Biology Topic Practice

DNA Structure & Nucleotides

DNA is a polymer made from four different nucleotides, forming a unique double-helix structure.

Which base always pairs with Cytosine?

What is DNA Structure & Nucleotides?

"DNA structure refers to the double-helix arrangement of two strands of nucleotides, where bases are linked by hydrogen bonds."

Question 1

How many times does the cell divide during meiosis?

Question 2

Why is understanding the human genome important for modern medicine?

Question 3

Which group belongs to the domain Archaea rather than true bacteria?

Question 4

If both parents are heterozygous (Bb) for a recessive trait (b), what is the probability their child will express the trait?

Molecular Structure

Each nucleotide consists of a sugar, a phosphate group and one of four bases (A, C, G, T).

The code is determined by the sequence of these bases.

In a complementary strand, C always pairs with G, and T always pairs with A.

Exam Tip

Three bases in a row code for a specific amino acid; these amino acids join to form a specific protein.

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