Structure of DNA showing key components and their labels.
Diagram of the DNA double helix structure showing components like sugar, phosphate, nitrogen base, base pair, hydrogen bond, and nucleotide.
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Step-by-step solution for: dna structure ws.pdf - 11/16/20 KaMya Dinkins Name: 2 Date: DNA ...
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Show Answer Key & Explanations
Step-by-step solution for: dna structure ws.pdf - 11/16/20 KaMya Dinkins Name: 2 Date: DNA ...
Let’s go through each question one by one and fill in the blanks correctly.
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1. Label the following parts of DNA:
Looking at the diagram:
- The sugar is part of the backbone — it alternates with phosphate.
- The nitrogen base sticks out from the sugar and pairs with another base on the opposite strand.
- A nucleotide = sugar + phosphate + nitrogen base (so it’s the whole unit).
- A base pair = two nitrogen bases connected together (like A-T or G-C).
- A hydrogen bond = the weak bond holding the two bases together.
- A phosphate = part of the backbone, connects sugars.
In the diagram, labels are already placed — we just need to confirm they’re correct based on standard DNA structure. They look right.
---
2. A nucleotide is made of three parts. These three parts are:
A nucleotide =
→ phosphate
→ deoxyribose (that’s the sugar in DNA)
→ nitrogenous base (or just “nitrogen base”)
So answer:
phosphate, deoxyribose, nitrogen base
*(Note: In the image, it says “deoxyribonucleic acid” for the second blank — that’s actually the full name of DNA, not the sugar. The sugar is called “deoxyribose.” So this might be a small error in the worksheet. But since the student filled it as “deoxyribonucleic acid”, we’ll note that technically it should be “deoxyribose”. However, if the worksheet expects that phrase, we’ll go with what’s written — but let’s correct it for accuracy.)*
Actually, looking again — the student wrote “deoxyribonucleic acid” under “what does the full name for DNA stand for?” — that’s correct! DNA = deoxyribonucleic acid.
But for the nucleotide parts, the three parts are:
✔ phosphate
✔ deoxyribose (the sugar)
✔ nitrogen base
So if the worksheet has “deoxyribonucleic acid” listed as one of the three parts — that’s wrong. It should be “deoxyribose”.
Wait — let me re-read the worksheet layout.
It says:
> A nucleotide is made of three parts. These three parts are:
> 1. ______ → student wrote “phosphate” ✔
> 2. ______ → student wrote “deoxyribonucleic acid” ✘ — that’s incorrect. Should be “deoxyribose”
> 3. ______ → student wrote “nitrogen base” ✔
So correction needed here.
But since the user is asking us to solve the problem accurately, we must give the correct answers.
---
3. What does the full name for DNA stand for?
DNA = Deoxyribonucleic Acid
Student wrote: “deoxyribonucleic acid” → ✔ Correct!
---
4. What are the sides of DNA made up of?
The sides (backbone) of DNA are made of alternating sugar (deoxyribose) and phosphate groups.
Student wrote: “phosphate and deoxyribose” → ✔ Correct!
---
5. What are the “rungs” of the DNA ladder made up of?
The rungs are the nitrogen bases paired together (A with T, G with C).
Student wrote: “nitrogen bases” → ✔ Correct!
---
6. What type of bonds hold the sides of DNA together?
The sides (backbone) are held together by covalent bonds between sugar and phosphate.
Student wrote: “covalent” → ✔ Correct!
---
7. What type of bonding holds the nitrogen bases together?
Nitrogen bases are held together by hydrogen bonds.
Student wrote: “hydrogen bonds” → ✔ Correct!
---
8. How is the base adenine bonded to thymine, and cytosine bonded to guanine?
Adenine (A) always bonds with Thymine (T) → 2 hydrogen bonds
Cytosine (C) always bonds with Guanine (G) → 3 hydrogen bonds
This is called complementary base pairing.
Student left this blank — so we need to fill it.
Answer:
Adenine bonds with thymine using 2 hydrogen bonds; cytosine bonds with guanine using 3 hydrogen bonds.
Or simply:
Through complementary base pairing: A with T, C with G.
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9. If the base sequence found in one strand of DNA is A T C, what would the base sequence of the other strand be?
Remember: A pairs with T, T pairs with A, C pairs with G.
So:
Original strand: A T C
Complement: T A G
Student wrote: “TAG” → ✔ Correct!
---
10. Which base is present in RNA but not in DNA?
RNA uses uracil (U) instead of thymine (T).
So answer: uracil
Student didn’t write anything — we need to add it.
---
11. What are the four kinds of DNA bases together? How many of each kind of base are there?
There are 4 bases: Adenine (A), Thymine (T), Guanine (G), Cytosine (C)
In double-stranded DNA:
- Amount of A = amount of T
- Amount of G = amount of C
Because they pair up.
So:
a. Adenine is present in the same amount as → Thymine
b. Guanine is present in the same amount as → Cytosine
c. Cytosine is present in the same amount as → Guanine
d. Thymine is present in the same amount as → Adenine
Student filled these correctly.
---
Now, let’s compile all corrected answers clearly.
---
Final Answer:
1. Labels on diagram: sugar, nitrogen base, nucleotide, base pair, hydrogen bond, phosphate — all correctly labeled as shown.
2. Three parts of a nucleotide:
- phosphate
- deoxyribose *(not “deoxyribonucleic acid” — that’s the full name of DNA)*
- nitrogen base
3. Full name of DNA: deoxyribonucleic acid
4. Sides of DNA made of: phosphate and deoxyribose
5. Rungs of DNA ladder made of: nitrogen bases
6. Bonds holding sides together: covalent
7. Bonds holding nitrogen bases together: hydrogen bonds
8. Base bonding rule: Adenine bonds with thymine (2 hydrogen bonds); cytosine bonds with guanine (3 hydrogen bonds)
9. Complement of ATC: TAG
10. Base in RNA but not DNA: uracil
11. Base amounts:
a. Adenine = Thymine
b. Guanine = Cytosine
c. Cytosine = Guanine
d. Thymine = Adenine
---
1. Label the following parts of DNA:
Looking at the diagram:
- The sugar is part of the backbone — it alternates with phosphate.
- The nitrogen base sticks out from the sugar and pairs with another base on the opposite strand.
- A nucleotide = sugar + phosphate + nitrogen base (so it’s the whole unit).
- A base pair = two nitrogen bases connected together (like A-T or G-C).
- A hydrogen bond = the weak bond holding the two bases together.
- A phosphate = part of the backbone, connects sugars.
In the diagram, labels are already placed — we just need to confirm they’re correct based on standard DNA structure. They look right.
---
2. A nucleotide is made of three parts. These three parts are:
A nucleotide =
→ phosphate
→ deoxyribose (that’s the sugar in DNA)
→ nitrogenous base (or just “nitrogen base”)
So answer:
phosphate, deoxyribose, nitrogen base
*(Note: In the image, it says “deoxyribonucleic acid” for the second blank — that’s actually the full name of DNA, not the sugar. The sugar is called “deoxyribose.” So this might be a small error in the worksheet. But since the student filled it as “deoxyribonucleic acid”, we’ll note that technically it should be “deoxyribose”. However, if the worksheet expects that phrase, we’ll go with what’s written — but let’s correct it for accuracy.)*
Actually, looking again — the student wrote “deoxyribonucleic acid” under “what does the full name for DNA stand for?” — that’s correct! DNA = deoxyribonucleic acid.
But for the nucleotide parts, the three parts are:
✔ phosphate
✔ deoxyribose (the sugar)
✔ nitrogen base
So if the worksheet has “deoxyribonucleic acid” listed as one of the three parts — that’s wrong. It should be “deoxyribose”.
Wait — let me re-read the worksheet layout.
It says:
> A nucleotide is made of three parts. These three parts are:
> 1. ______ → student wrote “phosphate” ✔
> 2. ______ → student wrote “deoxyribonucleic acid” ✘ — that’s incorrect. Should be “deoxyribose”
> 3. ______ → student wrote “nitrogen base” ✔
So correction needed here.
But since the user is asking us to solve the problem accurately, we must give the correct answers.
---
3. What does the full name for DNA stand for?
DNA = Deoxyribonucleic Acid
Student wrote: “deoxyribonucleic acid” → ✔ Correct!
---
4. What are the sides of DNA made up of?
The sides (backbone) of DNA are made of alternating sugar (deoxyribose) and phosphate groups.
Student wrote: “phosphate and deoxyribose” → ✔ Correct!
---
5. What are the “rungs” of the DNA ladder made up of?
The rungs are the nitrogen bases paired together (A with T, G with C).
Student wrote: “nitrogen bases” → ✔ Correct!
---
6. What type of bonds hold the sides of DNA together?
The sides (backbone) are held together by covalent bonds between sugar and phosphate.
Student wrote: “covalent” → ✔ Correct!
---
7. What type of bonding holds the nitrogen bases together?
Nitrogen bases are held together by hydrogen bonds.
Student wrote: “hydrogen bonds” → ✔ Correct!
---
8. How is the base adenine bonded to thymine, and cytosine bonded to guanine?
Adenine (A) always bonds with Thymine (T) → 2 hydrogen bonds
Cytosine (C) always bonds with Guanine (G) → 3 hydrogen bonds
This is called complementary base pairing.
Student left this blank — so we need to fill it.
Answer:
Adenine bonds with thymine using 2 hydrogen bonds; cytosine bonds with guanine using 3 hydrogen bonds.
Or simply:
Through complementary base pairing: A with T, C with G.
---
9. If the base sequence found in one strand of DNA is A T C, what would the base sequence of the other strand be?
Remember: A pairs with T, T pairs with A, C pairs with G.
So:
Original strand: A T C
Complement: T A G
Student wrote: “TAG” → ✔ Correct!
---
10. Which base is present in RNA but not in DNA?
RNA uses uracil (U) instead of thymine (T).
So answer: uracil
Student didn’t write anything — we need to add it.
---
11. What are the four kinds of DNA bases together? How many of each kind of base are there?
There are 4 bases: Adenine (A), Thymine (T), Guanine (G), Cytosine (C)
In double-stranded DNA:
- Amount of A = amount of T
- Amount of G = amount of C
Because they pair up.
So:
a. Adenine is present in the same amount as → Thymine
b. Guanine is present in the same amount as → Cytosine
c. Cytosine is present in the same amount as → Guanine
d. Thymine is present in the same amount as → Adenine
Student filled these correctly.
---
Now, let’s compile all corrected answers clearly.
---
Final Answer:
1. Labels on diagram: sugar, nitrogen base, nucleotide, base pair, hydrogen bond, phosphate — all correctly labeled as shown.
2. Three parts of a nucleotide:
- phosphate
- deoxyribose *(not “deoxyribonucleic acid” — that’s the full name of DNA)*
- nitrogen base
3. Full name of DNA: deoxyribonucleic acid
4. Sides of DNA made of: phosphate and deoxyribose
5. Rungs of DNA ladder made of: nitrogen bases
6. Bonds holding sides together: covalent
7. Bonds holding nitrogen bases together: hydrogen bonds
8. Base bonding rule: Adenine bonds with thymine (2 hydrogen bonds); cytosine bonds with guanine (3 hydrogen bonds)
9. Complement of ATC: TAG
10. Base in RNA but not DNA: uracil
11. Base amounts:
a. Adenine = Thymine
b. Guanine = Cytosine
c. Cytosine = Guanine
d. Thymine = Adenine
Parent Tip: Review the logic above to help your child master the concept of dna structure labeling worksheet.
