Mitosis Lab (Biology Final) Flashcards

Questions and Answers

Why is it more accurate to call mitosis nuclear replication rather than cellular division?

It is more accurate to call mitosis nuclear replication because the cell doesn't really divide. Mitosis is just the cell's nucleus dividing into 2 separate nuclei, not the cell.

Explain why whitefish blastula and onion root tip are selected for the study of mitosis.

They are selected because whitefish blastula and onion root tip have cells that rapidly divide, making it easier to see the different stages of mitosis under a microscope.

Many of the cells of the root meristem are not undergoing mitosis, rather they are in a stage called ______.

interphase

Based on the interpretations made, interphase appears to be much _____ than mitosis.

longer Signup and view all the answers

What processes occur in interphase cell prior to the onset of mitosis?

G1- cell growth and checking DNA to see if it's ready. Organelles and proteins are formed. S Phase- DNA replicated, the molecules are packaged into chromosomes, 2 chromatids are attached by adhesive proteins all along their lengths. G2- metabolic activity and growth, and 2 centrosomes have formed. Signup and view all the answers

Once cell division ends, the cells will exit the cell cycle and enter the _____ stage.

G0 Signup and view all the answers

Why is it incorrect to say that these cells are resting?

Because while the cells aren't dividing, they are still in a state of metabolic activity. Signup and view all the answers

If your observations had not been restricted to the area of the root tip that is actively dividing, how would your results have been different?

You may have found way more cells in interphase. Your results would have shown poor percentages of the other stages of mitosis. Signup and view all the answers

What evidence shows that mitosis is a continuous process and not a series of separate events?

One piece of evidence would be that it is a cycle, and it keeps going. Also, each stage of mitosis depends on one another. Signup and view all the answers

What would happen if the process of mitosis skipped metaphase? Telophase?

If mitosis skipped metaphase, the cell may not divide, because the chromosomes would not have enough time to line up on the metaphase plate. If mitosis skipped telophase, the cell wouldn't divide. Everything new forms in telophase. Signup and view all the answers

How many chromosomes are in each of the cells that you observed?

The number of chromosomes would be X because daughter and parent cells are the exact same. Signup and view all the answers

After meiosis, how many chromosomes would be in each sex cell?

It would be 1/2 X because meiosis splits the amount of chromosomes in half. Signup and view all the answers

How many chromosomes would be in the zygotes that are produced after sexual reproduction?

It would be X. Signup and view all the answers

Where does one find cells undergoing meiosis in plants?

I got this wrong, so if anyone has the answer, let me know. Signup and view all the answers

Where does one find cells undergoing meiosis in animals?

I got this wrong, so if anyone has the answer, let me know. Signup and view all the answers

Some tissues in both plants and animals rarely divide once the organism is mature. Where are they found in plants?

They are found in strengthening and fluid connecting tissues. Signup and view all the answers

Some tissues in both plants and animals rarely divide once the organism is mature. Where are they found in animals?

These tissues are found in heart muscles and neurons in the brain. Signup and view all the answers

Study Notes

Mitosis Overview

Mitosis is more accurately termed "nuclear replication" as it involves the division of the nucleus into two nuclei, not the entire cell.
Whitefish blastula and onion root tip are chosen for study due to their rapidly dividing cells, facilitating observation of mitosis stages.

Interphase

A significant portion of root meristem cells are in interphase, a stage different from mitosis.
Interphase is longer compared to mitosis.
Processes in interphase include:
- G1 Phase: Cell growth, DNA assessment for readiness, organelle, and protein synthesis.
- S Phase: DNA replication occurs, and chromosomes are prepared with chromatids attached.
- G2 Phase: Continued growth and metabolic activity, formation of centrosomes.

Cell Cycle and Metabolic Activity

Once cell division concludes, cells enter the G0 phase.
Cells in G0 are not resting; they maintain metabolic activity despite not dividing.

Observations and Results

Focusing observations only on actively dividing root tips likely leads to fewer interphase cells being counted, affecting mitosis stage percentages.

Continuous Nature of Mitosis

Mitosis is a continuous cycle where each stage relies on the preceding one, indicating that each phase is interconnected.

Consequences of Skipping Mitosis Stages

Skipping metaphase may prevent proper chromosome alignment, hindering division.
Omitting telophase would disrupt the formation of cells, as key structures develop during this phase.

Chromosome Count and Reproduction

An onion plant begins as a single cell with X chromosomes; daughter cells retain this chromosome count post-mitosis.
For sexual reproduction, meiosis reduces the chromosome number in sex cells to 1/2 X.
Zygotes formed post-fertilization would have X chromosomes, equal to the parent cell's count.

Meiosis in Plants and Animals

Cells undergoing meiosis in plants and animals were not specifically identified but are essential for sexual reproduction.
In mature plants, tissues that rarely divide include strengthening and fluid connective tissues.
In mature animals, non-dividing tissues include heart muscle and neurons.

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Description

This quiz focuses on key concepts related to mitosis, specifically in the context of a biology final. It covers the accuracy of the term 'nuclear replication' and the importance of specific organisms in studying mitosis. Test your understanding of these crucial biological processes!