Define what it means to be “alive.” Name: ________________ Period: _____

Life Science Notes Topic: To be considered alive, the following 6 things MUST exist:

Section 1 - Characteristics of Living Things All Living Things… All Living Things… Have cells Have cells Sense and Respond to Change Sense and Respond to Change Reproduce Reproduce Have DNA Have DNA Use Energy Use Energy Grow and Develop Grow and Develop

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Have Cells All living things are composed of one or more cells All living things are composed of one or more cells Cell - Membrane- covered structure that contains all of the materials necessary for life Cell - Membrane- covered structure that contains all of the materials necessary for life Very small Very small

Sense and Respond to Change All living things have the ability to sense change in their environment and respond to it. Stimulus - Something in an organism’s environment that affects the activities of the organism.

Sense and Respond to Change Cont. Homeostasis - the maintenance of a stable internal environment. Ex. Humans sweat to lower their body temperature and shiver to raise it.

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Reproduce Organisms make other organisms like themselves. Organisms make other organisms like themselves. Asexual Reproduction Asexual Reproduction One parent One parent Offspring are identical to parent Offspring are identical to parent Sexual Reproduction Sexual Reproduction Two parents Two parents Offspring share characteristics of both parents Offspring share characteristics of both parents Asexual reproduction in Bacteria

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DNA (deoxyribonucleic acid) Special molecule that provides instructions for the production of proteins. Proteins take part in nearly all of the activities of an organism’s cells

Use Energy Organisms use energy to carry out the activities of life Organisms use energy to carry out the activities of life Ex. Activities - making food, breaking down food, moving materials in and out of cells, and building cells Ex. Activities - making food, breaking down food, moving materials in and out of cells, and building cells Metabolism - total of all of the chemical activities that a organism performs Metabolism - total of all of the chemical activities that a organism performs

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Grow and Develop All living things grow and develop during periods of their lives

Growth and Development

The Simple Bare Necessities of Life All living things NEED… All living things NEED… Food Food Water Water Air Air A Place to Live A Place to Live

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Food All living things need food All living things need food Food provides organisms with the energy and raw materials to carry out life processes and build and repair damaged cells Food provides organisms with the energy and raw materials to carry out life processes and build and repair damaged cells

Food Cont. - Different Ways of Obtaining Food Making Food Making Food Producers - use energy from the sun to make food Producers - use energy from the sun to make food Ex. Plants Ex. Plants Getting Good Getting Good Consumers - must eat other organisms to get food Consumers - must eat other organisms to get food Decomposers - break down the nutrients in dead organisms and animal wastes Decomposers - break down the nutrients in dead organisms and animal wastes

Water Most of the chemical reactions involved in metabolism require water Cells are composed of approximately 70% water

Air Air Composition The sea-level composition of air (in percent by volume at the temperature of 15°C and the pressure of Pa) is given below. NameSymbolPercent by Volume Nitrogen N % OxygenO % Argon Ar0.934 % Carbon DioxideCO % Neon Ne % MethaneCH % HeliumHe % KryptonKr % HydrogenH % Xenon Xe % Mixture of several different gases Animals, plants, and many other living organisms use oxygen in a chemical process that releases energy from food

A Place to Live All organisms need a place to live that contains all of the things they need to survive. All organisms need a place to live that contains all of the things they need to survive. Competition for space Competition for space Space is limited and organisms sometimes must compete with each other for food, water, and other necessities Space is limited and organisms sometimes must compete with each other for food, water, and other necessities

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Adjusting to Surroundings Stimulus – anything that an organism responds to Stimulus – anything that an organism responds to Response – the reaction of an organism to a stimulus Response – the reaction of an organism to a stimulus Adaptation – any characteristic an organism has that makes it better able to survive in its surroundings Adaptation – any characteristic an organism has that makes it better able to survive in its surroundings Homeostasis – the regulation of an organisms internal environment to maintain conditions that allow it to live Homeostasis – the regulation of an organisms internal environment to maintain conditions that allow it to live

Pavlov’s Dog

Let’s test your skills… P- Producer C-ConsumerD-Decomposer

P, C, or D P

C

D

C

P,C or D C

P, C, or D D

The Building Blocks of Life

Chemistry of Life Proteins After water, they are the most abundant materials in cells We break down proteins to make new proteins Examples: Hemoglobin Enzymes

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Chemistry of Life Carbohydrates Compounds made of sugar Energy source Simple and Complex

Chemistry of Life Lipids Cannot mix with water Some store energy Some produce a membrane (waterproof layer) Fats and Oils

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Chemistry of Life Nucleic Acids Nucleic Acids “blueprints of life” “blueprints of life” DNA DNA RNA RNA

Let’s test your skills… For the following pictures, decide whether it BEST matches protein, carbohydrate, lipid, or nucleic acid!

Protein, Carbohydrate, Lipid, or Nucleic Acid?