Cell Transport - Weebly

Cell Transport - Weebly

Cell Transport Cell Membrane Review What is the function of the cell membrane? To control what enters and leaves the cell

Components of the Cell Membrane Phospholipids - composed of: A hydrophilic head Two hydrophobic tails Bilayer What can pass through the phospholipids? Small, hydrophobic, & uncharged

molecules Ex: O2, CO2 Components continued What molecules cant pass through the phospholipids?

Large, hydrophilic, & charged Ex: amino acids, water, , How does the cell move these? Transport proteins Other parts of cell membrane Glycoproteins Used for signaling other cells

Blood type Cholesterol Embedded within the membrane Helps to keep membrane fluid (in lower temperatures), but not too fluid (warmer temperatures)

Fluid Mosaic Model What does it mean for the cell membrane to be a fluid mosaic model? Fluid: shifting of the phospholipids Mosaic: interspersion of proteins How do we know this is the correct model? Freeze fracture Recap

1 What types of molecules can pass through just the phospholipids? 2 How do the others enter/exit the cell? Why is it important for

molecules to be able to move in and out of cells? Cells need things they dont make Eliminate waste Maintain regular internal conditions aka

Homeostasis Cell Transport The movement of molecules in and out of a cell is known as cell transport.

There are two types of transport Passive Active Molecules move from an area of high concentration to an area of low concentration Direction of flow is the

concentration gradient Does not require energy Passive Transport An example is diffusion Over time, the concentration of particles becomes

evenly dispersed and reaches equilibrium Examples: dye, perfume, smell of food Simple diffusion in a cell Molecules move down their

concentration gradient through the cell membrane For molecules that can pass between the phospholipids Small, uncharged, hydrophobic Simple

e l p Sim Example: Gas exchange What about molecules that

cant pass through the phospholipids? Some large, charged, hydrophilic molecules can diffuse through a transport protein Facilitated Diffusion Transport proteins help

molecules move across the membrane Still from high to low concentration Still requires no energy Two types of proteins: channel & carrier Carrier Proteins

Grabs the molecule, changes shape, and flips to the other side Example: glucose Channel Proteins Protein acts like a tunnel for molecules to pass through

Example: Ion channels allows charged ions to move past hydrophobic region of membrane Channel Proteins Aquaporins channel protein that allows water to move past the hydrophobic region

of the membrane Osmosis movement of water across a cell membrane Recap Passive transport No energy required Down concentration gradient Two types:

Simple diffusion Facilitated diffusion Carrier protein Channel protein Vocabulary Solution a liquid homogenous mixture of two or more substances Two components: Solute substance that gets

dissolved in a solution Solvent substance doing the dissolving in a solution More Vocabulary Concentration mass of solute in a volume of solution The more solute in

a given volume, the greater the concentration Scenario: What if there is a difference in concentration, but the solute is too big to pass through the membrane?

Semipermeable membrane https://youtu.be/GbudKs-49jo Water will move until equilibrium is reached Mass of solutes did not change, but the

volume of solution did change This brings the two concentrations closer together New concept: Tonicity Tonicity ability of a surrounding solution to cause a cell to gain or lose water Isotonic

The concentration is the same inside and outside of the cell Results in no net movement of water Preferred by animal cells. Why? Stable internal conditions are maintained: HOMEOSTASIS What if there is a difference in concentration? Hypotonic

Concentration outside the cell is less than inside the cell More water enters the cell than leaves the cell Hypertonic Concentration outside the cell is greater than inside the cell More water leaves the cell than enters the cell

If the cell cant maintain homeostasis Cytolysis Crenation Tonicity in Plant Cells Cell wall prevents bursting

Plasmolysis Elodea Left: Elodea in tap water, 400x Right: Elodea in 10% NaCl, 400x

Osmotic Pressure pressure exerted by the movement of water during osmosis Vacuole stores water Recap What is tonicity?

Practice: Active Transport 1 Moves molecules from low concentration to high concentration

2 Against concentration gradient 3 Requires ATP ATP 4

Occurs via pumps or vesicles Sodium Potassium Pump Uses membrane protein to move sodium and potassium ions against their

concentration gradients Requires ATP (energy) Ex: nerve cells Proton Pump Moves protons (H+) across the membrane Ex: Lysosomes need

acidic conditions for digestion pH = power of hydrogen Photosynthesis & Respiration Active Transport by Vesicle Endocytosis

Importing large particles or whole cells Ex: White blood cell engulfing bacteria Exocytosis Exporting substances outside the cell Ex: Golgi

Types of Endocytosis Pinocytosis Phagocytosis Taking in fluid or small molecules nonspecific Taking in large molecules or

whole cells Can be specific Recap Active Transport Low to high concentration (against gradient) Requires energy (ATP) Pumps (membrane proteins) Sodium-Potassium pump Proton pump

Vesicular Exocytosis Endocytosis Pinocytosis Phagocytosis

Recently Viewed Presentations

  • Copyright  2013, 2009, 2005 Mosby, Inc., an imprint

    Copyright 2013, 2009, 2005 Mosby, Inc., an imprint

    Ebner's glands at the back of the tongue secrete a lingual lipase. Salivary glands also secrete a mucous material to lubricate and bind food particles, facilitating the swallowing of the food bolus.
  • Title of presentation

    Title of presentation

    Quality Statements. Making a Difference Locally - A local Healthwatch needs to formulate views on the standard of health and social care provision andidentify where services need to be improved by formally or informally collecting the views and experiences of...
  • Weighted Average Cost of Capital

    Weighted Average Cost of Capital

    Because of homemade leverage, capital structure doesn't matter in the absence of taxes and bankruptcy. Taxes matter because debt generates tax shields. Bankruptcy matters because financial distress damages the assets of the firm. Weighted Average Cost of Capital And equivalent...
  • Counting Significant Figures

    Counting Significant Figures

    23.4 g (2 sig figs) 555001.0100 atoms (3 sig figs) 2001.0345mL (5 sig figs) 74.221g (3 sig figs) 3.100mm (3 sig figs) 0.001201kg (3 sig figs) Rules for Calculating with Significant Figures Writing a Lab Report Introduction Background Information What...
  • Chapter 26

    Chapter 26

    Chapter 26 Dada, Surrealism, and Developments in the U.S. Chapter 26 Dada, Surrealism, and Developments in the U.S. Artist: n/a Title: Hugo Ball Reciting the Sound Poem "Karawane" at the Cabaret Voltaire Date: 1916 Movement: Dadaism 1916-1923 The word Dada...
  • Chapter 11-Section 2- American Power Tips the Balance

    Chapter 11-Section 2- American Power Tips the Balance

    22 million people die during WWI. Civilian deaths . accounted for nearly half of that number. Military deaths are estimated to between nine and eleven million. Twenty million soldiers are wounded . but survive. Ten million refugees are forced to...
  • How do neurons communicate?

    How do neurons communicate?

    between neurons- Neuron receiving info Information traveling down neuron within neurons - electrically between neurons - chemically Synapse - space between neurons developed Golgi Stain first determined space between neurons "synapse" the "resting" state the "active" state neuron is firing...
  • Conversation in pairs - Canadian Union of Public Employees

    Conversation in pairs - Canadian Union of Public Employees

    CUPE leadership on climate change: Charles Fleury at UN negotiations, December 2015. CUPE leadership. Say: CUPE believes that the environment is a workers' issue. CUPE leaders speak out often on climate change. Here Brother Charles Fleury is in Paris at...