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Unit 4

Unit 4. Reproduction. Chapter 4. The Nucleus Controls the Functions of Life. The Nucleus Controls the Functions of Life. Think of how the workers at the Confederation Building control NL. All of the plans (DNA) for NL are kept there. The nucleus controls the life of a cell.

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Unit 4

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  1. Unit 4 • Reproduction

  2. Chapter 4 • The Nucleus Controls the Functions of Life

  3. The Nucleus Controls the Functions of Life • Think of how the workers at the Confederation Building control NL. • All of the plans (DNA) for NL are kept there.

  4. The nucleus controls the life of a cell • Nerve cells, for example, are controlled by its nucleus. • The nucleus sends out messages to the rest of the cell, allowing the cell to perform activities such as obtaining nutrients, turning these nutrients into energy, growing, reproducing and getting rid of waste.

  5. 4.1The Function of the Nucleus within the Cell • The nucleus controls the functions of a living cell. • DNA in the nucleus carry the master set of instructions for cell function.

  6. Traits • The color of your eyes, the pitch of your voice, and the size of your nose are all traits that are passed on to you by yours biological parents • A trait is a particular feature that can vary in size or form from individual to individual within a species

  7. Non-pathological (do not need to study)

  8. Pathological (do not need to study)

  9. Heredity • Is the process through which patterns of traits are passed on from an individual to its offspring

  10. The Nucleus is Responsible for Heredity • Cell have many organelles (cell membrane, cytoplasm, mitochondria...) • The nucleus is the organelle responsible for heredity and controlling function of the cell.

  11. Understanding Check • Give an example of a trait? • What is heredity? • Where is hereditary information stores?

  12. The Nucleus: Control Centre of the Cell • Every cell in your body has a function. • How do cells become retina cells vs. bone cells? • The nucleus contains the master set of instructions that determines what each cell will become, how it will function, when it will grow and divide, and when it will die.

  13. Cell Dying

  14. Cells • Every cell contains in your body contains all the same information. So the cells in your heart contain the DNA for your whole body. But the cells in your heart just activate and reproduce the cell in your heart. Think of a carpenter who has the blueprints for a house but when he is in the living room he just uses those instruction to work on that room.

  15. The nucleus contains the master instructions that determine • what each cell becomes • how it will function • when it will grow and divide • and when it will die.

  16. DNA carries the master set of instructions for cell function • Instruction in the nucleus are carried in long, two stranded molecules called DNA. • It looks like a twisted ladder. • The two strands, or sides, of the DNA ladder wrap around each other in a spiral shape that scientists call a double helix (Greek for “to wrap”)

  17. DNA continued... • The sides of the DNA are made of sugar and phosphate • The steps are made of four nitrogen bases, which are represented by the letters A (adenine), G (guanine), C (cytosine), and T (thymine)

  18. Arrangement of bases in DNA directs all cell activities • Everything that occurs in a cell is the result of how the bases on the DNA molecule are arranged • The arrangement is know as the DNA message • DNA bases always join in specific ways • A and T • G and C

  19. Arrangement of bases in DNA directs all cell activities continued..... • The order and number of bases can vary greatly within a DNA molecule. • In humans, a single DNA molecule can be several million base pairs in length.

  20. How is DNA stored? • Most of the time it is stored in the nucleus in a loosely coiled form • When a cell is growing, the DNA is uncoiled and aids in the making of proteins • Protein is essential material needed for the cell to carry out the activities necessary for its survival.

  21. How is DNA stored? Continued ... • When a cell is ready to divide, each strand of loosely coiled DNA folds up further into a very compact, X-shaped structure call a chromosome

  22. Every organism has a characteristic number of chromosomes • Chromosomes within the nucleus are found in pairs • Most humans have 46 chromosomes in 23 pairs • 1 pair helps determine gender • In males the 23rd pair of chromosomes is XY • In females it is XX

  23. Comparison of Chromosomes Number in Various Organisms • Human have 46 chromsomes

  24. Comparison of Chromosomes Number in Various Organisms • Cows have 60 chromosomes

  25. Comparison of Chromosomes Number in Various Organisms • Chickens have 78 chromosomes

  26. Comparison of Chromosomes Number in Various Organisms • Corn has 20 chromosomes

  27. Comparison of Chromosomes Number in Various Organisms • Butterflies had 80 chromosomes

  28. Comparison of Chromosomes Number in Various Organisms • Bats have 44 chromosomes

  29. Genes – most know for their function • Segments of DNA located at a specific place on a chromosome; each contains information to produce proteins • What gene scared Angelina Jolie?

  30. Genes are Found in Chromosomes • Genes are small segments of DNA located at specific places o a chromosome. • Genes store the information needed to produce 90,000 to 100,000 different proteins used in the cells of your body

  31. Chromosome contains the coded information for thousands of traits. • Chromosomes are made up of genes.

  32. Chromosomes are a train and genes are the cars that make up a long train.

  33. Proteins determine what body cells become and how they function • Each of your body cells has the same amount of genetic information stores within its 46 chromosomes. • However, only specific genes are “read “in each cell to produce specific proteins. • By making specific proteins , a cell becomes specialized to carry out a particular function.

  34. Special cells come together to form tissue (such as your retinas).

  35. Tissue comes together to form organs • Proteins needed to make your muscles work are made on in your muscle. • Proteins needed to help you read my notes are made only in your eyes.

  36. Enzymes and Hormones • Specialized proteins called enzymes speed up hundreds of chemical reaction in cell. • Digestive enzymes break down food into nutrients molecules that provide energy for cell • Some proteins act as chemical messengers called hormones. Growth hormones function to prepare a cell of division by making sure the ell has enough nutrients to divide.

  37. All the information is stored in long molecules called strands of DNA. When one cell breaks into two, it first copies the DNA so that each new cell gets a full copy. • On each strand of DNA are hundreds of Genes, each gene controls a particular aspect of you. Like telling if you have blue eyes or brown for example.

  38. During sexual reproduction a sperm and an egg fuse to make a new individual. Half of the DNA comes from each of the two cells to form one. So half of your DNA came from your father and half from your mother.

  39. 4.2 Mutations • This is a change in the sequence of DNA. If can cause changes in the individual and can be passed down to the next generation.

  40. Mutation can be one of three types • 1) Silent: Meaning that it did not have an effect on the product of the gene. • 2) Negative: Meaning that there was an effect and it somehow made things worse than before the mutation. • 3) Positive: Meaning that there was an effect but it made things better than they were before.

  41. Positive Mutation • A few individuals have been found to be resistant to the HIV virus and therefore, to AIDS

  42. Positive Mutation cont... • Some plants have developed resistance to bacterial and fungal infections. • Positive mutations create proteins that are beneficial to the plant and protect them from disease-causing invaders.

  43. Negative Mutation – Sickle Cell Anemia • Negative mutations reduce the probability that organisms will produce offspring or survive in their environment. • Substitution of base A for base T can cause hemoglobin to take on a different shape • Abnormal shaped molecules cannot carry oxygen efficiently.

  44. Negative Mutation – Sickle Cell Anemia cont... • Abnormal shaped molecules block blood flow, causing pain and often organ damage since blood carrying nutrients cannon reach organs such as the lungs, liver and kidneys.

  45. Negative Mutation – Cystic Fibrosis • It is another genetic disease caused by mutation • It can be caused by more than 1300 different mutations in one gene • Mucus builds up because the protein that normally functions to transport chloride ions into and out of the cell is not made correctly.

  46. Negative Mutation – Cystic Fibrosis • This causes respiratory problems

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