Science Revision Quiz 1

1. What is the main function of messenger RNA (mRNA) in protein synthesis?

• to carry amino acids to ribosomes

• To carry copies of DNA instructions to ribosomes

• to store genetic information

During DNA replication, which base pairs with thymine?

• Adenine

• Guanine

• Cytosine

Which of the following correctly describes DNA structure?

• A single helix made of phosphates only

• A straight ladder made of sugars

• A twisted ladder with sugar-phosphate sides

How many different types of amino acids are found in the human body?

• 10 amino acids

• 20 amino acids

• 30 amino acids

What is the role of transfer RNA (tRNA) in protein synthesis?

• To store genetic information

• to copy DNA instructions

• to carry amino acids to ribosomes

What is the primary mechanism Darwin identiFed that drives evolution?

• Artificial breeding

• Natural selection

• Genetic mutations

Which factor is NOT one of the three main effects on natural selection?

• Competition

• Overproduction

• Geographic isolation

How are epigenetic changes different from genetic mutations?

• They change the actual DNA sequence

• They cannot be inherited by offspring

• They turn genes on or off without changing the genetic code

According to the text, what happens when oxygen levels in water become too low?

• Some fish survive while others die

• The strongest fish teach others to survive

• Fish populations slowly migrate away

Which statement best explains how natural selection leads to change over time?

• Organisms choose their beneScial traits

• Environmental conditions select individuals with helpful traits

• Mutations always create better adaptations