MCAT Kaplan Biology: 1.1-1.2 Flashcards

Vocabulary-style flashcards based on the provided MCAT Kaplan Biology notes regarding cell theory, organelles, cytoskeleton, and tissue types.

4 tenets of cell theory

1. All living things are composed of cells 2. Cells are the basic unit of structure of life 3. Cells arise from other cells 4. Cells have DNA that is passed from parent to daughter

Eukaryotic cell

A cell that has a true nucleus.

Prokaryotic cell

A cell that has no nucleus.

Organelle Membrane Compartmentalization

Provides separation and transportation between different areas of the cell.

Phospholipid bilayer surface

Hydrophilic; interacts with aqueous environments inside and outside of the cell.

Inner membrane of phospholipid bilayer

Hydrophobic; allows selectivity in the membrane.

Cytosol

Allows diffusion of molecules throughout the cell.

Mitosis

The method by which eukaryotic cells replicate.

Nuclear membrane

A double membrane that maintains nuclear separation.

Nuclear pores

Allow for a 2-way exchange of material between the cytoplasm and the nucleus.

Genes

The specific coding regions on DNA.

Organization of DNA

Linear DNA $\rightarrow$ histones $\rightarrow$ chromosomes.

Transcription and Translation Separation

The reason why DNA is compartmentalized in the nucleus.

Nucleolus

Contains RNA, takes up $25\%$ of the space in the nucleus, and is often seen as a dark spot.

Outer membrane of mitochondria

Serves as a barrier between the cytosol and the inner cell.

Inner membrane of mitochondria

Contains cristae which house molecules and enzymes for the electron transport chain (ETC) and increases surface area.

Intermembrane space

The space located between the inner and outer membrane matrix of the mitochondria.

Matrix

The inner-most space of the mitochondria.

Proton motive force

The pumping of protons from the matrix to the intermembrane space; protons flow through ATP synthase to generate ATP for oxidative phosphorylation.

endosymiotic theory

Mitochondria have their own genes and can replicate independent of the nucleus via binary fission.

Binary fission

The splitting of a cell into two identical halves.

Serial Endosymbiosis Theory

The theory that organelles formed by an anaerobic prokaryote engulfing an aerobic prokaryote and forming a symbiotic relationship, explaining how all double membrane organelles were formed.

Mitochondrial Apoptosis

Occurs when the mitochondria releases enzymes via the ETC which kill the cell.

Lysosome

A membrane-bound organelle containing hydrolytic enzymes that break down substances; it can degrade products from the Golgi or cytosol.

Lysosome Enzyme Sequestration

The process by which the lysosome keeps enzymes contained to prevent damage to the cell.

Autolysis

The release of enzymes via the lysosome that leads to apoptosis.

RER (Rough Endoplasmic Reticulum)

Contains ribosomes for the translation of proteins into the lumen for transport.

SER (Smooth Endoplasmic Reticulum)

Responsible for lipid synthesis and detoxification.

Transport pathway of proteins

SER transports proteins from the RER to the Golgi in vesicles, which then use other vesicles to transport to specific locations or via secretory vesicles for exocytosis.

Golgi Apparatus

Stacked membrane-bound sacs that modify products by adding groups or introducing cell signals.

Peroxisome

Contains hydrogen peroxide for the breakdown of long fatty acid chains via beta oxidation and is used in phospholipid synthesis.

Cytoskeleton

Provides structure to the cell, helps maintain its shape, and acts as a conduit for transport of materials.

Types of cytoskeletal filaments

Microtubules, microfilaments, and intermediate filaments.

Microfilament

Solid polymerized rods of actin organized into bundles that are resistant to compression and fracture.

Actin

Uses ATP to generate muscle force for movement in conjunction with myosin.

Cytokinesis

The division of materials within daughter cells.

Cleavage furrow

Formed by microfilaments, it is a ring at the site of division between two daughter cells that contracts and pinches off.

Microtubules

Hollow polymers of tubulin that radiate to provide a pathway for motor proteins.

Kinesin and dynamin

Non-enzymatic microtubule proteins that travel along the cytoskeleton.

Cilia

Made of microtubules that project and move materials along the surface of the cell.

Flagella

Structures used for cell movement.

$9+2$ structure

The specific structure for microtubules in eukaryotic flagella and cilia.

Centrioles

Located in the centrosome; they organize microtubules by $9$ triplets with a hollow center and migrate to opposite poles to organize the mitotic spindle.

Kinetochore

Structures made of microtubules that attach to chromosomes to pull apart sister chromatids.

Intermediate Filament

Responsible for cell-cell adhesion and maintenance of integrity; can withstand tension and anchors organelles.

4 tissue types

Epithelial, nervous, muscle, and connective.

Epithelial tissue

Covers the body and cavities for protection against pathogen invasion and desiccation.

Functions of epithelial tissue

Absorption, secretion, and sensation.

Basement membrane

Connective tissue that joins epithelial tissue together.

Parenchyma

The functional part of an organ, typically composed of epithelial tissue.

Polarized cell

A cell where one side faces the lumen while the other faces the inside of the cell.

Epithelial shape classifications

Cuboidal, columnar, and squamous.

Simple epithelial

Epithelial tissue consisting of $1$ layer of cells.

Stratified epithelial

Epithelial tissue consisting of multiple layers of cells.

Pseudostratified epithelial

Cells that appear to be in multiple layers due to different sizes but are really only $1$ layer.

Connective tissue

Supports the body, provides a framework for epithelial tissue, and secretes collagen and elastin for the extracellular matrix.