Chapter 3 Cell Processes

Ch 3.1 – Chemistry of Life Everything around you is made of matter and energy 1. Matter – anything that has mass and takes up space 2. Energy – can hold matter together or break it apart

Atoms – make up matter Nucleus contains protons & neutrons Outside the nucleus are electrons which are involved in chemical reactions between atoms

Element – substance made of only one kind of atom a) cannot be broken down into a simpler form by ordinary chemical reactions b) arranged in a chart called the periodic table of elements

Compounds – when 2 or more elements combine a) Have different properties than the individual elements they are made of b) 2 types: 1. Molecular compound (molecules) – formed when different atoms share electrons; covalent bond 2. Ionic compound (ions) – formed when different atoms exchange electrons; ionic bond

Mixture – combination of substances in which each substance retains their own properties 1. Heterogenous – substances not spread evenly; can see individual components Example: salad

Homogenous – substances spread evenly; cannot see individual components a) Solution – homogenous mixture in which two or more substances are mixed evenly and will not separate example: sweat & cytoplasm

b) Suspension – forms when a liquid has b) Suspension – forms when a liquid has another substance evenly spread throughout it , however if left undisturbed the substance in the mixture will sink to the bottom example: blood

C. Organic Compounds – contain carbon and hydrogen and are usually associated with living things or things that were once alive

4 groups of organic compounds make up organisms: Carbohydrates – supply energy for cell processes a) Sugars – small molecules that give quick bursts of energy

b) Starches – large molecules that can b) Starches – large molecules that can supply energy for longer periods of time however if not used will turn to fat tissue

c) Fiber (cellulose) – molecule from plant cell walls that cannot be broken down for energy by animals however is needed to keep digestive tract running smoothly

Lipids – store and release large amounts of energy for the body a) fats, oils & waxes b) also needed as body insulation and to cushion internal organs

Proteins – are building blocks of many structures in the body; some obtained through diet while others made in the body a) make up hair, nails and cell membranes b) Enzymes – special proteins that regulate chemical reactions c) Amino acids – molecules that proteins are composed of

Nucleic acids – store important coded information in cells a) DNA – carries hereditary information inside the nucleus of all cells b) RNA – used to make proteins

Inorganic Compounds – made from elements other than carbon; found in nonliving substances but are still needed by living things 1. Water – in blood and cytoplasm 2. Calcium phosphate – in bones for strength 3. Hydrochloric acid – to break down food in stomach 4. Sodium & Potassium salts – to send messages along nerve cells

Importance of Water 1. Living things are composed of more than 50% water and depend on it to survive 2. All chemical reactions in living things take place in water solutions 3. Most living things use water to transport substances in their bodies

Ch 3.2 – Moving Cellular Materials A. Cells have a permeable membrane that regulates what goes into and out of the cell

B. Passive Transport – the movement of substances through a cell membrane without the use of energy

1. Diffusion – when molecules move away from areas where there are more of them into areas where there are fewer of them.

Stops when the molecules of one substance are spread evenly throughout the other substance and equilibrium occurs.

2. Osmosis – the diffusion of water through a cell membrane

3. Facilitated Diffusion – moves large substances across the cell membrane using transport proteins

C. Active Transport – requires energy to move a substance through a cell membrane; goes against the natural flow

1. Endocytosis – the process in which a substance is taken into a cell by surrounding it with the cell membrane, forming a sphere called a vesicle.

2. Exocytosis – the process in which the membrane of the vesicle fuses with cell’s membrane and the vesicle’s contents are released.

Ch 3.3 – Energy for Life Cells use chemical reactions to change the chemical energy stored in food into forms needed to perform activities (energy) 1. Metabolism – the total of all chemical reactions in an organism. 2. The chemical reactions of metabolism require enzymes.

B. Photosynthesis – the process that plants and some other organisms use to convert light energy into chemical energy or sugars (glucose) to be used as food 1. Producers – organisms that make their own food 2. Consumers – organisms that can’t make their own food

3. Chlorophyll – pigment used in photosynthesis to capture light energy from the sun which is then used to produce glucose and oxygen 6CO2 + 2H2O + E C6H12O6 + 6O2 Carbon Dioxide Water Energy Glucose Oxygen

C. Respiration – the process in which chemical reactions break down food molecules into simpler substances and release stored energy 1. Respiration of carbohydrates begins in the cytoplasm a) Carb’s are broken down into glucose molecules b) Each glucose is then broken down to release energy

2. Respiration then moves to the mitochondria a) The 2 simpler molecules are broken down again releasing more energy b) This process uses oxygen and produces carbon dioxide & water as waste products 6O2 + C6H12O6 6CO2 + 6H20 + E

D. Fermentation – cells that do not have enough 02 for respiration use this process to release some of the stored energy in glucose molecules 1. Entire process takes place in the cytoplasm 2. Produces lactic acid as waste

E. Photosynthesis & Respiration are opposite processes 1 E. Photosynthesis & Respiration are opposite processes 1. Photosynthesis uses carbon dioxide & water to produce sugar & oxygen 2. Respiration uses sugars & oxygen and produces carbon dioxide & water