MCAT - Eukaryotic Cells

Nucleus

DNA Storage; membrane is actually a set of two lipid bilayers; Proteins channels known as nuclear pores form holes in the nuclear envelope; filled with nucleoplasm;

Mitochondrion

Energy production; protects the cell from reactive oxygen species (ROS) molecules which could seriously damage the cell; the intermembrane space, and it has a low pH (is acidic) because the electron transport chain embedded in the inner membrane pumps protons (H+) into it

Smooth Endoplasmic Reticulum (SER)

Lipid and steroid production; Detoxification;

Rough Endoplasmic Reticulum (RER)

Protein production; in particular for export out of the cell; surface is studded with ribosomes; Proteins made in the rough endoplasmic reticulum as destined to either be a part of a membrane, or to be secreted from the cell membrane out of the cell

Golgi apparatus

Protein modification and export

Peroxisome

Lipid Destruction; contains oxidative enzymes; protects the cell from reactive oxygen species (ROS) molecules which could seriously damage the cell

Lysosome

Protein destruction; spheres full of enzymes ready to hydrolyze; only function properly in environments with a pH of 5

nucleolus

not bound by a membrane, so it is not an organelle; Ribosomes are assembled in the nucleolus, and exit the nucleus with nuclear pores

Endoplasmic reticulum

a plasma membrane found inside the cell that folds in on itself to create an internal space known as the lumen; lumen is actually continuous with the perinuclear space

Cytoskeleton

network of protein fibers within the cytoplasm; major components are microtubules, intermediate filaments, and microfilaments

Microtubules

found in cilia and flagella; involved in cell division as they are a part of the mitotic spindle

Intermediate Filaments

made of a variety of proteins such as keratin and/or neurofilament; help provide structure to the nuclear envelope and anchor organelles

Microfilaments

thinnest part of the cytoskeleton; made of actin, which is a useful protein in cell movement;

Chloroplasts

organelles that resemble mitochondria and are responsible for turning sunlight into useful energy for the plant cell

platelets

blood cells responsible for clotting, have no nucleus and are in fact just fragments of cytoplasm contained within a cell membrane