Cell Processes Chapter 9

Mixtures O mixture is a combination of substances not chemically bonded O solution is a mixture evenly combined O suspension is a mixture originally evenly combined, but the substance eventually sinks to the bottom

Organic Compounds O associated with living things O always contain carbon and hydrogen O Four groups make up all living things O carbohydrates O lipids O proteins O nucleic acids

Carbohydrates O supply energy for cell processes O short term energy storage O sugars and starches

Lipids O long-term energy storage O forms the cell membrane (phospholipids) O fats, oils, cholesterol

Proteins O regulate cell processes O build cell structures O skin, hair

Nucleic Acids O carry hereditary information O used to make proteins O DNA and RNA

Inorganic Compounds O generally made from elements other than carbon O used by living things O generally contain fewer atoms than organic molecules (smaller) O water is the most important inorganic compound

Importance of Water O living things are made up of over 50% water O all chemical processes take place in water O most organisms use water to transport materials through their bodies

Moving Cellular Material O cell’s membrane is selectively permeable – it allows some molecules to pass back and forth through it, but not all O movement depends on: O size O the path the molecule takes O whether or not energy is used

Passive Transport O movement of a substance through a cell’s membrane without the use of energy O three types O diffusion O osmosis – diffusion of water O facilitated diffusion

Diffusion O movement of any molecule from an area of high concentration to an area of low concentration O air freshener moving through a room O partial's continue to move until evenly spread out – equilibrium is reached

Diffusion

O high concentration to low concentration O occurs with smaller molecules, particles like gases (oxygen) O passive transport

Osmosis

O diffusion of water into a cell O cell’s are made up of water and are surrounded by water O cell’s shrink if water diffuses out of them, plant cells wilt O cell’s swell if too much water diffuses into them, red blood cell’s burst

Facilitated Diffusion

O some particles are too large to diffuse through the cell’s membrane O transport or carrier proteins create an opening through the membrane for these particles to pass through O still passive transport because particles are moving from high concentration to low

Active Transport O moving material into or out of the cell using energy O requires the use of transport or carrier proteins O moving against the concentration gradient, low concentration to high O moving against a crowd

Endocytosis and Exocytosis O transportation of large particles in and out of a cell O cell membrane folds in on itself and forms a vesicle around the particle O endocytosis – moving large particles into the cell O exocytosis – moving large particles out of cell

Section 2 Review O Cell membranes are selectively permeable because they allow some molecules to pass through, but not others. For example, iodine could pass through the dialysis membrane, however the starch could not.

Section 2 Review O Osmosis and diffusion are both ways cells move material across the cell membrane. They both move materials from areas of higher concentration to areas of lower concentration. However, osmosis is the diffusion of water across a cell membrane; diffusion can apply to any form of matter.

Section 2 Review O Endocytosis and exocytosis are both important cell processes. Molecules and particles that are too large to move by diffusion or by the cell’s transport proteins can move into a cell by endocytosis and out of a cell by exocytosis.

Section 2 Review O Fresh fruits and vegetables are sprinkled with water at produce markets because the water will diffuse into them and keep them crisp.

Section 2 Review O Drinking large amounts of seawater would be dangerous for humans because the high levels of salt in seawater would cause water to move out of the cells, resulting in dehydration.

Energy for Life O Where do you get energy from? O From food!

Energy for Life O As the food is broken down through chemical reactions, energy is released O Sum of all chemical reactions in an organism is called metabolism O Enzymes are a special type of protein that helps speed up chemical reactions in our bodies Enzymes

Photosynthesis O producers - organisms that can make their own food O consumers – organisms that cannot make their own food O photosynthesis – process where producers use light energy to make sugars O chloroplasts – organelle in green plants that captures light energy to use in photosynthesis

Photosynthesis

O reactants O carbon dioxide O water O products O sugar (glucose) O oxygen O Light energy stored in the glucose bonds

Respiration O respiration – chemical reaction that breaks down food to release their stored energy O both producers and consumers carry on respiration O opposite process of photosynthesis

Respiration

Fermentation O sometimes cells need to obtain energy, but there is no oxygen present to complete cellular respiration O glucose (sugar) breaks down and energy is released O lactic acid, alcohol and oxygen are released

Section 3 Review O Producers make food and consumers get energy by eating producers, by eating food made by producers, or by eating other consumers. Examples of producers are flowers, corn and grass. Examples of consumers are flies, humans and lions.

Section 3 Review O Energy used by living things is released from food molecules during cellular respiration. Photosynthetic producers convert light energy – usually from the Sun – into the chemical energy in the sugar molecules they produce. Consumers get this energy by eating producers or other consumers that eat producers.

Section 3 Review O Fermentation and respiration are both cellular processes that release energy. The amount of energy released by fermentation is less than that released by respiration. Also, fermentation does not use oxygen as a reactant.

Section 3 Review O Some indoor plants can improve the quality of the air in the room because they remove carbon dioxide, use it for photosynthesis, and release oxygen as a product of that cellular process.

Section 3 Review O The number of atoms before and after photosynthesis is the same: C= 6, H = 12, O = 18