DNA Replication: Unit 2

¡Supera tus tareas y exámenes ahora con Quizwiz!

What are the steps of DNA replication?

1. Strands of DNA seperate 2. base pairing 3. Bonding Nucleotides 4. Result of Replication

Preventing the separating DNA strands from reforming their hydrogen bonds ...

Gives other enzymes the opportunity to attach to the single stranded DNA in order to carry out replication

What directional does DNA polymerase read the template strand?

In the 3'-5' direction

What directional does DNA polymerase produce a new DNA strand?

In the 5'-3' direction

Does gradual loss of these sequences harm the cell?

It does not harm the cell

What does helicase enzymes do as replication of a DNA molecule proceeds?

It moves down the length of the DNA molecule opening more single stranded DNA that can be used as templates for replication

what happens to the replication for during replication?

It moves down the length of the DNA molecule unwinding and replicating more DNA and expanding the size of the replication bubble

One template is called the...

Leading strand

On what strand does DNA polymerase can continue to make a new DNA strand until the end of a chromosome is reached

Leading strands

During DNA replication the two strands of a DNA molecule separate and each is used as a _____________ to make a new complementary strand

Template

What is cell division used for?

To create the cells and tissues that make up an organism during embryonic development and replaces cells that have been worn out or damaged in adults

What happens after the tension in the DNA is released?

topoisomerase reforms the covalent bonds in the sugar phosphate backbone.

Each two daughter cells that can divide and produce how many more daughter?

two more daughter cells

During cell division...

a cell splits to form two daughter cells

What cells are generated from a single starting cell?

a fertilized egg

What are telomeres?

Specialized DNA sequences at the ends of the chromosome

Enzyme Topoisomerase ________________the sugar phosphate backbone of one strand of DNA?

temporarily cuts

Why is copying the ends of these chromosome is a challenge?

Because of the way DNA is replicated

Telomerase

An enzyme that can add more copies of the repeated sequence found in the telomeres on to the ends of the chromosome

In what locations does DNA replication begin?

At multiple different locations along a DNA molecule

Where does replication of DNA molecules begin at?

At special regions called origins of replication

Why is DNA able to quickly replicate and accurately copy DNA molecules?

Because of the structure of these DNA molecules

How does two new identical daughter cells obtain a complete set of DNA that identical to the original DNA?

By copying thier DNA using the proces of DNA replication

How do cells with linear chromosomes deal with chromosome losing valuable information and becoming unstable?

By maintaining telomers

What do some cells replace and repair cells in damaged or worn out tissue?

Continuously divide

What two things are DNA polymerase able to do?

Continuously replicate the newly opened template DNA and can produce a long strands of complementary DNA

Guanine (G) nucleotides on one DNA strand always form base pairs with...

Cytosine (C) nucleotides on the other strand

How does DNA ligase form a single continuous strand?

DNA ligase can form covalent bonds between the sugar phosphate backbones of the new DNA segments joining them together

Why are primers needed for DNA replication?

DNA polymerase can only add nucleotides to the 3'end of an existing nucleotide chain

Why cant DNA polymerase continue to make a new DNA strand until the end of a chromosome is reached on the lagging strand?

DNA polymerase needs an RNA primer to provide a starting point for replication

True or False: Neither of the DNA strands separate by helicase at a replication fork are used as templates to make new complementary strands

False: Both of the DNA strands seperate

What does cutting one strand of DNA allow?

For DNA molecule to untwist

DNA polymerase

Enzymes read the DNA sequence of a template strand and insert new, complementary DNA nucleotide across from it to form a new DNA chain

Helicase

Enzymes separate the two strands of a DNA molecule so that each strand can serve as a template for production of new complementary DNA strands

Most eukaryotes organize their DNA into ______________ chromosomes?

Linear

RNA Primase

Make "Primers" on the template DNA strands

Since DNA replication begins at multiple locations...

New DNA strands are produced as several separate pieces

DNA polymerase moves in the ______________ direction as the helicase enzyme and away from the replication fork

Opposite

In Helicase strand separation begins at specialized regions called...

Origins of replication

How many cells is the human body is composed of?

Over 1,000,000,000,000 cells

Single strand binding proteins (SSBPs)

Prevent the separated DNA strand from reforming their hydrogen bonds

What creates several smaller pieces of a new DNA

Production of a complementary DNA strand is restarted again and again as helicase opens new regions of template DNA

______________ provides these ends and are later removed and replaced with DNA nucleotides

RNA primers

What are telomeres composed of?

Repetitive sequences of nucleotides that do not code for information needed by cells

What does separating double stranded DNA into two individual strands create?

Replication form

The DNA polymerase moves in the _______________ direction as the helicase enzyme opening up new template DNA at the replication fork

Same

What creates a replication bubble?

Separating the strands in a DNA molecule for replication with a Y-shaped replication fork at each end

What are Okazaki fragments?

Several smaller pieces of new DNA

Primers

Short stretches of complementary RNA

Why does production of a complementary DNA strand must be restarted again and again as helicase opens new regions of template DNA?

Since DNA polymerase moves in the opposite direction as the helicase enzyme and away from the replication fork

What happens when the chromosome continues to becomes shorter every time the DNA is copied?

The chromosome may begin to lose valuable information and can become unstable

What causes tightly putting stress on the DNA molecule?

The double stranded DNA in front of helicase to twist even more

What is the other template called?

The lagging strand

What happens after the bubbles merge until the whole DNA molecule is eventually replicated?

The result of this process is the production of two double stranded DNA molecules with the same DNA sequences

What makes two double stranded DNA molecules each with the exact same sequence of nucleotides?

The separation of two strands of a DNA molecule that is used as a template to make a new complementary strand

What happens to the replication bubble during replication?

The size expands

Topoisomerase

The two separate strands of a DNA molecule spiral tightly around each other in a helical pattern

Why does replication take place somewhat differently for each of the template strands?

The two strands of a DNA molecule have opposite directionality and that DNA polymerase produces the new DNA strand in the 5-3' direction and must read the template strand in the 3'-5' direction

Why causes the chromosome to become shorter every time the DNA is copied?

The unreplicated end of the lagging stand is lost

What happens when the RNA primer is removed?

There is no 3' end onto which DNA polymerase can add new nucleotides and the very end of the lagging strand remains unreplicated

Do telomeres contain critical information?

They do not

What happens to bubbles formed at different locations along DNA during replication?

They eventually merge until the whole DNA molecule is eventually replicated

Adenine (A) nucleotides pair with ...

Thymine (T)

What directionality does DNA polymerase add new nucleotides to the 3' end of a new DNA strand?

To the 3' end of a new DNA strand

What reduces the twisting of the double stranded DNA in front of helicase?

Topoisomerase

True or False: DNA polymerase can only add nucleotides onto 3' of an existing DNA strand and use the DNA and use the short RNA primer created by primase as a starting point

True

True or False: In DNA replication the nucleotides in one strand are complementary to nucleotides in the others?

True

True or False: The two new daughter cells that are produced must have a complete set of DNA that is identical to the DNA in the original starting cell

True

How many daughter cells are produced when a cell divides?

Two new daughter cells

How many strands is DNA molecule composed of?

Two strands of DNA

What causes The double stranded DNA in front of helicase to twist even more?

When helicase enzymes separate the DNA strands at the replication fork?

How are stem cells and gametes able to avoid having their chromosomes get shorter?

With the help from the enzyme telomerase

Cells are generated from...

a single starting cell

How long does cell division last?

from fertilization through adulthood until an organism dies

DNA molecule untwisting ________________ the surface tension on the molecule?

reduces


Conjuntos de estudio relacionados

Principles of Management Final Study Guide

View Set

Advanced Networking Exam 2 (pt.2)

View Set