topic1

• Eukaryotic cells are complex and include all animal and plant cells
• Prokaryotic cells are smaller and simpler then eukaryotes. eg. bacteria
• Prokaryotes are unicellular organisms that do not have a nucleus or membrane bound organelles
• Animal subcelluar structures: Nucleus, mitochondria, cell membrane, cytoplasm, ribosomes
• Nucleus: contains genetic material that control the activities of the cell. Genetic material is arranged into chromosomes
• cytoplasm: gel-like substance where most of the chemical reactions happen. it contains enzymes that control the chemical reactions
• Cell membrane: A semi-permeable barrier that surrounds the cell and controls what enters and leaves the cell
• Mitochondria: where most of the reactions for respiration take place.
• Ribosomes: these are involved in the translation of genetic material in synthesis of proteins
• Plant cells have a cellulose cell wall, chloroplasts, and a large vacuole unlike animal cells.
• cellulose cell wall: supports and strengthens plant cell
• Large vacuole: contains cell sap, which is a weak solution of sugars and salts, maintains internal pressure to support cell
• Chloroplasts: where photosynthesis occurs, where chlorophyll is found
• subcellular structures in bacterial cells: chromosomal DNA, ribosomes, cell membrane, plasmid DNA, Flagellum, cytoplasm
• Chromosomal DNA: controls cell's activities and replication, floats free in cytoplasm
• Plasmid DNA: small loops of extra DNA that contain genes for things like drug resistance and can be passed down between bacteria
• Flagellum: a long hair like structure that rotates to make the bacterium move
• egg cells are adapted to their function by: containing nutrients in the cytoplasm, having a haploid nucleus, the membrane structure changes to stop anymore sperm coming in
• the sperm is adapted by having a long tail, having lots of mitochondria, having acrosome and a haploid nucleus
• ciliated epithelial cells have ciliated hairs that move mucus up and out of the trachea
• image size= magnification*actual size
• Enzymes are catalysts produced by living organisms that speed up chemical reactions.
• Enzymes reduce the need for high temperatures and only speed up useful chemical reactions
• chemical reactions involve things being split apart or joined together.
• The substrate is the molecule changed in the reaction
• active site: the part of the enzyme that binds to the substrate to catalyse and is the site of reaction
• Enzymes are substrate specific and only work with one substrate
• Lock and key mechanism: A substrate fits into an enzyme
• substrate + enzyme = enzyme substrate complex
• When enzymes get to hot the bonds holding it togther break denaturation occurs
• all enzymes had an optimum temperature
• When enzymes are to cold there is less kinetic energy for the enzymes so less collisions take place
• Rate= change/time
• digestive enzymes break down big molecules like proteins lipids and some carbohydrates into smaller molecules
• Plants store energy in the form of starch and use enzymes to break them down into sugars so can be used for respiration
• Enzymes called carbohydrasea convert carbohydrates into simple sugars
• Starch is broken down by amylase into maltose and other sugars
• Protease Converts proteins into amino acids
• Lipases converts lipids into glycerol and fatty acids
• Organisms need to be able to synthesise carbohydrates, proteins and lipids from their smaller components