Eukaryotes

• Eukaryotes are multicellular organisms made up of eukaryotic cells like animals, plants, fungi and protists
• Eukaryotic cells are more complex containing membrane-bound organelles and have their DNA in the form of chromosomes within a nucleus
• Nucleus is the largest organelle within an animal cell
• Nucleus contains genetic information in the form of chromosomes
• Nucleus is surrounded by nuclear envelope containing nuclear pores
• Nucleus controls the cell's activities as it contains DNA with instructions to produce proteins
• Nucleolus makes ribosomal RNA
• Ribosomes are made inside the nucleus
• Nucleus and the cytoplasm exchange substances which can leave or enter the nucleus via the nuclear pores
• Cell-surface membrane is found on the surface of animal cells and is made up of lipids and proteins
• Cell-surface membrane controls the movement of substances into and out of the cell as the membrane is partially permeable
• Cell-surface membrane controls cell-signalling as it has receptors which detect signals from other cells
• Mitochondria are found in large numbers in cells that require lots of energy
• Mitochondria contain an enzyme-rich liquid known as the matrix
• Mitochondria is surrounded by a double membrane in which the inner membrane is folded to form structures known as cristae
• Mitochondria contain their own DNA and ribosomes
• Mitochondria is the site of aerobic respiration and produces ATP
• Ribosomes are very small organelles found in the cytoplasm or attached to rough endoplasmic reticulum
• Ribosomes are measured in S units and eukaryotic cells contain 80S ribosomes
• Ribosomes are made up of proteins and rRNA
• Ribosomes consist of a large and small subunit and are not surrounded by a membrane
• Ribosomes are the site of protein synthesis and involved in the process of translation
• Golgi apparatus contains fluid-filled membrane bound sacs known as cisternae and contains smaller vesicles
• Golgi apparatus processes and packages lipids and proteins which is carried out by the cisternae
• Golgi apparatus stores and transports lipids and proteins which is carried out by the vesicles
• Golgi apparatus synthesise lysosomes by the specialised vesicles
• Rough endoplasmic reticulum is covered with ribosomes
• Rough endoplasmic reticulum contains a network of membranes enclosing a fluid-filled space known as cisternae
• Rough endoplasmic reticulum contains cisternae covered with ribosomes
• Rough endoplasmic reticulum synthesises and transports proteins which are made using the ribosomes
• Smooth endoplasmic reticulum does not have ribosomes
• Smooth endoplasmic reticulum synthesises stores and transports lipids and carbohydrates
• Lysosomes contain hydrolytic enzymes which digests pathogens
• Lysosomes are surrounded by a membrane to keep enzymes separate from the cytoplasm of the cell
• Lysosomes break down waste material which includes old organelles and cells
• Cytoskeleton is present throughout the cytoplasm and provides structure and support of the cell consisting of microfilaments, microtubules and intermediate filaments
• Microfilaments are made of the protein actin which is involved in cell movement and locomotion such as crawling and muscle contraction
• Microtubules are made of the protein tubulin and form a scaffold-like structure throughout the cell
• Microtubules form the main component of the mitotic spindle used for cell division and act as tracks for intracellular transport of vesicles and organelles
• Intermediate filaments maintain the position of organelles within the cell and are responsible for the mechanical strength of certain tissues such as the skin and hair