Biology worksheet asking students to identify DNA monomers and explain complementary base pairing rules using the provided diagram.

Let’s go through each question one by one, using what we know about DNA structure and base pairing.

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1. What does the word DNA stand for?

DNA stands for Deoxyribonucleic Acid.
It’s the molecule that carries genetic instructions in living things.

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2. DNA is a polymer... What are the monomers called?

The monomers (building blocks) of DNA are called nucleotides.
Each nucleotide has three parts: a sugar, a phosphate group, and a nitrogenous base.

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3. There are 4 different variations of these monomers (different bases), what are those?

The four nitrogenous bases in DNA are:
- Adenine (A)
- Thymine (T)
- Cytosine (C)
- Guanine (G)

These are the “letters” of the genetic code.

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4. The base ______ pairs with ______. The base ______ pairs with ______.

In DNA, bases pair up specifically:
- Adenine (A) pairs with Thymine (T)
- Cytosine (C) pairs with Guanine (G)

This is called complementary base pairing.

So fill in:
> The base A pairs with T. The base C pairs with G.

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5. Based on this base pairing system, which of the following is/are true?

Because A always pairs with T, and C always pairs with G, in any double-stranded DNA:

→ Amount of A = Amount of T
→ Amount of C = Amount of G

So let’s check the options:

a. Cells contain the same amount of T as A → ✔ TRUE
b. Cells contain the same amount of C as G → ✔ TRUE
c. Cells contain the same amount of T as G → ✘ FALSE (no reason they should be equal)
d. Cells contain the same amount of A as C → ✘ FALSE (not necessarily equal)

✔ Correct answers: a and b

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6. One strand of DNA faces the opposite direction of the other strand. This is called ______

This is called antiparallel.

Then it says: Because DNA has two strands coiled in a helix, it’s said to be a double helix.

Fill in:
> One strand of DNA faces the opposite direction of the other strand. This is called antiparallel.
> ...DNA is said to be a double helix.

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7. DNA is in the ______ of cells. DNA contains information to make ______ which are responsible for all activities in the cell. So the primary function of DNA is to store and transmit genetic information. The bases of DNA are linked together by intermolecular forces that are called ______.

Breakdown:

- DNA is located in the nucleus of eukaryotic cells.
- DNA contains instructions to make proteins, which do most of the work in cells.
- The bases are held together by hydrogen bonds — weak attractions between A-T and C-G pairs.

Fill in:
> DNA is in the nucleus of cells.
> DNA contains information to make proteins...
> ...forces that are called hydrogen bonds.

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Final Answer:

1. Deoxyribonucleic Acid
2. Nucleotides
3. Adenine, Thymine, Cytosine, Guanine (or A, T, C, G)
4. A pairs with T; C pairs with G
5. a and b
6. antiparallel; double helix
7. nucleus; proteins; hydrogen bonds