cell strcture

• All living organisms are made of cells, there are several different types of cells, some of them sharing some common features.
• Condensation of ADP and inorganic phosphate catalysed by ATP synthase produces ATP during photosynthesis and respiration.
• Human are made up of eukaryotic cells.
• All eukaryotic cells contain a nucleus and membrane bound organelles.
• A more detailed structure of cells called the ultrastructure can be obtained by using a microscope.
• The ultrastructure of eukaryotic cells includes a nucleus surrounded by a double membrane called the envelope containing pores which enable molecules to enter and leave the nucleus, chromatin, and a nucleolus which is the site of ribosome production.
• Eukaryotic cells contain rough endoplasmic reticulum which is a series of flattened sacs enclosed by a membrane with ribosomes on the surface.
• Rough endoplasmic reticulum folds and processes proteins made on the ribosomes.
• Eukaryotic cells contain smooth endoplasmic reticulum which is a system of membrane bound sacs.
• Smooth endoplasmic reticulum produces and processes lipids.
• Eukaryotic cells contain Golgi apparatus which is a series of fluid filled, flattened & curved sacs with vesicles surrounding the edges.
• The Golgi apparatus processes and packages proteins and lipids and also produces lysosomes.
• Eukaryotic cells contain mitochondria which are usually oval shaped, bound by a double membrane called the envelope.
• The inner membrane of mitochondria is folded to form projections called cristae with matrix on the inside containing all the enzymes needed for respiration.
• Centrioles are hollow cylinders containing a ring of microtubules arranged at right angles to each other and are involved in cell division.
• Ribosomes are composed of two subunits and are the site of protein production.
• Lysosome is a vesicle containing digestive enzymes bound by a single membrane.
• The cell surface membrane surrounds the cell and controls what enters and exits.
• Some animal cells may contain cilia on their surface membrane which are small hair-like structures composed of microtubules in a ‘9+2’ formation allowing movement of cilia therefore allowing movement of substances along the surface of the cell.
• Microvilli are finger-like projections of the cell membrane which increases the cell's surface area and line organs like the small intestine to maximise nutrient absorption.
• The vacuole is a fluid-filled sac present in plant cells, surrounded by a membrane called the tonoplast containing mineral salts, sugars, amino acids, waste substances and pigments.
• The cell wall of plant cells is made of cellulose microfibrils and its role is to strengthen the cell and prevent bursting due to osmosis.
• Chloroplasts are small flat organelles surrounded by a double membrane and contain thylakoid membranes which are stacked up to form grana and are linked together by lamellae.
• Chloroplasts are the site of photosynthesis.
• Plasmodesmata are small channels that pass through the cell wall of adjoining plant cells to allow communication between cells.
• Label lines should not have arrow heads.
• The inorganic phosphate can be used to phosphorylate other compounds, as a result making them more reactive.
• Prokaryotic cells contain a cell wall, capsule, plasmid, flagellum, pili, ribosomes, and mesosomes.
• Energy is released when ATP is hydrolysed to form ADP and a phosphate molecule, this process is catalysed by ATP hydrolase.
• Label lines should be straight and drawn with a ruler.
• Prokaryotic cells are unicellular and are typically 1–5μm in diameter, which is much smaller than eukaryotic cells.
• Label lines shouldn’t cross over each other.
• Draw continuous lines.
• Make sure the drawing takes up as much of the paper as possible.
• There are two types of microscopes: light microscopes, which are good for observing samples in a lab as they are cheap and portable, and have a lower magnification and resolution than electron microscopes, and electron microscopes, which are good for examining organelles in high detail, have a high magnification and resolution, but samples must be placed in a vacuum and prepared first.
• Microscopy is the most important technique used in biology as it enables us to see and examine organisms and structures which cannot be seen with the naked eye.
• No shading is allowed in scientific drawings.
• Include a title for the drawing.
• Mounting involves mounting onto a microscope slide making sure there is a coverslip placed on top.
• State the magnification.