Overview of Cells

Study Notes

Overview of Cells

Cells are the basic unit of life, serving as fundamental building blocks of all living organisms.
There are two main cell types: prokaryotic and eukaryotic.

Prokaryotic Cells

Characterized by the absence of a nucleus and membrane-bound organelles.
Generally smaller and simpler than eukaryotic cells.
DNA is circular and found in a region called the nucleoid.
Common examples include Bacteria and Archaea.

Eukaryotic Cells

They are distinguished by the presence of a nucleus and membrane-bound organelles.
Typically larger and more complex compared to prokaryotic cells.
DNA is linear and organized into chromosomes.
Examples encompass animal cells, plant cells, fungal cells, and protists.

Cell Structure

Cell Membrane:
- Composed of a phospholipid bilayer; it regulates the flow of substances in and out.
Cytoplasm:
- A gel-like substance where various cellular processes take place.
Nucleus:
- It houses genetic material (DNA) and governs cell activities.
Ribosomes:
- Sites for protein synthesis within the cell.
Endoplasmic Reticulum (ER):
- Rough ER, adorned with ribosomes, is responsible for protein synthesis; Smooth ER synthesizes lipids.
Golgi Apparatus:
- Modifies, sorts, and packages proteins and lipids for secretion or delivery to other locations.
Mitochondria:
- Known as the powerhouse of the cell; site of ATP production through cellular respiration.
Chloroplasts (specific to plant cells):
- Conduct photosynthesis and contain chlorophyll, which captures sunlight.

Cell Division

Mitosis:
- A type of somatic cell division that yields two identical daughter cells; includes phases such as Prophase, Metaphase, Anaphase, and Telophase.
Meiosis:
- Responsible for gamete formation, resulting in four genetically distinct daughter cells; involves two rounds of division termed Meiosis I and Meiosis II.

Cell Metabolism

Catabolism:
- The metabolic process that breaks down molecules to release energy.
Anabolism:
- The synthesis of compounds, which requires an input of energy.

Cellular Communication

Cells utilize chemical signals like hormones and neurotransmitters to communicate.
Receptors located on cell membranes play a pivotal role in detecting these signals and initiating cellular responses.

Cellular Transport

Passive Transport:
- Refers to the movement of substances across cell membranes without the need for energy, including processes like diffusion and osmosis.
Active Transport:
- Requires the expenditure of energy to move substances against their concentration gradients, exemplified by mechanisms such as the sodium-potassium pump.

Importance of Cells

Cells serve as the foundation for all biological processes.
The diversity of cell types enables specialization and the emergence of complex functions in multicellular organisms.

Description

This quiz covers the fundamental concepts of cell biology, focusing on the two main types of cells: prokaryotic and eukaryotic. You'll learn about cell structure, including the cell membrane, cytoplasm, nucleus, ribosomes, and more. Test your knowledge about the basic unit of life and its functions.