CELL

CELL

what is a cell?

unicellular and multicellular organisms

animal and vegetable cells

index

red blood cells, white blood cells and platelets

eukaryotic and prokaryotic cells

what is a cell?

Cells are the smallest living units of an organism and represent the basic unit of the living. The size of most cells varies from 1 micrometer to a few dozen, making them usually unidentifiable to the naked eye. The instrument that allows us to observe them is the microscope.

UNICELLULAR AND MULTICELLULAR ORGANISMS

Living organisms are divided into unicellular and pluricellular organisms. Unicellular organisms have only one cell. Examples are viruses, bacteria and yeasts. Multicellular organisms are made up of several cells, which work together, usually specialized in a specific function. Examples of multicellular organisms are moulds, mushrooms and mammals including humans.

UNICELLULAR

MultiCELLULAR

eukaryotic and prokaryotic cells

Prokaryotic and eukaryotic cells possess two common structures: - the plasma membrane; - the cytoplasm.

PROKARYOTIC CELL

EUKARYOTIC CELL

The prokaryotic cell is typical of unicellular organisms. It's consists of: - a cell membrane; - a cytoplasm. The prokaryotic cell has no nucleus and DNA is in the form of a circular molecule.

The eukaryotic cell, ten times larger than the prokaryotic cell, constitutes both unicellular and multicellular organisms. It’s made up of: - the nucleus; - the DNA; - a cell or plasma membrane; - a cytoplasm containing organelles. The cellular organelles are: - ribosomes, - the endoplasmic reticulum, - the Golgi apparatus, - the mitochondria; - lysosomes;

animal and vegetable cells

ANIMAL CELL

LYSOSOME

CELL MEMBRANE

NUCLEOLUS

NUCLEAR MEMBRANE

ENDOPLASMIC RETICULUM

MITOCHONDRION

GOLGI APPARATUS

VEGETABLE CELL

CHLOROPLASTS

NUCLEAR MEMBRANE

CELL MEMBRANE

NUCLEOLUS

ENDOPLASMIC RETICULUM

MITOCHONDRION

VACUOLE

GOLGI APPARATUS

red blood cells, white blood cells and platelets

Blood is a liquid that contains billions of small living cells: red blood cells, white blood cells, and platelets.

RED BLOOD CELL

WHITE BLOOD CELL

PLATELETS

Red blood cells give the blood red color and are responsible for carrying oxygen. They have a rounded shape, swollen at the edges and thinner at the center. They survive for an average of 120 days and represent the largest part of the blood.

Platelets are small fragments produced by larger cells and help the blood to clot. They have the shape of a disk and their diameter can have a length between two and three micrometers.

White blood cells help the body defend against infection. They are spheroidal and have a nucleus. Their life cycle is about 14 days and represents a small part of the blood.

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