/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 21 Which portion of a chromosome co... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 14: Problem 21

Which portion of a chromosome contains Okazaki fragments? a. helicase b. lagging strand c. leading strand d. primer

Short Answer

Expert verified
b. lagging strand

Step by step solution

01

- Understand Okazaki fragments

Okazaki fragments are short sequences of DNA nucleotides synthesized discontinuously and later linked together. They are formed because DNA replication occurs in a 5' to 3' direction.
02

- Identify where Okazaki fragments are formed

DNA has two strands: the leading strand and the lagging strand. The leading strand is synthesized continuously in the direction of the replication fork, whereas the lagging strand is synthesized discontinuously, producing Okazaki fragments.
03

- Evaluate answer choices

a. Helicase: This enzyme unwinds the DNA helix. It does not involve the synthesis of Okazaki fragments.b. Lagging strand: Since the lagging strand is synthesized discontinuously, Okazaki fragments are formed here.c. Leading strand: This strand is synthesized continuously, so no Okazaki fragments are formed.d. Primer: This is a short segment of RNA used to initiate the synthesis of Okazaki fragments, not part of the chromosome.
04

- Conclude the correct answer

The lagging strand is the part of the chromosome where Okazaki fragments are formed.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

DNA replication
DNA replication is the process by which a cell duplicates its DNA, creating two identical copies. This is crucial before cell division, ensuring that each new cell receives an exact copy of the parent cell鈥檚 DNA.
The process begins at specific locations in the DNA called origins of replication. Here鈥檚 a step-by-step breakdown of DNA replication:
  • Initiation: Proteins bind to the origin of replication, unwinding the DNA helix to create two single strands.
  • Elongation: New nucleotides are added to the exposed DNA strands by an enzyme known as DNA polymerase. This enzyme works only in a 5' to 3' direction.
  • Termination: This phase concludes replication once the entire molecule has been copied.
The two resulting DNA molecules each have one original strand and one new strand, a process referred to as semiconservative replication.
Lagging strand
During DNA replication, the lagging strand is one of the two strands formed at the replication fork. Unlike the leading strand, which is synthesized continuously, the lagging strand is synthesized in small sections known as Okazaki fragments.
This happens because DNA polymerase can only add nucleotides in a 5' to 3' direction, which is opposite to the way the lagging strand unwinds. As a result:
  • Primase adds a short RNA primer to the lagging strand.
  • DNA polymerase then extends the RNA primer, forming an Okazaki fragment.
  • Once an Okazaki fragment is completed, the enzyme moves to the next primer to synthesize another fragment.
  • Finally, an enzyme called DNA ligase joins these fragments together to form a continuous strand.
This discontinuous synthesis is necessary because the lagging strand runs in the opposite direction of the unwinding DNA.
Leading strand
The leading strand is the opposite of the lagging strand in the DNA replication process. It is synthesized continuously in the same direction as the replication fork.
Here are the key points about the leading strand:
  • Continuous synthesis: DNA polymerase adds nucleotides in a smooth, uninterrupted flow.
  • Direction: The synthesis of the leading strand occurs in a 5' to 3' direction, which matches the direction of the unwinding DNA helix.
  • Replication fork: As the replication fork progresses, the leading strand keeps elongating without any gaps.
This mechanism ensures that one of the newly forming DNA strands is quickly and efficiently replicated, reducing the chances of errors in the genetic code.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Discuss how mutations can increase variation within a population. a. Substitution mutations may cause a different amino acid to be placed at a specific location, causing small changes in the protein. Frame shift mutations usually cause multiple amino acid changes, increasing chances that a new protein will form, leading to radically different characteristics in the offspring. b. Substitution mutations may cause multiple amino acid changes, increasing chances that a new protein will form, leading to radically different characteristics in the offspring. Frame shift mutations may cause a different amino acid to be placed at a specific location, causing small changes in a protein. c. Substitution mutations may cause a different amino acid to be placed at a specific location, resulting in major changes to the protein and leading to radically different characteristics in the offspring. Frame shift mutations cause multiple amino acid differences in a protein, leading to small changes in the protein. d. Substitution mutations result in a different amino acid being placed at a specific position in a protein, causing small changes. Silent mutations could result in new characteristics possessed by an offspring when a stop codon is substituted for an amino acid.

Which type of point mutation would result in the substitution of a stop codon for an amino acid? a. frame shift b. missense c. nonsense d. silent

Compare and contrast the similarities and differences between eukaryotic and prokaryotic DNA. a. Eukaryotes have a single, circular chromosome, while prokaryotes have multiple, linear chromosomes. Prokaryotes pack their chromosomes by super coiling, managed by DNA gyrase. Eukaryote chromosomes are wrapped around histone proteins that create heterochromatin and euchromatin, which is not present in prokaryotes. b. Prokaryotes have a single, circular chromosome, while eukaryotes have multiple, linear chromosomes. Prokaryotes pack their chromosomes by super coiling, managed by DNA gyrase. Eukaryote chromosomes are wrapped around histone proteins that could form heterochromatin, which is not present in prokaryotes. c. Prokaryotes have a single, circular chromosome, while eukaryotes have multiple, linear chromosomes. Eukaryotes pack their chromosomes by super coiling, managed by DNA gyrase. Prokaryotes chromosomes are wrapped around histone proteins that could form heterochromatin, which is not present in eukaryotes. d. Prokaryotes have a single, circular chromosome, while eukaryotes have multiple, linear chromosomes. Prokaryotes pack their chromosomes by super coiling, managed by DNA gyrase. Eukaryote chromosomes are wrapped around histone proteins that could form heterochromatin, which is present in prokaryotes.

Discuss the effects of point mutations on a DNA strand. a. Mutations can cause a single change in an amino acid. A nonsense mutation can stop the replication or reading of that strand. Insertion or deletion mutations can cause a frame shift. This can result in non-functional proteins. b. Mutations can cause a single change in amino acid. A missense mutation can stop the replication or reading of that strand. Insertion or deletion mutations can cause a frame shift. This can result in non-functional proteins. c. Mutations can cause a single change in amino acid. A nonsense mutation can stop the replication or reading of that strand. Substitution mutations can cause a frame shift. This can result in non-functional proteins. d. Mutations can cause a single change in amino acid. A nonsense mutation can stop the replication or reading of that strand. Insertion or deletion mutations can cause a frame shift. This can result in functional proteins.

How do the linear chromosomes in eukaryotes ensure that their ends are replicated completely? a. The ends of the linear chromosomes are maintained by the activity of the telomerase enzyme. b. The ends of the linear chromosomes are maintained by the formation of a replication fork. c. The ends of the linear chromosomes are maintained by the continuous joining of Okazaki fragments. d. The ends of the linear chromosomes are maintained by the action of the polymerase enzyme.
See all solutions

Recommended explanations on Biology Textbooks

Energy Transfers

Read Explanation

Substance Exchange

Read Explanation

Ecology

Read Explanation

Cellular Energetics

Read Explanation

Heredity

Read Explanation

Biological Structures

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.