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Warmup January 21, 2014

Warmup January 21, 2014. Write the function of each organelle: n ucleolus endoplasmic reticulum r ibosomes Golgi complex cytoplasm. Warmup : January 22, 2014. What is homeostasis? The maintenance of a constant internal body temperature 2. How is the human body organized?

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Warmup January 21, 2014

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  1. Warmup January 21, 2014 Write the function of each organelle: • nucleolus • endoplasmic reticulum • ribosomes • Golgi complex • cytoplasm

  2. Warmup: January 22, 2014 • What is homeostasis? The maintenance of a constant internal body temperature 2. How is the human body organized? Cells-tissues-organ-organ system-organism

  3. Warmup: January 23, 2014 • What are the four types of tissue in the stomach? Nervous, epithelial, muscle, connective • Define them. Nervous- controls stomach muscle movement (sends electrical signals through the body) Epithelial-lines the stomach (covers and protects other tissues) Muscle- mixes food and stomach acids (made of cells that contract and relax to produce movement) Connective-blood is an example (joins, insulates, nourishes, and keeps organs from falling apart)

  4. Warmup January 24, 2014 What are the six characteristics of living things? Characteristics of living things Metabolism DNA Stimulus homeostasis Reproduction cells

  5. Review—on Quiz THURSDAY, JANUARY 23rd • heterozygous/homozygous • hybrid/purebred • allele-different forms of a gene • gene-instructions for an inherited trait—each have 2 alleles, both of these make up a genotype • trait • characteristic • incomplete dominance • genotype/phenotype • Be able to solve Punnett square problems

  6. January 21, 2014 Exceptions to Mendel’s Principal’s: • Incomplete dominance: one trait isn’t completely dominant over another. Each allele has an influence on the traits of the offspring • One gene, many traits: a gene that controls fur color may also control eye color • Many genes, one trait: different combinations of alleles can result in a variety such as: your skin, hair, and eye color can act together---in humans, a variety of heights can occur

  7. Question… If I flip a coin, what are the chances of it landing on heads? Suppose I flip the coin once, get heads, and flip it again. What are the chances I will get heads again?

  8. Objectives • Explain the difference between mitosis and meiosis • Describe how chromosomes determine sex • Explain why sex-linked disorders occur in one sex more often than in the other • Interpret a pedigree

  9. Meiosis (to make smaller) vs. Mitosis (“threads”) • asexual reproduction-mitosis—most single celled organisms and the cells inside your body • sexual reproduction-meiosis—two parents form offspring • sex cells-parent cells that form offspring • homologous chromosomes-chromosomes that carry the same set of genes • meiosis-a copying process that produces cells with half the usual number of chromosomes (chromosomes are copied once and nucleus divides twice)

  10. Mitosis Revisisted… RESULT: two identical copies of the original cell—each contains four chromosomes

  11. Meiosis 1. During interphase, chromosomes are copied. 2. Mitosis begins with prophase. The chromosomes condense. 3. During metaphase, the nuclear membrane dissolves. The chromosomes align. 4. During anaphase, the chromatids separate and move to opposite sides of the cell. 5. During telophase, the nuclear membrane forms. The chromosomes lengthen, and mitosis ends. 6. During cytokinesis, the cytoplasm divides RESULT: FOUR CELLS, EACH CONTAINING TWO CHROMOSOMES (1/2 the amount of the adult)

  12. Step 1: Before meiosis begins, each chromosome is making an exact copy of itself, forming two halves called chromatids. The chromosomes then thicken and shorten into a form that is visible under a microscope. The nuclear membrane disappears.

  13. Step 2: Prophase Each chromosome is now made up of two identical chromatids. Similar chromosomes pair with one another, and the paired homologous chromosomes line up at the equator.

  14. Phase 3: Metaphase The chromosomes separate from their homologous partners and then move to opposite ends of the cell.

  15. Phase 4: Anaphase The nuclear membrane reforms and the cell divides. The paired chromatids are still joined.

  16. Phase 5: Telephase Each cell contains one member of each homologous chromosome pair. The chromosomes are not copied again between the two cell divisions.

  17. Four Daughter haploid cells (half the number of chromosomes from the original cell) “n”

  18. Meiosis and Mendel

  19. How are children sexed?

  20. Some Sex-linked Disorders: Martin-Bell syndrome colorblindness Hemophilia Cystic fibrosis So, do these genetic disorders come from the male or female? Take 10 minutes to look up these diseases. Write down: what it is and what issues the fetus might have

  21. Selective breeding…

  22. DNA • Erwin Chargaff-biochemist-found amount of adenine in DNA always equals the amount of thymine and the amount of guanine always equals the amount of cytosine. • Rosalind Franklin-using x-ray diffraction, she was able to make images of DNA (showing the spiral shape) • James Watson and Francis Crick-explained how DNA was copied and built a model from their laboratory, DNA looked liked a twisted ladder

  23. Objectives • Describe the basic structure of a DNA molecule. • Explain how DNA molecules can be copied.

  24. nucleotide-a subunit of DNA consisting of a sugar, phosphate, and base. • DNA-deoxyribonucleic acid • 4 bases of nucleotides: adenine, thymine, guanine, cytosine (A, T, G, C) Description of DNA (double helix) -sides of ladder are sugar and alternating phosphates -rungs of ladder are bases -adenine with thymine -guanine with cytosine

  25. To replicate… Base pairs ALWAYS bond to each other’s bases…. EXAMPLE: CGAC will bond to GCTG

  26. *DNA is copied every time a cell divides*Half the DNA molecules are old, and half are new

  27. Practice with base pairs

  28. G=grey fur B=black eyes g=white fur b=red eyes

  29. Gene changes • Mutations-changes in the number, type, or order of bases on a piece of DNA • Substitution-a wrong base is used • Insertion-an extra base is added • Deletion-when a base is left out

  30. Mutations • Good: can help survive better in an environment • Bad: can cause color changes that might get a predator’s attention • Cells make proteins to fix mutations; although not all mutations can be fixed…

  31. Homework this week: • Chapter 5 Review: page 137 #1-23 Due Thursday • Genetics with a smile homework due Friday (E group) • Genetic engineering homework due Friday (S, M Groups) • Quiz Chapter 5 Thursday

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