G12 1Q SUMMARIZED NOTES BIOLOGY

What is Microscopy?

The science of using microscopes to view objects too small for the naked eye. The word comes from the Latin "microscopium," derived from the Greek words mikros (small) and skopein (to look at).

Who invented the first compound microscope and when?

Hans and Zacharias Janssen (1595).

What were the features of the first compound microscope?

Built using 3 draw tubes and lenses inserted into the ends of the flanking tubes.

Who first observed and named cells, and when?

Robert Hooke (early 1600s).

How did Robert Hooke discover cells?

He used a primitive compound microscope to examine cork and saw small box-like structures resembling a honeycomb, which he named "cells" after monks’ living quarters.

What is "Micrographia"?

A book by Robert Hooke (1665) containing detailed illustrations of specimens viewed under a microscope, including the first depiction and naming of "cells."

Who first observed microorganisms and when?

Antonie van Leeuwenhoek (late 1600s).

What did Antonie van Leeuwenhoek discover and how?

He made his own single-lens microscope and was the first to see Bacteria, protists, WBC, RBC, yeast, sperm cells, water, plaque, and dental scrapings.

What was the significance of Antonie van Leeuwenhoek's discoveries?

His discovery showed that life exists beyond what the naked eye can perceive.

Who laid the foundation for understanding cellular organization with early cell theory?

Matthias Schleiden (botanist) and Theodor Schwann (zoologist) in the 1800s.

What was a key observation made by Schleiden and Schwann?

Both observed that cells have a central structure, the nucleus.

What were the tenets of the Unified Cell Theory?

1. All organisms consist of one or more cells. 2. Cells are the basic unit of structure for all organisms. 3. Cells form by spontaneous generation.

Who refuted the idea of spontaneous generation in cell theory?

Rudolf Virchow (late 1800s).

What was Rudolf Virchow's famous statement regarding cell reproduction?

"All cells come from pre-existing cells" (Latin: Omnis cellula e cellula).

What does Virchow's concept of cellular reproduction mean?

This concept emphasizes that cells do not spontaneously regenerate, but every cell arises from another cell.

Who truly first published the idea that all cells come from other cells, and who popularized it?

Robert Remak first published the idea that all cells come from other cells in 1852, while Rudolf Virchow popularized it in his 1855 essay "Cellular Pathology."

What are the tenets of the Revised Cell Theory?

1. All organisms consist of one or more cells. 2. Cells are the basic unit of structure for all organisms. 3. Cells come from other pre-existing cells.

How did Francisco Redi support cell theory?

His meat in jars experiment disproved "spontaneous generation."

How did Louis Pasteur support cell theory?

His swan-neck flask experiment proved microbes come from other microbes, refuting spontaneous generation of microorganisms.

How did Walther Flemming support cell theory?

He observed mitosis (cell division), showing how cells reproduce and the orderly distribution of chromosomes during cell division.

What is Binary Fission?

Asexual reproduction in prokaryotic cells where a single cell divides into two identical daughter cells.

How did August Weismann contribute to modern cell theory?

He proposed the germ plasm theory, stating that DNA in the nucleus passes traits, and discovered meiosis as the process that creates germ cells.

What are the tenets of the Modern Cell Theory?

1. All organisms consist of one or more cells. 2. Cells are the basic unit of structure for all organisms. 3. Cells come from other pre-existing cells. 4. Cells contain hereditary information (DNA). 5. All cells have the same basic chemical composition. 6. Energy flow occurs within cells.

What four basic features are shared by all cells (prokaryotic and eukaryotic)?

1. DNA (chromosomes) – the genetic material. 2. Plasma membrane – the outer layer that controls what enters and exits the cell. 3. Cytoplasm (or cytosol) – the fluid inside the cell where cellular components are suspended. 4. Ribosomes – structures that produce proteins.

What are the key features of Prokaryotic Cells?

• Cytoplasm: The fluid inside the cell. - Nucleoid: Area where DNA is located. - Plasmids: Small circular DNA that can be shared between cells. - Ribosomes: RNA-protein complexes that make polypeptides (proteins). - Cell membrane: Semi-permeable and selective barrier surrounding the cell. - Cell wall: Made of peptidoglycan; gives the cell shape and protection. - Slime capsule: Thick polysaccharide layer; protects the cell from desiccation (drying out) and phagocytosis (immune system attacks). - Flagella: Tail-like structures used for movement. - Pili: Hair-like structures used to stick to surfaces or transfer DNA.

Describe common Prokaryotic Cell Arrangements.

• Coccus: Single round cell. - Diplococcus: A pair of round cells. - Tetrad: Four round cells in a square. - Streptococcus: A chain of round cells. - Staphylococcus: A cluster of round cells. - Bacillus: A single rod-shaped cell. - Streptobacillus: A chain of rod-shaped cells. - Vibrio: A curved rod shape. - Coccobacillus: A short rod. - Spirillum: Spiral-shaped. - Spirochete: Long, loose helical spiral.

What are the main features of Eukaryotic Cells?

• Have a nucleus containing DNA ("eu" = good/true; "karyon" = nucleus). - Have a more complex structure and are believed to have evolved from prokaryotic cells (via endosymbiosis). - Contain membrane-bound organelles like mitochondria, chloroplasts, endoplasmic reticulum, and the Golgi apparatus. - Larger and more complex than prokaryotic cells. - Can reproduce through mitosis (asexual) or meiosis (sexual). - Have multiple linear chromosomes.

Compare the major differences between Prokaryotic and Eukaryotic Cells.

• SIZE: Typical prokaryotic cell: 0.1-5 \; µm. Typical eukaryotic cell: 10-100 \; µm. - PRESENCE OF NUCLEUS: Typical prokaryotic cell: No true nucleus. Typical eukaryotic cell: Has a true nucleus. - INTERNAL ORGANIZATION: Typical prokaryotic cell: No membrane-bound organelles. Typical eukaryotic cell: Contains membrane-bound organelles. - REPRODUCTION/CELL DIVISION: Typical prokaryotic cell: Asexual reproduction by binary fission. Typical eukaryotic cell: Can reproduce asexually (mitosis) or sexually (meiosis).

What are the basic functions of cells?

• Provides Support and Structure: Cells form the basic structure of all living organisms; in plants, the cell wall and membrane maintain shape and protection. - Facilitates Growth Through Mitosis: Cells divide to produce more cells, helping organisms grow and replace old or damaged cells. - Allows Transport of Substances: Cells bring in nutrients and remove waste to support all cellular processes. - Energy Production: Cells produce energy to carry out functions (e.g., photosynthesis in plants, cellular respiration in animals). - Aids in Reproduction: Cells reproduce through meiosis to create genetically unique offspring, especially in sexually reproducing organisms.