Cell biology Flashcards
what is the largest membrane-bound organelle in the center of most eukaryotic cells. It contains the cell’s genetic code (its DNA). Its function of the nucleus is to direct the cell by storing and transmitting genetic information.
The Nucleus
It is a region inside the nucleus where ribosomal RNA (rRNA) is transcribed, and ribosomal subunits are assembled.
The Nucleolus.
Here, rRNA joins together to form the subunits of a complete ribosome. These subunits are then exported to the cytoplasm for final assembly into the complete ribosome used for translation of mRNA into proteins
The boundary of the nucleus, made of phospholipid bilayer
Nuclear Envelope
What allows certain particles through the nuclear envelope, wo that essential cell processes and communications can occur.
Nuclear pores.
The nuclear pores is subject to change based on the needs of the cell. Through the pores, signal molecules, nucleoplasm proteins, nuclear membrane proteins, lipids, and transcription factors can enter the nucleus, while mRNA, rRNA and ribosomal proteins exit into the cytoplasm.
The endomembrane system is a series of intracellular membranes that compartmentalize the cell.
What is the typical pathway through the endomembrane system is?
- Proteins produced in rough ER (endoplasmic reticulum) and lipids from smooth ER are carried in vesicles to the Golgi apparatus.
- The Golgi apparatus modifies these products and then sorts and packages them in vesicles that are transported to various cell destinations
- Secretory vesicles transport products to organelles or to the membrane, where they are secreted via exocytosis
* Including also lysosomes, peroxisomes, and all the organelles within the cell
This unique double membrane organelle is responsible for aerobic respiration which uses oxygen to create ATP
Mitochondria.
The mitochondria is unique in that it has its own genome that is distinct from the genome from within the nucleus, that has its own circular DNA. It also has it own ribosomes
What part of the mitochondria that separates the mitochondria from the cytoplasm?
The outer membrane
What part of the mitochondria has folds as cristae
Inner membrane
This small membrane-bound organelle vesicles are produced by the Golgi apparatus and produces hydrolytic enzymes for the digestion of macromolecules
Lysosomes.
They are especially important in specialized immune cells, which is used to digest invaders. Autodigestion is the process by which lysosomes digest parts of the body’s cells, either to due to disease or trauma or for immune purposes ( e.g. programmed cell death)
Mutations in the genes that encode for lysosomal enzymes cause lysosomal storage disorders. When a mutation renders certain lysosomal enzymes inefficient ( or completely inoperable), waste products accumulate in the cells and cause serious, often incurable complications
Continuous with the nuclear envelope and studded with ribosomes, This organelle is where proteins are synthesized, processed and modified.
Rough Endoplasmic Reticulum {R.E.R.)
It synthesizes key membrane components, not just the plasma membrane, but the membrane of the ER, Golgi apparatus, lysosomes, and other organelles before heading to their destination at the plasma membrane-bound organelle
It is the site of various synthesis, detoxification and storage processes, such as the synthesize of lipids and steroids, and the metabolism of carbohydrates and other molecules
Smooth ER
What are the three key organelles that have a double membrane
Mitochondria- has a double membrane due to their proposed evolution from endosymbiotic prokaryote. It is crucial for creating proton gradient that drives ATP synthesis
Chloroplast- is the site of photosynthesis and ATP synthesis in plant cells
Nucleus- Its organization and compartmentalizing is important for the regulation of gene expression.
Flattened sacs that receives transport vesicles from the ER and then may further modify their content before packing the proteins or lipid to be sent in vesicles to its final destination
Golgi apparatus
This organelle is involved in catabolism and anabolism of many macromolecules including fatty acids, proteins and carbohydrate
Peroxisomes- it is most abundant in the liver where they are notable for producing bile salts from cholesterol and metabolizing alcohol
What does it mean to be Semi-permeable
It means it only allows certain molecules to pass through. A molecule’s ability to diffuse through the plasma membrane depends on the molecule’s size, charge, and polarity. The greater the lipid solubility of the diffusing particle, the more easily it passes through the membrane.
Generally, smaller particles diffuse more rapidly than larger ones, and hydrophobic particles diffuse more rapidly than hydrophilic particles.
Enables the movement of molecules across a membrane without the expenditure of energy by the cell
Passive transport
The process by which smaller, lipid-soluble molecules freely diffuse through the phospholipid bilayer unassisted.
Simple diffusion
What are transport proteins?
Transport proteins move materials into and out of the cell. These include channel proteins and carrier proteins. Channel proteins provide a passageway large, polar or charged molecules that cannot pass through the lipid bilayer without assistance. These proteins facilitate the passive transports molecules, that is, they do not require ATP.
Carrier proteins, however, may facilitate both passive and active transport of molecules. They bind to a specific molecules on one side of the cell membrane and then change conformation to release the molecule on the other side of the membrane.
What are adhesive proteins?
They attach cells to neighboring cells for cell-to-cell communication and tissue structure. These proteins generally attach to the cytoskeleton of one
What are transport proteins?
Moves materials into and out of the cell. These include channel proteins and carrier proteins. Channel proteins provide a passageway large, polar or charged molecules that cannot pass through the lipid bilayer without assistance. These proteins facilitate the passive transport of molecules, that is, they do not require ATP to operate. Carrier proteins, however may facilitate both passive and active ( energy-requiring) transport of molecules. They bind to specific molecules on one side of the cell membrane and then change conformation to release molecule in the other side of the membrane.
What are receptor proteins?
Receptor proteins provide a binding site for hormones, neurotransmitters, and other signaling molecules. Receptor proteins are usually specific in that they bind to a single molecule or certain class of molecules.
What are integral membrane proteins?
They are permanently attached to the membrane and thus cannot be removed without disrupting the lipid bilayer. They possess hydrophilic domains which are anchored to hydrophobic lipids. Most integral membrane proteins are transmembrane proteins, spanning the entire membrane
What is a solute?
It is the dissolved substances
What is a solvent?
It is usually the fluid (usually water) in which substances
