Cell Structure and Function

1. Cell Structure and Function

2. The Discovery of the Cell • Robert Hooke – first to see and identify cork “cells” using a microscope. www.nerdscience.com 7-1

3. The Cell Theory Cell Theory: • All living things are made of one or more cells. • Cells are the smallest unit of life. • New cells are produced from pre-existing cells. Schleiden Schwann Virchow www.nerdscience.com 7-1

4. Basic Cell Substances • The main ingredient of any cell is water. • The structure of a water molecule makes it ideal for dissolving many other substances

5. Macromolecules • Macromolecules form when many small molecules join • The 4 types of macromolecules are: • Nucleic acids- • form when long chains of nucleotides join. • Important because they contain genetic information • Ex: DNA and RNA

6. Macromolecules 4. Proteins- • Necessary for nearly everything cells do • Made up of long chains of molecules called amino acids. • Some help break down nutrient in food 3. Lipids- • large molecule that does not dissolve in water • Store energy • Plays an important role as protective barriers in cells (membranes)

7. Macromolecules 4. Carbohydrates- • Made up of one or more sugar molecules • Store energy • Provide structural support • Used for communication between cells

8. Prokaryotes and Eukaryotes Cells can be grouped into 2 types: • Prokaryotes – cells that do not contain nuclei. • Ex: (Bacteria) • Eukaryotes – cells that contain nuclei and have membrane-surrounded components called organelles which have specialized functions • Ex: plants, animals, fungi, protist

9. Eukaryotic Cell Structure • Organelles – structures in a cell that act like “little organs.” • Cytoplasm – the jelly-like fluid where the organelles “float.” • It contains salts and other molecules

10. The Nucleus • Nucleus – large membrane-enclosed structure that contains the cell’s genetic informationand directs cell activities • Nuclear Envelope – membrane that surrounds the nucleus. Nuclear Envelope

11. Mitochondria • Mitochondria – converts chemical energy stored in food into energy(ATP). • “Powerhouse of the Cell!” • Converts glucose and oxygen into ATP, Carbon Dioxide (CO2) and Water (Cellular Respiration) • ATP- the fuel for cellular processes such as growth, cell division, and material transport www.nerdscience.com

12. Mitochondria Mitochondria

13. Ribosomes • Ribosomes – Make Proteins! • Found in a cells cytoplasm or attached to the endoplasmic reticulum (E.R) Ribosome

14. Endoplasmic Reticulum (ER) • Endoplasmic reticulum –transports proteins to the Golgi apparatus and breaks down toxic material. • Rough ER – has ribosomes • Smooth ER – no ribosomes

15. Endoplasmic Reticulum (ER) Rough ER Smooth ER

16. Golgi Apparatus Golgi Apparatus (Golgi bodies)-prepares proteins and packages them into ball-like structures called vesicles Golgi Apparatus

17. Lysosomes Lysosomes – small organelles filled with enzymes that help recycle cellular components

18. Vacuoles • Vacuoles – store food, water, and waste material • Animal cells have small vacuoles • Plant cells have large Central Vacuoles Vacuoles

19. Chloroplasts Chloroplasts – organelles that capture energy from sunlight and convert it into chemical energy. (Photosynthesis) • Found only in plants. Chloroplast

20. Cytoskeleton Cytoskeleton – made of a network of threadlike proteins that are jointed to form a framework inside a cell. • helps cell to maintain shape, move, and move organelles.

21. Cell Boundaries Cell membrane – thin, flexible membrane that surrounds the cell and protects the inside of a cell from the environment outside. • Controls what enters and leaves the cell. • Made of phospholipids (2 layers) and proteins. Two layers!

22. Cell Boundaries Cell wall – rigid layer around the membrane that provides structure and support. • found only in bacteria, fungi and plants.

23. Cell Appendages Cell appendages are often used for movement. • Flagella- long, tail- like appendage that whip back and forth and move a cell. • Cilia- short hair like structures that can move a cell or move molecules away from a cell.

24. Moving Cellular Material

25. The exchange of materials between as cell and its environment takes place at the cell membrane. • A cell membrane is semipermeable- it allows only certain substance to enter or leave a cell

26. Passive Transport • Passive transport – the movement of substances through a cell membrane without using the cell’s energy • Diffusion – movement of particles from an area of high to low concentration. • Diffusion continues until the concentration of a substance is the same on both sides of a membrane. • Osmosis – the diffusion of water through a membrane.

27. Osmosis Practice Concentrations areequal, so no netmovement of water! 90% H2O 10% NaCl Cell 90% H2O 10% NaCl www.nerdscience.com 7-3

28. Osmosis Practice Concentration ofwater is greater inthe cell than out, sowater will move out! 80% H2O 20% NaCl Cell 90% H2O 10% NaCl www.nerdscience.com www.nerdscience.com

29. Osmosis Practice Concentration ofwater is greateroutside the cell than in, so water will move In! 90% H2O 10% NaCl Cell 80% H2O 20% NaCl www.nerdscience.com 7-3

30. Active Transport 2. Active Transport- The movement of materials across a cell membrane with the use of energy • Moves substances from areas of low concentration to areas oh high concentration • Exocytosis – a cell’s vesicles releases their contents outside of the cell. • Endocytosis– the cell surrounds a large particle and brings it into the cell

31. Cell Size and Transport • For a cell to survive, its surface area must be large compared to its volume. • As a cell grows, its volume increases faster than its surface area

32. Cells & Energy

33. CELLULAR RESPIRATION All living things need energy to survive Cellular Respiration – converts the energy in food molecules into a usable form of energy called ATP

34. CELLULAR RESPIRATION • Step 1: Glycolysis- occurs in the cytoplasm of all cells • Glucose is broken down into smaller molecules • Step 2: Occurs in the mitochondria of Eukaryotic cells and requires oxygen • Small molecules made during glycolysis are broken down • Large amounts of usable energy called ATP are produced • Water and Carbon Dioxide is given off

35. CELLULAR RESPIRATION www.nerdscience.com 7-3

36. FERMENTATION • Eukaryotic and prokaryotic cells use fermentation to obtain energy from foods when oxygen levels are low. • It occurs in the cell’s cytoplasm • Lactic- acid fermentation-Occurs in muscles • C6H1206ATP + Lactic Acid • (Glucose) (energy) • Some types of bacteria and yeasts make ATP during alcohol fermentation. • C6H1206ATP + Alcohol + CO2 • (Glucose) (energy)

37. PHOTOSYNTHESIS • Plants and some unicellular organisms obtain energy from light (radiant energy) • Photosynthesis is a series of chemical reactions that converts light energy into chemical energy (Glucose)

38. PHOTOSYNTHESIS • In plants light energy is absorbed by pigments called chlorophyll • Photosynthesis occurs in the chloroplasts • Uses CO2 that is released during cellular respiration to make food energy and release oxygen.