The chemical structure of DNA | Starter Quiz | Oak National Academy

The drawing shows a bacterial cell. Which structure (A, B or C) contains the genetic material?

• A

• B

• C

Answer explanation

In bacteria, the genetic material is stored in the cytoplasm as a continuous loop of DNA.

Which is the best definition of a gene?

• A large chemical molecule made of smaller groups.

• All the DNA of an organism.

• A short section of DNA carrying the genetic code for a process or feature.

• All the chromosomes in the nucleus.

Answer explanation

Each chromosome is a long DNA molecule. A gene is a short section of this DNA molecule. Each gene provides instructions to the cell that allow it to carry out a process or build a feature.

All organisms have similarities in their DNA. Put these examples in order, starting with the example of two things that have the most similar DNA.

• a human being and a lion

• two brothers

• a granddaughter and her grandmother

• a human being and a banana

• a human being and a chimpanzee

Answer explanation

All organisms on Earth have similarities in their genome but, unless they are identical twins, no two genomes are exactly the same; this makes us all unique.

What do scientists call the sections of DNA in a chromosome that lie between genes?

Answer explanation

The genome is the whole of the coding and non-coding DNA. Some non-coding DNA plays a part in regulating which genes are being used by a cell.

True or false? Only genes make up the genome of an organism.

• true

• false

Answer explanation

The genes and non-coding sections of DNA all together make up the genome.

Which is the best explanation for why the genomes of humans and bananas have similarities?

• Humans and bananas are very closely related.

• Humans and bananas share many similar features.

• Humans and bananas have no similar features.

• Humans and bananas have common life processes.

Answer explanation

All living things have common life processes, such as respiration, and these processes are very similar in all living things. So the genes and DNA that code for them are also very similar.