DNA, genes and protein synthesis - Yr 1

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

Chromosome

Answer 2

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

Question 3

Chromatin

Answer 3

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

Question 4

Autosome

Answer 4

A chromosome which is not a sex chromosome

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

Degenerate

Answer 6

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

Question 7

Non-overlapping

Answer 7

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

Question 8

Universal

Answer 8

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

Question 9

Histones

Answer 9

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

Question 10

Chromatid

Answer 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

Question 11

Locus

Answer 11

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

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

Genome

Answer 14

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

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

Transcription

Answer 17

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

Question 18

RNA Polymerase

Answer 18

Enzyme that joins together nucleotides to form messenger RNA during transcription

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

mRNA

Answer 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

Question 21

Triplet

Answer 21

A sequence of three bases in DNA.

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

Codon

Answer 23

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

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

Exon

Answer 25

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

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

Translation

Answer 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.

Question 28

tRNA

Answer 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.

Question 29

Anti-codon

Answer 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.

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

Polypeptide

Answer 31

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