DNA RNA Worksheet | PDF - Free Printable
Educational worksheet: DNA RNA Worksheet | PDF. Download and print for classroom or home learning activities.
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Step-by-step solution for: DNA RNA Worksheet | PDF
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Step-by-step solution for: DNA RNA Worksheet | PDF
Here is the completed worksheet with accurate answers and explanations for each question:
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Worksheet on DNA, RNA, and Protein Synthesis
1. The letters “DNA” stand for
Deoxyribonucleic Acid
*Explanation: DNA is the abbreviation for deoxyribonucleic acid, the molecule that carries genetic instructions in living organisms.*
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2. DNA is composed of smaller subunits known as
Nucleotides
*Explanation: Nucleotides are the building blocks of DNA. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.*
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3. The three parts of a nucleotide are
Phosphate group, Deoxyribose sugar, and Nitrogenous base
*Explanation: These three components form the basic structure of every nucleotide in DNA.*
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4. The four nitrogen bases that are found in DNA are
Adenine, Thymine, Cytosine, and Guanine
*Explanation: These are the four bases that pair specifically to form the rungs of the DNA ladder. Their abbreviations are A, T, C, and G.*
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5. Two of the nitrogen bases are single ring structures known as
Pyrimidines. These two bases are Cytosine and Thymine.
*Explanation: Pyrimidines are nitrogenous bases with a single-ring structure. In DNA, cytosine (C) and thymine (T) are pyrimidines.*
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6. The other two bases are double ring structures known as
Purines. These two bases are Adenine and Guanine.
*Explanation: Purines have a double-ring structure. Adenine (A) and guanine (G) are the purines in DNA.*
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7. ________ and ________ are the two scientists that discovered the structure of the DNA molecule.
James Watson and Francis Crick
*Explanation: In 1953, Watson and Crick proposed the double helix model of DNA based on X-ray diffraction data from Rosalind Franklin and Maurice Wilkins.*
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8. DNA looks like a ladder twisted into a shape known as a
Double Helix
*Explanation: The twisted ladder shape of DNA is called a double helix — two strands coiled around each other.*
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9. The two molecules that make up the sides of the ladder or the side portion of a DNA molecule are
Deoxyribose sugar and Phosphate group
*Explanation: The sugar-phosphate backbone forms the outer sides of the DNA ladder, alternating between deoxyribose and phosphate.*
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10. The molecules that meet across the middle, forming the steps of the “ladder” are known as
Nitrogenous bases (or Base pairs)
*Explanation: The rungs of the DNA ladder are formed by complementary base pairs: A-T and G-C.*
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11. Which nitrogen bases always pair with one another?
Adenine pairs with Thymine; Guanine pairs with Cytosine
*Explanation: Base pairing follows strict rules: A always bonds with T via two hydrogen bonds, and G always bonds with C via three hydrogen bonds.*
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12. According to Chargaff’s rules, the percentages of ________ are equal to those of thymine and the percentages of ________ are equal to those of guanine in the DNA molecule.
Adenine; Cytosine
*Explanation: Chargaff’s rule states that in double-stranded DNA, the amount of adenine equals thymine (A = T), and cytosine equals guanine (C = G).*
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13. The nitrogen bases are held together in the center of the molecule by
Hydrogen bonds
*Explanation: Hydrogen bonds form between complementary nitrogenous bases, holding the two DNA strands together.*
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14. True or False? According to the principle of base pairing, hydrogen bonds could form only between adenine and cytosine.
False
*Explanation: Adenine pairs with thymine (not cytosine), and guanine pairs with cytosine. A-C pairing does not occur under normal conditions.*
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15. The type of sugar found in DNA is
Deoxyribose
*Explanation: DNA contains deoxyribose sugar, which lacks an oxygen atom at the 2’ carbon compared to ribose (found in RNA).*
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16. If the sequence on the right hand side of the DNA molecule was TAGGCTCA, the complimentary side would have a sequence of
ATCCGAGT
*Explanation: Complementary base pairing rules:
- T → A
- A → T
- G → C
- C → G
So, TAGGCTCA becomes ATCCGAGT.*
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✔ All questions answered accurately with biological context. Let me know if you’d like this turned into a printable answer key or need diagrams explained!
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Worksheet on DNA, RNA, and Protein Synthesis
1. The letters “DNA” stand for
Deoxyribonucleic Acid
*Explanation: DNA is the abbreviation for deoxyribonucleic acid, the molecule that carries genetic instructions in living organisms.*
---
2. DNA is composed of smaller subunits known as
Nucleotides
*Explanation: Nucleotides are the building blocks of DNA. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.*
---
3. The three parts of a nucleotide are
Phosphate group, Deoxyribose sugar, and Nitrogenous base
*Explanation: These three components form the basic structure of every nucleotide in DNA.*
---
4. The four nitrogen bases that are found in DNA are
Adenine, Thymine, Cytosine, and Guanine
*Explanation: These are the four bases that pair specifically to form the rungs of the DNA ladder. Their abbreviations are A, T, C, and G.*
---
5. Two of the nitrogen bases are single ring structures known as
Pyrimidines. These two bases are Cytosine and Thymine.
*Explanation: Pyrimidines are nitrogenous bases with a single-ring structure. In DNA, cytosine (C) and thymine (T) are pyrimidines.*
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6. The other two bases are double ring structures known as
Purines. These two bases are Adenine and Guanine.
*Explanation: Purines have a double-ring structure. Adenine (A) and guanine (G) are the purines in DNA.*
---
7. ________ and ________ are the two scientists that discovered the structure of the DNA molecule.
James Watson and Francis Crick
*Explanation: In 1953, Watson and Crick proposed the double helix model of DNA based on X-ray diffraction data from Rosalind Franklin and Maurice Wilkins.*
---
8. DNA looks like a ladder twisted into a shape known as a
Double Helix
*Explanation: The twisted ladder shape of DNA is called a double helix — two strands coiled around each other.*
---
9. The two molecules that make up the sides of the ladder or the side portion of a DNA molecule are
Deoxyribose sugar and Phosphate group
*Explanation: The sugar-phosphate backbone forms the outer sides of the DNA ladder, alternating between deoxyribose and phosphate.*
---
10. The molecules that meet across the middle, forming the steps of the “ladder” are known as
Nitrogenous bases (or Base pairs)
*Explanation: The rungs of the DNA ladder are formed by complementary base pairs: A-T and G-C.*
---
11. Which nitrogen bases always pair with one another?
Adenine pairs with Thymine; Guanine pairs with Cytosine
*Explanation: Base pairing follows strict rules: A always bonds with T via two hydrogen bonds, and G always bonds with C via three hydrogen bonds.*
---
12. According to Chargaff’s rules, the percentages of ________ are equal to those of thymine and the percentages of ________ are equal to those of guanine in the DNA molecule.
Adenine; Cytosine
*Explanation: Chargaff’s rule states that in double-stranded DNA, the amount of adenine equals thymine (A = T), and cytosine equals guanine (C = G).*
---
13. The nitrogen bases are held together in the center of the molecule by
Hydrogen bonds
*Explanation: Hydrogen bonds form between complementary nitrogenous bases, holding the two DNA strands together.*
---
14. True or False? According to the principle of base pairing, hydrogen bonds could form only between adenine and cytosine.
False
*Explanation: Adenine pairs with thymine (not cytosine), and guanine pairs with cytosine. A-C pairing does not occur under normal conditions.*
---
15. The type of sugar found in DNA is
Deoxyribose
*Explanation: DNA contains deoxyribose sugar, which lacks an oxygen atom at the 2’ carbon compared to ribose (found in RNA).*
---
16. If the sequence on the right hand side of the DNA molecule was TAGGCTCA, the complimentary side would have a sequence of
ATCCGAGT
*Explanation: Complementary base pairing rules:
- T → A
- A → T
- G → C
- C → G
So, TAGGCTCA becomes ATCCGAGT.*
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✔ All questions answered accurately with biological context. Let me know if you’d like this turned into a printable answer key or need diagrams explained!
Parent Tip: Review the logic above to help your child master the concept of dna rna proteins starts with worksheet answers.
