Exam 2 Flashcards
Compare Prokaryotes and Eukaryotes.
Prokaryote cells have no membrane bound nucleus and no membrane bound organelles.
Eukaryote cells have a membrane bound nucleus, which houses DNA, and have membrane bound organelles which house specific cell processes.
Describe the structure of a virus.
Capsid- protein coat nucleic acid- DNA or RNA Some have an envelope that surround the capsid. They are made of lipids, proteins, and glycoproteins. Lipids come from the host cell membrane. Viruses are not considered organisms because they: *lack cellular structure *lack independent metabolism *lack independent replication *described as active or inactive *infect by transferring genetic material into cell
What are the similarities between Prokaryotes and Eukrayotes?
They both have:
- plasma membrane
- cytosol (jelly like fluid inside cell)
- chromosomes (carry genes in the form of DNA), Prokaryotes are circular and Eukaryotes are Linear
- Ribosomes that make proteins
What are membranes?
membranes are phospholipid bilayers. Polar hydrophilic heads face outward. Nonpolar hydrophobic tails face inward.
What is a Vesicle?
Vesicles are small membrane bound sacs. They store and transport materials. They form off of the endomembrane system
What is a Nucleus?
A nucleus houses chromosomes; chromosomes discrete units of organized DNA. The nucleolus: rRNA synthesized here. Nuclear envelope is two bilayers
What is the Endoplasmic Reticulum and what are its two types?
It consists of two phospholipid bilyaers embedded with proteins.
Two types:
Rough ER- outer surface contains ribosomes. Produces proteins that will be secreted. Manufactures membranes by producing membrane proteins and phospolipids.
Smooth ER- outer surface lacks ribosomes. Contains enzymes that synthesize lipids. Contains enzymes that help detoxify drugs and poisons. Stores calcium ions which are used as signaling molecules.
Describe the Fluid Mosaic Model.
It is a model to describe the structure of the cell membrane. Membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids.
What are the components of a cell membrane?
- Phospholipid bilayer, polar hydrophilic phosphate heads, nonpolar hydrophobic fatty acid tails
- transmembrane proteins (integral proteins)
- requires energy inform of ATP
- Sodium Potassium pump: one type of active transport system
what is endocytosis and its 3 types?
The taking in of matter by a living cell invagination of its membrane to form a vacuole. 3 types:
- Phagocytosis (eat) is the ingestion of bacteria or other material by phagocytes and amoeboid protozoans.
- Pinocytosis (drink) is the ingestion of liquid into a cell by the budding of small vesicles from the cell membrane
- Receptor-mediated Endocytosis is a process by which cells absorb metabolites hormones, proteins, sometimes viruses, by the inward budding of plasma membrane vesicles containing proteins with receptor sites
What is exocytosis?
a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane
describe Osmosis.
Diffusion of water across a permeable membrane. Water moves across a membrane from lower solute concentration to higher solute concentration
Describe diffusion.
The net passive movement of molecules from high concentration to lower concentration until it is uniform throughout
Describe facilitated diffusion.
Transport of proteins speed the passive movement of molecules across the membrane
What is the Golgi Apparatus?
Consists of flattened membranous sacs that are not physically connected. Collects, packages, and distributes molecules that are made at one location and used at another
What is a Lysosome?
Membranous sac of hydrolytic enzymes. They arise from the Golgi Apparatus. Contains enzymes that catalyze breakdown of macromolecules. Can also destroy cells or foreign matter engulfed by cells
What are Vacuoles?
Large vesicles derived from ER and Golgi. Their functions are:
Food vacuole
Contractile vacuole
Central vacuole
What are microbodies?
Enzymes bearing vesicles. One way for Eukaryoktic cells to organize their metabolism. An example is Peroxisome which contains enzymes function to oxidize fatty acids and detoxify harmful chemicals (like alcohol). It is a byproduct of reactions, hydrogen peroxide (enzyme catalase furhter breaks down hydrogen peroxide)
Describe the Mitochondria.
It is found in all types of Erukaroyitc cells. It is the site of cellular respiration - metabolizes sugar to get ATP. It is surrounded by 2 membranes - has its own circular DNA and has its own ribosome
Describe the Chloroplast.
It is found in photosynthetic Eukaryotic cells (plants and some protist). It is the site of photosynthesis - use energy from sun to generate sugars. Has a green pigment and is surrounded by 2 membranes. It has its own circular DNA and its own ribosomes.
What is the Endosymbiont Theory?
The Mitochondria and Chloroplasts evolved as a consequence of symbiosis between an early ancestor of eukaryotic cells and a prokaryotic cell.
Mitochondria: oxygen using, non photosynthetic prokaryotic
Chloroplast: photosynthetic prokaryotic
the evidence: circular DNA, 2 membranes, ribosomes are similar to prokaryotic ribosomes, replicate independently of cell chromosomes and similar to bacterial replication
What are membrane proteins?
Perform different functions: membrane receptor proteins relay signals between the cell’s internal and external environments. Transport proteins move molecules and ions across the membrane.
What is potential energy?
It is stored energy in an object or system and is not relative to an objects environments.
What is kinetic energy?
It is when an object is in motion. It is relative to other moving and stationary objects in its main environment.