Nucleic Acids

Question 1

What is adenosine triphosphate (ATP)

Answer 1

An activated nucleotide composed of adenine, a ribose sugar and three phosphate groups. Acts as the universal energy currency for cells.

Question 2

What’s an anticodon

Answer 2

A sequence of three bases at the end of a tRNA molecule that determines the specific amino acid carried by the tRNA. Forms hydrogen bonds with the codon in mRNA during translation.

Question 3

What’s the coding strand

Answer 3

The strand of DNA with the same base sequence as the mRNA (except T is replaced with U in mRNA)

Question 4

What’s a codon

Answer 4

A sequence of three bases in mRNA that codes for one amino acid.

Question 5

What are complimentary base pairs

Answer 5

Specific base pairing rules in DNA and RNA. A pairs with T (DNA) or U (RNA) forming two hydrogen bonds and C pairs with G forming three hydrogen bonds.

Question 6

What is deoxyribonucleic acid

Answer 6

The molecule responsible for the storage of genetic information in a cell.

Question 7

What’s DNA gyrase

Answer 7

Unwinds a specific section of the DNA molecule

Question 8

What is DNA helicase

Answer 8

Unzips a specific section of the DNA molecule by breaking the hydrogen bonds between the two DNA strands.

Question 9

What’s a DNA mutation

Answer 9

A change to the sequence of bases in DNA.

Question 10

What’s a gene

Answer 10

A length of DNA that carries the code for the synthesis of one (or more) specific polypeptide chains or for other RNA molecules that regulate other genes.

Question 11

What is genetic code

Answer 11

A sequence of three bases in DNA codes for a particular amino acid in a polypeptide chain

Question 12

What is messenger RNA (mRNA)

Answer 12

A single-stranded polynucleotide formed as a result of the transcription of a gene from the template strand of the DNA. Carries the information coding for a polypeptide from the nucleus to the ribosomes in the cytoplasm.

Question 13

What is a mutation

Answer 13

A change in the base sequence of DNA, or in the structure or number of chromosomes

Question 14

What is a nucleotide

Answer 14

The monomer of nucleic acids consisting of a phosphate group, a pentose sugar and a nitrogen-containing organic base

Question 15

What is a phosphodiester bond

Answer 15

Covalent bond joining the 3’ carbon atom of one nucleotide to the 5’ carbon of another.

Question 16

What’s a polynucleotide

Answer 16

Large polymer molecule made of many nucleotide monomers joined by phosphodiester bonds.

Question 17

What’s a promoter

Answer 17

DNA sequence at the start of a gene, to which RNA polymerase binds to start transcription.

Question 18

What’s a purine

Answer 18

Nitrogenous base consisting of a double ring structure e.g. adenine and guanine.

Question 19

What’s a pyrimidine

Answer 19

Nitrogenous base with a single ring structure e.g. thymine, cytosine and uracil.

Question 20

What’s reverse transcriptase

Answer 20

An enzyme originally derived from retroviruses. This enzyme catalyses the synthesis of a DNA strand using an RNA molecule as a template.

Question 21

What’s ribonucleic acid (RNA)

Answer 21

Single-stranded polynucleotide that exists in three forms. Each form plays a part in the synthesis of proteins within cells

Question 22

What is ribosomal RNA (rRNA)

Answer 22

Types of RNA molecules found in both small and large subunits of ribosomes.

Question 23

What are ribosomes

Answer 23

Structures composed of two subunits, made from RNA and proteins, which are the site of protein synthesis

Question 24

What is RNA polymerase

Answer 24

Binds to a specific binding site on the DNA at the start of the gene.

Question 25

What is semi conservative replication

Answer 25

The replication of a DNA molecule where the two strands separate and each strand acts as a template for the synthesis of a new DNA strand according to the complementary base-pairing rules.
Two identical DNA molecules are produced consisting of one old strand and one newly synthesised strand.

Question 26

What’s a template strand

Answer 26

The strand of DNA that acts as the template for transcription and has a

complementary base sequence to both the mRNA and the DNA sense (or coding) strand

Question 27

What’s transcription

Answer 27

The process of formation of an mRNA copy of a section of the template strand of DNA that corresponds to a gene, catalysed by RNA polymerase

Question 28

What’s a transcription factor

Answer 28

Protein that binds to a specific DNA sequence to alter the expression of a gene.

Question 29

What’s transfer RNA (tRNA)

Answer 29

Single RNA-polynucleotide chain that carries a specific activated amino acid to the ribosomes during translation to be added to the growing polypeptide chain

Question 30

What’s translation

Answer 30

The production of a polypeptide chain at a ribosome using the sequence of codons in the mRNA to direct the order amino acids are joined together.