Unit 2 AP Bio

Endomembrane System

Includes the ER, Golgi apparatus, lysosomes, vesicles, vacuoles, plasma membrane, and nuclear envelope, characterized by membrane-bound organelles.

Membrane-bound

What do organelles have to be in order to be in the endomembrane system

ribosomes

What organelle do prokaryotic cells have too?

How do prokaryotes perform the same jobs as eukaryotes

they perform vital life functions on their cell membranes and directly in their cytoplasm.

Protein synthesis process

Starts in the nucleus, moves to the endoplasmic reticulum, then to the cis Golgi, trans side, and finally to the vesicle for exit from the cell.

Endosymbiotic Theory

mitochondria and chloroplasts were once free-living and now function within eukaryotic cells; they possess their own ribosomes and can divide.

Microtubules, microfilaments, and intermediate filaments

types of fibers in a cell

Function of microtubules

Help maintain cell shape, serve as transport tracks, and drive cell division.

Function of microfilaments

Support cell shape and power cell movement.

Function of intermediate filaments

Reinforce cell shape, fix positions of some organelles, and make up the nuclear lamina.

Plant cell junctions

Plasmodesmata, which are membrane-lined channels filled with cytosol that allow water and small solutes to pass freely.

Animal cell junctions

Tight junctions, desmosomes, and gap junctions.

Function of tight junctions

Help prevent leakage between cells.

Function of desmosomes

hold cells together

Function of gap junctions

Provide channels between cells for ions and small molecules.

Similarity to plasmodesmata

Gap junctions, both a channel

Integral proteins

Proteins that are embedded within the membrane.

Peripheral proteins

Loosely bound proteins usually near integral proteins.

Amphipathic proteins

Integral proteins that have both hydrophilic and hydrophobic regions.

Carrier and channel proteins

Integral proteins

Diffusion is for small nonpolar particles while facilitated diffusion requires a protein for larger, polar, charged molecules.

diffusion vs. facilitated diffusion

Examples of diffusion

Oxygen (O2) and carbon dioxide (CO2)

Examples of facilitated diffusion

Glucose and water

uncharged, nonpolar particles

What can pass through membranes without help?

Active transport

Movement of substances against the concentration gradient, which requires ATP.

Hypertonic solution

Has more solute compared to the inside of a cell, causing the cell to lose water and become plasmolyzed.

Hypotonic solution

Has less solute compared to the inside of a cell, causing the cell to gain water and become turgid (ideal for plants, but dangerous for animals).

Isotonic solution

Equal concentration of solute and solution, ideal for animal cells but can cause plant cells to become flaccid.

Exocytosis

Process by which the cell secretes molecules by the fusion of vesicles with the membrane.

Endocytosis

Process by which the cell takes in molecules and matter by forming new vesicles from the membrane.

Types of endocytosis

Phagocytosis, pinocytosis, and receptor-mediated endocytosis.

Phagocytosis

Intake of food particles, often performed by white blood cells.

Pinocytosis

Intake of extracellular fluid in a nonspecific manner.

Receptor-mediated endocytosis

Specialized form of endocytosis that uses receptors to trigger intake more specifically than pinocytosis.

Glycolipids and glycoproteins

What serves as ID tags for cell identification.

genes

Proteins are made from…

Gene expression over time

typically decreases over time.

Information to make proteins

DNA