Year 11 Biology Notes

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Biology

Major substances:

Organic compounds – are compounds that contain carbon and were originally made by living things e.g. carbohydrates, lipids, proteins, nucleic acids Inorganic compounds – are compounds do not contain carbon as a main element

Organic compounds| Composition| Function|
Proteins| Carbon, hydrogen, oxygen and nitrogen| Used in the structure, storage, movement and transport of cells for growth and repair.| Lipids| Carbon, hydrogen and oxygen| Stores energy but is more difficult to release than carbohydrates. It breaks down into fatty acids and glycerol. Used as stores of energy| Lignin| Composed of a complex polymer| Provided support for stems and leaves of cells to prevent them from collapsing| Starch| Consists of glucose units joined together| Made by plants to store excess sugar| Glucose| Comes from digesting the sugar and starch in carbohydrates.| Provides energy to the cell|

Cell chemical| Test Reagent| Negative result| Positive result| Glucose| Benedict’s solution| Pale blue or no colour change| Yellow or orange| Starch| Iodine solution| Yellow brown or no colour change| Dark blue or black| Protein| Biuret| Blue or no colour change| Purple|

Lignin| Toluidine blue| Blue or green or no colour change| Pale blue| Chloride ions| Silver nitrate| No precipitate| White precipitate|

 Protein can be identified by Biuret reagent, and if starch is present iodine solution will turn from yellow/brown to black/dark blue

 If Benedict’s solution turns from blue to yellow, this proves that glucose is present.

Cell Organelles

Key terms
Light microscopes: an instrument that uses light and lenses to magnify very small specimens Electron microscopes: an instrument that uses electron beams to enlarge images more than 200 times Organelle: specialised part of the cell

DNA: deoxyribonucleic acid contains hereditary information that can be passed on through reproduction Cytoplasm: gel material that makes up a living cell, not including the nucleus Cellulose: inorganic complex carbohydrate

Chlorophyll: green pigment used in photosynthesis
Photosynthesis: the process of how plants make glucose and the by product oxygen from the reaction water and carbon dioxide in the presence of sunlight and chlorophyll. Stroma: the fluid in the chloroplast holding the grana and starch Granum: a stack of membranes that photosynthesis in the chloroplasts Electron micrographs: pictures that have been taken by an electron microscope Cellular respiration: the process of creating energy using glucose and oxygen in mitochondria Crista: the folding of the inner membrane in a mitochondrion which increases the surface area for reactions Matrix: the fluid in the mitochondria that contains enzymes for respiration Vesicle: small fluid filled sacs

Chromatin: material that makes up nucleus and DNA which holds hereditary information Pores: holes
Protein: macro molecule made of aminoacids used for structure and function Lipids: are fats, they are high in energy

Identify cell organelles seen with current light and electron microscopes Organelles and Structures that can be seen with light microscopes Organelle or Structure| Description| Function|
Nucleus| Large circular membrane bound organelle in the cytoplasm that contains DNA.| Controls all cell activity.| Cell Membrane| Semi permeable structure made of phospholipids that surrounds the contents of the cell.| Control what substances enter and leave the cell.| Vacuole| Membrane bound sac of dissolved ions in water.| Stores water and ions and provides support stopping it from becoming flaccid.| Chloroplast| Double membrane bound green organelle containing chlorophyll.| Photosynthesis which involves the creation of glucose using sunlight.| Cell Wall| Rigid membrane of cellulose that surrounds a plant cell.| Provides support and structure.|

Organelles and Structures that can be seen with...
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