Eukaryotes

• What is the nucleus?


  Double nuclear membrane with pores. AKA Nuclear envelope. Contains chromosomes, both uncoiled and coiled. AKA chromatin. Where the chromosomes are uncoiled it will appear lighter on the microscope and where they are coiled it will appear darker, and is known as dense chromatin. Dense chromatin is typically present near the double membrane. The chromosomes are in a fluid called the nucleoplasm. The nucleus also contains a nucleolus in the centre. Each cell should contain 23 pairs of chromosomes, 46 in total.
• What is the Nucleolus?


  Spherical body within the Nucleus, and is composed of RNA and proteins.
• What is the rER?


  Flattened membrane sacs, AKA cisternae, with ribosomes attached. The ribosomes in an Eukaryotic cell are larger than those in Prokaryotes- 80s.
• What is the smooth ER?


  Branched network of tubular membranes. No ribosomes attached to it, so is smooth.
• What are free ribosomes?


  They are created in the nucleolus, and are not surrounded by a membrane. They are the same size as those in the rER- 80s. They are formed from two subunits, and are complexes of proteins and RNA.
• What is the mitochondria?


  Has a double membrane, with the inner membrane forming crista, which is within the mitochondria. Within the mitochondria is a fluid known as the matrix. They are either spherical or oval.
• What is the peroxisome?


  Contains a crystalline core (not always), and a lipid bilayer which is within the membrane.
• What is a centriole?


  Two groups of nine microtubules. Microtubules are small cylindrical fibres. Microtubules are typically in triplets.
• What is the cytosol?


  Water-based fluid of the cytoplasm.
• What is the Golgi apparatus?


  Consists of flattened membrane sacs (cisternae), which are often curved and have vesicles nearby.
• What is the lysosome?


  Spherically shaped, with a single membrane (known as the lysosome membrane). They are formed by Golgi vesicles, and contain digestive enzymes. They therefore have a very high protein concentration.
• What is the Pinocytotic vesicle?


  Is a small vacuole that contains a material that is transported.
• What is the cytoskeleton?


  Networks of protein fibres. Tubulin is used to make microtubules and actin is used to make protein microfilaments.
• What is the plasma membrane?


  AKA cell membrane. Is semi-permeable, and is a thin and flexible barrier made of Phospholipids and proteins. There is a hydrophilic phosphate head on the outside and inside of the membrane, with a phospholipid tail on the inside of the membrane. This makes the plasma membrane amphipathic, meaning that it has polar and non-polar parts (the tails are nonpolar while the heads are.)
• What is a chloroplast?


  Contain a double membrane with stroma and stacks of thylakoids (flattened membranes) within. They are typically spherical or oval and if they have been photosynthesising quickly then will contain starch grains. they also contain chlorophyll, which is what makes a plant green
• What is a vacuole?


  Is a single membrane with fluid. The membrane is known as a tonoplast. They are large and occupy over half of the volume of the cell.
• What is an Amyloplast?


  Is a membrane-bound sac, containing starch
• What is the cellulose cell wall?


  Surrounds the plasma membrane, and is made of cellulose, pectin and lignin.
• What is the function of the Nucleus?


  Contains genetic information and DNA within chromosomes.
• What is the function of the nucleolus?


  Produces ribosomes and regulates gene expression. It also is where DNA is replicated and transcribed to form RNA, which is then released via pores to the cytoplasm.
• What is the function of the rER?


  Synthesises proteins which are then carried through vesicles to the Golgi apparatus.
• What is the function of the smooth ER?


  Synthesises lipids, phospholipids and steroids. They may also store calcium ions in muscles when they are relaxed.
• What is the function of a free ribosome?


  Synthesises proteins and polypeptides so that they can be released to work in the cytoplasm (as enzymes, etc)
• What is the function of the mitochondria?


  Produces ATP through aerobic respiration, and is also the site where fat is digested.
• What is the function of peroxisome?


  Metabolises lipids and converts reactive forms of oxygen to oxygen.
• What is the function of Centrioles?


  Microtubules move chromosomes during division, and the centriole is an anchor point for microtubules during division.
• What is the function of cytosol?


  Allows the functions of life to take place and controls enzymes, signalling, and offers structural support.
• What is the function of the Golgi apparatus?


  Processes the proteins that are brought through vesicles from the rER. After they are processed, the proteins are carried through the vesicles to the plasma membrane for secretion.
• What is the function of lysosome?


  Contains digestive enzymes, which are used to break down ingested food in vesicles, to break down organelles, and the break down cells.
• What is the function of the Pinocytotic vesicle?


  It is responsible for transportation of materials within the cell, and pinocytosis (cell-drinking). Pinocytosis is used to take in ECF (extracurricular fluid), and is when the cell surrounds particles and 'pinches off' their membranes, enclosing the particle within the pinocytotic vesicle.
• What is the function of the cytoskeleton?


  They hold organelles in position, giving the cell shape. They also assist with molecular transport, and aid the construction of the cell wall in plant cells.
• What is the function of the Plasma membrane?


  Regulates movement in and out of the cell and protects the cell. The proteins in the plasma membrane can open and close forming aqueous channels and in and out of the cell, and use ATP from aerobic respiration in the mitochondria to carry out active transport.
• What is the function of a chloroplast?

  Produce glucose and other organic compounds through photosynthesis. The glucose produced by photosynthesis can be used by SCARF
• What is the function of a vacuole?


  Food is absorbed and digested within the vacuole. Sometimes the vacuoles will also store water, and they keep the plant cells rigid shape.
• What is the function of an amyloplast?

  Converts glucose to starch and stores starch
• What is the function of a cellulose cell wall?

  Provides strength and structure to the cell, protects from pathogens, and turgor pressure (water)
• What is the Cila?


  Small microtubules on the outside of a cell
• What is the function of a Cila?

  Help to move the cell or other substances that may touch the cell