Presentation on theme: "Section 3-3, 3-4, 3-5 “Movement across the cell membrane”"— Presentation transcript:
1 Section 3-3, 3-4, 3-5 “Movement across the cell membrane” Write everything that is underlined
2 3.3 KEY CONCEPT: The cell membrane is a barrier that separates a cell from the external environment.
3 Cell membranes are composed of two phospholipid layers. It forms a boundary between inside and outside of the cell…and controls passage of materialscell membraneoutside cellinside cell
4 The cell membrane is made of a phospholipid bilayer. There are other molecules embedded in the membrane.The fluid mosaic model describes the membrane.cell membraneproteincholesterolcarbohydratechainprotein channel
5 How many layers is the cell membrane made up of? 1234
6 The cell membrane is selectively permeable (only certain things get through) like a screen door
7 3.4 KEY CONCEPT: Materials move across membranes because of concentration differences.
8 Passive transport does not require energy There are two types of passive transport:diffusionosmosis
9 Diffusion: Molecules move down a concentration gradient “From an area of high concentration to low concentration”
10 Osmosis is the diffusion of water There are three types of solutions: isotonic, hypertonic, hypotonic
11 What is passive transport? Does not require energy to move materialsRequires energy to move materialsDepends on your definition of movementOnly sometimes does it use energy
12 What is/are the different types of passive transport? DiffusionIsotonicOsmosisA and C
13 Diffusion is the movement of materials from an area of ___________ concentration to ______ concentrationLow to HighHigh to HighLow to LowHigh to Low
14 Osmosis it the diffusion of ___________ MaterialsSugarWaterAmino acids
15 Facilitated diffusion: diffusion through transport proteins Some molecules can only diffuse through transport proteins.Facilitated diffusion: diffusion through transport proteins
16 3.5 KEY CONCEPT: Cells use energy to transport materials that cannot diffuse across a membrane.
17 Active transport requires energy to move a substance against its concentration gradient (from LOW to HIGH)Passive transport requires no energy from the cellActive transport is powered by chemical energy (ATP)Cells use active transport to maintain homeostasis
18 A cell can import and export large materials or large amounts of material in vesicles during the processes of endocytosis and exocytosis.Endocytosis is the process of taking material into the cell – also called Phagocytosis
19 Exocytosis is the process of expelling (pushing out) material from the cell
20 What is the difference between active transport and passive transport? Active requires energy and passive does notPassive requires energy and active does notPassive moves big materials into the cell and active does notB and C
21 What does the following picture show? EndocytosisExocytosisDiffusionOsmosis