Unit 7 Cell Processes Essential Question: How is matter transferred or energy transferred in living systems?

Energy Without the ability to use and get energy cells would die They use energy to make molecules/building blocks and enzymes and get rid of waste They also carry out all the jobs in your body: circulation oxygen, breaking down food, contracting muscles, etc.

ATP Living things use chemical energy ATP (Adenosine Triphosphate) – one of the most important chemicals the cell uses to store and give off energy – It is made up of adenine, a sugar called ribose and three phosphate groups – The phosphate groups are the key to how ATP stores and releases energy

ADP Adenosine diphosphate is similar to ATP ADP only has two phosphate groups instead of 3 This is how living things store energy When a cell has extra energy it stores it by adding a phosphate group to ADP turning it into ATP

Releasing Energy Cells can give off energy that is stored in ATP by breaking the chemical bond between the second and third phosphate groups

Using Chemical Energy ATP is used to power active transport Helps to move protein in muscle helping them to flex Makes proteins, carbohydrates, lipids Responds to chemical signals If cells move they use this energy

Short-Term Storage ATP is good for giving off a small amount of energy very quickly It is not good at storing large amounts for a long time For that we have the sugar glucose

ATP comes from food Once cells use up their ATP they must make more of it somehow Cells use the energy from the food we eat to make more ATP Different living things get their food from different sources

Heterotrophs Living things that get food by eating other living things Some eat plants and grasses Some eat other animals Some break down the tissues of dead things

Autotrophs Make their own food Plants, algae and some bacteria use light energy from the sun to make their own food The energy in nearly all food molecule started from the sun All life on earth depends on autotrophs making their own food using energy from the sun This process is called photosynthesis

Light From The Sun The sun gives off energy called visible light Visible light appears white but actually contains every color

Plant Pigments Autotrophs – organisms that make their own food using the sun’s energy – They have specific pigments – Pigments – absorb certain wavelengths of light and reflect others. The color that is reflected is the color you see Pigments determine what is absorbed and what is reflected Autotrophs need pigments to trap energy from the sun to carry out photosynthesis

Chlorophyll The most common and important photosynthetic pigment It absorbs violet, blue and red light which provide energy for photosynthesis It reflects green light which is why most plants look green Found in the cholorplasts of plant cells This is where photosynthesis takes place

Other Plant Pigments