UNIT 4 CELL BOUNDARIES AND TRANSPORT. Unit 4 test: October 16, 2018

Transcription

1 UNIT 4 CELL BOUNDARIES AND TRANSPORT Unit 4 test: October 16, 2018

2 Cell Wall CELL BOUNDARIES support protect & the cell cell membrane Lies outside of the Is made of & carbohydrates proteins Plant cell walls are mainly cellulose Fungi cell walls are mainly chitin

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4 CELL BOUNDARIES II. CELL Membrane A cell is defined as the smallest working unit of life. In order to maintain, homeostasis nutrients must be moved into the cell and wastes must be transported out of the cell. In addition, some cells produce hormones and other materials designated for export. All materials moving in and out of the cell must pass through the a cell membrane boundary semi permeable found in all cells.

5 Cell Membrane in a Nutshell ( ) Made mainly of phospholipid & proteins Hydrophobic tails of phospholipids make molecules line up as a bilayer with polar head facing out and nonpolar in tails facing.

6 Function Membranes are selectively permeable = Semipermeable, picky Allow certain molecules to pass through; but keeps others out Controls what enters & leaves the cell Helps maintain homeostasis

7 Other components of the cell membrane Proteins- Peripheral- on the inside or outside surface. Can be partially embedded into the cell membrane or can be found attached to an integral membrane protein. On the outside surface, transmit signals to inside cell; receptor protein On the inside surface, anchors the call membrane to the cell s internal support structure (cytoskeleton) giving cell its shape. Anchor proteins Transport proteins (also called integral)- embedded all the way through the membrane; used as channels or tunnels to move things in or out of the cell

8 Other components of the cell membrane Cholesterol- only in cells Helps prevent fatty acid tails from sticking together stability Provides for cell (no cell wall) animal animal

9 Other components of the cell membrane Carbohydrates- in chain form; on outside surface Used to recognize self ; cell ID tags If found on top of a protein the whole structure is called a glycoprotein If found on top of a phospholipid the whole structure is called a glycolipid

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11 Label the following cell membrane 1. Transport/Integral Protein 2. Peripheral Protein on the inside 3. Glycoprotein 4. Glycolipid 5. Cholesterol

12 CARBOHYDRATES On the outside of the cell membrane to identify as self or non-self

13 PROTEINS Embedded in the bilayer Serve as channels & pumps for transport of specific molecules across the cell membrane

14 What biomolecule regulates what can enter or leave the cell w/o a channel or pump? A. Lipid B. Carbohydrate C. Protein D. Nucleic Acid

15 What biomolecule Serve as channels & pumps for transport A. Lipid B. Carbohydrate C. Protein D. Nucleic Acid

16 What biomolecule is used to to identify as self or non-self A. Lipid B. Carbohydrate C. Protein D. Nucleic Acid

17 A. a B. b C. c D. d E. e Non-polar, middle portion of cell membrane

18 Embedded in cell membrane, serve as channels & pumps A. a B. b C. c D. d E. e

19 Polar portion of cell membrane oriented towards water A. a B. b C. c D. d E. e

20 A. a B. b C. c D. d E. e Provides stability for animal cell membrane

21 Serve as id tags for cell A. a B. b C. c D. d E. e

22 CELL TRANSPORT Passive Transport Does NOT require energy Movement of substances from a high concentration to low 3 Types: o Diffusion o Facilitated diffusion o Osmosis

23 DIFFUSION Diffusion: Random movement of molecules in a liquid or gas Many substances move across the cell membrane by diffusion, for example Example: odor gradually fills a room water, oxygen, & small molecules

24 FACILITATED DIFFUSION Facilitated Diffusion: Diffusion of through large molecules a protein channel Ex: glucose as it is transported across a cell membrane by a protein channel

25 FACILITATED DIFFUSION Protein channels provide larger openings for larger molecules like glucose, & fructose. In addition, due to the fatty acid tails that make up most of the phospholipid bilayer, polar non-polar molecules and utilize protein channels. ions

26 FACILITATED DIFFUSION This includes, Na & K which utilizes specialized protein channels known as. Protein pumps ***A protein pump is active transport so this sentence should be in the active transport section

27 OSMOSIS Osmosis: Diffusion of from water a high water concentration to a low water concentration through a Selectively permeable membrane. There are comparative terms used to describe the water versus solute concentration on either side of the a membrane:

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29 OSMOSIS Hypertonic = solute; higher concentration water lower concentration lower concentration Hypotonic = solute; higher water concentration Water always moves from hypotonic hypertonic

30 OSMOSIS Isotonic = Relative concentrations of water and solute are equal There will be no net movement of water if two solutions are isotonic

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32 OSMOSIS Cells must have a mechanism for counteracting the pressure osmosis can create, otherwise a cell could swell & burst or explode when it is placed in a environment hypotonic How to control Osmotic Pressure: o Cell wall - Rigid boundary found in o Physically prevents cell from expanding o Contractile vacuole- Actively pumps water out of cell single-celled organisms without Cell walls o Blood/Extracellular Fluid- is mostly water to equalize osmotic pressure. Designed to be with cells. Plants, bacteria, fungi & some protists isotonic

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35 -Hypotonic; -cell will undergo cytolysis or lyse (the cell will burst) -This can kill the animal cell -Hypertonic; -cell will crenate (the cell will shrivel up) -This causes cell to dehydrate and not function -isotonic; -preferred cell state -Hypertonic; -cell will undergo plasmolysis (cell membrane pulls away from cell wall) -isotonic; -Cell does not mind being in this state; neither beneficial or harmful to the cell -Hypotonic; -cells see increased turgor pressure -This is the preferred state for plant cells

36 ACTIVE TRANSPORT Requires energy in the form of ATP 3 types: Protein Pumps Endocytosis Exocytosis

37 PROTEIN PUMPS Protein Pumps: 1. Protein Pumps Energy-requiring process during which membrane proteins pump molecules across a membrane from a low concentration to a concentration. high concentration gradient

38 PROTEIN PUMPS An example is the sodium-potassium pump. Its purpose is to establish an electrochemical gradient in cells by pumping 3 sodium ions ( ) Na out of the cell for every 2 potassium ions ( ) K pumped into the cell. This slight negative charge inside the cell relative to the outside is very important for muscle contractions and. Nerve impulses

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40 ENDOCYTOSIS AND EXOCYTOSIS Endocytosis: cell eating or sucking. Larger substances are moved into the cell from the exterior by extending the cell membrane, forming a vesicle around the substance. Examples include macrophages, amoeba, etc. Exocytosis- cell spitting. Export of molecules from the inside of the cell to the exterior of the cell by a vesicle fusing with the cell membrane. Mechanism used to release hormones from cells

41 ENDOCYTOSIS AND EXOCYTOSIS

42 ENDOCYTOSIS

43 Endocytosis

44 Exocytosis

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46 Random movement of molecules in a A. Active transport B. Diffusion C. Endocytosis D. Exocytosis E. Facilitated Diffusion F. Osmosis G. Passive Transport H. Protein Pump liquid or gas

47 Requires energy in the form of ATP A. Active transport B. Diffusion C. Endocytosis D. Exocytosis E. Facilitated Diffusion F. Osmosis G. Passive Transport H. Protein Pump

48 cell sucking in or eating A. Active transport B. Diffusion C. Endocytosis D. Exocytosis E. Facilitated Diffusion F. Osmosis G. Passive Transport H. Protein Pump

49 Diffusion of specific molecules through A. Active transport B. Diffusion C. Endocytosis D. Exocytosis E. Facilitated Diffusion F. Osmosis G. Passive Transport H. Protein Pump a protein channel

50 Diffusion of water through a selectively permeable membrane A. Active transport B. Diffusion C. Endocytosis D. Exocytosis E. Facilitated Diffusion F. Osmosis G. Passive Transport H. Protein Pump

51 Movement of molecules from high concentration to low, does NOT require energy A. Active transport B. Diffusion C. Endocytosis D. Exocytosis E. Facilitated Diffusion F. Osmosis G. Passive Transport H. Protein Pump

52 Movement of ions and molecules against the concentration gradient, requires energy A. Active transport B. Diffusion C. Endocytosis D. Exocytosis E. Facilitated Diffusion F. Osmosis G. Passive Transport H. Protein Pump

53 Cell spitting out or pooping A. Active transport B. Diffusion C. Endocytosis D. Exocytosis E. Facilitated Diffusion F. Osmosis G. Passive Transport H. Protein Pump