3.4. Eukaryotic Cell Structure

• The golgi can label proteins to ensure they end up in the right destination
• The golgi can modify proteins, often adding non-protein components such as carbohydrates
• The proteins and lipids produced from the RER are passed through the golgi apparatus in a strict sequence
• Vesicles: smooth rounded hollow structures
• Membranes are folded to form cisternae because it produces a large surface area
• Golgi apparatus contain cisternae (flattened sacs of folded membranes)
• The golgi apparatus appears in every eukaryotic cell and is similar to that of the smooth endoplasmic reticulum
• Lamellae of the rough endoplasmic reticulum make up the double membrane
• The SER is more tubular in appearance and is involved in the synthesis of lipids and carbohydrates
• The rough endoplasmic reticulum has ribosomes on the outer surface of the membranes
• The RER provides a pathway for the transport of materials throughout the cell
• The membranes of the RER enclose a network of tubules and flattened sacs called cisternae
• The RER is continuous with the outer nucleus membrane
• The RER is an elaborate, three dimensional stem of sheet-like membranes, spreading through the cytoplasm of the cells
• Soluble products inside a golgi vesicle can be absorbed into the cytoplasm
• The golgi has two faces: cis and trans
• The golgi vesicles can travel to the cell surface where they can fuse with the membrane, releasing their contents to the outside
• When sorted, the modified proteins and lipids are transported in golgi vesicles which are pinched off from the ends of the golgi cisternae
• Chloroplast is the site of photosynthesis in eukaryotic cells, being either biconcave or planoconvex in shape.
• Chloroplast can be found in the mesophyll of plant leaves. And are spheroid, discoid or ovoid shaped too.
• Chloroplasts are vesicular and have a colourless centre and has ends that are filled with chlorophyll
• Chloroplast: The outer membrane is semi porous and is permeable to small molecules and ions, diffusing easily. However, not permeable to larger proteins
• Chloroplast: The intermembrane space is 10-20nm between the inner and outer membranes
• Chloroplast: The inner membrane is the border to the stroma and regulates the passage of materials. Synthesising fatty acids, lipids and cartenoids
• Chloroplast: The thylakoid system is suspended in the stroma. It is a collection of membraneous sacs. Alongside chlorophyll being found here. Chlorophyll is the site in which light reactions for photosynthesis take place
• Thylakoids are in stacks known as granums. Granums consist of 10-20 thylakoids
• Chloroplasts carry out the absorption of light energy then being converted into biological energy
• Chloroplast granal membranes provide a large surface area for the attachment of chlorophyll, electron carriers and enzymes. These carry out the last stages of photosynthesis . These are ordered in a strict fashion
• The fluid of the stroma contains all the enzymes needed in order to make sugars in the second stage of photosynthesis
• Chloroplasts contain both DNA and ribosomes in order to be able to quickly and easily manufacture their own proteins
• Mitochondria has a folded inner membrane so that it has a larger surface area in order to attach to enzymes and proteins needed for respiration. This is called the cristae
• mitochondria matrix is equivalent to cytoplasm but is more liquid in nature. Containing proteins, lipids, ribosomes and DNA
• Mitochondria has it's own ribosomes and DNA in order to control its production of proteins and enzymes and it means it is quicker to produce proteins
• Mitochondria is the site of aerobic respiration and is the site of ATP synthesis
• The golgi vesicles are made from lysosomes. Lysosomes contains lysozymes which digest the cell contents
• Lysosome is an organelle containing hydrolytic enzymes used to break down macromolecules such as carbohydrates, fats and proteins
• All plant cells have a cell wall
• Cell walls consist of microfibrils from the polysaccharide cellulose, embedded in a matrix. Microfibrils are considerably strong so contribute to the strength of the cell wall
• Cell walls provide mechanical strength in order to prevent the cell bursting under the pressure created by the osmic entry of water. Giving strength to the plant as a whole. Alongside contributing to the movement of water through the plant
• Cell walls have a thin layer called the middle lamellae which is the boundary between adjacent cell walls and cements the adjacent cells together.