Transcript Chapter 3
Chapter 3 Cell Processes Chemistry of Life • Everything-made of matter and energy – matter- anything that has mass and takes up space – energy- holds matter together or breaks it apart Chemistry of Life-cont. • Matter – made of atoms • nucleus contains protons and neutrons • electrons are outside the nucleus Chemistry of Life-cont. • Elements – made of one kind of atom • cannot be broken down into a simpler form by an ordinary chemical reaction • arranged in the periodic table of elements Chemistry of Life-cont. • Compounds – made of two or more elements – have different properties from the elements they are made of – smallest part of a molecular compound is a molecule – molecule-group of atoms held together by the energy of chemical bonds – form when atoms share electrons Chemistry of Life-cont. • Ionic compounds – ions-electrically charges atoms • positive or negative • electrically neutral- ions of opposite charges attract one another. Chemistry of Life-cont. • Mixture-combination of substances – solution-two or more substances are mixed evenly – suspension-forms when a liquid or gas has another substance spread throughout it Chemistry of Life-cont. • Organic compounds-contain carbon or hydrogen – carbohydrates-supply energy for cell processes – lipids-store and release large amounts of energy – proteins-building block of many structures • amino acids • enzymes – nucleic acids-stored coded information in cells Chemistry of Life-cont. • Inorganic compounds – usually made from elements other than carbon Chemistry of Life-cont. • Importance of water – living things-composed of more than 50% water – all chemical reactions take place in water solutions – most living things use water to transport materials Moving Cellular Materials • Cells have a permeable membrane that regulates what goes into and out of a cell. Moving Cellular Materials-cont. • Passive transport- movement of substances without energy – diffusion-move away from areas where there are more of them into areas where there are fewer of them – osmosis-diffusion of water – facilitated diffusion-transport proteins move substances Moving Cellular Materials-cont. • Active transport- requires energy to move substances through a cell membrane Moving Cellular Materials-cont. • Endocytosis and Exocytosis – endo-taken into the cell – exo- released outside the cell Energy for Life • Cells use chemical reactions to change the chemical energy stored in food into forms needed. – metabolism-total of all chemical reactions – chemical reactions require enzymes Energy for Life-cont. • Photosynthesis-converts sunlight energy into chemical energy or sugars to be used as food. – producers- make their own food – consumers-can’t make their own food – chlorophyll (pigments)-capture sunlight to produce sugar and oxygen Energy for Life-cont. • Respiration- chemical reaction to break down food molecules into simpler substances and release stored energy. – begins in the cytoplasm • carbohydrates are broken down into glucose molecules • glucose molecules break down into simpler molecules releasing energy – continues in mitochondria • two simpler molecules are broken down again, releasing more energy • process uses oxygen and produces CO2 Energy for Life-cont. • Fermentation- cells that do not have enough oxygen for respiration use this process to release some of the stored energy in glucose molecules. – process occurs in cytoplasm – produces lactic acid, alcohol, and carbon dioxide as wastes Energy of Life-cont. • Photosynthesis and respiration – photosynthesis-produces sugars and oxygen, which are used in respiration – respiration-produces carbon dioxide and water, which are used in photosynthesis.