The Cell Flashcards
The four basic tenets of cell theory
- All living things are composed of ells
- The cell is the basic functional unit of life
- Cells arise only from pre-exsisting cells
- Cells carry genetic information in the form of DNA; this genetic material is passed on from parent to daughter cell
Are viruses considered living things? Why or why not?
They are not considered living things because they are acellular, cannot reproduce without the assistance of a host cell, and may contain RNA as their genetic material
Eukaryotes
They have membrane-bound organelles, a nucleus, and may form multicellular organisms
Cell membrane & membranes of organelles
They contain phospholipids, which organize to form hydrophilic interior and exterior surfaces with a hydrophobic core
Cytosol
Suspends the organelles and allows diffusion of molecules throughout the cell
Nucleus
Contains DNA organized into chromosomes
Nuclear membrane/envelope
A double membrane that surrounds the nucleus and contains nuclear pores
Nuclear pores
Facilitate two-way exchange of materials between the nucleus and cytosol
Genes
DNA is organized into these coding regions
Nucleolus
A subsection of the nucleus in which rRNA is synthesized
Mitochondria
Contain an outer and inner membrane; can divide independently of the nucleus via binary fission; they can trigger apoptosis by releasing mitochondrial enzymes into the cytoplasm
Outer membrane of the mitochondria
Forms a barrier with the cytosol
Inner membrane of the mitochondria
Folded into cristae and contains enzymes for the ETC
Intermembrane space
Space between the outer and inner membranes of the mitochondria
Mitochondrial matrix
Space inside the inner mitochondrial membrane
Lysosomes
Contain hydrolytic enzymes that can break down substances ingested by endocytosis and cellular waste products; when these enzymes are released, autolysis of the cell occur
Endoplasmic reticulum (ER)
A series of interconnected membranes and is continuous with the nuclear envelope
Rough ER (RER)
Studded with ribosomes, which permit translation of proteins destined for secretion
Smooth ER (SER)
Used for lipid synthesis and detoxification
Golgi apparatus
Consists of stacked membrane-bound sacs in which cellular products can be modified, packaged, and directed to specific cellular locations
Peroxisomes
Contain hydrogen peroxide and can break down very long chain fatty acids via beta oxidation; they also participate in phospholipid synthesis and the pentose phosphate pathway
Cytoskeleton
Provides stability and rigidity to the overall structure of the cell, while also providing transport pathways for molecules within the cell
Microfilaments
Composed of actin; they provide structural protection from the cell and can cause muscle contraction through interactions with myosin; they also help form the cleavage furrow during cytokinesis in mitosis
Microtubules
Composed of tubulin; they create pathways for motor proteins like chines and dyne to cary vesicles; they also contribute to the structure of cilia and flagella
9 + 2 structure
In eukaryotes, cilia and flagella are organized into nine pairs of microtubules in a ring with two microtubules at the center
Centrioles
Found in centrosomes and are involved in microtubule organization in the mitotic spindle
Intermediate filaments
Involved in cell-cell adhesion or maintenance of the integrity of the cytoskeleton; they help anchor organelles
Epithelial tissues
Cover the body and line its cavities, protecting against pathogen invasion and desiccation; some absorb or secrete substances, or participate in sensation
Parenchyma
In most organs, epithelial cells form this, which are the functional parts of the organ
Polarization of epithelial cells
They may have one side facing a lumen or the outside world, and the other side facing blood vessels and structural cells
Types of epithelia (3) Simple epithelia
Simple (have one layer)
Stratified (have many layers)
Pseudostratified (appear to have multiple layers because of differences in cell heights, but actually only have one layer)
Eukaryote shape classifications (3)
Cuboidal cells (cube-shaped) Columnar cells (long and narrow) Squamous cells (flat and scale-like)
Connective tissues
Support the body and provide a framework for epithelial cells
Stroma
In most organs, connective tissues form this, or support structure by secreting materials to form an extracellular matrix