2.3 nucleotides and nucleic acid definitions

Question 1

Adenosine triphosphate (ATP)

Answer 1

A nucleotide consisting of a molecule of ribose joined to the nitrogenous base adenine and three phosphate groups

Question 2

Degenerate (genetic code)

Answer 2

A term used to describe the fact that some amino acids can be coded for by multiple different codons

Question 3

Deoxyribonucleic acid (DNA)

Answer 3

double helix composed of two polynucleotides joined together by hydrogen bonds between complementary bases that contains the genetic material of an organism and is made up of deoxyribonucleotide monomers joined together by phosphodiester bonds

Question 4

components of a DNA nucleotide

Answer 4

The monomer that makes up DNA and consists of deoxyribose, a nitrogenous base (organic bases adenine, cytosine, guanine or thymin) and a phosphate group.

Question 5

DNA polymerase

Answer 5

An enzyme that catalyses the formation of phosphodiester bonds between nucleotides during the synthesis of a new DNA strand.

Question 6

RNA polymerase

Answer 6

An enzyme that catalyses the formation of phosphodiester bonds between nucleotides during the synthesis of a new RNA strand

Question 7

Helicase

Answer 7

An enzyme that catalyses the unwinding and unzipping of DNA in many processes like replication and transcription

Question 8

Messenger RNA (mRNA)

Answer 8

A type of RNA that carries genetic information from the DNA in the nucleus to the ribosomes for translation

Question 9

Non-overlapping (genetic code)

Answer 9

A term used to describe the fact that each base is only

part of one codon and that each codon is read one at a time in order.

Question 10

Nucleotide

Answer 10

The monomer from which nucleic acids are made that consists of a pentose sugar, nitrogenous base and phosphate group

Question 11

Phosphodiester bond

Answer 11

A type of bond that joins nucleotides together to create polynucleotides.

Question 12

Purines

Answer 12

A class of nitrogenous bases which are made up of two rings that adenine and guanine. (smaller ones)

Question 13

Pyrimidines

Answer 13

A class of nitrogenous bases which are made up of a single ring that cytosine, thymine and uracil. (larger ones)

Question 14

Ribosomal RNA (rRNA)

Answer 14

A type of RNA that makes up ribosomes.

Question 15

components of a RNA nucleotide

Answer 15

The monomer that makes up RNA and consists of ribose, a nitrogenous base (organic bases adenine, cytosine, guanine or uracil) and a phosphate group

Question 16

Semi-conservative replication

Answer 16

The replication of DNA to produce two new DNA molecules which both contain one new strand and one old strand from the original DNA molecule. meaning that genetic information is passed on from one generation from the next.

Question 17

Transcription

Answer 17

The process of synthesising a new mRNA strand from a molecule of DNA.

Question 18

Transfer RNA (tRNA)

Answer 18

A type of RNA that has three hairpin loops, an anticodon for attachment to the mRNA codon and an amino acid binding site and is used to carry amino
acids to the ribosome.

Question 19

Translation

Answer 19

The process of protein synthesis where complementary tRNAs carrying amino acids are brought to each codon in an mRNA molecule as it moves through a ribosome

Question 20

Triplet (genetic code)

Answer 20

A term used to describe the fact that DNA is grouped into three base long codons that are read together and code for an amino acid.

Question 21

Universal (genetic code)

Answer 21

A term used to describe the fact that the same codons code for the same amino acids in all organisms.

Question 22

what happens when ATP is hydrolysed

Answer 22

Energy is released to form ADP and a phosphate

molecule. This process is catalysed by ATP hydrolase

Question 23

what can an inorganic phosphate be used for

Answer 23

used to phosphorylate other compounds, as a

result making them more reactive.

Question 24

Condensation of ADP and inorganic phosphate produces what

Answer 24

produces ATP during photosynthesis and respiration when catalysed by ATP synthase

Question 25

what are the steps of semi conservative replication of DNA

Answer 25

1) The double helix unwinds and the hydrogen bonds between the complementary bases break using DNA helicase thus separating the two strands of DNA.
2) Both strands are used as templates and complementary base pairing occurs between the template strands and free nucleotides.
3) Adjacent nucleotides are joined by phosphodiester bonds formed in condensation reactions using DNA polymerase.

Question 26

what is the genetic code

Answer 26

The order of bases on DNA

Question 27

what does the genetic code consist of

Answer 27

triplets of bases - each triplet of bases codes for a particular amino acid and is known as a codon

Question 28

how are amino acids joined

Answer 28

by peptide bonds and form a polypeptide chain

Question 29

what is a gene

Answer 29

a sequence of bases on a DNA molecule coding for a sequence of amino acids in a polypeptide chain

Question 30

not all the genome codes for proteins - what are non-coding sections of DNA called

Answer 30

introns

Question 31

what are the coding regions of DNA called

Answer 31

exons

Question 32

Features of the genetic code

Answer 32

non-overlapping and degenerate

Question 33

what does degenerate mean

Answer 33

more than one triplet codes for the same amino acids reducing the phenotypic effect of mutations

Question 34

what are mutations in the genetic code

Answer 34

mistakes in the base sequence such as base deletion, insertion or substitution

Question 35

what does a change in the base sequence of DNA lead to

Answer 35

may alter the amino acid sequence and the
protein therefore cause mutations which leads to production of sticky mucus and causes cystic fibrosis or sickle cell anaemia in which a mutated form of haemoglobin distorts the shape of red blood cells

Question 36

what does the genetic code contain

Answer 36

start and stop codons which either start or stop protein

synthesis