Cell Biology Quiz

Cell Biology

Definition: Study of the structural and functional units of life, primarily at the microscopic level.
Cell Theory:
- All living organisms are composed of one or more cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Types of Cells:
- Prokaryotic Cells:
  - Lack a nucleus.
  - Smaller and simpler (e.g., bacteria).
  - DNA is in a singular circular form.
- Eukaryotic Cells:
  - Have a nucleus and membrane-bound organelles.
  - Larger and more complex (e.g., plants, animals, fungi).
Cell Structure:
- Cell Membrane:
  - Phospholipid bilayer with embedded proteins.
  - Regulates entry and exit of substances.
- Nucleus:
  - Contains genetic material (DNA).
  - Site of transcription.
- Mitochondria:
  - Powerhouse of the cell; site of ATP production through respiration.
- Ribosomes:
  - Sites of protein synthesis; can be free in cytoplasm or attached to the rough endoplasmic reticulum.
- Endoplasmic Reticulum (ER):
  - Rough ER: Studded with ribosomes; involved in protein synthesis and processing.
  - Smooth ER: Lacks ribosomes; synthesizes lipids and detoxifies certain chemicals.
- Golgi Apparatus:
  - Modifies, sorts, and packages proteins and lipids for secretion or delivery to organelles.
- Lysosomes:
  - Contain digestive enzymes for breaking down waste materials and cellular debris.
- Cytoskeleton:
  - A network of fibers providing structural support and shape; involved in cell movement and division.
Cell Division:
- Mitosis:
  - Produces two identical daughter cells; asexual reproduction.
  - Phases: Prophase, Metaphase, Anaphase, Telophase.
- Meiosis:
  - Produces gametes (haploid cells); involves two rounds of division.
  - Introduces genetic variation through crossing over and independent assortment.
Cell Metabolism:
- Anabolism: Building up molecules (e.g., protein synthesis).
- Catabolism: Breaking down molecules (e.g., glucose during cellular respiration).
Cell Communication:
- Cells communicate via signaling molecules (e.g., hormones, neurotransmitters).
- Receptor proteins on target cells receive signals, initiating a cellular response.
Cell Transport Mechanisms:
- Passive Transport: Movement of substances across cell membranes without energy use (e.g., diffusion, osmosis).
- Active Transport: Requires energy to move substances against their concentration gradient (e.g., sodium-potassium pump).
Cell Cycle Regulation:
- Controlled by checkpoints, cyclins, and cyclin-dependent kinases (CDKs).
- Dysregulation can lead to cancer.
Stem Cells:
- Undifferentiated cells capable of self-renewal and differentiation into specialized cell types.
- Types: Embryonic stem cells (pluripotent) and adult stem cells (multipotent).

Cell Biology

Definition: Study of the basic structural and functional units of life, primarily at the microscopic level.
Cell Theory:
- All living organisms are composed of one or more cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.

Types of Cells

Prokaryotic Cells:
- Lack a nucleus
- Smaller and simpler than eukaryotic cells (e.g., bacteria).
- DNA is in a singular circular form.
Eukaryotic Cells:
- Have a nucleus and membrane-bound organelles
- Larger and more complex than prokaryotic cells (e.g., plants, animals, fungi).

Cell Structure

Cell Membrane:
- Phospholipid bilayer with embedded proteins.
- Regulates the entry and exit of substances into and out of the cell.
Nucleus:
- Contains genetic material (DNA)
- Site of transcription (the process of copying DNA into RNA).
Mitochondria:
- Powerhouse of the cell; site of ATP production through respiration
- Respiration is how cells break down glucose for energy.
Ribosomes:
- Sites of protein synthesis;
- Ribosomes can be free in the cytoplasm or attached to the rough endoplasmic reticulum.
Endoplasmic Reticulum (ER):
- Rough ER: Studded with ribosomes; involved in protein synthesis and processing
- Smooth ER: Lacks ribosomes; synthesizes lipids and detoxifies certain chemicals.
Golgi Apparatus:
- Modifies, sorts, and packages proteins and lipids for secretion or delivery to organelles.
Lysosomes:
- Contain digestive enzymes for breaking down waste materials and cellular debris.
Cytoskeleton:
- A network of fibers providing structural support and shape; involved in cell movement and division.

Cell Division

Mitosis:
- Produces two identical daughter cells; asexual reproduction.
- Phases: Prophase, Metaphase, Anaphase, Telophase.
Meiosis:
- Produces gametes (haploid cells); involves two rounds of division.
- Introduces genetic variation through crossing over and independent assortment.

Cell Metabolism

Anabolism: Building up molecules (e.g., protein synthesis).
Catabolism: Breaking down molecules (e.g., glucose during cellular respiration).

Cell Communication

Cells communicate via signaling molecules (e.g., hormones, neurotransmitters).
Receptor proteins on target cells receive signals, initiating a cellular response.

Cell Transport Mechanisms

Passive Transport: Movement of substances across cell membranes without energy use (e.g., diffusion, osmosis).
Active Transport: Requires energy to move substances against their concentration gradient (e.g., sodium-potassium pump).

Cell Cycle Regulation

Controlled by checkpoints, cyclins, and cyclin-dependent kinases (CDKs).
Dysregulation can lead to cancer.

Stem Cells

Undifferentiated cells capable of self-renewal and differentiation into specialized cell types.
Types: Embryonic stem cells (pluripotent) and adult stem cells (multipotent).