Bio: chapter 16

one

A critical characteristic of DNA polymerases is that they can only work in________ direction

Telomeres

Act as insulators No genes Short repeating stretches of nucleotides example: "TTAGGGTTAGGGTTAGGG"

thymine (T)

Adenine (A) hydrogen bonds with .

Proofreads: check for errors Requires a primer : Adds nucleotides in the 5'→ 3' direction: actually connects to the 3 prime end

Characteristics of DNA Polymerases

reduces

DNA Polymerase III proofreading process _______ the error rate

last, cannot

DNA Polymerase III proofreading process can only fix the ______ nucleotide placed. Once another nucleotide is placed it______ go back and fix it.

paired bases

DNA Polymerase Proofreadsby checking the match between _______ __________, and can correct mismatched bases when they do occur.

thymine dimers

DNA can be broken or altered by various chemicals and types of radiation. For example, UV light can cause ______ _____ to form, causing a kink in the DNA strand.

proofread

DNA polymerase can _________ its work—it checks the match between paired bases, and can correct mismatched bases when they do occur.

primer

DNA polymerase requires a_______ to synthesize DNA

3′ end

DNA polymerases can add deoxyribonucleotides to only the ___ ____ of a growing DNA chain

5′ → 3′

DNA synthesis always proceeds in the _____ direction.

DNA, bases

DNA synthesis occur when existing strands of ______ served as a template for the production of new strands, with_______ being added to the new strands according to complementary base pairing.

cytosine (C).

Guanine (G) hydrogen bonds with

Proofreading Mismatch Repair nucleotide excision repair

How does the cell Repair Mistakes and Damage? (3 ways)

Proofreading

If it doesn't't catch it immediately it cant go back to fix the problem It can only remove the very Last nucleotide.

bacteria (prokaryotic)

In_____________ chromosomes, the replication process begins at a single location (circle)

DNA polymerase I

Lagging synthesis: ____ _________ __ removes the RNA primer at the beginning of each Okazaki fragment and replaces it with DNA.

section

Mismatch repair enzymes recognize the mismatched pair, remove a _______ of the newly synthesized strand that contains the incorrect base, and fill in the correct bases.

replisome

Most of the enzymes responsible for DNA synthesis around the replication fork are joined into one large multi-enzyme machine called the __________.

bidirectional

Replication bubbles grow as DNA replication proceeds, because synthesis is____________.

RNA template

Telomerase has its own _________ ________

nucleotide excision repair

The __________ _______ _______ system recognizes physical types of damage. Its enzymes then remove the single-stranded DNA in the damaged section.

double helix.

The antiparallel strands twist to form a ________

DNA ligase

The enzyme ______ __________ then joins the Okazaki fragments to form a continuous DNA strand.

helicase

The enzyme ________ catalyzes the breaking of hydrogen bonds between the two DNA strands to separate them

topoisomerase

The enzyme__________ cuts and rejoins the DNA downstream of the replication fork, relieving this tension.

template

The presence of a DNA strand complementary to the damaged strand provides a _____ for resynthesis of the defective sequences.

complementary base pairing

The secondary structure is stabilized by _____________ _________ ________.

DNA Polymerases

These are characteristics of what enzyme: Proofreads: check for errors Requires a primer : Adds nucleotides in the 5'→ 3' direction: actually concects to the 3 prime end

Telomeres (process), Telomerase (enzyme)

This prevents the lagging strand from getting shorter with each replication.

lagging strand

What DNA synthesis strand is this?

DNA polymerase III

What enzyme catalyzes DNA replication???

topoisomerase

What helps alleviate tension as the DNA unwinds farther down the helix?

circle

What shape does Bacteria chromosome have?

elongated

What shape does Eukaryotic chromosome have?

Telomere replication process (4 steps)

Whats this process 1. unreplicated end 2. Telomerase extends unreplicated end 3. Again Telomerase extends unreplicated end 4. Lagging strand complete

replication fork

______ ______ is the Y-shaped region where the DNA is split into two separate strands for copying.

Mismatch repair

________ ______ occurs when mismatched bases are corrected after DNA synthesis is complete.

Primase, ligase

_________ makes an RNA primer, which DNA polymerase uses to synthesize the lagging strand. _______ connects the new sequence.

Eukaryotes

____________ have multiple origins of replication and thus have multiple replication bubbles. (linear)

primary structure of DNA

_________________ has two major components: A backbone made up of the sugar and phosphate groups of deoxyribonucleotides. A series of nitrogen-containing bases that project from the backbone.

Origin of replication

a particular sequence the chromosome at which replication is : In bacteria chromosomes, the replication process begins at a single location. (circular) Eukaryotes have multiple origins of replication and thus have multiple replication bubbles. (linear)

Primase

a type of RNA polymerase, synthesizes a short RNA segment that serves as a primer for DNA synthesis

Semiconservative replication

all cells use ______to replicate

Telomeres

are the regions at the ends of linear chromosomes (doesn't code for anything)

lagging strand

discontinuously in the direction away from the replication fork and so lags behind the fork.

replication bubble

forms in a chromosome that is actively being replicated

Okazaki

fragments called in the lagging strand

discontinuous, moves away from the replication fork

how is the Lagging strand synthesis different from leading stand synthesis ?

primase (synthesizes a RNA primer) DNA polymerase III (then adds bases to the 3' end of the primer. )

how is the Lagging strand synthesis similar to leading stand synthesis?

DNA polymerase III

main enzyme of DNA replication

leading strand

or continuous strand, leads into the replication fork and is synthesized continuously in the 5′  3′ direction.

Primer is unable to attach at the beginning. Enzymes come in and cut those ends off. Linear chromosomes shorten after each replication

problem with DNA synthesis?

semiconservative replication

the parental DNA strands separate and each is used as a template for the synthesis of a new strand. Daughter molecules each consist of one old and one new strand.

helacase, single-strand DNA-binding proteins (SSBPs)

two proteins are responsible for opening and stabilizing the double helix.

Telomerase

used in cells who frequently divide Enzyme Adds nucleotides to the lagging strand Carries its own primer

leading strand

what DNA synthesis strand is this?

single-strand DNA-binding proteins (SSBPs)

what attaches to the separated strands to prevent them from closing.

Watson and Crick

who proposed that two DNA strands line up in the opposite direction to each other, in what is called antiparallel fashion.