Dehydration Synthesis Gizmo Answer Key

Name: Kareem Decker Date: 08-04-2022 Student Exploration: DNA Analysis Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: allele, codon, DNA, DNA sequence, gene, genotype, identical twins, nitrogenous base, phenotype, trait Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. The two navy officers shown at left are identical twins. Why do you think identical twins look so similar? Because they were conceived by the same egg, identical twins share the same genetic composition and hence have a similar appearance. 2. Most brothers and sisters don’t look exactly the same. What causes most siblings to have different appearances? Since everyone has two copies of most of their genes, and these copies might differ, brothers and sisters don't always look identical. Children inherit one of each parent's two copies of each gene. Gizmo Warm-up Most of an organism’s traits, or characteristics, are determined by genes encoded in DNA. Traits are determined by the sequence of the four nitrogenous bases in the DNA molecule: adenine, thymine, cytosine, and guanine. Except for identical twins, the DNA sequence of every individual is unique. In the DNA Analysis Gizmo, you will analyze partial DNA sequences of frogs. 1. Select the POPULATION tab. What are the three main traits that vary between the frogs? The three key characteristics that distinguish the frogs according to their body spots are. the skin's hue and the color of the eyes. 2. Which frog would you expect to have the most similar DNA sequence to frog A? Why? Frog I resembles frog A in that we share a number of characteristics, such as the fact that both of us have orange patches on our bodies and the same eye color. Activity A: Identical twins Get the Gizmo ready: ● Select the FIND THE TWINS tab. Question: How are DNA sequences used to analyze relationships? 1. Observe: Look at the three frogs on the TWINS tab. How does their appearance compare? All three frogs share the same characteristics. They all have orange skin, scorching pink eyes, and black spots all over their bodies. 2. Predict: What do you expect the DNA sequences of the three frogs to look like? I anticipated appearing differently. 3. Identify: Drag frog A to the scanning station and click SCAN. Drag the resulting DNA sequence to the bin at the upper right of the Gizmo. Each band on the sequence represents a single nitrogenous base of DNA. The band is dark if that base is present and pink if that base is absent. Scan frogs B and C. Drag their DNA sequences into the bin. If two frogs are identical twins, they will have exactly the same DNA sequence. Compare the three sequences. Could any of these frogs be identical twins? If so, which frogs? yes a and b 4. Analyze: DNA is composed of four different nitrogenous bases. For the type of DNA sequence used by the Gizmo, a complete DNA sequence would have scan readouts for all four nitrogenous bases. Knowing this, why can you not be entirely certain the frogs are identical twins using the simplified sequences on the Gizmo? I'm the guest mode, which scans only one of the four nitrogenous bases, only displays DNA fingerprints. As a result, it provides inaccurate results, leading to some frogs not being completely identical twins. 5. Apply: Click New. For the new frogs, find the possible pair of identical twins. A. Which two frogs could be identical twins? A and B are related since their DNA strands are identical. B. How do you think DNA sequences can be used in the real world to identify relationships between individuals? By identifying whether the individuals are connected, it can be used to identify relationships between people in the actual world. The heritage can also be checked by examining the generations. Activity B: Comparing genes Get the Gizmo ready: ● Select the POPULATION tab. Introduction: In this frog population, traits such as eye color, skin color, and spots are coded for in the DNA. For each gene, there are two alleles, or versions. The sequence of nitrogenous bases in a strand of DNA make up an organism’s genotype. The physical traits resulting from the genotype makes up the organism’s phenotype. Question: How are DNA sequences used to analyze traits? 1. Observe: Describe frog A’s phenotype. Frog's A has a presence HubSpot located on the body Karma in the eye color is pink. Also, the skin color is orange 2. Compare: Which frogs share frog A’s skin color, but not its eye color or spots? Frogs H and p.3 3. Analyze: A group of three consecutive nitrogenous bases in a strand of DNA is a codon. In a real organism, genes are made up of hundreds of codons. In the Gizmo, a single codon codes for a trait. Scan frog A and the two frogs that share only frog A’s skin color. Turn on the Comparison guides, and compare the three DNA sequences. Codon 1 is made up of bases 1–3, codon 2 is made up of bases 4–6, etc. The last two bases are part of codon 7, which was cut off when the scan was made. A. Which codon or codons are identical in all three frogs? For frogs, codon 6 All three frogs share the same initials A, I, and J. B. Scan more frogs with orange skin until you are confident that you have identified the correct codon that represents the allele for orange skin. Describe the results: The codon 6 is present in all frogs with orange skin, including those without spots and with various eye colors. C. Which codon codes for orange skin in this frog population? For this girl population, the sex codes for orange skin are codons. 4. Analyze: Pick out two frogs with blue skin and nothing else in common. A. Which codon do they share? Codons for insects were common and frogs G & D B. Scan two more frogs with blue skin to confirm you have identified the correct codon. Describe the results: All four frogs-G, D, K, and H-share codon 6 in common, but codon 4 is unique to none of them. 5. Collect Data: Fill in the column for orange skin in the table below. For the codon pattern, shade in the dark bands but not the light colored bands. Then, continue scanning frogs until you are able to complete the rest of the columns in the table. Codon Orange skin Blue skin Pink eyes Green eyes Spots No spots 7 7 3 3 1 1 111110 00 00 11 00p 00 Bases 0 Codon pattern 00 511 0000 6. Analyze: Does the same codon always control skin color, eye color, and the presence of spots? Why do you think this is the case? The same codon does, in fact, always regulate skin color when there are spots. An amino acid in the organism is encoded by each codon. Since the genetic code is universal, nearly every organism produces proteins using the same genetic code. 7. Apply: Look at the DNA sequence at right. Describe the frog’s phenotype. Blueskin, spots and pink eyes 8. Interpret: Click New to get a new population. Again, determine which codons code for which traits. Compare the results with the table above. How do the codons used to code for skin color, eye color, and spots in this new population of frogs compare to the first population you tested? It can be present in genes, DNA segments that code for particular proteins, or phenotypic characteristics. If a section of DNA has been sequenced, it can be checked for genes with carrot-and-stick characteristics. 9. Explain: Suppose a biologist found a rare frog and wanted to determine which species it belonged to. How could a biologist use a DNA sequence of the frog to accomplish this task? She would compare its DNA into the other frogs to which it seemed to be related. Significant differences in DNA indicate a different species. of course, this is in addition to the usual testing of cross-species breeding experiments. 10. Extend your thinking: What other applications of DNA sequences can you think of? If a section of DNA has been sequenced, it can be checked for gene traits and characteristics.