Lecture 4 - The Cell - The Fundamental Unit of Life

Flashcards covering the fundamental units of life, including cell theory, prokaryotic and eukaryotic structures, organelle functions, and the origins of cellular complexity.

What are the three core tenets of Cell Theory including its modern additions?

All living organisms are composed of cells (unicellular or multicellular); cells come from pre-existing cells; all cells use energy and have a metabolism; all cells have similar chemical composition; and all cells have genetic information in the form of DNA.

Why is the surface area to volume ratio critical for cell size?

A greater surface area allows for greater diffusion rates, which is necessary for transporting materials into and out of the cell.

What are the three Domains of Life?

Bacteria (unicellular prokaryotes), Archaea (unicellular prokaryotes and extremophiles), and Eukarya (unicellular and multicellular eukaryotes).

What specific substance in the cell wall distinguishes Bacteria from Archaea?

Peptidoglycan.

What are the three types of extremophiles found in the Domain Archaea?

Thermophiles (live in extremely hot environments), Halophiles (live in extremely salty environments), and Methanogens (methane-releasing archaea poisoned by $O_2$).

According to the transcript, why is a virus considered a "non-living" infectious particle?

They are obligate parasites that cannot reproduce or carry out protein synthesis outside of a host cell because they lack ribosomes and enzymes.

Match the prokaryotic structures: Pili, Glycocalyx, and Nucleoid.

Pili: attachment structures; Glycocalyx: sticky outer coating; Nucleoid: location of the cell's DNA not enclosed in a membrane.

What is the process of prokaryotic reproduction called?

Binary fission, where DNA replicates and the cell divides into two separate daughter cells.

How do organelles facilitate larger cell size in Eukarya?

They allow for compartmentalization, which increases efficiency and enables the separation of chemical reactions.

What is the difference between chromatin and chromosomes?

Chromatin is uncoiled DNA, while a chromosome is coiled DNA containing genes.

What is the function of the nucleolus?

It is the region inside the nucleus where ribosomal subunits are manufactured.

Contrast the functions of the Rough ER and the Smooth ER.

The Rough ER is studded with ribosomes and aids in protein processing; the Smooth ER lacks ribosomes and functions in the synthesis of lipids and the detoxification of harmful molecules like alcohol and drugs.

What is the primary role of the Golgi complex?

Protein processing, sorting, and distribution.

What organelle acts as the cell's "digestive system" by recycling old cellular products?

Lysosomes.

What is the correct sequence of protein production?

1. DNA instructions copied to mRNA (Transcription); 2. mRNA moves to ribosome; 3. Ribosome moves to ER for translation; 4. Amino acid chain folds into protein in ER; 5. Protein moves to Golgi complex; 6. Protein moves to plasma membrane for export.

What molecule is created by the mitochondria during cellular respiration?

Adenosine Triphosphate (ATP).

Identify the three types of protein fibers in the cytoskeleton and their functions.

Microfilaments: aid in cell division/shape changes; Intermediate filaments: provide strength and maintain shape; Microtubules: long hollow tubes for movement of molecules and organelles.

According to the comparison table, how do prokaryotic and eukaryotic chromosomes differ?

Prokaryotic cells usually have a single, circular chromosome, while eukaryotic cells have multiple, linear chromosomes.

What are the functional differences between cilia and flagella?

Cilia are short, hair-like projections used for locomotion or moving fluid; Flagella are long, tail-like extensions typically limited to one per cell for locomotion.

What are the functions of the central vacuole in plant cells?

Maintains cell pressure, stores organic compounds and toxins, and degrades cell waste products.

What is the main structural component of plant cell walls?

Cellulose.

Define Plasmodesmata in plant cells.

Pores between plant cell walls that create a continuous cytoplasm for cell communication.

What are the three types of cell junctions found in animal cells?

Tight junctions (prevent leakage), Desmosomes (anchoring junctions), and Gap junctions (communicating channels).

Contrast the theories of Endosymbiosis and Autogenesis in the origin of organelles.

Endosymbiosis explains the origin of mitochondria and chloroplasts via one organism engulfing another; Autogenesis explains the origin of the ER, Golgi, and nuclear membrane through infoldings of the plasma membrane.