Cell Biology: Growth and Reproduction

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Questions and Answers

What is one reason why cells cannot grow indefinitely large?

They have limited types of materials to absorb.

They require a larger membrane for every increase in size.

They cannot produce enough ATP for larger volumes.

The surface-area-to-volume ratio decreases as they grow. (correct)

Which process occurs to resolve the limitations of the surface-area-to-volume ratio?

Cell division (correct)

Cell elongation

Mitosis only

Diffusion

How does the volume of a cell change relative to its surface area as it grows?

Both surface area and volume increase at the same rate.

Volume increases more rapidly than surface area. (correct)

Volume increases more slowly than surface area.

Surface area increases more quickly than volume.

What must occur before a cell can successfully divide?

It must replicate its DNA. Signup and view all the answers

In which type of organisms does asexual reproduction primarily occur?

In both single-celled and some multicellular organisms. Signup and view all the answers

What analogy is used to explain the issue with a cell's surface-area-to-volume ratio?

A traffic jam in a growing town. Signup and view all the answers

What characteristic of a smaller cube (cell) enhances its efficiency in nutrient exchange?

Greater surface area relative to its volume. Signup and view all the answers

What is the main challenge cells face as they grow larger?

Insufficient surface area for material movement. Signup and view all the answers

What is the primary advantage of cell division in terms of cell size?

It helps maintain a higher surface-area-to-volume ratio. Signup and view all the answers

What type of reproduction occurs in single-celled organisms like bacteria?

Asexual reproduction Signup and view all the answers

Which of the following is a characteristic of asexual reproduction?

Generates a large number of genetically identical offspring. Signup and view all the answers

What is the main disadvantage of asexual reproduction in changing environments?

It cannot adapt to new environmental challenges. Signup and view all the answers

In sexual reproduction, offspring inherit traits from how many parents?

Two Signup and view all the answers

Why might rapid reproduction be beneficial under unlimited resource conditions?

To occupy available resources quickly. Signup and view all the answers

What is a key characteristic of offspring produced through sexual reproduction?

They show genetic variation. Signup and view all the answers

Which of the following is NOT a reason for asexual reproduction's efficiency?

Offspring have increased genetic variability. Signup and view all the answers

Study Notes

Cell Growth, Division & Reproduction

Single-celled organisms are very small and often invisible to the naked eye. Larger organisms are made of numerous tiny cells, not a few large ones.
Some organisms reproduce asexually and some sexually.
Cells in a human body reproduce asexually continuously, while the human organism itself reproduces sexually.

Surface Area to Volume Ratio

A cell's size creates a surface area-to-volume ratio problem. As a cell gets larger, its volume increases faster than its surface area.
To find a cube's surface area, calculate the area of one side and multiply by six. Surface area is length times width for each side.
To find a cube's volume, multiply length times width times height.
Volume increases faster than surface area in growing cells.

Cell Growth Limitations

Cell growth requires more materials to move across the cell membrane.
Increasing volume of a cell means there are not enough "traffic lanes" (surface area) for materials to move across the membrane.
Materials like nutrients and oxygen need to enter efficiently into the cell and waste products leave with equal efficiency. Too much volume relative to surface area causes the exchange process to slow to a crawl.
If a cell gets too large, not enough material can pass through its membrane fast enough to sustain the cell, hindering growth.

Cell Division

To solve the surface-area-to-volume ratio problem that growing cells face, cells divide, producing two "daughter cells".
Sufficient DNA must be present to ensure each daughter cell has enough to support its own function. Before cell division, DNA must replicate, thereby creating a backup for the daughter cells.

Asexual Reproduction

Reproduction is important for life. For single-celled organisms like bacteria, simple cell division creates a simple form of reproduction.
Asexual reproduction is a fast method of creating many genetically identical "offspring"
This form of reproduction is known as binary fission, and is a rapid method for population growth and survival.

Sexual Reproduction

Multicellular organisms like humans reproduce through sexual reproduction.
Sexual reproduction creates offspring that are not genetically identical to either parent.
Sexual reproduction involves the fusion, or combination, of cells like egg and sperm.

Comparing Sexual and Asexual Reproduction

Asexual reproduction is fast when resources needed for survival are abundant
When environmental conditions are stable, and offspring must be genetically identical to their parent, asexual reproduction is the preferred method.
Sexual reproduction generates offspring that are not genetically identical to either parent. This allows for more genetic variation, which is essential when environments are changing and new combinations of traits are beneficial.

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Description

Explore the fundamental concepts of cell growth, division, and reproduction in this quiz. Understand how single-celled and multi-celled organisms differ in their reproductive strategies and the implications of surface area to volume ratios in cells. Discover the limitations faced by cells as they grow and how these factors influence their functionality.