BIOL 141 Lecture Notes - Lecture 19: Dna Polymerase Iii Holoenzyme, Dna Polymerase I, Dna Replication

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apricotlouse11

30 Mar 2018

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Needs an rna primer and a free 3" -oh group, needs something to hang onto. Leading and lagging strand: antiparallelism of dna structure. 2 dna forks: affects understanding of leading/lagging strand. 2 single stranded pieces: cell thinks its been damaged, would destroy itself. Get around antiparallelism: solution is a leading/lagging strand. Can"t synthesize both strands in the same direction. Sliding clamp: grabs onto single stranded dna, keeps it associated. Dna polymerase iii: good at not making errors, but it does mess things up. This adds to the mutability of the genetic code. Dna polymerase iii: just kind of does this. Gene therapy: virus integrates into host chromosomes, replace with good copies of chromosome gene. Telomeres: "garbage" dna at the ends of all chromosomes. Shorter chromosome length after each round of replication. Cancer cells: physically crawl, extended telomeres: increase survival. "hard copy" locked away in nucleus (safe space)

Related Questions

1) What is the difference between the leading strand and the lagging strand in DNA replication? Place the following steps of DNA replication in right chronological order.

1. Primase adds an ribonucleotide primer
2. Initiator proteins bind the origin of replication and helicase breaks hydrogen bonds between complementary bases of double stranded template DNA
3. DNA polymerase III extends by complementary base pairing deoxyribonucleotides to the template strands
4. Ligase phosphodiester bonds the nucleotides to connect okazaki fragments nad connect fragments at the origin and where the "crotches or forks" collide
5. DNA polymerase I removes RNA primer and replaces with Deoxyribonucleotides

2) Given the template DNA and primer sequences below, what bases will be added to the primer as DNA replication proceeds? (The bases should appear in the order that they will be added)

5'-GTCGTCTCCCTTTTTAAAAACCCCCCC-3'
5'-UUUUUAAAAAGGG-3'

3) Given the DNA sequence below, what could be a primer sequence used in its replication?
5'-CGTACGGCCCCAAAATTGCTACTCTGCTG-3'

raspberryleopard304

Order the following steps of the DNA replication process fromfirst to last. (From 1 to 8)

DNA ligase joins Okazaki fragmments together

Elongation of leading strands occurs continuosly and elongationof lagging strands occurs via generation of Okazaki fragments. Bothare synthesized in 5' to 3' direction.

DNA polymerase I removes the RNA primers and replaces them withDNA nucleotides

DNA polymerase III starts adding DNA nucleotides to the 3' endof the existing RNA chain.

Helicase untwists the double helix at the replication fork

Single-stranded binding proteins bind the unpaired DNA strands,keeping them from re-pairing.

Topoisomerase helps releive the strain caused by DNA untwisting.It breaks, swivels and rejoins DNA strands.

Primase starts a complementary RNA chain using parental DNAstrand as a template

lilacgoose192

Double check to see if I got these right? 3 questions

Some Processes Involved in DNA Replication

1.The replication origin is identified.

2 DNA primase builds RNA primer.

3Okazaki fragments are spliced by DNA ligase.

4Helicases bind and uncoil the DNA double helix.

5 RNA primer is the starting point for DNA polymerase.

6 DNA replication ends at the telomere where DNA codes fortermination.

7 DNA polymerase adds complementary nucleotides in the 5' to 3'direction in short segments called Okazaki fragments.

The sequence in which the events numbered above occur during DNAreplication of the lagging strand: Number 1 - 7 in order.

I put: 1,4,2,5,7,3,6

__________________Question 2:

Some Functions of Enzymes

Build DNA strands
Build RNA primers
Build mRNA strand
Cleave DNA strands
Splice Okazaki fragments

Enzyme:
Helicase :4
DNA ligase :5
RNA primase :1
RNA polymerase :3
DNA polymerase:2

Question 3:

like mRNA, tRNA has a ribose sugar, U instead of T, and issingle stranded. Unlike mRNA, which remains a long single strand ofnucleotides, tRNA folds so that some areas pair up.

The resulting structure has an anticodon on one end and a site foran amino acid to attach on the other end. There is basecomplementarity (A pairs with U and G pairs with C) between an mRNAcodon and tRNA anticodon.

If the amino acid tyrosine attaches to a tRNA, which of thefollowing anticodons could be at the opposite end of the tRNAmolecule?

Select one:

a. ATA and ATG

b. UAU and UAC

c. AUA and AUG

d. AGA and AGU

I picked B.

purpleturtle13

BIOL 141 Lecture Notes - Lecture 19: Dna Polymerase Iii Holoenzyme, Dna Polymerase I, Dna Replication

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