DNA and the Genome - Gene Expression

Question 1

amino acid

Answer 1

one of twenty different types of organic compound which are the basic building blocks of protein

Question 2

antibody

Answer 2

type of protein made by white blood cells to defend the body against pathogens

Question 3

chromatography

Answer 3

technique used to separate components of a mixture which differ in their degree of solubility in a solvent

Question 4

enzyme

Answer 4

• type of protein possessing an active site which combines with a specific substrate
• they are natural catalysts which speed up reaction by lowering the activation energy

Question 5

gel electrophoresis

Answer 5

technique used to separate electrically charged molecules by subjecting them to an electric current which forces them to move through a sheet of gel

Question 6

hormone

Answer 6

type of protein which acts as a chemical messenger

Question 7

type of bond which holds polypeptide chains into a coil

Answer 7

hydrogen bonds

Question 8

chemicals present in all proteins

Answer 8

• carbon
• hydrogen
• oxygen
• nitrogen

Question 9

peptide bond

Answer 9

stong chemical link joining adjacent amino acids in a polypeptide chain

Question 10

polypeptide

Answer 10

chain-like molecule composed of several amino acids

Question 11

protein

Answer 11

molecule composed of one or more polypeptides folded or coiled into a specific shape

Question 12

anticodon

Answer 12

triplet of bases on a tRNA molecule which is complimentary to an mRNA codon

Question 13

attachment site

tRNA

Answer 13

region of a tRNA molecule to which a specific amino acid becomes temporarily fixed

Question 14

codon

Answer 14

unit of genetic information consisting of three mRNA bases

Question 15

exon

Answer 15

coding region of a gene

Question 16

intron

Answer 16

non-coding region of a gene

Question 17

mRNA

Answer 17

type of nucleic acid which carries a copy of the DNA code from the nucleus to the ribosome

Question 18

primary transcript

Answer 18

mRNA strand formed as the compliment of a DNA strand

Question 19

ribose

Answer 19

sugar present in RNA

Question 20

ribosome

Answer 20

sub-cellular structure made of rRNA and protein which is the site of protein synthesis (translation)

Question 21

RNA polymerase

Answer 21

enzyme which controls transcription

Question 22

splicing

Answer 22

joining of exons from a primary transcript of RNA (following the removal of introns) to form the mature transcript

Question 23

transcription

definition

Answer 23

process by which a complimentary molecule of mRNA is made from a region of a DNA template

Question 24

translation

definition

Answer 24

conversion of the genetic information on mRNA into a sequence of amino acids in a polypeptide

Question 25

tRNA

Answer 25

type of nucleic acid which carries a specific amino acid to a ribosome

Question 26

uracil

Answer 26

base present in RNA that is complimentary to adenine

replaces thymine

Question 27

transcription

process

Answer 27

• RNA polymerase unwinds DNA exposing the bases
• mRNA nucleotides align with complimentary base pairs on the template strand (A-U G-C) - 3’ end
• strong chemical bonds form between adjacent nucleotides
• temporary hydrogen bonds between the mRNA and DNA strand are broken allowing the primary transcript to separate from the tamplate strand
• the primary transcript udergoes RNA splicing to form the mautre transcript which goes to the ribosome for translation
• DNA molecule reforms

Question 28

translation

process

Answer 28

• tRNA nolecules receive an amino acid and carry it to the ribosome
• the first tRNA moves in by codon-anticodon complimentary pairing
• another molecule does the same; peptide bond forms between adjacent amino acids
• the first tRNA detaches from the mRNA strand for reuse
• translation continues to form a polypeptide chain

Question 29

alternative RNA splicing

Answer 29

alternative splicing is when sections of the primary transcript can be treated as both introns and exons, different exons are spliced together to form the mature transcript