It looks like you've uploaded an image of a worksheet titled
"DNA – The Double Helix", which includes a diagram of the DNA double helix and several questions related to DNA structure. Since I can't view images directly, I’ll guide you through how to solve typical problems found on such worksheets based on common content.
Let’s assume the worksheet contains the following types of tasks (based on the title and visible elements):
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Common Questions on "DNA – The Double Helix" Worksheet:
1.
Label the parts of the DNA molecule.
- You’re likely asked to label:
- Sugar-phosphate backbone
- Nitrogenous bases (A, T, C, G)
- Hydrogen bonds
- Complementary base pairs
2.
Identify complementary base pairs.
- Adenine (A) pairs with Thymine (T) via
two hydrogen bonds.
- Guanine (G) pairs with Cytosine (C) via
three hydrogen bonds.
3.
Fill in the missing bases in a strand.
- Example: Given one strand: 5'–ATCGGC–3', find the complementary strand.
- Answer: 3'–TAGCCG–5'
4.
Explain the significance of the double helix structure.
- Stability due to hydrogen bonding and hydrophobic interactions.
- Ability to replicate accurately (each strand serves as a template).
- Protection of genetic information.
5.
Describe the sugar-phosphate backbone.
- Made of alternating deoxyribose sugar and phosphate groups.
- Forms the outer “rails” of the ladder.
6.
Why is DNA described as antiparallel?
- One strand runs 5' to 3', the other runs 3' to 5'.
- This orientation is essential for replication and transcription.
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Example Problem & Solution:
Problem:
Given the sequence of one DNA strand:
5'–AATCGGCT–3'
What is the sequence of the complementary strand?
Solution:
Use base pairing rules:
- A ↔ T
- T ↔ A
- C ↔ G
- G ↔ C
So:
5'–A A T C G G C T–3'
↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓
3'–T T A G C C G A–5'
Answer: 3'–TTAGCCGA–5'
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How to Approach the Diagram:
If the diagram shows a section of the double helix:
- Identify the two strands winding around each other.
- Look for the nitrogenous bases inside, paired across the center.
- Note that the backbones are on the outside.
- Color-coding often shows:
- Sugar = green or blue
- Phosphate = red or yellow
- Bases = different colors (e.g., A = orange, T = pink, etc.)
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Final Tips:
- Always remember:
A pairs with T, G pairs with C.
- DNA is
antiparallel: one strand runs 5'→3', the other 3'→5'.
- The
double helix structure was discovered by Watson and Crick in 1953.
- Hydrogen bonds hold base pairs together; covalent bonds link sugars and phosphates.
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Parent Tip: Review the logic above to help your child master the concept of dna double helix coloring worksheet.
