Genetics: Replication/Transcription/Translation

Question 1

Conflict of Stable Heredity

Answer 1

• Spontaneous Generation
• Preformation
• Inheritance of Acquired Traits

Question 2

Mendel

Answer 2

Picked simple traits, easily bread organisms, used large numbers, different traits controlled by gene

Question 3

Chargaff

Answer 3

• Levels of nucleotides not identical
• Varies by species
• A = T , C = G

Question 4

Griffith

Answer 4

• Growing R cells with ground up (dead) S cells TRANSFORMS R to S
• After transformation S is stably inherited

Question 5

Avery

Answer 5

Figured out that DNA is what caused transformation by blocking proteins, amino acids, and DNA in experiments

Question 6

Hershey-Chase

Answer 6

• See if DNA and/or protein gets in side host cell
• Made protein or DNA radioactive
• Protein outside cells –> can be washed off
• DNA inside cells –> can’t be washed off

Question 7

DNA Structure

Answer 7

1. Nucleotides covalently linked into a strand
2. Two strands of helix running in opposite directions
3. Complementary base pairing

Question 8

Replication

Answer 8

• Base pairing to make an exact copy

- Semi conservative

Question 9

Helicase

Answer 9

Unwinds DNA strands

Question 10

Binding Proteins

Answer 10

Stabilize Strands

Question 11

DNA Polymerase

Answer 11

Covalently links nucleotides together to form strands

Releases 2 Phosphates

Replaces RNA primer w/ DNA

Question 12

Primase

Answer 12

Synthesizes RNA primer to give DNA polymerase a starting point

Question 13

Origin of Replication

Answer 13

The site where helicase and polymerase start replication

Makes replication bubble with 2 forks

Question 14

Topoisomerase

Answer 14

Cuts strands
Allows them to unwind
Rejoins them

Solves supercoliing problem

Question 15

DNA Ligase

Answer 15

Joins DNA fragments

Joins Okazaki fragments

Question 16

Okazaki Fragments

Answer 16

Small sections formed because Polymerase has to keep restarting (polymerase only 5’ to 3’)

Question 17

Telomere

Answer 17

End of linear chromosome

Question 18

Telomerase

Answer 18

The enzyme that adds nucleotides to template strand –> extension where primer can bind

Made in germ line cells, stem cells, cancer cells

Question 19

Ribosomes

Answer 19

Catalyze protein synthesis

Question 20

mRNA

Answer 20

Carries sequence info from DNA to ribosome

Question 21

Why mRNA?

Answer 21

Amplification
Control
Evolution

Question 22

Transcription

Answer 22

• One single strand of RNA made from 1 DNA template strand
• Separation of DNA strands = temporary
• RNA/DNA binding = temporary
• RNA uses U instead of T
• Only part of DNA used as template
• Can make many mRNA from 1 DNA template

Question 23

Transcription Unit

Answer 23

Region of DNA used as template for a type of mRNA

Area btwn promoter and terminator DNA

Question 24

Promoter DNA

Answer 24

Where transcription begins

Question 25

Terminator

Answer 25

Where transcription ends

Question 26

Transcription Factor

Answer 26

Recognize and bind specific nucleotides | Promote or inhibit transcription

Question 27

How to get mRNA to ribosome

Answer 27

mRNA goes through 2 lipid bilayers and needs to be protected/modified

Question 28

mRNA Processing

Answer 28

- 5' Cap (done by special nucleotide) (attaches RNA to ribosome) - 3 ' end cleaved and poly-A tail added (binds proteins that help stabilize RNA and export from nucleus) - Removal of non-coding introns - Removed part = intron - Remaining part = exons

Question 29

Spliceosome

Answer 29

- Proteins and snRNAs remove introns - snRNAs bind and recognize nucleotides at exon/intron junctions - snRNAs help splice

Question 30

Alternative Splicing

Answer 30

Keep different exons --> get different mRNAs --> get different proteins from the same DNA

Question 31

Transcription Summary

Answer 31

RNA polymerase, with the help of transcription factor proteins, binds promoter DNA, begins transcription of primary RNA, stops at terminator DNA • Region = transcription unit • RNA is complementary to 1 template DNA strand • RNA detaches from DNA • In eukaryotes, primary RNA is processed into mRNA by: A) addition of a 5’ cap B) addition of polyA tail C) removal of introns using spliceosome guided by snRNAs, joining exons

Question 32

Translation

Answer 32

- Ribosome matches mRNA triplet codons to tRNA anticodons - Each tRNA brings appropriate amino acids - Ribosome links amino acids - Ribosome reads along mRNA from 5' to 3' - Builds protein from amino to carboxyl end

Question 33

What is at the ribosome?

Answer 33

mRNA rRNA (enzyme) adaptors for matching amino acids with codons

Question 34

Aminoacyl tRNA Synthases

Answer 34

Specific Aminoacyl tRNA synthase uses ATP to attach specific amino acid to specific tRNA

Question 35

Start and stop codons

Answer 35

Tell ribosome where to start and stop translation

Question 36

Start Codon

Answer 36

AUG | matches initiator tRNA (binds Methionine)

Question 37

Stop Codon

Answer 37

Binds release factor which releases polypeptide

Question 38

Open Reading Frame

Answer 38

Nucleotide sequence that can be translated without running into a stop codon

Question 39

Operon

Answer 39

single mRNA has several consecutive start-stop intervals | Translation by ribosomes to make different protein have shared function

Question 40

Non Coding Transcription Units

Answer 40

* Not all RNAs are made into proteins at ribosomes * Examples: tRNA, rRNA, snRNA, telomerase RNA, * Still transcribed from templates (‘genes’) in DNA, * Often different promoters, polymerases than mRNA * Do not have 5’ caps, can lack polyA tails, not sent to ribosome