Genes and Protein and the Genetic Code

Question 1

Gene

Answer 1

Section of DNA on a chromosome that controls a feature by coding for formation of one or more specific polypeptides or a functional RNA (including rRNA and tRNA).

Question 2

A thread like structure made of protein and DNA by which hereditary information is physically passed from one generation to the next.

Answer 2

Chromosome

Question 3

The material that makes up chromosomes. It consists of DNA and the protein histone.

Answer 3

Chromatin

Question 4

A chromosome which is not a sex chromosome

Answer 4

Autosome

Question 5

Genetic code

Answer 5

The sequence of triplets of nucleotides (codons) in DNA which determines the sequence of amino acids in an organism’s proteins. It is degenerate; non-overlapping; universal ; has start and stop codons

Question 6

A single amino acid may be coded for by more than one triplet code.

Answer 6

Degenerate

Question 7

Each base appears in only one triplet – each base is only read once.

Answer 7

Non-overlapping

Question 8

The genetic code is the same in all organisms – this is indirect evidence for evolution.

Answer 8

Universal

Question 9

Histones

Answer 9

Proteins, which together with DNA, make up the chromosomes of eukaryotic cells.

Question 10

Each of the two thread-like strands into which a chromosome divides that are joined together by a single centromere prior to cell division

Answer 10

Chromatid

Question 11

The specific linear position of a particular gene on a certain chromosome

Answer 11

Locus

Question 12

Alleles

Answer 12

Alternative forms of a particular gene with different base sequences, and therefore different codes

Question 13

Protein synthesis

Answer 13

The process by which the genetic code codes for proteins in the cell. The template strand of DNA codes for mRNA in transcription, which is then translated into an amino acid sequence at the ribosomes.

Question 14

The complete set of genetic material present in a cell or an organism.

Answer 14

Genome

Question 15

Human Genome

Answer 15

The complete set of genes in a cell, including those in mitochondria and/or chloroplasts

Question 16

Proteome

Answer 16

The full range of proteins produced by the genome. This is sometimes called the complete proteome, in which case the term proteome refers to the proteins produced by a given type of cell under a certain set of conditions.

Question 17

Formation of messenger RNA molecules from the DNA that makes up a particular gene. It is the first stage of protein synthesis.

Answer 17

Transcription

Question 18

Enzyme that joins together nucleotides to form messenger RNA during transcription

Answer 18

RNA Polymerase

Question 19

nucleotides

Answer 19

Complex chemicals made up of an organic base, a sugar and a phosphate. They are the basic units of which the nucleic acids DNA and RNA are made.

Question 20

The type of RNA that is a long strand arranged in a single helix and its base sequence is determined by the sequence of bases on a length of DNA

Answer 20

mRNA

Question 21

A sequence of three bases in DNA.

Answer 21

Triplet

Question 22

Template strand

Answer 22

The strand of DNA which is used during transcription to make mRNA. It runs in a 3’ to 5’ direction so the mRNA is built in a 5’ to 3’ direction.

Question 23

A sequence of three adjacent nucleotides in mRNA that codes for one amino acid

Answer 23

Codon

Question 24

Intron

Answer 24

Portions of DNA within a gene that do not code for a polypeptide. They are removed from pre-messenger RNA after transcription.

Question 25

Portions of DNA within a gene that codes for proteins. They are joined together during splicing.

Answer 25

Exon

Question 26

Splicing

Answer 26

The process by which base sequences corresponding to the introns are removed and the functional exons are joined together.

Question 27

The latter part of protein synthesis when the mRNA is used as template to which complementary tRNA molecules attach and the amino acids link to form a polypeptide.

Answer 27

Translation

Question 28

The type of RNA made of around 80 nucleotides and has an anticodon, which is complementary to a section of mRNA. Each molecule is specific to one amino acid.

Answer 28

tRNA

Question 29

A sequence of three adjacent nucleotides on a molecule of transfer RNA that is complementary to a particular codon on a messenger RNA molecule.

Answer 29

Anti-codon

Question 30

Ribosome

Answer 30

An organelle consisting of rRNA and proteins found in large numbers in the cytoplasm and on the RER of living cells. They bind to mRNA and use tRNA to synthesise polypeptides.

Question 31

A polymer consisting of a large chain of amino acids bonded together by peptide bonds.

Answer 31

Polypeptide

Question 32

Gene Mutation

Answer 32

A change to one or more nucleotide bases in DNA that could result in a change in genotype which may be inherited

Question 33

If a nucleotide is changed in the DNA sequence

Answer 33

Substitution mutation

Question 34

If the base change results in the formation of a stop codon

Answer 34

Nonsense mutation

Question 35

Mis-sense mutation

Answer 35

If the base change results in a code for a different amino acid completely

Question 36

Silent mutation

Answer 36

If the base change still codes for the same amino acid as before (as code is degenerate)

Question 37

If a nucleotide is lost from the DNA sequence, resulting in a ‘frame shift’ in translation

Answer 37

Deletion mutation

Question 38

Mutagen (mutagenic agent)

Answer 38

A material or other factor which increases the normal mutation rate eg high energy radiation, chemicals

Question 39

Chromosome mutation

Answer 39

A change that occurs in a chromosome. These changes are most often brought on by problems that occur during meiosis and can result in changes in the number of chromosomes in a cell or changes in the structure of a chromosome.

Question 40

The process of the genome doubling that gives rise to organisms with multiple sets of chromosomes.

Answer 40

Polyploidy

Question 41

Non-disjunction

Answer 41

The failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division,usually resulting in an abnormal distribution of chromosomesin the daughter nuclei.