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Bell Work: 1/22/13

Bell Work: 1/22/13. Based on the figure to the left, which of the following statements best describes cross-pollination? A The stigma comes in contact with flowers from another plant. B Pollen from the anther travels to the stigma of the same flower.

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Bell Work: 1/22/13

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  1. Bell Work: 1/22/13 Based on the figure to the left, which of the following statements best describes cross-pollination? A The stigma comes in contact with flowers from another plant. B Pollen from the anther travels to the stigma of the same flower. C Pollen from the anther travels to the ovule of a different flower. D Wind transfers pollen from other plants, delivering it to the stigma.

  2. Challenge Question • During pollination, what determines the characteristics (type, color, size, etc.) of the new flower that will be produced from the seeds?

  3. Objectives • Describe the relationship between genes, chromosomes, and inherited traits (SPI 0707.4.3) Table of Contents: • #55.DNA Notes

  4. Cells • What is the control center of both the plant and animal cell? • nucleus

  5. Nucleus • The nucleus is a large organelle in a eukaryotic cell that contains chromosomes. • What part of the school are the chromosomes like? • Chromosomes are made up of protein and DNA. • The proteins carry out all the functions and characteristics of living organisms, such as carrying substances, sending messages, & protecting the body. • DNA, or deoxyribonucleic acid, is genetic material that determines a plant or an animal's inherited traits. • Genes are sections of DNA that give instructions for inherited traits, which are passed from one generation to the next. • Traits are the different forms of characteristics, such as purple petals or brown hair, that plants and animals have.

  6. Relationship among chromosomes, DNA, & genes... Nucleus contains chromosomes Chromosomes are made of DNA (& proteins) Sections of DNA are called genes. Genes are sets of instructions for inherited traits

  7. Brain Pop

  8. DNA • A strand of DNA looks like a twisted ladder. • This shape is known as a double helix.

  9. DNA Structure • DNA is made of nucleotides. • A nucleotide consists of a sugar, a phosphate, and a base. • Four types of nucleotides: • Sides or backbone = phosphate + sugar • Rungs of the ladder = pair of bases

  10. Making Copies of DNA • The pairing of bases allows the cell to replicate, or make copies of, DNA. • Each base always bonds with only one other base. • Adenine (A) > Thymine (T) • Guanine (G) ] Cytosine (C) The sequence CGAC will bond with what? Sequence GCTG

  11. How & When Copies are Made • During replication, a DNA molecule is split down the middle, where the bases meet. • The bases on each side of the molecule are used as a pattern for a new strand. • DNA is copied every time a cell divides. • The job of unwinding, copying, and re-winding the DNA is done by the proteins within a cell.

  12. How DNA Works:Use pgs. 134-135 to create a flow chart that explains how DNA works.

  13. A cell’s DNA codes for proteins that determine traits, like skin color DNA is part of a material called chromatin, which is bundled in the nucleus. A single strand of chromatin= DNA that is coiled around proteins. DNA = 2 halves connected in the middle (double helix) Cell is ready to divide= packages chromatin into chromatids. Two identical chromatids=a chromosome ready to divide Before division, human cell=46 chromosomes (two identical copies of genetic material)

  14. 3-2-1 • 3 things you learned today… • 2 questions you have… • 1 way this relates to your daily life…

  15. Changes in Genes • Check out pg. 138 & 140! • Changes in the number, type, or order of bases on a piece of DNA are known as mutations. • Sometimes bases are left out, extras are added, or the most common, the wrong base is used. • Consequences of Mutations: • improved trait, no change, harmful trait • Most of the time proteins detect an error and fix it. • Mutagens, like radiation, can cause mutations in DNA. • When scientists manipulate or change individual genes within organisms it is called genetic engineering. • DNA fingerprinting identifies the unique patterns in an individual’s DNA. • A clone is an exact copy of another organism’s genes.

  16. DNA Drawing • Draw a portion of a DNA strand. • You must show the following: • Double helix structure • Phosphate + sugar backbone • Paired bases in the middle (must be correctly bonded base pairs)

  17. Paper DNA Step 1: label the bases on the paper model with A, T, G, or C from the bottom to the top. Color code the boxes lightly with colored pencil, using the DNA guide on the board. Step 2: “Unzip” the paper model by cutting it in half vertically and glue the pieces in the correct location on your worksheet so the bases match up correctly.

  18. Step 3: Label the empty boxes using A, T, G, or C and then color them using the colors on your DNA Guide (see below). Remember to match the bases correctly! A – T T – A G – C C - G Step 4: Have me check your work & build a DNA model!

  19. 3-2-1 • 3 things you learned today… • 2 questions you have… • 1 way this relates to your daily life…

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