Cell Biology Study Notes

Prokaryotic Cells:
- Lack a nucleus and membrane-bound organelles.
- Smaller and simpler (e.g., bacteria and archaea).
Eukaryotic Cells:
- Have a nucleus and membrane-bound organelles.
- Larger and more complex (e.g., animal, plant, fungal cells).

Plasma Membrane:
- Semipermeable barrier that controls the movement of substances in and out of the cell.
Cytoplasm:
- Jelly-like substance where organelles are suspended.
Nucleus:
- Contains genetic material (DNA); controls cell activities.
Organelles:
- Mitochondria: Powerhouse of the cell; site of ATP production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum (ER):
  - Rough ER: Studded with ribosomes; involved in protein synthesis and processing.
  - Smooth ER: Synthesizes lipids and detoxifies substances.
- Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or delivery.
- Lysosomes: Digests waste materials and cellular debris.
- Chloroplasts (in plant cells): Site of photosynthesis.

Metabolism: All chemical processes that occur within a cell.
Homeostasis: The maintenance of a stable internal environment.
Reproduction: Cells can reproduce through processes like mitosis (asexual) and meiosis (sexual).

Passive Transport: Movement of substances without energy (e.g., diffusion, osmosis).
Active Transport: Movement of substances against their concentration gradient, requiring energy (e.g., sodium-potassium pump).

Cells communicate via chemical signals (hormones, neurotransmitters) and receptors.
Signal transduction pathways convert external signals into cellular responses.

Interphase: Cell growth and DNA replication (G1, S, G2 phases).
Mitosis: Division of the nucleus (prophase, metaphase, anaphase, telophase).
Cytokinesis: Division of the cytoplasm, resulting in two daughter cells.

Mitosis: Produces two identical diploid cells.
Meiosis: Produces four genetically varied haploid gametes for sexual reproduction.

Undifferentiated cells with the potential to develop into various cell types.
Types:
- Embryonic Stem Cells: Pluripotent; can become any cell type.
- Adult Stem Cells: Multipotent; limited to certain cell types.

Programmed cell death, a crucial process for development and maintaining homeostasis.

Process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water.
Three stages: Glycolysis, Krebs Cycle, Electron Transport Chain.

Process by which plants convert sunlight, carbon dioxide, and water into glucose and oxygen.
Occurs in chloroplasts; involves light-dependent and light-independent reactions (Calvin cycle).

Living organisms consist of cells, which are the fundamental unit of life.
All cells originate from preceding cells, establishing the principle of cellular continuity.

Prokaryotic Cells:
- Characterized by the absence of a nucleus and membrane-bound organelles; examples include bacteria and archaea.
Eukaryotic Cells:
- Feature a nucleus and membrane-bound organelles; encompass animal, plant, and fungal cells, which are larger and more intricate.

Plasma Membrane:
- Functions as a semipermeable barrier regulating substance movement in and out of the cell.
Cytoplasm:
- Gel-like substance that houses organelles, facilitating cellular processes.
Nucleus:
- Houses genetic material (DNA) and governs cellular activities.
Organelles:
- Mitochondria: Key site for ATP production and energy metabolism.
- Ribosomes: Essential for protein synthesis.
- Endoplasmic Reticulum (ER):
  - Rough ER: Involved in protein synthesis, marked by ribosome presence.
  - Smooth ER: Responsible for lipid synthesis and detoxification.
- Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for transport.
- Lysosomes: Digest cellular waste and debris through enzymatic action.
- Chloroplasts (specific to plant cells): Sites for photosynthesis.

Metabolism: Encompasses all chemical reactions occurring within the cell to maintain life.
Homeostasis: The process of maintaining internal balance despite external changes.
Reproduction: Can occur through mitosis (asexual) or meiosis (sexual), enabling the propagation of cells.

Passive Transport: Involves substance movement without energy expenditure (e.g., diffusion, osmosis).
Active Transport: Requires energy to move substances against their concentration gradient (e.g., sodium-potassium pump).

Cells exchange information through chemical signals (hormones, neurotransmitters) and their corresponding receptors.
Signal transduction pathways translate external cues into internal cellular responses.

Interphase: Prepares the cell for division with growth and DNA replication (comprising G1, S, G2 stages).
Mitosis: The process of nuclear division, encompassing prophase, metaphase, anaphase, and telophase.
Cytokinesis: The final step, dividing the cytoplasm to form two distinct daughter cells.

Mitosis: Results in two identical diploid daughter cells for growth and repair.
Meiosis: Generates four genetically diverse haploid gametes for sexual reproduction.

Unique undifferentiated cells capable of differentiating into various cell types.
Types:
- Embryonic Stem Cells: Pluripotent, meaning they can develop into any cell type.
- Adult Stem Cells: Multipotent, limited to differentiating into a restricted range of cell types.

A programmed cell death mechanism essential for organism development and maintaining tissue homeostasis.

The process through which cells transform glucose and oxygen into usable energy (ATP), along with carbon dioxide and water as byproducts.
Consists of three stages: Glycolysis, Krebs Cycle, and Electron Transport Chain.

The process utilized by plants to convert sunlight, carbon dioxide, and water into glucose and oxygen.
Takes place in chloroplasts, involving light-dependent and light-independent reactions, including the Calvin cycle.