It’s What Makes Me Me Time to Split! Picture This Pass the Trait Mixed Bag 1 pt 1 pt 1 pt 1 pt 1 pt 2 pt 2 pt 2 pt 2 pt 2 pt 3 pt 3 pt 3 pt 3 pt 3 pt 4 pt 4 pt 4 pt 4 pt 4 pt 5 pt 5 pt 5 pt 5 pt 5 pt Who are the two scientists credited for discovering DNA? James Watson and Francis Crick Scientists describe the shape of the DNA molecule as this? Double Helix Name the 4 nitrogen bases found in DNA and explain how they bond. Adenine (A), Thymine (T), Guanine (G) and Cytosine (C) A and T bond together. G and C bond together. What holds the nitrogen bases together to make up the rungs of the ladder in DNA? Nitrogen bases bond to their corresponding nitrogen base by hydrogen bonds What is the three part basic building block of DNA called and what are the three parts? It is called a nucleotide. It is made up of a sugar called deoxyribose, a phosphate group and a nitrogen base. Name the 6 phases of the cell cycle in order. Interphase,Prophase, Metaphase, Anaphase,Telophase and Cytokinesis This is the stage of the cell cycle where the chromosomes split at the centromere into two separate chromatids. Sister chromatids move to opposite poles of the cell. Anaphase Explain what happens during Interphase. During Interphase the cell obtains nutrients to grow. The cell prepares to divide by making a copy of its DNA. What stage of the cell cycle does the cell spend most of its time in? Interphase Explain how DNA replication occurs. DNA replication is another way of saying the DNA is copied. This occurs during interphase. 1) Hydrogen bonds between the nitrogen bases break and the two strands separate much like a zipper coming apart. 2) Nucleotides that are floating in the nucleus fill in correct spots on both strands of DNA. There are now two complete identical double helixes of DNA Describe this phenotype. Blue eyes This is a picture of one cell in one of the phases in the cell cycle. What phase is it in? Metaphase *You can notice that the chromosomes are lined up in the center of the cell. What is the name of this tool that is used to predict the probability of offspring genotypes? Punnett Square What phase comes directly before this picture? What phase directly follows it? This cell is in Anaphase so the phase that comes directly before it is Metaphase and the phase that directly follows it is Telophase. The green shape is Thymine and the purple shape is Cytosine. 1) What does the red represent? 2) What does the yellow represent? 3) What is the dark blue on the sides of molecule? 4) What is the aqua on the side of the molecule? 5) What do the small circles in the center of the molecule represent? 1) Red = Adenine 2) Yellow = Guanine 3) Blue = Deoxyribose 4) Aqua = Phosphate group 5) Circles = Hydrogen bonds In Mendel’s experiments yellow seed color is dominant to green seed color. Explain why the phenotype of a pea plant would be yellow seed color if it had a genotype of Yy. You must use correct vocabulary. Answers will vary-because yellow is dominant to green the one dominant allele (Y) masks or hides the one recessive allele and all you can see is the dominant color. Explain the below genotypes using two different sets of vocabulary (purebred/hybrid or homozygous/heterozygous). 1) FF 2) Ff 3) ff 1) Either Homozygous Dominant or Purebred Dominant 2) Heterozygous or Hybrid 3) Either Homozygous Recessive or Purebred Recessive Angelina Jolie is a hybrid for straight hairline. Brad Pitt is homozygous recessive for widow’s peak. Angelina is pregnant AGAIN! (no not really) Predict the probabilities for both genotype and phenotype by completing a punnett square. s S s s Ss Ss ss ss 50% homozygous recessive, widow’s peak 50% heterozygous, straight hairline Having a cleft chin is dominant over not having a cleft chin. Predict the percentages for having a child with a cleft chin if a hybrid man is crossed with a woman that does not have a cleft chin. c c C c Cc cc Cc cc 50% would have a cleft chin In rabbits, the allele for a spotted coat is dominant over the allele for a solid colored coat. A spotted rabbit was crossed with a solid color rabbit. The offspring all had spotted coats. What were the genotypes of the parents. Explain. We know that if spotted is dominant and one parent has a solid coat that that parent must have a genotype of ss because the only way you can see the recessive trait is to have two recessive alleles. If all offspring had spotted coats than the other parent must be SS because if it had a recessive allele then that allele would be passed down to 50% of the offspring and 50% would be solid. A chromosome is made up of 2 sister _______________ and held together by a ___________________. chromatids , centromere This stage ends with the cell membrane pinching into two daughter cells. This stage is different in an animal cell compared to a plant cell because a plant cell has a cell wall therefore a cell plate forms to divide cell in two. Cytokinesis Below you are given half a strand of DNA . What would be the other half? ATTTGGCGATG Given-ATTTGGCGATG Answer-TAAACCGCTAC What are the different forms of a gene called? Alleles How many chromosomes does each sex cell (egg and sperm) carry? Each carry 23 chromosomes, ½ the number needed to make a human.