Figure 7-20 Active Transport-going against concentration gradient (low to high). Natural is from high to low (diffusion and facilitated diffusion). Molecule to be carried Molecule being carried Energy

Phagocytosis Large particles taken into cell Extension of cytoplasm engulfs large particles outside cell Pocket folds into cell with contents and breaks loose from cell membrane forming vacuole inside cell (in cytoplasm).

Other examples of active transport

Unicellular Organisms A single cell is the entire organism Includes all prokaryotes and some eukaryotes Examples include: algae, yeasts, bacteria

Multicellular Organisms Cells are interdependent (like a team) Cell specialization- separate roles for each type of cell (ex. Blood cell, nerve cell, muscle cell) Cells are specialized to perform particular functions within organism

Levels of Organization Individual cellstissuesorgans organ systemsorganism Tissue- group of similar cells that perform particular function Organ- groups of tissues working together Organ Systems- group of organs working together to perform specific function (11 major systems in human body)

Smooth muscle tissue Stomach Muscle cell Digestive system