Unit 1.1: Why are cells important? Mr. Royiwsky Don Bosco Catholic Secondary School SNC2P1

Key Concepts Studying cells helps us understand how organisms function Cellular organelles work together to carry out life functions Cellular processes enable organisms to meet their basic needs

Key Terms Organelle – a structure within a cell that carries out specific functions to support the life of the cell Diffusion – the movement of molecules (or other particles) from an area of high-concentration to an area of low- concentration until they are evenly distributed Concentration – the number of molecules of a substance in a given volume Osmosis – the movement of water molecules across a membrane in response to concentration differences

Unit 1.1: Why are cells important? In our high tech world, one of the hottest areas of development is nanotechnology – the science and the technology of the very, very small A group of researchers in Europe has taken on the mind-boggling challenge of creating an artificial cell that can replicate on its own and even evolve under certain conditions

Unit 1.1: Why are cells important? In other words, their goal is to create the world`s first robotic cell To achieve their goal, these researchers will have to create artificial components that mimic the components found in a real cell Only by studying real cells will they be able to create the perfect fake!

Studying cells helps us understand how organisms function

Much of this unit focuses on how cells function, divide, and work together But, take a moment to think about one very important question: Why should we learn about cells? The answer is that studying cells helps us understand how organisms, including humans, function After all, our bodies are made up of trillions of cells

Studying cells helps us understand how organisms function By learning about cells, we come to understand how we can: -protect cells to prevent infection and other harmful effects -observe cells to diagnose disease -treat cells to heal illness -stop harming cells through our choices and actions

Studying cells helps us understand how organisms function Consider the medical advances in the following slides None of these advances would have been possible without an understanding of how different cells work

Malaria Malaria is a deadly disease It is transmitted by mosquitoes Scientists have developed a vaccine that can protect human cells from malaria by studying human and mosquito cells

Skin Graph A person with severe burns is often treated with skin graphs from another region of their body If there is no skin, doctors will use an artificial skin made of nylon that works with the blood to heal the wound Knowledge of skin and blood cells make this possible

Heart Conditions Medical doctors have discovered that reducing body temperature can help a person survive a heart attack Cold temperatures reduce the harm to heart and brain cells after a heart attack By studying cells, doctors have been able to develop this new life-saving treatment

Artificial Sweeteners Scientists have discovered that consuming artificially sweetened foods and beverages “disappoints” brain cells that were expecting sugar, based on the taste As a result, our brain tells us to keep eating, hoping to get the sugar it was promised

Cellular organelles work together to carry out life functions

Plants, flies, humans and all other living things are made up of one or more cells Each cell, in turn, is made up of smaller components These smaller components are called organelles

Organelle An organelle is a structure within a cell Organelles work together to carry out specific functions that support the life of the cell These functions include: -bringing in nutrients -removing wastes -generating and releasing energy for the cell to use -making substances that the cell needs -reproducing

Organelles and other structures in cells have different tasks

Each organelle and cell part has a specific role within a cell This role is important to the proper functioning of both the cell and the organisms Some cells have more of one type of organelle than another This is because different cells require a lot of energy As a result, it may have many organelles that make energy available to the cell

Organelles and other structures in cells have different tasks These organelles are called the mitochondria Figures 1.1 and 1.2 show the organelles that are found in a typical animal cell and a typical plant cell

Figure 1.1 (Animal Cell)

Figure 1.2 (Animal Cell)

Cellular processes enable organisms to meet their basic needs

Cellular processes are the activities that organelles perform to carry out the cell’s life functions Two (2) of the most important cellular processes are diffusion and osmosis

How Diffusion Works

Figure 1.3 shows ink particles spreading through water The ink particles move from an area where there is a lot of ink to an area where there is little or no ink This process is called diffusion – the movement of particles of a substance from an area of high concentration to an area of low concentration until all the particles are evenly distributed

Figure 1.3 (Diffusion)

How Diffusion Works Diffusion is an essential cellular process Without it, life as we know it would not be possible Diffusion occurs: -within a cell -across the membrane -outside a cell in body fluids

How Diffusion Works: Within a Cell Example: Substances are produced by one organelle may travel to another organelle or the cell membrane by diffusing through the cytoplasm

How Diffusion Works: Across the Cell Membrane Example: Each time you breathe in, you blood picks up oxygen. Your blood then transports this oxygen to your cells. The concentration of oxygen molecules pass through the cell membrane into the cytoplasm. They continue to do so until there is an equal concentration of oxygen inside and outside the cell.

How Diffusion Works: Outside a cell in body fluids Example: Nerve cells release chemicals to communicate with each other. These chemicals diffuse through the fluid in the space between nerve cells.

How Osmosis Works

Osmosis involves the diffusion of water through a semi- permeable membrane A semi-permeable membrane lets water and some molecules diffuse across it, but keeps molecules of other substances from penetrating it Cell membranes control the movement of substances into and out of cells Cell membranes are semi-permeable – water can penetrate the membrane, but molecules of many substances cannot

Figure 1.4A

Figure 1.4B

Figure 1.4C

Homework Unit 1.1 Review Questions #1-7 Complete all work sheets Due tomorrow