The following 8 Anchor Papers represent a range of score points and are used in conjunction with the rubric to assess student responses.

Score for Anchor Paper #1: Rubric Score 1

Annotation: This response demonstrates some understanding of the problem. A minimal description of the composition of a DNA molecule (nucleotides; contain phosphate groups and nitrogen containing bases) is provided. The structure of a DNA molecule (double helix) is also identified. The attempt to describe the process by which DNA replicates is incorrect (Protein synthesis), and although a description of the arrangement of nitrogen bases is given in general terms (must be like this: a-T, C-G), the student does not explain how this ensures error-free replication. Overall, the supporting details are minimally effective.

Score for Anchor Paper #2: Rubric Score 1

Annotation: This response demonstrates some understanding of the problem. The composition of a DNA molecule is described (consist of ademine, thymine, cytosine, guanine, sugar, and phosphate). The student provides a description of the structure with respect to the components (ademine connects with thymine and guamine connects with cytosine; sides that are made of sugars and phosphates), but there is no mention of the double helix. Although the student provides a brief explanation for the relatively error-free replication of DNA (because every base has a match), as well as a general description of DNA replication (making a copy of itself), the remainder of the response describes a different process, transcription, which is irrelevant. The supporting details are minimally effective.

Score for Anchor Paper #3: Rubric Score 2

Annotation: This response demonstrates a basic understanding of the problem. The student describes the composition of a DNA molecule (4 nitrogen bases: Adenine [A], Thymine [T], Cytosine [C], and Gyamine [G]) and describes the structure (double helix with bonds connecting the nitrogen bases). The process by which DNA replicates is described using adequate details (two strands separating and then the nitrogen bases being doubled; end up with another DNA strand). An explanation of how the arrangement of nitrogen bases ensures error-free replication (know exactly which nitrogen base should be where; only pair up a certain way so it is very unlikely that there will be a mistake) is given. Overall, the supporting details are adequate.

Score for Anchor Paper #4: Rubric Score 2

Annotation: This response demonstrates a basic understanding of the problem. The student describes the composition (four different nitrogen bases; bases are paired … adenine to thymine and cytosine to guanine; connected by sugars and phosphate groups) and structure (form a double helix shape) of a DNA molecule. A description of the process by which DNA replicates is given in terms of the composition and structure (“unzips” down the middle, breaking the bonds between the nitrogen bases; New bases are then paired with those on each side; one strand … two identical strands). The supporting details are adequate.

Score for Anchor Paper #5: Rubric Score 3

Annotation: This response demonstrates a good understanding of the problem. The use of scientific terminology (deoxyribose; adenine; thymine; corresponding half) strengthens the response, and supporting details about DNA replication are generally complete (bonds between the base pairs is broken; DNA is “unzipped”; A goes with T; G goes with C; will be identical; 1 strand of DNA is replicated so that there are two). Some synthesis of information is demonstrated, as the student relates data in the chart to the structure of DNA (pairs cannot switch partners; amount of adenine and thymine are the same; amount of guanine and cytosine are also the same), but more supporting details about the replication process are needed for a higher score.

Score for Anchor Paper #6: Rubric Score 3

Annotation: This response demonstrates a good understanding of the problem. The composition is described using generally complete supporting details (adenine, thymine, guanine and cytosine, and a sugar-phosphate backbone; adenine and thymine bases always pair with hydrogen bonds … guanine always pairs with cytosine). The student synthesizes the composition into a description of the process by which DNA replicates (enzyme helps “unzip” or break the hydrogen bonds … two DNA templates; Free nitrogen bases come and attatch to these templates; adenine to thymine, guanine to cytosine, creating two new … DNA strands). An explanation for how the arrangement of nitrogen bases ensures error-free replication continues to incorporate the composition (bases cannot pair with the wrong one … cannot be switched since they are attached to the sugar-phosphate backbone). The use of accurate scientific terminology (hydrogen bonds; templates; free nitrogen bases) strengthens the response, and the supporting details are generally complete.

Score for Anchor Paper #7: Rubric Score 4

Annotation: Scientific terminology, especially about enzymes involved in DNA replication, enhances this response, which demonstrates a full and complete understanding of the problem. Full and pertinent supporting details about the roles of several enzymes are integrated throughout the response (Helicase unwinds the double helical strand by breaking the hydrogen bonds; DNA polymerase attaches the compliment base to the bases on each side), which also provides complete details about the composition of DNA (deoxyribose sugar and phosphate “backbone” and nitrogenous bases held together) and the structure of the DNA molecule (double helical structure; hydrogen bonds between the bases). A complete synthesis of information is demonstrated, as the student explains how the arrangement of nitrogen bases ensures relatively error-free replication (DNA replicates itself with enzymes; works from 3' to 5' to prevent errors; get attached to the right spot and to the right base; A must exist in the DNA molecule bound to T unless an error has occurred).

Score for Anchor Paper #8: Rubric Score 4

Annotation: This response demonstrates a full and complete understanding of the problem. A full integration of ideas is present throughout the response, as the student addresses the overarching question of how the relative amounts of nitrogen bases is closely linked to DNA replication. The composition (nucleotides, composed of a deoxyribose, phosphate, and nitrogen base), structure (twists in the shape of a double helix), and relative amounts of nitrogen bases (base pairing rule states that adenosine bonds to thymine, and cytosine … guanine) are described with pertinent supporting details. The student continues to synthesize information, as the description of the process by which DNA replicates addresses a relevant cell process (Before cell division … must be split apart), specific enzymes (Helicase binds to a section of DNA, which causes it to split; Numerous DNA polymerase molecules bind to the split DNA), and the relative amounts of nitrogen bases (begin assembling complementary nucleotides). The explanation of how the arrangement of nitrogen bases ensures error-free replication continues to incorporate specific components of DNA replication (enzymes go down … correct any errors) and composition (combination of the base pairing rule and correcting enzymes). The use of accurate scientific terminology (deoxyribose; base pairing rule; helicase; DNA polymerase; complementary nucleotides) enhances the response, making the supporting details pertinent and complete.