Chapter 8- Transcription, Translation

Question 1

What are the 3 steps of DNA becoming an amino acid/polypeptide?

Answer 1

First-DNA replication
Second-Transcription
Third-Translation

Question 2

What is DNA polymerases? RNA polymerases?

Answer 2

Enzymes that bond nucleotides together and proof read errors

Enzymes that bond nucleotides together during transcription

Question 3

3 stages of DNA replication?

Answer 3

1. Double helix separates
2. Free nucleotides pair with the bases exposed
3. DNA polymerases bonds the nucleotides

Question 4

What is leading strand and lagging strand in DNA replication?

Answer 4

Leading-when DNA replication occurs in one direction

Lagging-when replication is discontinuous and in opposite direction

Question 5

What are the three differences from DNA and RNA?

Answer 5

1. RNA has a ribose sugar
2. RNA has uracil (U) instead of thyme(T)
3. RNA is a single stranded structure

Question 6

What does uracil bond with in RNA?

Answer 6

Adenine

Question 7

What does transcription do? Translation?

Answer 7

Transcription-converts DNA into RNA

Translation-converts an RNA message into polypeptide chains

Question 8

What is the central dogma?

Answer 8

Idea that information flows in one direction from DNA to RNA from nucleus to cytoplasm.

Question 9

What is RNA polymerase and what does it due? What happens in transcription?

Answer 9

RNA polymerase is a group of enzymes that catalyze transcription

In transcription, RNA polymerase strings together a complementary strand of RNA nucleotides. Once all the pairings have occurred, the RNA strand completely separates

Question 10

What are the 3 types of RNA and what do they do?

Answer 10

1. mRNA-carries information from a gene to a ribosome
2. rRNA-forms parts of ribosomes
3. tRNA-brings amino acids from cytoplasm to a ribosome

Question 11

What is a codon? Stop codon?

Answer 11

Codon-3 nucleotide sequence that codes for an amino acid

Stop codon-3 nucleotide sequence that signal the end of an amino acid chain

Question 12

What are the 4 stages in translation?

Answer 12

1. Exposed codon site of Ribosome attracts tRNA bearing amino acid
2. tRNA anticodon pairs with the codon site, next to other tRNA
3. Ribosome form peptide bond between the amino acids of tRNA
4. Old tRNA without polypeptide enters cytoplasm

Question 13

What is a promoter?Operator? What is an operon?

Answer 13

Promoter-a DNA segment that allows a gene to be transcribed

Operator-a DNA segment that turns a gene on or off

Operon-a region of DNA that includes a promoter, an operator, and one or more structural genes that code for all the proteins for a task

Question 14

What happens when lactose is absent in the lac operon? Present?

Answer 14

Absent-a protein binds to the operator which blocks the RNA polymerase from transcribing the genes

Present-lactose bings the repressor, causing it to change its shape and fall of the lac operon

Question 15

What do the cap and tail of mRNA do?

Answer 15

Cap-helps mRNA strand bind to a ribosome and prevents strand from breaking

Tail-helps mRNA exit the nucleus

Question 16

What do exons and introns do?

Answer 16

Exons-nucleotide segments that code for parts of the protein

Introns-nucleotide segments that intervene between exons. They increase genetic diversity without increasing the genome size

Question 17

What is a point mutation? Frameshift mutation?

Answer 17

Point-one incorrect nucleotide is substituted for the other

Frameshift-insertion or deletion of a nucleotide that shifts the entire sequence

Question 18

What is a translocation mutation-

Answer 18

A piece of one chromosome moves to a nonhomologous chromosome and they start exchanging non homologous genes

Question 19

What does ultra violent light do to the DNA?

Answer 19

Causes thymine to break bonds with adenine