Select your language

Suggested languages for you:
Log In Start studying!
StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free
|
|

All-in-one learning app

  • Flashcards
  • NotesNotes
  • ExplanationsExplanations
  • Study Planner
  • Textbook solutions
Start studying

Cell Division

Save Save
Print Print
Edit Edit
Sign up to use all features for free. Sign up now
Biology

Did you know that every time you scraped your knee or elbow, some of your skin cells were damaged? Luckily, thanks to cell division, your body produces cells to replace the damaged ones, i.e. the healthy cells divide and create replacements.

Cell division refers to how a parent cell divides to produce two or more daughter cells. There are two types of cell division in the eukaryotic cells - mitosis and meiosis. Mitosis will produce two genetically identical daughter cells, while meiosis will produce four daughter cells that are genetically different.

Cell division in the cell cycle

A cell will undergo a series of events during its life cycle before it goes into division (mitosis). There are five main phases in the cell cycle (Figure 1).

  1. G1 - The cell grows in size and increases the number of organelles such as mitochondria and ribosomes.

  2. S - DNA is copied and replicated in the preparation of cell division.

  3. G2 - The cell grows and increases protein synthesis to prepare for nuclear division.

  4. Mitosis and cytokinesis - The cell goes through a series of events (these will be covered later in this article!) and divides to produce two or more daughter cells.

  5. G0 - There is a brief period where the cell will rest, also known as quiescence. The cell will not be growing or preparing for cell division.

G0, G1, G2 and S phases are collectively referred to as interphase.

Cell Division [+] an overview of the cell cycle [+] StudySmarter

Figure 1. An overview of the cell cycle; M - Mitosis, I - Interphase. Source: Zephyris at English Wikipedia. derivative work: Beao, CC-BY-SA-3.0

Some cells will never leave G0. This commonly occurs in fully differentiated cells, for example, adult neurons. You have probably heard about Dementia and Alzheimer’s as incurable diseases. This is because neurons do not renew themselves. The treatments for these neurological disorders only slow further damage.

Mitotic cell division

Mitosis is the division of somatic (body) cells. Mitosis does not take place in the production of sex cells (gametes). Mitosis, although a continuous process, to simplify, can be divided into four main stages - prophase, metaphase, anaphase and telophase (and cytokinesis).

What is the difference between the chromosome and the chromatid?

Before we dive into the cell division, let’s make sure you can understand the difference between the chromosome and the chromatid. It can be easy to confuse them (they sound pretty similar).

Chromosomes are x-shaped structures that contain DNA, i.e. the hereditary information used during the cell division. They are present in the nucleus of eukaryotic organisms. Prokaryotes will have a ring-shaped genophore (which contains DNA) instead.

A chromosome will contain two sister chromatids. They are held together at the centromere.

Stages in Mitosis

  1. Prophase - The nuclear envelope breaks down, and the chromosomes condense and become visible. Centrioles (microtubules found near the nuclear membrane) start to move to the opposite poles of the cell. Centrioles will start forming spindle fibres.
  2. Metaphase - Chromosomes line up at the equator, and spindle fibres attach to the centromeres (a region of a chromosome that holds the two chromatids together).
  3. Anaphase - Sister chromatids are pulled apart and pulled towards the opposite poles.
  4. Telophase - Chromatids reach the opposite poles. Cell pinches in the middle, and the nuclear membrane forms around the new nucleus. Spindle fibres will start to break down.

Cytokinesis goes hand in hand with telophase. It defines the final physical split of the cell to produce two genetically identical cells.

Cell Division [+] an overview of mitosis [+] StudySmarter

Figure 3. An overview of mitosis. 2n - a diploid (two sets of chromosomes) cell. Source: Schoolbag.info, via Wikimedia Commons, CC-BY-SA-4.0.

Meiotic cell division

Meiosis and mitosis are different processes. However, the interphase in both these types of cellular division is the same.

The development of sperm is called spermatogenesis, and the development of an egg is oogenesis. Spermatogenesis in males will continue throughout their lives, while oogenesis in females will only occur until menopause.

Most of the other animals will not go through menopause like human females. Only killer whales and pilot whales have been observed to do so. Other animals’ reproductive organs will last about as long as they will.

Meiosis has two parts - meiosis I and meiosis II.

Meiosis I

The first time the cell divides, the daughter cells will have two sets of chromosomes (diploid).

Unique to meiosis I, paired homologous chromosomes (bivalents) will go through recombination in which they exchange genetic information with each other. Homologous chromosomes (same genetic information) will line up and swap segments.

The stages in meiosis I are the same as in mitosis. The only difference lies in prophase I. During the prophase I stage, in addition to the DNA being copied and replicated to produce two sets of chromosomes, the chromosomes will also undergo recombination.

Meiosis II

The second time the cell divides, the sister chromatids of the two daughter cells will split, and each will form two haploid (single-set of chromosomes) cells (also known as granddaughter cells).

There is an importance to egg and sperm cells being haploid. Male and female gametes will meet, and sperm will fertilise the egg. The embryo will contain two sets of chromosomes during fertilisation, becoming a diploid.

The principle of Meiosis II is almost identical to that of Meiosis I. The two differences are:

  • Meiosis I will produce two diploid cells, and Meiosis II will produce four haploid cells.
  • Genetic recombination only occurs in Meiosis I.

Cell Division [+] an overview of meiosis [+] StudySmarterFigure 4. An overview of meiosis. 2n - a diploid cell, n - a haploid (one set of chromosomes) cell, Ali Zifan, CC-BY-SA-4.0 via Wikimedia Commons

Cell division in prokaryotes

Binary fission is the asexual reproduction of the cell into two identical organisms.

Cell division in prokaryotes is referred to as binary fission. Binary fission is simpler than mitosis or meiosis in eukaryotic cells (Figure 5).

To help you understand the steps better here are some key points:

  1. 1-2: Chromosomes uncoil in the parent cell;
  2. 3: DNA is replicated, and segregation of DNA occurs;
  3. 4: Cleavage starts forming; 5-6:
  4. Two identical daughter cells produced.

Cell Division [+] a binary fission in a prokaryotic cell [+] StudySmarterFigure 5. Binary fission in a prokaryotic cell. Source: Ecoddington14, CC-BY-SA-3.0, via Wikimedia Commons.

Cell division (asexual reproduction) in unicellular yeast is called budding.

The adult yeast cell is spherical and larger than the forming bud. After the nucleus divides, an identical daughter cell is produced (Figure 6).

Cell Division - Key takeaways

  • Cell division of eukaryotic cells is either mitotic (somatic cells) or meiotic (sex cells). Unicellular cell divisions are for reproductive purposes such as budding in yeast and binary fission in bacteria.

  • Mitosis has four main stages - prophase, metaphase, anaphase and telophase. The cell will then physically split by cytokinesis. Mitosis produces two genetically identical cells.

  • Meiosis has two parts - Meiosis I and Meiosis II.

  • Both meiosis parts have the same stages as in mitosis. However, meiosis will produce four genetically different haploid cells.

Cell Division

Mitosis

Mitosis

Cell division refers to the process during which a parent cell divides to produce two or more daughter cells.

Two

One

Final Cell Division Quiz

Question

Mitosis will produce four genetically identical diploid cells. True or False?


Show answer

Answer

False

Show question

Question

What is quiescence?

Show answer

Answer

A state of rest in the cell cycle.

Show question

Question

What happens in G1 and G2 phases in interphase?


Show answer

Answer

G1 is the first phase of growth where it will grow and synthesise important molecules for division. In G2 (the third phase), the cell will continue to grow further and prepare for nuclear division.

Show question

Question

Telophase and cytokinesis are both about division. What is the difference?


Show answer

Answer

During the telophase, the nucleus splits. In cytokinesis, the cytoplasm completely divides and two separate cells form.

Show question

Question

How many sets of chromosomes do sex cells have?


Show answer

Answer

One set of chromosomes.

Show question

Question

What is oogenesis?

Show answer

Answer

Development of the egg cell.

Show question

Question

Fill in the blanks about Meiosis I. Meiosis I is the _______ cell division in Meiosis. The resulting daughter cells will have ________ ________ of chromosomes. Paired chromosomes are also known as _________. Before the recombination, the chromosomes will be___________. During the recombination, the chromosomes will swap _________ information. The chromosomes will now be ____________.

Show answer

Answer

Meiosis I is the first cell division in Meiosis. The resulting daughter cells will have two sets of chromosomes. Paired chromosomes are also known as bivalents. Before the recombination, the chromosomes will be homologous. During the recombination, the chromosomes will swap genetic information. The chromosomes will now be different.

Show question

Question

Choose one correct answer about Meiosis I. During which phase is Meiosis I, do the chromosomes line up at the equator of the cell?


  1. Anaphase I
  2. Metaphase I
  3. Anaphase II
  4. None of the above

Show answer

Answer

Metaphase I

Show question

Question

How does a granddaughter cell form?

Show answer

Answer

During Meiosis II, each diploid cell will form two haploid cells which results in four haploid granddaughter cells overall.

Show question

Question

Genetic recombination only occurs in Meiosis I. True or False?


Show answer

Answer

True

Show question

Question

What is binary fission?


Show answer

Answer

Asexual reproduction in prokaryotes.

Show question

Question

What helps the movement of the chromosomes to the different poles of the cell during meiosis and mitosis?


Show answer

Answer

Spindle fibres/spindle apparatus.

Show question

Question

What is cytokinesis?


Show answer

Answer

Cytokinesis is the physical split of the cell.

Show question

Question

During which phase, do the chromosomes condense in mitosis?


Show answer

Answer

Prophase.

Show question

Question

Why are sex cells haploid?


Show answer

Answer

Gametes are haploid (one set of chromosomes) because they will need to join the other sex cell to produce a diploid cell. The embryo formed from sperm and egg cells will have a combined number of parental chromosomes and become diploid.

Show question

Question

What are the four phases of mitosis?

Show answer

Answer

Prophase, metaphase, anaphase and telophase.

Show question

Question

What is cytokinesis and when does it occur?

Show answer

Answer

Cytokinesis is the physical split of the cell, when the cytoplasm separates. It will occur following telophase.

Show question

Question

What happens before mitosis?


Show answer

Answer

The cell grows, replicates its DNA and gets ready for mitosis.

Show question

Question

What is the difference between the centromere and the kinetochore?


Show answer

Answer

Centromere refers to the constricted region that holds the two chromatids in the chromosome together. Kinetochore is the protein structure associated with the centromere to which spindle fibres will attach during mitosis.

Show question

Question

Interphase is the first stage of mitosis. True or False?


Show answer

Answer

False.

Show question

Question

Fill in the blanks about metaphase. ________ fibres have fully arrived at the _________ poles of the cell. They are organised by the ______________ when they arrive. _________ line up at the ___________. ____________ fibres are attached to the ___________ which are at the __________ of the chromosome.

Show answer

Answer

Spindle fibres have fully arrived at the opposite poles of the cell. They are organised by the centrosomes when they arrive. Chromosomes line up at the equator/metaphase plate. Spindle fibres are attached to the kinetochores which are at the centromere of the chromosome.

Show question

Question

The centromeres of the chromosome are pulled apart by the spindle apparatus. True or False?

Show answer

Answer

True.

Show question

Question

Telophase and cytokinesis is all about the split of the cell. How are they different?


Show answer

Answer

During telophase the nucleus splits into two and the nuclear membrane will form around each new nucleus. Cytokinesis is the final split of the cytoplasm.

Show question

Question

During what stage of the cell cycle are chromatids replicated?


Show answer

Answer

Interphase.

Show question

Question

What are the two differences between plant and animal mitosis?


Show answer

Answer

The differences are:

  1. Plants do not have centrioles.
  2. Plant cell does not create a cleavage (like in an animal cell) and instead a cell wall plate will form at the equator.


Show question

Question

To observe mitosis in the plant cells, the practical requires the tissue to be squashed. Why is this?


Show answer

Answer

To produce a layer that is only one cell thick and can be observed under the microscope.

Show question

Question

What is binary fission?


Show answer

Answer

Equivalent to mitosis in eukaryotic cells, binary fission occurs in the prokaryotic cells. Two clone daughter cells are produced. During binary fission, replication of DNA and plasmids and the division of the cytoplasm will occur.

Show question

Question

A cell (2^0) takes five minutes to divide. How many times will it divide in one hour?


Show answer

Answer

4096 cells per hour produced.

Show question

Question

Calculate the mitotic index (in the ratio form) in the 100 cells. 70 of the cells were observed to be in the interphase.


Show answer

Answer

7:3 (undividing:dividing)

Show question

Question

During meiosis, four genetically identical diploid cells are produced. True or False?

Show answer

Answer

False.

Show question

Question

Fill in the blanks about uncontrolled mitosis. Cell division is carefully controlled by the _______. These can _________ and become _________ to the cellular signals. These cells become _________. They will not undergo __________ __________ __________ (PCD). PCD is regulated by the ___________.


Show answer

Answer

Cell division is carefully controlled by the genes. These can mutate and become unresponsive to the cellular signals. These cells become cancerous. They will not undergo programmed cell death (PCD). PCD is regulated by the mitochondria.

Show question

Question

What is Oncology?

Show answer

Answer

Oncology is the study of cancer.

Show question

Question

 Benign tumours are aggressive and will spread to the rest of the body. True or False?

Show answer

Answer

False.

Show question

Question

At what stage in the cell division cycle will mutations in the DNA synthesis occur?


Show answer

Answer

Mutations in the DNA synthesis will occur in the interphase.

Show question

Question

Fill in the blanks about the development of cancerous cells.


During the interphase, the DNA is _______ and _________. At this stage, ________ can occur in the DNA code. Accumulation of these can alter the sequence of __________. Genes that are responsible for cancer are called __________. ___________ _________ _________ will work to slow the cell division and help repair or destroy damaged DNA. When these genes malfunction, the cell will not respond to programmed cell death or ________. 


Show answer

Answer

During the interphase, the DNA is copied and replicated. At this stage, errors/mutations can occur in the DNA code. Accumulation of these can alter the sequence of nucleotides. Genes that are responsible for cancer are called oncogenes. Tumour suppressor genes will work to slow the cell division and help repair or destroy damaged DNA. When these genes malfunction, the cell will not respond to programmed cell death or cell cycle arrest.

Show question

Question

What is an agent for causing cancer?


Show answer

Answer

Carcinogen.

Show question

Question

What could happen if a benign tumour presses on a blood vessel?


Show answer

Answer

A vessel could rupture or become obstructed and impact the blood flow.

Show question

Question

Name two causes of benign tumours.


Show answer

Answer

Genetics and diet.

Show question

Question

What are two examples of benign tumours?

Show answer

Answer

Lypoma and myoma.

Show question

Question

What is metastatic cancer?


Show answer

Answer

Metastatic cancer is cancer that spreads from its primary (origin) site to secondary sites in the body.

Show question

Question

How will a malignant tumour spread to other parts of the body?


Show answer

Answer

A malignant tumour will spread via the lymphatic system and the bloodstream.

Show question

Question

Give two examples of an exam to detect cancer.


Show answer

Answer

Laboratory tests and biopsy.

Show question

Question

What is special about the HeLa cell line?


Show answer

Answer

The cancerous cells are immortal.

Show question

Question

At what stage does Melanoma spread to other organs?


Show answer

Answer

Melanoma spreads to other organs in the last stage (progression)/Stage IV.

Show question

Question

What happens during chemotherapy?

Show answer

Answer

Drugs will be used to stop or slow the growth of cancerous cells. Healthy cells are also affected.

Show question

Question

Why are clinical trials for cancer treatments important?


Show answer

Answer

Clinical trials are crucial for the development of new cancer treatments.

Show question

Question

Viruses are non-living microorganisms. True or False?

Show answer

Answer

False.

Show question

Question

How is the genetic information contained in a virus?

Show answer

Answer

As a chain of nucleic acids of DNA or RNA.

Show question

Question

Name two features that are present in a viral agent.


Show answer

Answer

Any features of viruses can be named. For example: chain of nucleic acids and attachment proteins.

Show question

Question

What is a viral tegument?


Show answer

Answer

A group of clustered proteins that line up between the envelope and nucleocapsid.

Show question

60%

of the users don't pass the Cell Division quiz! Will you pass the quiz?

Start Quiz

Discover the right content for your subjects

No need to cheat if you have everything you need to succeed! Packed into one app!

Study Plan

Be perfectly prepared on time with an individual plan.

Quizzes

Test your knowledge with gamified quizzes.

Flashcards

Create and find flashcards in record time.

Notes

Create beautiful notes faster than ever before.

Study Sets

Have all your study materials in one place.

Documents

Upload unlimited documents and save them online.

Study Analytics

Identify your study strength and weaknesses.

Weekly Goals

Set individual study goals and earn points reaching them.

Smart Reminders

Stop procrastinating with our study reminders.

Rewards

Earn points, unlock badges and level up while studying.

Magic Marker

Create flashcards in notes completely automatically.

Smart Formatting

Create the most beautiful study materials using our templates.

Sign up to highlight and take notes. It’s 100% free.