The Building Blocks of Life Cells The Building Blocks of Life

How Did the Earth Form? We do not know for certain how the Earth formed. Most scientists agree that the Earth formed about 4.6 billion years ago. That is 4,600,000,000 years ago.

Two Theories of How Life on Earth Formed Stanley Miller’s Theory of Life The Volcanic Theory of Life

Stanley Miller’s Theory of Life This theory states that a mixture of gases and water was struck by lightning and formed a “tar-like” substance that allowed living things to develop. Also known as “Primordial Soup”

The Volcanic Theory of Life The Volcanic Theory of Life states that the cooling planet had lots of volcanoes putting gases into the air. These gases condensed into rain that formed oceans. Single cell organisms evolved into plant life then animal life.

How did Cells Form? Several Theories of How Cells Formed: Cells arose in shallow pools containing “soup” of chemicals. These chemicals become combined and formed cells. Cells formed in beds of clay that allowed substances (chemicals) to be contained and produce living things – cells. Meteors and asteroids carried water, containing life (cells) to the Earth.

Which Cell Theory Is True? We still do not know for sure how cells formed.

Spontaneous Generation? The Theory of Spontaneous Generation states that life could arise from non-living matter. This theory was disproved in 1668 by Francesco Redi who used raw meat for his experiments.

Francesco Redi

Redi’s Experiment

Producers and Consumers A producer is any organism that makes it’s own food. Example: green plants A consumer is any organism that can not produce it’s own food. Consumers are dependent on other organisms to survive. Example: Man

How Do Producers Make Food? Photosynthesis: the process by which green plants convert sunlight into food. As a waste product, oxygen is released. At some point in history, early cells evolved and became able to perform photosynthesis. This is important because this allowed an oxygen atmosphere to form and eventually allows for animal life to evolve.

Characteristics of Living Things All living things share characteristics, they: Are made of cells Are able to move Perform complex chemical activities Are able to grow and develop Are able to respond to their environment Are able to reproduce

What is a Cell? The cell is the basic building block of all living things. The first cells on Earth are thought to have evolved ~3.5 billion years ago. These cells could not produce their own food.

All living things are made of cells Plant Cells Animal Cells

What are the Needs of Living Things? In order to survive all living things need: Energy Food Water Oxygen Living space To maintain a proper temperature

Cell Theory The current cell theory states that: All living things are made of cells. Cells are the basic unit of structure and function in living things. Living cells only come from other living cells.

What Are Cells Made Of? Organelles, or “tiny organs”, are the structures that make up a cell. Organelles were discovered by Robert Hooke in 1665 while looking at cork cells.

How Do Cells Function? Each of the organelles in a cell has a defined function. There are many organelles that make up a cell. These include the cell wall, cell membrane, nucleus, cytoplasm, endoplasmic reticulum, ribosomes, lysosomes, mitochondria, vacuoles, chloroplasts. All organelles working together create the cells structure.

All living things are able to move

All living things perform complex chemical activities “building up and breaking down” Metabolism is the sum total of all the chemical reactions that occur in a living thing. In humans these chemical reactions are ingestion, digestion, respiration, and excretion.

Ingestion Ingestion is taking in food to process.

Digestion Digestion is the process of breaking down food into simpler substances.

Respiration Respiration is the process of taking in oxygen and using it to produce energy.

Excretion Excretion is the process of getting rid of waste material.

All living things are able to grow and develop Life span is the maximum length of time that an organism is expected to live.

All living things are able to respond to their environment A stimulus is something that comes from outside the organism or from within the organism that triggers a reaction. Examples: cold breeze stomach growl A response is the reaction that occurs as a result of the stimulus. Examples: goose bumps eat food

All living things are able to reproduce “Like produces like” Sexual reproduction: Requires two parents Results in offspring that show variations Asexual reproduction: Requires one parent Results in identical offspring with no variations Both forms of reproduction give a chemical “blueprint” to the next generation.

Cellular Reproduction

Egg and Sperm Cells - Fertilization

Meiosis - Sexual Reproduction Result is daughter cells with half the chromosomes

Mitosis – Asexual Reproduction Result is two identical cells

What is Competition? Competition is the struggle among living things to get the proper amounts of food, water, oxygen and space. Competition plays an important role in shaping a community.

How Do Living Things Maintain Proper Temperature Homeostasis is the ability of an organism to keep the conditions inside the body the same even though external environmental conditions change. Warm blooded animals maintain a constant body temperature at all times. Examples are man and mammals Cold blooded animals have body temperatures that change with the environment. Examples are fish and reptiles

What Makes Up All Living Things? “The Chemistry Of Life” All living things are made of elements and compounds.

What is an Element? An element is a pure substance that can not be broken down into any simpler substances. Only 90 natural elements exist on earth. Only 11 elements are common in living things. 4 elements (carbon, nitrogen, oxygen and hydrogen) make up 96% of the weight of the human body.

What is a Compound? A compound is formed when 2 or more elements join together chemically. Examples are: water H2O, and sugar C6H12O6

A water molecule is an example of a compound

There are 2 Types of Compounds Inorganic Compounds: are compounds that do not contain carbon. (carbon dioxide, CO2, is an exception) Examples: salt NaCl, Ammonia NH3, Rust Fe3O2 Organic Compounds: are compounds that do contain carbon; many are basic to life. There are many types of organic compounds including: carbohydrates, fats, oils, proteins, enzymes, and nucleic acids.

Organic Compounds - Carbohydrates Carbohydrates are the main source of energy for living things. Examples are sugar, starch (fruits, vegetables) Carbohydrates are made of carbon, hydrogen and oxygen.

Carbohydrates

Organic Compounds – Fats and Oils Fats and oils: known as “lipids” are energy rich compounds. At room temperature fats are solid and oils are liquid. Fats and oils are made of carbon, hydrogen and oxygen.

Fats and Oils

Organic Compounds - Proteins Proteins are necessary for growth and repair of the body. In addition to carbon, hydrogen and oxygen, proteins are also made of nitrogen (sometimes made of sulfur and phosphorous). Amino acids are the building blocks of proteins.

Proteins

Organic Compounds - Enzymes Enzymes are special proteins that regulate chemical activities in the body. Enzymes act as catalysts. A catalyst is a substance that speeds up or slows down a chemical reaction.

Enzymes

Organic Compounds – Nucleic Acids Nucleic acids are the “blue prints” of life. They are large compounds that store information that helps the body make the proteins it needs. Example: DNA or deoxyribonucleic acid

Nucleic Acids

What Is Cell Specialization? In multicellular organisms, cells not only complete its own life activities, but also performs a function that contributes to the life of the organism. Within multicellular organisms there is division of labor or specialization. The work of keeping the organism alive is divided up among different parts of the organism.

Levels of Specialization Cells combine to form Tissues combine to form Organs combine to form Organ systems combine to form Organism

More Specialization Students combine to form Classes combine to form Grades combine to form Schools combine to form District

What are Tissues? Tissues are cells that are similar in structure and function that combine together. Example: bone cells form bone tissue Other examples: muscle tissue, nerve tissue, connective tissue.

Bone Tissue and Muscle Tissue

What are Organs? Organs are groups of different tissues that work together. Example: the heart is an organ made of muscle tissues and blood tissue Other organs: brain, stomach, skin

Organs – Heart and Stomach

What are Organ Systems? Organ systems are a group of organs working together to perform a specific function for the organism. Examples: skeletal system, muscular system, digestive system.

Organ Systems

What are Organisms? Organisms are an entire living thing that carries out all the basic life functions. Examples: Humans, cat, fish, fly

Some Organisms