Cytology Introduction and Size Comparison

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Questions and Answers

What did Matthias Schleiden and Theodor Schwann contribute to the field of biology?

They discovered the structure of DNA.

They proposed that all living organisms are composed of cells. (correct)

They identified the function of mitochondria.

They created the first microscope.

Which of the following correctly defines a prokaryotic cell?

A unicellular organism with no membrane-bound nucleus or organelles. (correct)

A unicellular organism with membrane-bound organelles.

A multicellular organism with complex structures.

Any cell containing a defined nucleus.

What is the relative size of a frog egg on a logarithmic scale?

1 millimeter (correct)

10 micrometers

1 micrometer

10 millimeters

Which type of microscopy would be best for observing cellular structures in detail?

Electron Microscope Signup and view all the answers

Which cellular organization is characterized by having only one cell?

Unicellular Signup and view all the answers

What is a common misconception about eukaryotic cells?

They are always multicellular. Signup and view all the answers

Robert Hooke is primarily known for what significant observation?

The description of cells as open spaces in plant tissue. Signup and view all the answers

What is the primary characteristic of a multicellular organism?

Made up of many differentiated cells. Signup and view all the answers

What key feature distinguishes prokaryotic cells from eukaryotic cells in terms of genetic material structure?

Prokaryotic cells contain plasmids. Signup and view all the answers

Which of the following statements accurately describes the ribosomes in prokaryotic and eukaryotic cells?

Prokaryotic ribosomes are smaller than eukaryotic ones. Signup and view all the answers

Which of the following components is present in plant cells but absent in animal cells?

Plastids Signup and view all the answers

What primarily influences the growth rate of prokaryotic cells compared to eukaryotic cells?

Prokaryotic cells have a simpler metabolism. Signup and view all the answers

Which statement about the cell wall in plant and eukaryotic cells is correct?

Plant cells have a complex cell wall, while animal cells lack a cell wall entirely. Signup and view all the answers

In which aspect do eukaryotic cells primarily differ from prokaryotic cells during DNA replication?

Eukaryotic cells replicate their genome in segments. Signup and view all the answers

Which feature is exclusive to animal cells compared to plant cells?

Presence of small vacuoles Signup and view all the answers

What is a significant functional difference between the organelles in plant and animal cells?

Plant cells contain organelles for photosynthesis. Signup and view all the answers

Study Notes

Cytology

The study of cells as the fundamental units of living organisms.
Cells are the basic building blocks of all living things.
Microorganisms such as bacteria and amoebae exist as single cells.
Animals have millions of differentiated cells.
Cells come in a wide range of sizes (large, medium, small) and shapes (rounded, flattened, spindle, cuboidal, columnar, rod).

Relative Sizes on a Logarithmic Scale

The scale begins with atoms at 0.1 nanometers and ends with adult females at 1 meter.
Notable sizes include:
- Protein at 1 nanometer
- Lipids at 1 nanometer
- Flu virus at 10 nanometers
- Mitochondria at 100 nanometers
- Bacteria at 1 micrometer
- Plant cell at 10 micrometers
- Animal cell at 100 micrometers
- Human egg at 100 micrometers
- Frog egg at 1 millimeter
- Chicken egg at 10 millimeters
- Ostrich egg at 100 millimeters

Historical Figures:

Robert Hooke: The first person to observe cells and described them as open spaces within plant tissue.
Van Leeuwenhoek: First acknowledged microscopist and microbiologist in history.
Matthias Schleiden & Theodor Schwann: Proposed the "cell theory" that all living organisms are composed of cells.

Cellular Organization

All living organisms except viruses have cellular organization and consist of one or many cells.
Unicellular: Organisms with only one cell, such as bacteria and protozoa.
Multicellular: Organisms with many cells such as most plants and animals.

Cell Types

Prokaryotic: Unicellular organisms with no membrane-bound nucleus or organelles.
- Examples include bacteria.
Eukaryotic: Any cell containing a defined nucleus with membrane-bound organelles.
- Examples include animal, plant, and fungi cells.

Prokaryotic vs. Eukaryotic Cells

Characteristic	Prokaryotic Cell	Eukaryotic Cell
Nucleus	Absent (nucleoid region)	Present (membrane bound)
Cell Size	Small (less than 1 micrometer to 5 micrometers)	Large (10-100 micrometers)
Organism Type	Unicellular	Usually multicellular
Organelles	Absent	Present
DNA Replication	Replicates entire genome at once	Highly regulated with selective origins and sequences
Chromosomes	One long single loop of DNA and plasmids	More than one
Ribosomes	Small	Large
Growth/Generation time	Faster	Slower
Cell Wall	Complex	Simple (Plant+Fungi)

Similarities Between Prokaryotic and Eukaryotic Cells

Both types of cells contain cytoplasm and a plasma membrane.
Both can store hereditary information.

Plant Cell vs. Animal Cell

Feature	Plant Cell	Animal Cell
Cell Wall	Present (cell membrane + cellulose)	Absent
Vacuoles	Large central vacuole	Many small vacuoles
Centrioles	Absent	Present
Microvilli	Absent	Present in intestinal lining
Cilia and Filaments	Absent	Present
Plastids	Present	Absent

Plant Cell vs. Animal Cell: Similarities

Both plant and animal cells are eukaryotic.
Both have a true nucleus.
Both have similar reproduction processes of mitosis and meiosis.
Both have membrane-bound organelles performing similar functions.

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Description

This quiz explores the fundamental concepts of cytology, focusing on the structure and function of cells as the building blocks of life. It also delves into relative sizes of various biological entities on a logarithmic scale. Additionally, the historical significance of figures like Robert Hooke in cell discovery is highlighted.