DNA Quiz for 10th Grade Students

What is the overall shape of a DNA molecule called?

• Single helix

• Triple helix

• Double helix

• Spiral coil

Answer explanation

The overall shape of a DNA molecule is called a 'double helix'. This structure consists of two intertwined strands, resembling a twisted ladder, which is essential for its function in genetic information storage.

What are the individual units that make up DNA called?

• Amino acids

• Nucleotides

• Proteins

• Chromosomes

Answer explanation

The individual units that make up DNA are called nucleotides. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base, which together form the building blocks of DNA.

Which of the following is NOT one of the three parts of a nucleotide?

• Phosphate

• Sugar

• Base

• Enzyme

Answer explanation

A nucleotide consists of three parts: a phosphate group, a sugar molecule, and a nitrogenous base. An enzyme is not a part of a nucleotide, making 'Enzyme' the correct answer as it does not belong to the nucleotide structure.

How many different types of bases are there in DNA?

• 2

• 3

• 4

• 5

Answer explanation

DNA contains 4 different types of bases: adenine (A), thymine (T), cytosine (C), and guanine (G). Therefore, the correct answer is 4.

What concept ensures that A always pairs with T and C always pairs with G in DNA?

• Base sequencing

• Complementary base pairing

• Nucleotide bonding

• Genetic coding

Answer explanation

The concept of complementary base pairing ensures that adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G) in DNA, maintaining the structure and stability of the double helix.

What structure forms the outer part of the DNA molecule, protecting the bases?

• Protein shell

• Lipid membrane

• Sugar phosphate backbone

• Base pair ladder

Answer explanation

The sugar phosphate backbone forms the outer structure of the DNA molecule, providing stability and protection for the nitrogenous bases that carry genetic information.

In the genetic code, how many bases form a "triplet" that codes for an amino acid?

• 2

• 3

• 4

• 5

Answer explanation

In the genetic code, a triplet consists of 3 bases that together code for a specific amino acid. This is fundamental to the process of translation in protein synthesis, making 3 the correct answer.

What is the term for a specific sequence of bases that codes for a particular protein?

• Chromosome

• Genome

• Gene

• Allele

Answer explanation

A gene is a specific sequence of bases in DNA that codes for a particular protein. It is the fundamental unit of heredity, distinct from chromosomes and alleles, which are broader terms related to genetic information.

Which of the following is NOT mentioned as a main use of proteins in the body?

• Enzymes

• Hormones

• Structural proteins

• Antibodies

Answer explanation

Antibodies are indeed proteins, but they are not typically listed as a main use of proteins in the body. The main uses include enzymes, hormones, and structural proteins, making antibodies the correct choice for this question.

What is the final step in protein formation after the amino acids are joined together?

• DNA replication

• Base pairing

• Folding

• Translation

Answer explanation

The final step in protein formation is folding, where the linear chain of amino acids folds into a specific three-dimensional shape, essential for its function. This occurs after the amino acids are joined together during translation.