Microscopic Observations of Mitosis 2

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of immersion oil in microscopy?

  • To lubricate the lens and prevent scratches during movement.
  • To increase the refractive index of the medium between the objective lens and the specimen, minimizing light scattering and improving resolution. (correct)
  • To act as a sealant, preventing the entry of dust and particles into the microscope.
  • To enhance the contrast of the image by absorbing specific wavelengths of light.

What is the relationship between the resolving power of a microscope and the minimum distance between two objects that can be seen as separate entities?

  • The resolving power is independent of the minimum distance, meaning the ability to distinguish objects is unrelated to the distance between them.
  • The resolving power is directly proportional to the minimum distance, meaning a higher resolving power requires objects to be farther apart to be distinguished.
  • The resolving power is inversely proportional to the minimum distance, meaning a higher resolving power allows for the distinction of objects closer together. (correct)
  • The resolving power is a logarithmic function of the minimum distance, meaning there is a non-linear relationship between them.

What is the total magnification of a microscope with an objective lens magnification of 40x and an eyepiece magnification of 10x?

  • 400x (correct)
  • 50x
  • 10x
  • 40x

Which mechanical component of a microscope is responsible for adjusting the position of the condenser vertically?

<p>The mechanical system of the condenser (A)</p> Signup and view all the answers

What is the primary function of the mechanical stage in a microscope?

<p>To move the specimen horizontally in the X and Y axes. (D)</p> Signup and view all the answers

What is the typical magnification range of ocular lenses?

<p>2x - 30x (B)</p> Signup and view all the answers

Which of the following is NOT a key component of the mechanical elements of a microscope?

<p>The ocular lens (C)</p> Signup and view all the answers

Which component of the microscope is responsible for creating the magnified image that is viewed through the eyepiece?

<p>The objective lens (C)</p> Signup and view all the answers

What is the primary function of the lighting system in an optical microscope?

<p>To illuminate the observed object optimally (A)</p> Signup and view all the answers

Which component of the microscope is responsible for concentrating light to illuminate the specimen?

<p>The condenser (C)</p> Signup and view all the answers

How do immersion lenses enhance the observation of a specimen?

<p>By requiring a liquid between the lens and specimen (C)</p> Signup and view all the answers

What type of image do lenses in a microscope create?

<p>Both B and C (C)</p> Signup and view all the answers

What is the role of the diaphragm in a microscope?

<p>To adjust the amount of light entering the condenser (C)</p> Signup and view all the answers

Which type of lens typically allows for higher magnification in microscopy?

<p>Wet (immersion) lenses (B)</p> Signup and view all the answers

What is the typical maximum magnification achieved by dry lenses?

<p>60 times (C)</p> Signup and view all the answers

What is the significance of using immersion oil in microscopy?

<p>It reduces light refraction and improves resolution (C)</p> Signup and view all the answers

What happens during the G1 phase of interphase?

<p>Cell mass and volume increase intensively. (B)</p> Signup and view all the answers

Which phase immediately precedes the M phase in the cell cycle?

<p>G2 phase. (A)</p> Signup and view all the answers

During which phase does the DNA content increase from 2n to 4n?

<p>S phase. (A)</p> Signup and view all the answers

What characterizes the G0 phase of the cell cycle?

<p>Cells undergo significant metabolic functions without division. (A)</p> Signup and view all the answers

What key event occurs during the transition from the G2 phase to the M phase?

<p>Cell cycle checkpoints ensure readiness for division. (B)</p> Signup and view all the answers

In which of the following situations might a cell enter the G0 phase?

<p>The cell's genetic material is damaged. (B)</p> Signup and view all the answers

What are the two main processes that make up the M phase?

<p>Karyokinesis and cytokinesis. (C)</p> Signup and view all the answers

What occurs during the G2 phase before mitosis starts?

<p>Cellular organelles are synthesized and prepared. (D)</p> Signup and view all the answers

What occurs during prophase in mitosis?

<p>Chromatin condenses and doubles chromosomes become visible (D)</p> Signup and view all the answers

What is the main event that characterizes prometaphase?

<p>Nuclear envelope breakdown occurs (C)</p> Signup and view all the answers

During which phase do chromatids align at the equatorial plane?

<p>Metaphase (C)</p> Signup and view all the answers

What happens during anaphase?

<p>Sister chromatids separate and move to opposite poles (D)</p> Signup and view all the answers

Which process follows telophase in cell division?

<p>Cytokinesis (D)</p> Signup and view all the answers

What is the role of the contractile ring in cytokinesis?

<p>It constricts to divide the cell into two daughter cells (D)</p> Signup and view all the answers

Which structures allow chromatids to attach to spindle microtubules during prometaphase?

<p>Kinetochores (D)</p> Signup and view all the answers

What happens to the chromosomes at the conclusion of telophase?

<p>They are organized into the nuclear envelope (A)</p> Signup and view all the answers

What is the primary function of the G1 phase in the cell cycle?

<p>Preparation for DNA replication occurs. (D)</p> Signup and view all the answers

Which phase of the cell cycle is characterized by chromosome condensation?

<p>M phase (A)</p> Signup and view all the answers

During which phase of the cell cycle do metabolic activities peak and chromosomes are in a non-condensed state?

<p>Interphase (C)</p> Signup and view all the answers

What is the outcome of the S phase in the cell cycle?

<p>Chromatid doubling occurs. (A)</p> Signup and view all the answers

What role does the cell-cycle control system serve?

<p>Ensures the proper sequence of cell cycle events. (D)</p> Signup and view all the answers

Which of the following best describes the function of the G2 phase?

<p>It serves as a checkpoint before mitosis. (A)</p> Signup and view all the answers

What is a key characteristic of the chromatin state during interphase?

<p>It is in a non-condensed state and not visible. (D)</p> Signup and view all the answers

How does the cell cycle contribute to the growth and regeneration of organisms?

<p>By doubling the DNA content precisely. (C)</p> Signup and view all the answers

During which phase of mitosis do chromosomes align at the equatorial plane of the cell?

<p>Metaphase (B)</p> Signup and view all the answers

What is the key characteristic of anaphase in mitosis?

<p>Chromatids are separated and pulled to opposite poles (B)</p> Signup and view all the answers

In which mitotic phase do chromosomes condense and become visible under a microscope?

<p>Prophase (A)</p> Signup and view all the answers

Which phase follows metaphase during mitosis?

<p>Anaphase (C)</p> Signup and view all the answers

What happens to the nuclear envelope during prophase?

<p>It dissolves, allowing chromosomes to move freely (C)</p> Signup and view all the answers

Which of the following best describes telophase in mitosis?

<p>Chromosomes reach opposite poles and begin to de-condense (A)</p> Signup and view all the answers

What do we observe during cytokinesis?

<p>Cell membrane pinches inwards to separate the daughter cells (A)</p> Signup and view all the answers

How are double and single chromatids present during the stages of mitosis?

<p>Both double and single chromatids appear in anaphase (D)</p> Signup and view all the answers

Flashcards

Optical Microscope

A device used to magnify small objects in biology.

Optical System

The part of a microscope that lights and magnifies the specimen.

Mechanical System

The components of the microscope that position the optical system.

Condenser

A set of lenses that concentrates light onto the specimen.

Signup and view all the flashcards

Diaphragm

A component that regulates light entering the condenser.

Signup and view all the flashcards

Dry Lens

A lens that magnifies objects up to 60 times without immersion.

Signup and view all the flashcards

Immersion Lens

A lens that magnifies objects from 90 to 150 times using oil.

Signup and view all the flashcards

Resolution

The ability of a microscope to distinguish between two close objects.

Signup and view all the flashcards

Ocular Lens

Lenses that magnify images, creating a virtual image of the preparation.

Signup and view all the flashcards

Total Magnification

The product of objective lens magnification and ocular lens magnification, can reach up to 2000 times.

Signup and view all the flashcards

Resolving Power

The minimum distance required to distinguish two separate objects, important for clarity.

Signup and view all the flashcards

Mechanical Stage

A platform used to hold and move the specimen horizontally during observation.

Signup and view all the flashcards

Coarse Adjustment Knob

Used to set the distance between the preparation and the objective lens quickly.

Signup and view all the flashcards

Fine Adjustment Knob

Used for precise focusing of the microscope view.

Signup and view all the flashcards

Nose Piece (Revolver)

Rotating disk that holds the objective lenses, allowing easy magnification changes.

Signup and view all the flashcards

Cell Cycle

An ordered sequence of events in a cell between mitotic divisions, comprising interphase and mitosis.

Signup and view all the flashcards

Interphase

The longest stage of the cell cycle; period between cell divisions where metabolic changes occur.

Signup and view all the flashcards

Phases of Interphase

The G1, S, and G2 phases; where cells grow, replicate DNA, and prepare for mitosis.

Signup and view all the flashcards

G1 Phase

The first gap phase of interphase where the cell grows and prepares for DNA replication.

Signup and view all the flashcards

S Phase

Synthesis phase of the cell cycle where DNA replication occurs, doubling the chromatid content.

Signup and view all the flashcards

G2 Phase

The second gap phase where the cell prepares for mitosis after DNA replication.

Signup and view all the flashcards

M Phase

Mitosis, the phase of the cell cycle where the cell actually divides into two daughter cells.

Signup and view all the flashcards

Chromosome Condensation

Process during mitosis where chromatin condenses into visible chromosomes for division.

Signup and view all the flashcards

Mitosis

The division of a cell nucleus into two daughter nuclei, each identical to the parent nucleus.

Signup and view all the flashcards

Karyokinesis

The division of the cell nucleus during mitosis.

Signup and view all the flashcards

Cytokinesis

The division of the cytoplasm, following karyokinesis.

Signup and view all the flashcards

Chromosome Duplication

Occurs during S phase; DNA content increases from 2n to 4n.

Signup and view all the flashcards

Prophase

The first stage of mitosis where chromosomes condense and become visible.

Signup and view all the flashcards

Metaphase

The second stage of mitosis where chromosomes align in the cell's equatorial plane.

Signup and view all the flashcards

Anaphase

The third stage of mitosis where sister chromatids are pulled apart to opposite sides of the cell.

Signup and view all the flashcards

Telophase

Final stage of mitosis where chromosomes decondense and the nuclear envelope re-forms.

Signup and view all the flashcards

Chromatids

Identical halves of a duplicated chromosome, connected at the centromere.

Signup and view all the flashcards

Apical Meristem

Region of actively dividing cells at the tips of roots and shoots in plants.

Signup and view all the flashcards

Onion Root Cells

Cells from onion roots commonly used to study mitosis due to their large nuclei.

Signup and view all the flashcards

Prometaphase

Phase where the nuclear envelope breaks down and chromosomes attach to spindle microtubules.

Signup and view all the flashcards

Mitotic spindle

A structure made of microtubules that segregates chromosomes during mitosis.

Signup and view all the flashcards

Kinetochores

Protein structures on chromosomes where spindle fibers attach during cell division.

Signup and view all the flashcards

Study Notes

Microscopic Observations of Mitotic Divisions

  • Theoretical Part: A student should know the structure of an optical microscope and the phases of mitosis.

Microscope Construction

  • Optical and Mechanical Systems: Microscopes combine optical (lighting and magnifying) and mechanical (positioning) systems.
  • Optical System: The first part focuses on optimal illumination, the second magnifies the image.
  • Mechanical System: Positioning of individual optical system elements.
  • Image Characteristics: The resulting image is magnified, and virtual.

Optical Elements

  • Light Source: Modern microscopes use a built-in light bulb with a reflector. Light intensity adjusts based on magnification.
  • Condenser: A set of lenses concentrate light into a cone to illuminate the specimen.
  • Diaphragm: Controls the amount of light entering the condenser.
  • Lenses: Magnify the image, creating a real image of the specimen. Dry lenses magnify up to 60 times, immersion lenses up to 150 times. Immersion oil is used with immersion lenses for enhanced resolution up to 0.16 µm.
  • Ocular Lens (Eyepiece): Creates a virtual magnified image; magnification typically ranges from 2-30 times.
  • Immersion Oil: Used with immersion lenses, increasing resolution.

Mechanical Elements

  • Base and Arm: Provide structural rigidity.
  • Mechanical Stage: Allows for horizontal movement to change the field of view.

Cell Cycle

  • Interphase: The period between mitotic divisions. It involves G1 (pre-DNA synthesis), S (DNA synthesis), and G2 (pre-division) phases.
  • M Phase (Mitosis): The actual division of the cell nucleus. Consists of prophase, prometaphase, metaphase, anaphase, and telophase, followed by cytokinesis.

Mitosis Phases

  • Prophase: Chromatin condenses, chromosomes become visible, and the mitotic spindle forms outside the nucleus.
  • Prometaphase: The nuclear envelope breaks down. Chromosomes attach to the spindle microtubules.
  • Metaphase: Chromosomes align in the equatorial plane of the spindle.
  • Anaphase: Sister chromatids separate and move to opposite poles of the cell.
  • Telophase: Daughter chromosomes reach the spindle poles, new nuclear envelopes form, and two nuclei are formed.

Cytokinesis

  • Cytoplasmic Division: The cell cytoplasm divides, creating two daughter cells, each with one nucleus.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

More Like This

Use Quizgecko on...
Browser
Browser