Cell Structure and Function Unit 4

Cell Structure and Function Unit 4

Definition of Cell A cell is the smallest unit that is capable of performing life functions. RECALL... Levels of Organization!

Why do we call them cells?

In 1665, Robert Hooke was the first to view cells from cork (dead plant material). He called them cells because they looked like tiny rooms.

What is the Cell Theory? 1. All living things are composed of cells 2. Cells are the basic units of structure and function in living things. 3. New cells are produced from existing cells.

Why Cells are Important? What happens inside cells causes us to be who we are. What is it that is found inside of all cells??? GENES!! (DNA/RNA) All diseases start at the level of the cell. All growth and life starts from a single cell. Cell specialization: allows cells to perform different functions in multicellular organisms

2 main types of cells 1. Prokaryote: ex. Bacteria 2. Eukaryote: ex. Plant, Animal, Fungi, Protist

HOW DO PROKARYOTES DIFFER FROM EUKARYOTES? Flagella 1.) No Nucleus 2.) DNA floats in cytoplasm 3.) Flagella

As we discuss the differences between Eukaryotic and Prokaryotes fill in your venn diagram. Eukaryotes both Prokaryotes

What Makes Prokaryotic Cells Different? ONLY WRITE THE UNDERLINED WORDS Much smaller Less complex (SIMPLE) No nucleus Circular DNA that is found free floating in the cytoplasm NO membrane bound organelles found in the cytoplasm Always has a cell wall

What Makes Eukaryotic Cells Different? ONLY WRITE THE UNDERLINED WORDS Much larger Much more complex Contain a nucleus to house the genetic material (DNA) Linear DNA packaged into chromatin found inside the nucleus Contains MEMBRANE BOUND organellesspecialized structures in the cytoplasm Not all have a cell wall

Characteristics Shared (BOTH) ONLY WRITE THE UDNERLINED WORDS IN VENN DIAGRAM same basic functions Plasma membrane to control what enters and leaves the cell Filled with cytoplasm Contain ribosomes to make protein Contain Nucleic Acids (DNA/RNA)

Eukaryotic Cells

What does size have to do with it? Prokaryotic cells are much smaller than eukaryotic cells. Why? Smaller surface area to volume allows nutrients to easily and quickly reach inner parts of the cell. No specialization because they are UNICELL ; one cell must be able to do all life functions Eukaryotic cells are larger and can not pass nutrients as quickly. They require specialized organelles to: carry out metabolism provides energy transport chemicals throughout the cell

Examples of MBOs Nucleus Smooth endoplasmic reticulum Rough endoplasmic reticulum Golgi apparatus Lysosome Mitochondria Centrioles Vacuole Chloroplast *Ribosomes are NOT membrane bound*

Prokaryote Eukaryote (Pro No) (Eu True) No Nucleus No membrane bound organelles Simple, small Genetic Material (DNA) Cell Membranes Cytoplasm Ribosomes Has TRUE Nucleus Membrane bound organelles Large, complex

Prokaryotic vs. Eukaryotes Size does matter! Which type of cell is bigger? Watch

What does size have to do with it? Prokaryotic cells are much smaller than eukaryotic cells. Why? Smaller surface area to volume allows nutrients to easily and quickly reach inner parts of the cell. No specialization because they are UNICELL ; one cell must be able to do all life functions Eukaryotic cells are larger and can not pass nutrients as quickly. They require specialized organelles to: carry out metabolism provides energy transport chemicals throughout the cell

Amoeba Video Complete Cell Structure Flip Book Write the function for each cell organelle and label pictures ***Major Test Grade: Cell Comparison Poster

Day 2 Notes: Cell membrane, transport and solutions

Function of the Cell Membrane To be a barrier between a cell and its environment Allow nutrients and water to enter while removing waste products The membrane is selectively permeable (controls what molecules come in and keeps other molecules out) Ex. Bouncer at a club

Cell / Plasma membrane Function Maintains an internal balance inside the cell: Homeostasis

Parts of the plasma membrane The phospholipid form 2 layers. Each layer contains hydrophilic heads (water-loving) and hydrophobic (waterfearing) tails

Parts of the plasma membrane Carbohydrate chains are at the surface and are sites where viruses or chemical messengers can attach. Proteins will help transport (move) macromolecules (glucose) in & out of the cell. Transport Protein Carb Chain Phospholipid Bilayer Transport Protein Hydrophobic

Parts of the Cell (Plasma) Membrane Phospholipid bilayer Transport proteins INSIDE OF CELL

Molecular Movement All the substances important to life are almost always part of a solution. Solute: The substance dissolved in the solvent Ex. Sugar, salt, starch Solvent: dissolves the solutes Ex. Water is the universal solvent of most solutions involved in cellular activities.

Molecular Movement Factors that affect the rate of diffusion: 1. concentration (higher=faster) 2. temperature (warmer=faster, colder=slower) 3. pressure (high pressure=faster)

Concentration = amount of material in an area Draw a higher concentration of solutes inside the cell than outside the cell. Draw a lower concentration of solutes inside the cell than inside the cell. How would these cells go back into homeostasis?

A B C Where is there a higher conc.? Where is there a lower conc.? What does B represent? SELECTIVELY PERMEABLE MEMBRANE C A Predict what will happen in the diagram? PARTICLES WILL MOVE FROM A TO C TO REACH EQUILIBRIUM

Passive Transport- Passive Transport requires NO energy Goes from high to low concentration 3 main types: diffusion, facilitated diffusion, osmosis

1. Diffusion Movement of molecules through the cell membrane from high to low conc. 3 Types of Passive Transport 2. Facilitated Diffusion Movement of molecules through the cell membrane using transport proteins from high to low conc. 3. Osmosis Movement of water molecules through the cell membrane from high to low conc.

Facilitated diffusion Why? Uses a TRANSPORT PROTEIN going from H to L concentration Diffusion (any particles) or Osmosis (water only)

Assessment When no energy is required for molecules to move through the membrane it is called A. Active transport B. Passive transport

Assessment What transport moves particles into and out of the cell? A. Osmosis B. Diffusion WATER ONLY! C. Facilitated Diffusion D. Both B and C

Passive Transport: Osmosis Osmosis - Movement of water from high to low concentration through a membrane Water molecule Solute molecule Ex. sugar

Passive Transport: Osmosis Water is so small and Osmosis animation can easily pass through the membrane so it REQUIRES NO ENERGY (passive transport). Water is ALWAYS flowing. Water moves freely through pores. Solute (green) too large to move across.

3 types of Osmotic solutions

3 types of Osmotic solutions Remember! Solution: Mixture of water (solvent) and particles (solutes) Ex. The environment of the cell is a solution. Blood is a solution. 3 types of osmotic solutions for cells a. Isotonic b. Hypertonic c. Hypotonic

Cell remains same size Water moves? In and out equally Where is there more water, cell or environment? Equal conc. of water inside and outside of cell Isotonic Solution When you have balance its called? Homeostasis

Hypotonic Solution ex. distilled water Cell gets BIG- blows up (Hypo Hippo) Water moves? Inside the cell Where is there more water, cell or environment? Animal cell may LYSIS or BURST Solution has more water Cell has less water

Hypertonic Solution ex. salt solution Cell Shrinks Water moves? Out of cell What has more water? Solution has less water concentration Cell has more water concentration Video Plant will WILT

Osmosis Across Membranes

Questions What type of solution is in side A? Hypotonic Solution What type of solution is in side B? Hypertonic Solution Which way will water move to balance out the tube? Right to left (There is more water) Are the black dots moving through the membrane? Yes or no, explain. No, only water is!

Outside Cell Inside Cell Outside Cell Inside Cell Outside Cell Inside Cell A B C Isotonic Hypertonic Hypotonic

How Organisms Deal with Osmotic Pressure Paramecium (protist) removing excess water video Bacteria and plants have cell walls that prevent them from over-expanding. In plants the pressure exerted on the cell wall is called tugor pressure. A protist like paramecium has contractile vacuoles that collect water flowing in and pump it out to prevent them from over-expanding. Salt water fish pump salt out of their specialized gills so they do not dehydrate. Animal cells are bathed in blood. Kidneys keep the blood isotonic by remove excess salt and water.

Osmotic Solutions: Real Life If you put salt onto a slug, it dies. Why? Explain using information about the osmotic solutions.

Osmotic Problems 2. Water moves in or out of cell? 3. Water moves in or out of cell? What happens to the cell? What happens to the cell? 20% water What solution is this? 90% salt What solution is this? 80% water 10% salt 6. Water moves in or out of cell? What happens to the cell? 83% salt What solution is this? 17% water

Active Transport cell uses ATP energy actively moves molecules to where they are needed Movement from an area of low concentration to an area of high concentration (Low High) Goes against the concentration gradient

3 Types of Active Transport 1. Protein Pumps 2. Endocytosis 3. Exocytosis

Types of Active Transport Sodium Potassium Pumps (Active Transport using proteins) 1. Protein Pumps - transport proteins that require energy to do work Example: Sodium / Potassium Pumps are important in nerve responses. Protein changes shape to move molecules: this requires energy!

Types of Active Transport 2. Endocytosis: taking bulky material into a cell Uses energy Cell membrane in-folds around food particle cell eating forms food vacuole & digests food Ex. This is how white blood cells eat bacteria!

Types of Active Transport 3. Exocytosis: Forces bulky material out (exit) of cell in membrane surrounding the material fuses with cell membrane Cell changes shape requires energy EX: Hormones or wastes released from cell Exocytosis

Exocytosis and Endocytosis Exocytosis

The process in which the movement of materials across a membrane from low to high concentration requiring energy is. A. passive transport B. diffusion C. active transport D. facilitated diffusion

Which one is different? How is it different? A. B. Does ACTIVE transport require ENERGY? Does passive transport require energy? C. D.