Cells The Building Blocks of 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.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

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 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 CellsAnimal Cells

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.

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

Cell Organelles – Cell Wall cell wallsupport protectionThe cell wall provides support and protection for the cell. cell wallThe cell wall is rigid. Cell wallsCell walls are only found in plant cells.

Cell Wall – only in plants

Cell Organelles – Cell Membrane The cell membrane is the “doorway” of the cell. Cell membranes control the movement of materials into and out of the cell. –Pores are the openings in the cell membrane. Cell membranes provide support and protection. –In plant cells the cell membrane is found just inside the cell wall. –In animal cells the cell membrane is the outermost organelle.

Cell Membrane

Cell Organelles - Nucleus The nucleus is the “control center”, or “brain” of the cell which controls all activities in the cell.The nucleus is the “control center”, or “brain” of the cell which controls all activities in the cell. The nucleus has three parts:The nucleus has three parts: –Nuclear membrane –Chromosomes –Nucleolus

Cell Organelles - Nucleus nuclear membraneThe nuclear membrane controls the movement of materials into and out of the nucleus. chromosomesThe chromosomes direct the activities within the cell and also pass on genetic traits to the next generation. nucleolusThe nucleolus, or “little nucleus” is the site of ribosome production.

Cell Organelles - Cytoplasm Cytoplasm is the clear, thick jelly- like substance that contains all the organelles.Cytoplasm is the clear, thick jelly- like substance that contains all the organelles.

Cell Organelles – Endoplasmic Reticulum The endoplasmic reticulum, or ER, is the tubular transportation system throughout the cell.The endoplasmic reticulum, or ER, is the tubular transportation system throughout the cell.

Endoplasmic Reticulum Smooth and Rough

Cell Organelles - Ribosomes Ribosomes are the protein factories of the cell. Most ribosomes are found attached to the outside of the endoplasmic reticulum. –This location helps the cell with efficiency of production and transport.

Ribosomes

Cell Organelles - Lysosomes Lysosomes are the “clean up crew” of the cell. Lysosomes are involved in the digestive process of the cell. –Enzymes break down large food into smaller bits for the mitochondria to use. –Lysosomes are not common in plant cells.

Cell Organelles - Mitochondria Mitochondria are the “powerhouse” of the cell and supply most of the energy for the cell.

Cell Organelles - Vacuoles VacuolesVacuoles are the “storage tanks” of the cell. VacuolesVacuoles can store food, water, or waste. vacuoles –In plant cells vacuoles are common. Usually one large vacuole per cell. vacuoles –In animal cells vacuoles are not common. Usually several small vacuoles per cell.

Cell Organelles - Chloroplasts Chloroplasts“energy producers”Chloroplasts are the “energy producers” of plant cells. Chloroplastsonly found in plant cellsChloroplasts are only found in plant cells. ChloroplastschlorophyllChloroplasts contain green chlorophyll that captures energy from the sun.

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.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.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