A eukaryote (juË�ËˆkÃ¦ri.oÊŠt or juË�ËˆkÃ¦riÉ™t|) is an organism whose cells contain complex structures enclosed within membranes. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear envelope, within which the genetic material is carried. The presence of a nucleus gives eukaryotes their name, which comes from the GreekÎµÏ… (eu, "good") and ÎºÎ¬Ï�Ï…Î¿Î½ (karyon, "nut" or "kernel"). Most eukaryotic cells also contain other membrane-bound organelles such as mitochondria, chloroplasts and the Golgi apparatus. All species of large complex organisms are eukaryotes, including animals, plants and fungi, although most species of eukaryotic protists are microorganisms.
Cell division in eukaryotes is different from that in organisms without a nucleus (prokaryotes). It involves separating the duplicated chromosomes, through movements directed by microtubules. There are two types of division processes. In mitosis, one cell divides to produce two genetically identical cells. In meiosis, which is required in sexual reproduction, one diploid cell (having two instances of each chromosome, one from each parent) undergoes recombination of each pair of parental chromosomes, and then two stages of cell division, resulting in four haploid cells (gametes). Each gamete has just one complement of chromosomes, each a unique mix of the corresponding pair of parental chromosomes.
Eukaryotes appear to be monophyletic, and so make up one of the three domains of life. The two other domains, Bacteria and Archaea, are prokaryotes and have none of the above features. Eukaryotes represent a tiny minority of all living things; even in a human body there are 10 times more microbes than human cells.
Eukaryotic cells are typically much larger than prokaryotes due to their enlarged shell. They have a variety of internal membranes and structures, called organelles, and a cytoskeleton composed of microtubules, microfilaments, and intermediate filaments, which play an important role in defining the cell's organization and shape. Eukaryotic DNA is divided into several linear bundles called chromosomes, which are separated by a microtubular spindle during nuclear division.
Eukaryotic cells include a variety of membrane-bound structures, collectively referred to as the endomembrane system. Simple compartments, called vesicles or vacuoles, can form by budding off other membranes. Many cells ingest food and other materials through a process of endocytosis, where the outer membrane invaginates and then pinches off to form a vesicle. It is probable that most other membrane-bound organelles are ultimately derived from such vesicles.
The nucleus is surrounded by a double membrane (commonly referred to as a nuclear envelope), with pores that allow material to move in and out. Various tube- and sheet-like extensions of the nuclear membrane form what is called the endoplasmic reticulum or ER, which is involved in protein transport and maturation. It includes the rough ER where ribosomes are attached, and the proteins they synthesize enter the interior space or lumen. Subsequently, they generally enter vesicles, which bud off from the smooth ER. In most eukaryotes, these protein-carrying vesicles are released and further modified in stacks of flattened vesicles, called Golgi bodies or dictyosomes.
Vesicles may be specialized for various purposes. For instance, lysosomes contain enzymes that break down the contents of food vacuoles, and peroxisomes are used to break down peroxide, which is toxic otherwise. Many protozoa have contractile vacuoles, which collect and expel excess water, and extrusomes, which expel material used to deflect predators or capture prey. In multicellular organisms, hormones are often produced in vesicles. In higher plants, most of a cell's volume is taken up by a central vacuole, which primarily maintains its osmotic pressure.
Mitochondria and plastids
From Yahoo Answers
Question:Question 1 (Multiple Choice Worth 3 points)
Some argue that a prokaryote cell is more complex than a eukaryote cell even though it does not have all the cell parts. Which of the following best defends this argument?
A.)Prokaryote cells are much larger and carry out more processes.
B.)Prokaryote cells must do perfectly timed chemical life processes in one open space as opposed to different organelles doing their special job all the time.
C.)Prokaryote cells genetic material is not bound by a nucleus and can carry out protein synthesis faster.
D.)None of the above
Question 2 (Multiple Choice Worth 3 points)
Studying a picture of a cell with an electron microscope, you find that the cell has a cell wall, a nucleus, and a large central vacuole. You conclude that the cell is probably a(n)
Question 3 (Multiple Choice Worth 3 points)
Which organelle is used for the storage of food, water or waste?
Question 4 (Multiple Choice Worth 3 points)
The _____________ controls what enters and exits the cell and is found in all cell types.
Question 5 (Multiple Choice Worth 3 points)
Which of the following is NOT a eukaryote type cell?
Question 6 (Multiple Choice Worth 3 points)
Which cell organelle, responsible for helping build proteins, is also found in prokaryote cells because it is not surrounded by a membrane?
D.)None of the above
Question 7 (Multiple Choice Worth 3 points)
Which of the following can be found inside the nucleus?
D.)None of the above
Question 8 (Multiple Choice Worth 3 points)
The mitochondrion is the cell organelle responsible for _____________.
A.)The process of photosynthesis and making food
B.)The process of cellular respiration and releasing energy
C.)The process of digestion and waste removal
D.)None of the above
Question 9 (Multiple Choice Worth 3 points)
The _______________carries on the process of photosynthesis.
Question 10 (Multiple Choice Worth 3 points)
Which type of cell does NOT contain a nucleus?
D.)None of the above
Question 11 (Multiple Choice Worth 3 points)
The collective term that describes the jellylike substance and the organelles suspended in it is the:
Question 12 (Multiple Choice Worth 3 points)
Which of the following organelles provides protection for a plant cell?
Question 13 (Multiple Choice Worth 3 points)
Which of the following pairs do NOT go together?
A.)Animal cell - Centrioles
B.)Plant cell - Chloroplast
C.)Animal cell - Cell wall
D.)Plant cell - Eukaryote
Question 14 (Multiple Choice Worth 3 points)
Which of the below is not true about the cytoplasm:
A.)It fills the space between the nucleus and cell membrane
B.)It is found only in the animal cell
C.)Contains and supports the cell organelles
D.)It is full of proteins that control the cell metabolism
Question 15 (Multiple Choice Worth 3 points)
The term used to describe a cell part that does a specific job is ___________.
Question 16 (Essay Worth 5 points)
Choose one cell part from a eukaryote type cell. Relate that organelle to a part of a city and describe how they are similar. (For example the lonesomes are like waste management in that they help get rid of the garbage inside the cell.)
Question:i forgot my stupid bio book and cant find the asnwers on the net. ne body know a thing or two about bio?
Answers:prokaryotic- no nucleus, cell wall, all other organelles
eukaryotic- same as prokaryotic but has an nucleus and no cell wall
Question:1.What is thdifferencece between a eukaryotic call and a prokaryotic cell?
2.what structures are found in plant cells but not in animal cells?
Answers:Eukaryotic cells have membrane bound organelles, chromosomes,and nuclear membrane
Prokaryotic cell lacka nuclear membran, complex chromosomes, and known as bacteria
Question:What are the advantages of eukaryotic cell structure over prokaryotic cell structure? How are they different? How does the structure make eukaryotes more adaptable?
Yeah I have no idea what these questions mean. PLEASE HELP!
Answers:Eukaryotic cells have membranous organelles which help to compartmentalize the cell so that each reaction in the organelle is separate from those of other organelles. Eukaroyotic cells also have a variety of organelles that carry out different functions. Prokaryotic cells came before eukaryotic cells so they do not have the organelles that eukaryotic cells have. Eukaryotic cells have a membrane bound nucleus, while prokaryotic cells store the DNA in a region called the nucleoid. Prokaryotic cells also have the outermost layer, the capsid, while eukaryotoic cells do not have this layer.
The nuclear membrane around the DNA allows for the regulation of different materials into and out of the nucleus. This is the same for each organelle too. The most important plasma membrane (cell membrane) is the one that surrounds the eukaryotic cell itself. This plasma membrane separates the extracellular matrix from the cytoplasm, and helps regulate what enters and exits.
I could make it longer, but I think thats too long already.
Inner Structure of an Eukaryotic Cell :Electron cryotomographic reconstruction of an Ostreococcus tauri cell (a photosynthetic eukaryote). The three-dimensional reconstruction of a single cell is shown slice-by-slice, from which the segmented model emerges in a second pass. After the various subcellular organelles are identified, the substructure of first the Golgi body and then the mitochondrion are shown in isolation, including the position and shape of the cristae junctions. Citation: Henderson GP, Gan L, Jensen GJ (2007) 3-D Ultrastructure of O. tauri: Electron Cryotomography of an Entire Eukaryotic Cell. PLoS ONE 2(8): e749. doi:10.1371/journal.pone.0000749 Copyright: 2007 Henderson et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Freely available at www.plosone.org
Eukaryotic Cell Cycle | Biology | Genetics :To purchase this DVD please visit www.greatpacificmedia.com Segment from the program Cellular Reproduction: Mitosis, Cytokinesis, and the Cell Cycle DVD Description Our Mitosis DVD starts by introducing the cell cycle and briefly describing the process of binary fusion in prokaryotic cells before going on to a detailed look at the eukaryotic cell cycle from the G1, S and G2 phases of interphase through the prophase, metaphase, anaphase and telophase phases of mitosis. The difference between cytokinesis in animal and plant cells is then illustrated. The program concludes by explaining why an understanding of cellular division is critical to: conquering cancer, cloning organs, and perhaps even reversing aging.