Unit 5 Notes I CAN A

1. Unit 5 NotesI CAN A • The Characteristics of Living Things • Organisms = living things • All living things: • Have cellular organization • Contain similar chemicals • Use energy • Respond to their surroundings • Grow and develop • Reproduce

2. Cellular Organization • Cell = the basic unit of structure and function in an organism • A microscope is needed to see most cells • Unicellular Organism = single-celled organism • Ex: a bacterium or bacteria • Multicellular Organism = many-celled organism • In Multicellular organisms: • Each cell is specialized to do a certain task • Ex: muscle and nerve cells are found in humans

3. The Chemicals of Life • All cells are made of chemicals • Carbohydrates provide cells with energy • Proteins and lipids are the building materials of cells • Nucleic acids carry genetic material which controls the cell’s activities • The most abundant chemical found in living cells is water

4. Energy Use • An organism’s cells use energy to perform all functions • Ex: stomach cells use energy to digest food • Ex: blood cells use energy to move chemicals around your body

5. Response to Surroundings • Stimulus = a change in an organism’s surroundings that causes the organism to react • Stimuli (plural) include: • Temperature • Light • Sound • Response = an action or change in behavior • -Do some examples in class • When a plant grows toward light. • The light would be the stimulus • The planting growing toward the light is the response

6. Growth and Development • Growth = the process of becoming larger • Development = the process of change that occurs during an organism’s life to produce a more complex organism • Ex: you have gotten taller with age (growth), but you have also gotten smarter (development)

7. Reproduction • Reproduce = the ability to produce offspring that are similar to the parents • Ex: birds lay eggs that develop into birds who look like their parents • Ex: apples produce seeds that develop into apple trees

8. Four hundred years ago people believed that life could appear from a nonliving material call spontaneous generation however we now know that living things are only produced by other living things. This was proven by two scientist Francesco Redi and Louis Pasteur

9. - What Is Life? Four hundred years ago people believed that life could appear from a nonliving material call spontaneous generation however we now know that living things are only produced by other living things.

10. - What Is Life?

11. I CAN B • What is a Virus? • Virus=a tiny, nonliving particle that enters and then reproduces inside a living cell. • No organisms are safe from viruses! • (remember an organism is a living thing)

12. Characteristics of Viruses • Viruses are considered non living because they do not have all the characteristics essential for life • The only way in which viruses are like organisms is they are able to multilpy. • Although viruses can multiply, they do so differently than organisms. Viruses can multiply only when they are inside a living cell.

13. Virus Sizes • Viruses are much smaller that cells (even the smallest cells in bacteria) • Measured in units called “nanometers” one billionth of a meter.

14. - Viruses Show size of viruses on “Cells Alive Web Page”

15. - Viruses

16. How Viruses Multiply • Once inside a cell, a virus’s genetic material takes over many of the cell’s functions • It instructs the cell to produce the virus’s proteins and genetic material. • These proteins and genetic material then assemble into new viruses • Some viruses take over immediately (Active Viruses) cold • Some viruses wait for a while (Hidden Viruses) cold sore

17. - Viruses

18. - Viruses

19. Viruses and the Living World • Viruses and Disease • Some viral disease keep people sick for only a short period of time; (such as a cold) • Others can be fatal (such as AIDS) • Viruses can also cause diseases in organisms other than humans such as: • Apple trees infected by apple mosaic virus • Dogs and cats can get rabies

20. I CAN C • The Bacterial Cell • There are more bacteria in your mouth than there are people on Earth!! • Although there are billion of bacteria on Earth, they were not discovered until the late 1600’s. • Anton Van Leeuwenhoek discovered them by accident when looking at scrapings from his teeth under a microscope. • Bacteria= single celled organism • Bacteria are prokaryotes. The genetic material in their cells is not contained in a nucleus.

21. - Bacteria Bacteria are prokaryotes. The genetic material in their cells is not contained in a nucleus

22. Cell Shapes • Three basic shapes: • Spherical • Rodlike • Spiral • The shape of the cell helps scientists identify the type of bacteria. • For example, bacteria that cause strip throat are spherical.

23. Live in guts of Surgeon Fish

24. Found in intestines of humans and is used to manufacture yogurt. Can cause meningitis

25. Cell Sizes • The largest known bacterium is about as big as a period in your book. • Most bacteria are much smaller. • The bacterium that causes strep throat are about .5 to 1 micrometer in diameter. A micrometer is one millionth of a meter.

26. Reproduction • When bacteria have plenty of food, the right temperature, and other suitable conditions, they thrive and reproduce frequently. • It is a good thing that growing conditions for bacteria are rarely ideal. Otherwise, there would be no room on Earth for other organisms!

27. Asexual Reproduction • Asexual Reproduction= a reproductive process that involves only one parent and produces offspring that are identical to the parent. • During binary fission the cell first duplicates its genetic material and then divides into two new cells, each cell gets a complete copy of the genetic material as well as some of the parent’s ribosomes and cytoplasm.

29. Reproduces by binary fission every 20 minutes.

31. Sexual Reproduction • Sexual Reproduction= involves two parents who combine their genetic material to produce a new organism, which differs from both parents. • This results in new bacteria that are genetically different from the parent cells

33. The Role of Bacteria in Nature • Oxygen Production • Food Production • Pasteurization= food is heated to a temperature that is high enough to kill most harmful bacteria without changing the taste. • Environmental Recycling • Decomposers= organisms that break down large chemicals in dead organisms into small chemicals • Environmental Cleanup • Health and Medicine

34. Treating Infectious Diseases • Bacterial Diseases • Can be cured with medications known as antibiotics • Antibiotic= a chemical that can kill bacteria without harming a person’s cells • Example: Penicillin (works by weakening the cell walls of some bacteria and causing the cells to burst. • Antibiotic resistance= results when some bacteria are able to survive in the presence of an antibiotic.

35. - Viruses, Bacteria, and Your Health

36. Treating Infectious Diseases Cont. • Viral Diseases • Unlike bacterial diseases, there are currently no medication that can cure viral infections. • Medications help relieve symptoms

37. - Viruses, Bacteria, and Your Health

38. Preventing Infectious Diseases • Vaccine= a substance introduced into the body to stimulate the production of chemicals that destroy specific viruses or bacteria. • May be made from dead or altered viruses or bacteria that puts our body on “alert” for that disease. • Vaccines are important tools that help prevent the spread of infectious diseases.

39. I CAN D,E and F • In 1663, Robert Hooke observed the first cells while looking at cork under his microscope • He called them “cells” because they reminded him of the small rectangular rooms called cells • At about the same time, Anton van Leeuwenhoek observed pond water and teeth scrapings • He saw “animalcules” (little animals) in the water and bacteria from the teeth

40. Development of the Cell Theory • In 1838, Matthais Schleiden concluded that all plants are made of cells • In 1839, Theodor Schwann concluded that all animals are also made of cells • Therefore, all living things are made of cells • In 1855, Rudolf Virchow proposed that new cells are formed only from existing cells

41. The observations and conclusions of these five men led to the cell theory: • All living things are composed of cells • Cells are the basic units of structure and function in living things • All cells are produced from other cells

42. Examples of Cells Amoeba Proteus Plant Stem Bacteria Red Blood Cell Nerve Cell

43. Inside tiny cells are even smaller structures called organelles • Organelles = tiny cell structures which carry out specific functions within the cell • Organelles are to cells, as organs are to the human body! • See pgs. 20 & 21 (know all structures/functions) • Cell wall = in plant cells, a stiff wall that surrounds the cell membrane giving the cell a box-like shape • Cell membrane = protects the cell and regulates what enters and leaves the cell

44. “Typical” Plant Cell

45. - Looking Inside Cells

46. Nucleus = directs all of the cell’s activities, including reproduction • Nuclear membrane = protects the nucleus and regulates what enters and leaves the nucleus • Chromatin = strands of genetic material which direct the functions of the cell • Nucleolus = where ribosomes are made

47. Organelles in the Cytoplasm • Cytoplasm = area between the cell membrane and the nucleus filled with a gel-like fluid

48. - Looking Inside Cells • Mitochondria = rod-shaped organelles which produce most of the cell’s energy

49. - Looking Inside Cells • Endoplasmic reticulum (ER)= network of passageways that carries materials from one part of the cell to another • Ribosomes = produce proteins (can be free-floating or attached to the ER)

50. - Looking Inside Cells • Golgi bodies = receives materials from the ER and sends them to other parts of the cell