Biology Chapter: Cell Structure and Division

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Questions and Answers

What process forms somatic cells?

Meiosis

Cloning

Mitosis (correct)

Binary fission

What type of cells are gametes classified as?

Diploid

Haploid (correct)

Triploid

Tetraploid

How genetically diverse are gametes?

Genetically identical

Homogeneous

Genetically diverse (correct)

Identical to parent cells

Which stage of the cell cycle is not involved in mitosis?

Interphase Signup and view all the answers

If an organism is diploid with 44 chromosomes, how many chromosomes would it have in its haploid cells?

22 Signup and view all the answers

What is one reason why mitosis occurs in an organism?

To replace old or damaged cells Signup and view all the answers

Which characteristic applies to meiosis but not to mitosis?

Results in genetic diversity Signup and view all the answers

What is a disadvantage of asexual reproduction?

Low genetic diversity Signup and view all the answers

What does independent assortment refer to in meiosis?

The random alignment of chromosomes during metaphase I Signup and view all the answers

Which statement accurately describes mitosis?

It maintains the chromosome number in daughter cells Signup and view all the answers

What occurs during apoptosis?

Cells undergo programmed cell death Signup and view all the answers

Why do cancer cells divide uncontrollably?

They lose the ability to control their growth Signup and view all the answers

In which phase of meiosis does independent assortment primarily take place?

Metaphase I Signup and view all the answers

How many genetically diverse daughter cells are produced by meiosis?

Four Signup and view all the answers

Which of the following is a characteristic of meiosis?

Reduces chromosome number by half Signup and view all the answers

What often triggers apoptosis in cells?

Damage or unneeded cells Signup and view all the answers

What distinguishes cancerous cells from normal cells in terms of cell cycle regulation?

Cancer cells do not undergo apoptosis. Signup and view all the answers

Which statement about cyclins is accurate?

Cyclins are proteins that help regulate the cell cycle. Signup and view all the answers

How do the growth patterns of cancer cells compare to those of healthy cells?

Cancer cells grow and divide uncontrollably. Signup and view all the answers

What is one key difference in the cell cycle between regular cells and cancerous cells?

Regular cells have longer cell cycles with checkpoints. Signup and view all the answers

Identifying why cancer cells may not function properly, which is true?

Cancer cells are often unable to perform their functions due to uncontrolled growth. Signup and view all the answers

What happens to the surface area to volume ratio as a cell increases in size?

It decreases. Signup and view all the answers

Why is it inefficient for cells to grow too large?

Because their volume increases faster than surface area. Signup and view all the answers

How is DNA structured in prokaryotic cells compared to eukaryotic cells?

Prokaryotic cells contain single circular DNA, whereas eukaryotic cells have multiple chromosomes. Signup and view all the answers

Which of the following stages is NOT part of Interphase?

M Signup and view all the answers

What occurs during the S phase of Interphase?

Replication of DNA. Signup and view all the answers

Which statement best describes the G1 phase of Interphase?

Cell increases in size and synthesizes proteins. Signup and view all the answers

What is the longest stage of mitosis?

Prophase Signup and view all the answers

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

The cell prepares for division and checks its readiness. Signup and view all the answers

What event occurs first during the process of mitosis?

Chromatin condenses into chromosomes Signup and view all the answers

During which phase do chromosomes align in the center of the cell?

Metaphase Signup and view all the answers

What happens during anaphase?

Sister chromatids move to opposite ends of the cell Signup and view all the answers

What is the main difference in cytokinesis between plant and animal cells?

Plant cells pinch inwards while animal cells form a cell plate Signup and view all the answers

Which of the following statements about telophase is correct?

Chromatids reach opposite poles and the nuclear envelope begins to reform Signup and view all the answers

What role do spindle fibers play during mitosis?

They pull sister chromatids apart Signup and view all the answers

What defines somatic cells?

All non-reproductive cells in the body Signup and view all the answers

What begins to occur during prophase?

The nuclear envelope disappears and spindle fibers form Signup and view all the answers

Study Notes

Surface Area to Volume Ratio

As a cell grows, its surface area to volume ratio decreases.
This makes it less efficient for the cell to transport nutrients and waste in and out.

DNA in Prokaryotic and Eukaryotic Cells

Prokaryotes have a single circular DNA chromosome found in the cytoplasm.
This chromosome contains all of the cell's genetic information.
Eukaryotes have much more DNA than prokaryotes and therefore contain multiple chromosomes.

Interphase

This is the longest phase of the cell cycle.
During this phase the cell grows, replicates its DNA, and prepares for division.
Interphase is divided into three subphases:
- G1: the cell increases in size and synthesizes new proteins and organelles.
- S: DNA is synthesized when the chromosomes are replicated.
- G2: the cell prepares for nuclear and cellular division and does a double check to make sure it is ready to divide.

Mitosis

This is the process of nuclear division that produces two daughter cells that are genetically identical.
It's divided into four stages:
- Prophase: The chromatin condenses into chromosomes, the nuclear envelope begins to disappear, centrioles migrate to opposite ends of the cell, and spindle fibers begin to form.
- Metaphase: Chromosomes move to the center of the cell along microtubules and line up on the imaginary "metaphase plate".
- Anaphase: Sister chromatids separate at the centromere and are pulled to opposite poles of the cell.
- Telophase: Chromatids reach the opposite poles of the cell, unwind into chromatin, and the spindle fibers disappear. The nuclear envelope reforms around the chromosomes, and cytokinesis begins.

Cytokinesis

This is the division of the cytoplasm.
In animal cells, the plasma membrane pinches together inwards, separating the two daughter cells.
In plant cells, a cell plate forms at the equator, separating the two daughter cells.

Somatic Cells

Somatic cells are any cells in the body that are not reproductive cells.
They are formed through mitosis.
They are diploid, meaning they have two sets of chromosomes.
They are genetically identical to the parent cell.

Gamete Cells

Gamete cells are reproductive cells.
They are formed through meiosis.
They are haploid, meaning they have one set of chromosomes.
They are genetically diverse because of crossing over and independent assortment that occurs during meiosis.

Reasons for Mitosis

Growth and development of an organism.
To replace old or damaged cells.
To repair cell tissue.

Diploid Number

If an organism has a haploid number of 22, then the diploid number would be 44.

Asexual Reproduction

Advantages:
- Faster than sexual reproduction because it doesn't need a mate.
Disadvantages:
- Produces offspring that are genetically identical to the parent, limiting genetic diversity.
- This means the offspring may not be as well adapted to changing environments.

Independent Assortment

This is the process during meiosis where chromosomes randomly align at the metaphase plate.
It occurs in metaphase I of meiosis.

Nuclear Division (Mitosis vs. Meiosis)

Mitosis: The chromosome number remains the same in daughter cells and the cells are genetically identical.
Meiosis: Two rounds of division occur, and the chromosome number is halved in daughter cells, resulting in four genetically diverse daughter cells.

Apoptosis

This is the process of programmed cell death.
It can happen to remove damaged cells or cells that are no longer needed.

Cancer

It occurs when cells lose the ability to control their growth.
Cancer cells don't respond to the signals that regulate the growth of normal cells, and divide uncontrollably.
This can be due to genetic mutations or environmental factors.

Comparing Healthy Cells to Cancer Cells

Healthy cells go through the cell cycle slower, with regular checkpoints, while cancer cells don't.
Healthy cells go through apoptosis when needed, while cancer cells don't.
Cancer cells grow and divide uncontrollably.
Cancer cells may not do their functions properly.

Cyclins

Cyclins are a family of proteins that regulate the cell cycle.

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Description

Explore the essential concepts of cell structure and division through this quiz. Covering topics such as surface area to volume ratio, DNA differences in prokaryotic and eukaryotic cells, interphase stages, and the process of mitosis, this quiz will test your understanding of cellular biology.