Higher Biology Unit 1. Key Area 1: The structure of DNA

What is the structure of DNA described as?

• Quadruple stranded triangle

• Double stranded helix

• Single stranded circle

• Triple stranded square

Which molecules are DNA strands held together by?

• Sodium and chloride bonds

• hydrogen bonds between adenine, thymine, cytosine, guanine

• Carbon and nitrogen bonds

• Hydrogen and oxygen bonds

What is a nucleotide made of?

• Two phosphate molecules and a sugar molecule

• Two sugar molecules and a base

• A phosphate molecule, a sugar molecule, and a base

• A phosphate molecule and two bases

What kind of bonds hold the sugar and phosphate molecules together?

• Sugar-phosphate bonds

• Hydrogen bonds

• Covalent bonds

• Ionic bonds

What is the significance of the 3' and 5' ends in DNA?

• They indicate the direction of DNA replication

• They are used to classify the type of DNA

• They determine the strength of the DNA molecule

• They represent the number of carbon atoms in the DNA molecule

What are prokaryotes characterized by?

• Containing plasmids and linear chromosomes

• Having a nucleus

• Not having any membrane-bound organelles

• Having linear chromosomes

What do eukaryotes possess that prokaryotes do not?

• Membrane-bound organelles including a nucleus

• Only one circular chromosome

• No genetic material

• Circular chromosomes only

How is DNA organized in eukaryotic cells?

• As a loose collection of genes

• In linear chromosomes within the nucleus

• In singular circular chromosomes

• Through a single strand of DNA

What is the role of histones in DNA packaging?

• To replicate DNA

• To transcribe DNA into RNA

• To transport DNA out of the nucleus

• To coil DNA tightly for packaging into the nucleus

What unique feature do some yeast cells have that distinguishes them from other eukaryotes?

• They do not have membrane-bound organelles

• They have singular circular chromosomes

• They lack a nucleus

• They contain plasmids