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MCAT Biology Ch 1: Cells

Terms in this set (42)

Cell Theory
1. All living things are made of cells
2. The cell is the basic unit of life
3. Cells only come from preexisting cells
4. Cells carry genetic information in the form of DNA which is passed from the parent to the daughter cell
Eukaryotic Cells
Contain a true nucleus enclosed in a membrane
Prokaryotic Cell
Does not contain a nucleus
Nuclear Membrane/Envelope
a double membrane that maintains a nuclear environment separate and distinct from the cytoplasm
Nuclear Pores
allow for selective two-way exchange of material between the cytoplasm and the nucleus
Nucleolus
where the ribosomal RNA (rRNA) is synthesized
Mitochondria: Outer membrane
barrier between the cytosol and the inner environment of the mitochondria
Cristae
The inner membrane of the mitochondria which contains the molecules and enzymes necessary for the electron transport chain
Increase the surface area because of folding
Intermembrane space
The space between the inner and outer membranes
Mitochondrial Matrix
the space inside the inner membrane
Pumping of protons occurs from here to the intermembrane space establishes the proton-motive force
Cytoplasmic/Extranuclear Inheritance
transmisson of genetic material independent of the nucleus
Evolution of Mitochondria
an anerobic prokaryote engulfed an aerobic prokaryote and established a symbiotic relationship
Apoptosis in Mitochondria
The termination of a cell started by the mitochondria with the release of enzymes from the electron transport chain
Lysosomes
organelles that contain hydrolytic enzymes that breakdown substrates ingested by endocytosis or cellular waste products
Endosomes
transport, package, and sort cell material travelling to and from membranes like the trans-golgi, cell membrane, and lysosomal pathways for degradation
Autolysis
the release of enzymes sequestered on the lysosomal membrane which prevent damage to the cell
Apoptosis in Lysosomes
The release of the hydrolytic enzymes inside a lysosome which triggers cell death
Endoplasmic Reticulum (ER)
Organelle with a series of interconnected membranes which are contiguous with the nuclear envelope and is folded into numerous invaginations making a complex structure with central lumens
Rough ER
Is studded with ribosomes that permit the translation of proteins for secretion into the lumen
Smooth ER
Lacks ribosomes and is center for lipid synthesis and detoxification of certain drugs in addition to transporting proteins from the Rough ER to the Golgi Apparatus
Golgi Apparatus
Made of stacked membrane bound sacs. Materials from the ER are modified by the addition of carbohydrates, phosphates, and sulfates or the introduction of signal sequences which direct the delivery of the materials after repackaging into vesicles
Vesicles
Transport materials from the Golgi to their correct cellular location
Exocytosis
The expulsion of cellular material which occurs when a secretory vesicle merges with the membrane and its contents are released outside the cell
Peroxisomes
Contain hydrogen peroxide and breaks down long chains of fatty acids with Beta-Oxidation and synthesize phospholipids and sometimes contain enzymes involved in the pentose phosphate pathway
Cytoskeleton
Provides structure to the cell, helps maintain its shape, and provides a way for materials to be transported throughout the cell. Has three main parts: microfilaments, microtubules, and intermediate filaments
Microfilaments
Made of solid polymerized actin which are formed into bundles and networks resistant to compression and fracture which provides protection for the cell.
Can use ATP to generate movement with interaction with myosin
Forms the cleavage furrow in cytokinesis to separate the two daughter cells
Microtubules
Hollow polymers of tubulin that provide a primary pathway for motor proteins like kinesin and dynein to transport vesicles.
Also for Cilia and Flagella for cell movement
Cilia
Projections from a cell involved in the movement of materials on the surface of the cell.
Follows the 9+2 Structure
Flagella
Long projection involved in movement of the entire cell
Follows 9+2 Structure
9+2 Structure
Structure of cilia and flagella; composed of 9 pairs of microtubules forming an outer ring with 2 microtubules in the center
This structure is only found in eukaryotic cells
Centrioles
Found in the centrosome, they are organizing centers for microtubules and are structured into 9 triplets with a hollow center.
They migrate to opposite ends of the cell and organize the mitotic spindle by attaching to the kinetochores of sister chromatids and exerting a force on them to cause them to separate during mitosis
Intermediate Filament
Diverse group of filamentous proteins including keratin, desmin, vinentin, and lamins which are specific to the cell depending on cell and tissue type
They are involved in cell-cell adhesion and maintainence of the overall integrity of the cytoskeleton. It is very rigid and can withstand a lot of tension
Is also used to anchor organelles
Epithelial Tissues
Covers the body and lines its cavities often involved in protection from pathogens and desiccation or are involved in absorption, secretion, and sensation.
They are joined tightly to each other and the basement membrane
In most organs they make up the Parenchyma or the functional parts of the organ
They are often polarized with one side facing out of the organ and one facing into the organ, each with different functions
Basement Membrane
The underlying layer of connective tissue
Parenchyma
The functional parts of an organ made up of epithelial cells in most organs
Simple Epithelial
Has one layer of cells
Stratified Epithelial
Has multiple layers of cells
Psuedostratified Epithelia
Has one layer but appears to have multiple due to differences in cell height
Cuboidal Epithelial Cells
Cube shaped epithelial cells
Columnar Epithelial Cells
Long and thin epithelial cells
Squamous Epithelial Cells
flat and scalelike epithelial cells
Connective Tissue
supports body and provides a framework for epithelial cells to function
Is the main contributor to the Stroma of support structure
Most connective cells produce and secrete materials such as collagen and elastin which form the extracellular matrix
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