3.2.1.1 Eukaryotic cell structure

• Mitochondria- double, folded membrane for increased surface area for chemical reactions (ATP synthesis providing energy for cell)
• Nucleus- controls the activities of the entire cell, contains linear DNA (chromosomes)
• Nucleolus- site of ribosome production and RNA synthesis
• Nuclear pores- controls movement of molecules between cytoplasm and nucleus
• Chloroplasts- in plants and algae, double membraned, contains chlorophyll, own ribosomes and DNA
• Golgi body- series of flattened membrane-bound sacs which modify, package and transport modified proteins and lipids
• Lysosomes- fluid-filled sac, containing hydrolytic enzymes bound in a membrane, gets rid of worn-out organelles
• Ribosomes- site of protein synthesis, made up of two sub-units which fit together, with mRNA fitting between them. Made from rRNA and proteins. Can be free floating or attached to endoplasmic reticulum. 80s size
• Rough endoplasmic reticulum- synthesises and transports proteins, membrane bound, close to golgi body, cisterne
• Smooth endoplasmic reticulum- synthesises and transports lipids to golgi body, membrane bound, cisterne
• Cell wall- made of cellulose or chitin, provides support, strength, maintains shape
• Vacuole- in plants, tonoplast membrane, contains water, nutrients, cell sap and waste, maintains pressure inside cell, acts as storage
• Eukaryotic cells - have a true nucleus, membrane bound organelles, larger than prokaryotic cells
• Palisade mesophyll tissue- many closely packed cells containing chlorophyll, at the top of leaf, large vacuole
• Root hair cell- large surface area for absorbing water and minerals from soil, many mitochondria, thin cell wall, no chloroplasts
• White blood cell (neutrophil)- multi-lobed nucleus, many lysosomes, many mitochondria, many RER
• Red blood cell- binds to oxygen to oxygenate cells, contains haemoglobin, biconcave shape, no nucleus
• Sperm cell- fertilises egg cell, haploid cell, many mitochondria, hydrolytic enzymes in tip of head, flagella, no cytoplasm
• B lymphocytes- produce antibodies and memory cells to fight pathogens, many RER, many mitochondria, protein receptors on surface membrane
• Small intestinal cell- absorbs nutrients and water from digested food, microvilli, many RER, many mitochondria, secretes hydrolytic enzymes, packed closely
• Outline the role of organelles in the production, transport and release of proteins from eukaryotic cells (4 marks):

  Ribosomes produce proteins (1), Mitochondria produce ATP energy which is used for protein synthesis (2). Golgi body modifies and packages proteins (3) into vesicles that fuse with the cell membrane to transport proteins (4).
• Suggest an explanation for the appearance of the cell membrane as two dark lines (3 marks):

  The membrane has a phospholipid bilayer (1), stain binds to the phosphate heads (2) on the inside and the outside of the membrane (3).