Home › IB Biology › Practice › Nucleic AcidsIB Diploma · Biology A1.2
IB Biology A1.2: Nucleic Acids — Practice Questions & Answers
IB Biology A1.2 Nucleic acids study notes: DNA and RNA structure, nucleotides, base pairing, antiparallel strands, and how a sequence stores information.
Here are 10 practice questions with full answers and explanations.
Start an interactive IB Biology quiz →
Practice questions with answers
1
Multiple choice
What is the primary function of nucleic acids?
Catalyzing reactions
Storing hereditary information
Providing structural support
Storing energy
Tap an answer to check it.
Why Nucleic acids such as DNA store and transmit hereditary information between generations.
2
Multiple choice
What is the genetic material in most living organisms?
Tap an answer to check it.
Why DNA is the genetic material carrying inherited instructions in the vast majority of organisms.
3
Multiple choice
Which of the following is NOT considered a living organism?
Bacteria
Viruses
Animals
Plants
Tap an answer to check it.
Why Viruses lack cells and independent metabolism, so they are not usually classed as living organisms.
4
Multiple choice
What are the three components of a nucleotide?
DNA, RNA, tRNA
Histones, nucleosomes, DNA
Phosphate, pentose sugar, nitrogenous base
Nitrogenous backbone, pentose sugar, phosphate base
Tap an answer to check it.
Why Every nucleotide is built from a phosphate group, a pentose sugar and a nitrogenous base.
5
Multiple choice
In a nucleotide diagram, what shape represents the pentose sugar?
Triangle
Circle
Rectangle
Pentagon
Tap an answer to check it.
Why The five-carbon pentose sugar is conventionally drawn as a pentagon in nucleotide diagrams.
6
Multiple choice
What type of bond forms the sugar-phosphate backbone of DNA and RNA?
Van der Waals force
Hydrogen bond
Covalent bond
Ionic bond
Tap an answer to check it.
Why Strong covalent phosphodiester bonds link the sugars and phosphates that make up the nucleic acid backbone.
7
Multiple choice
What connects the nucleotides in a single strand of DNA or RNA?
Sugar-phosphate bonds
Glycosidic bonds
Hydrogen bonds
Peptide bonds
Tap an answer to check it.
Why Nucleotides within one strand are joined through covalent sugar-phosphate (phosphodiester) bonds.
8
Multiple choice
Which nitrogenous base is unique to DNA?
Guanine
Cytosine
Uracil
Thymine
Tap an answer to check it.
Why Thymine occurs only in DNA, whereas RNA uses uracil in its place.
9
Multiple choice
What is RNA formed from?
Amino acid monomers
Fatty acid monomers
Nucleotide monomers
Glucose monomers
Tap an answer to check it.
Why RNA is a polymer assembled from repeating nucleotide monomers.
10
Multiple choice
What type of bond links the two strands of DNA?
Hydrogen bonds
Ionic bonds
Peptide bonds
Covalent bonds
Tap an answer to check it.
Why The two DNA strands are held together by hydrogen bonds between complementary bases.
Key terms in Nucleic Acids
Nucleotide: The monomer of a nucleic acid, made of a pentose sugar, a phosphate group and a nitrogenous base.
Sugar–phosphate backbone: The repeating chain of alternating sugars and phosphates that forms the structural framework of a nucleic acid strand.
Complementary base pairing: The rule that A pairs with T (or U in RNA) and G pairs with C, joined by hydrogen bonds.
Purine: A double-ring nitrogenous base; adenine and guanine.
Pyrimidine: A single-ring nitrogenous base; cytosine, thymine and uracil.
Double helix: The two-stranded, spiral structure of DNA held together by hydrogen bonds between paired bases.
Antiparallel: Describing the two DNA strands running in opposite directions (one 5′→3′, the other 3′→5′).
Deoxyribose: The pentose sugar found in DNA; ribose (in RNA) has one additional oxygen atom.
See the full study notes for this topic.
Practise other IB Biology topics