Chapter 10.6 - 10.16

Question 1

what are the two stages of protein synthesis

Answer 1

transcription and translation

Question 2

transcription

Answer 2

transfer of genetic information from DNA to RNA; in the nucleus

Question 3

translation

Answer 3

transfer of information in RNA into a protein; at ribosomes

Question 4

what is a gene

Answer 4

Sequences coding for specific proteins

Genotype (DNA) -> phenotype (trait)

Question 5

what is a codon

Answer 5

nitrogenous bases represent “letters” in an “alphabet” that can form “words”
codon is a three letter “word”
one codon codes for one amino acid

Question 6

how many nucleotides make up a codon

Answer 6

three

Question 7

what is the AUG triplet

Answer 7

methionine / START codon

Question 8

what are the three STOP triplets

Answer 8

UAA, UAG, UGA

Question 9

what information does the genetic code supply

Answer 9

correspondence between codons in mRNA and amino acids

Question 10

initiation (transcription)

Answer 10

RNA polymerase attaches to promoter (specific binding site, humans TATA), RNA synthesis begins

Question 11

elongation (transcription)

Answer 11

RNA synthesis continues, transcribed section releases, helix reforms

Question 12

termination (transcription)

Answer 12

RNA polymerase reaches a terminator (specific sequence of bases) signaling the end of the gene and detaches

Question 13

what is RNA polymerase

Answer 13

an enzyme that copies a DNA sequence into an RNA sequence during transcription

Question 14

what is the purpose of mRNA

Answer 14

carries the information from DNA to make proteins

Question 15

In RNA processing, what purpose does adding extra nucleotides to the ends of mRNA serve?

Answer 15

facilitate export of mRNA from nucleus, protect mRNA from cellular enzymes, help mRNA bind to ribosomes

Question 16

introns

Answer 16

noncoding regions that are removed in RNA processing in eukaryotes

Question 17

exons

Answer 17

expressed areas that are spliced by RNA

Question 18

tRNA

Answer 18

transfers specific amino acids to ribosome

Question 19

anticodon

Answer 19

end base pairs with mRNA codon

Question 20

what role do ribosomes play in translation?

Answer 20

help build polypeptides

create peptide bonds between amino acids to create a polypeptide chain

Question 21

what are ribosomes made up?

Answer 21

2 subunits made up of proteins and ribosomal RNA (rRNA)

Question 22

initiation (translation)

Answer 22

Step 1: mRNA binds to a small ribosomal subunit, initiator tRNA carrying the amino acid Met binds to start codon
Step 2: large ribosomal subunit binds to the small unit, initiator tRNA fits into the P site, A site is vacant to receive tRNA

Question 23

elongation (translation)

Answer 23

Codon recognition: anticodon pairs with codon
Peptide bond formation (covalent bonds between amino acids): amino acid separates from tRNA and forms a peptide bond with the next amino acid
Translocation: P site tRNA leaves and ribosome moves tRNA in A site to P site, repeat steps

Question 24

termination (translation)

Answer 24

when a STOP codon reaches the A site polypeptide is released

Question 25

what is a mutation?

Answer 25

any change in the nucleotide sequence of DNA

positive, negative, or neutral (silent mutation) effect

Question 26

mutagens

Answer 26

physical or chemical agents causing mutations

Question 27

types of genetic mutations

Answer 27

base substitutions (point)
base insertions or deletions (frameshift)

Question 28

base substitutions (point)

Answer 28

replace one base with another

Question 29

base insertions or deletions (frameshift)

Answer 29

alter the reading frame