Explanation:
Let’s go through each part step by step, using the information in Model 1.
1a. What are the three parts of a nucleotide?
Looking at the “Nucleotide” diagram: it shows three labeled parts —
- Phosphate
- Deoxyribose sugar
- Nitrogen-containing base
So the three parts are: phosphate, deoxyribose sugar, and nitrogenous base.
1b. What kind of sugar is found in a nucleotide?
The diagram labels it clearly as “Deoxyribose sugar”. That’s the sugar in DNA nucleotides.
1c. Which nucleotide component contains nitrogen?
The label points to the “Nitrogen-containing base”, and the name itself tells us — the base has nitrogen. The phosphate and sugar do not contain nitrogen.
1d. Name the four nitrogen bases shown in Model 1.
The legend under “Nitrogen Bases” lists:
- Adenine
- Thymine
- Guanine
- Cytosine
These are the four DNA bases.
2. DNA is often drawn in a “ladder model.” Locate this drawing in Model 1.
In Model 1, there are two main diagrams on the right: “Ladder Model of DNA” (straight, like a ladder) and “Helix Model of DNA” (twisted). The ladder model is the middle one — vertical backbone with rungs.
2a. Circle a single nucleotide on each side of the ladder model of DNA.
A nucleotide includes one phosphate, one sugar, and one base. In the ladder model, each “rung” connects two bases, and each side strand is made of alternating phosphate and sugar units. So on each side, one full nucleotide = one circle (phosphate) + one pentagon (sugar) + one base shape attached to the sugar. You would circle one such unit on the left strand and one on the right strand.
Since we’re only writing answers (not drawing), we describe what to do — but for the answer format, we list only what’s asked in parts 1a–d and identify the ladder model.
Final Answer:
1a. Phosphate, deoxyribose sugar, nitrogen-containing base
1b. Deoxyribose sugar
1c. Nitrogen-containing base
1d. Adenine, Thymine, Guanine, Cytosine
2. The “Ladder Model of DNA” is the middle diagram; a single nucleotide on each side consists of one phosphate, one deoxyribose sugar, and one nitrogen base (e.g., circle one phosphate–sugar–base unit on left strand and one on right strand).
Parent Tip: Review the logic above to help your child master the concept of dna basics worksheet.
