Download 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.