Chapter 1 Cells: The Basic Units of Life

Cells Tissues Organ (stomach, heart, lungs, skin) Organ systems (nervous system, digestive system Organism

Population: same organisms living in same area Community: two or more different populations. Ecosystem: a community and all the nonliving things that affect it. –Terrestrial –Aquatic

Organisms Organism-anything that can live on its own. Unicellular-a single cell living on its own Multicellular-exists only as a group of cells.

Discovery of Cells Robert Hooke: –He was the first to discover cells in 1665 by looking at a piece of cork The invention of the microscope led to the discovery of cells because they are too small to see with the naked eye.

Anton von Leeuwenhoek Dutch merchant 1673 Made his own microscopes Looked at pond scum Named small organisms “animalcules” Looked at blood First person to see bacteria Discovered that yeast is unicellular

Matthias Schleiden Theodor Schwann Rudolf Virchow Found in 1838 that all plant parts are made of cells Wrote first two parts of cell theory In 1858 he wrote the third part of the cell theory

Cell Theory 1.All organisms are composed of one or more cells 2.The cell is the basic unit of life in all living things 3.All cells come from existing cells

Surface to Volume Ratio Cell needs a larger surface area to exchange materials The surface to volume ratio is the area of a cell’s outer surface in relation to its volume.

The smaller the cell the larger the surface to volume ratio is. Cells become less efficient as they grow.

Two types of Cell Prokaryotic CellsEukaryotic Cells No NucleusNucleus No membrane-covered organelles Membrane-covered organelles BacteriaAll other Cells Circular DNALinear DNA

Eukaryotic Cell

Prokaryotic Cell

Parts of a Cell

The Cell

Cell Membrane Surrounds all cells Protective layer Separates cell from its environment Controls materials going into and out of the cell

Cell membrane Structure Contains proteins, lipids, and phospholipids ________ - the part of the cell membrane that is water fearing ________ - the part of the cell membrane that is water loving The cell membrane controls the movement of materials into and out of the cell. hydrophobic hydrophilic

Fluid in the cell Structures in the cell that perform specific functions within the cell Cytoplasm Organelles

Nucleus Contains DNA (deoxyribonucleic acid) which is the genetic material that carries information Surrounded by a membrane (nuclear membrane) that contains pores

Cell Wall Outermost layer of PLANT cells, as well as fungi and some prokaryotes Gives support to a cell Contains cellulose

Cytoskeleton Web of proteins in the cytoplasm Maintains structure of cell

Nucleolus Dark area in the nucleus Produces ribosomes

Ribosomes Smallest organelles Most numerous organelles Some ribosomes float freely in cytoplasm and others are attached to membranes in the cytoskeleton Function – to make proteins out of amino acids

Endoplasmic Reticulum Rough ER – A system of folded membranes which are covered in ribosomes – protein transport Smooth ER – A system of folded membrane with no ribosomes –lipid transport

Mitochondria Power House Breaks down sugar to produce energy Stores energy in ATP (Adenosine triphosphate)

Chloroplasts In plant cells only Photosynthesis – process by which plants use sunlight, carbon dioxide,a nd water to make sugar and oxygen Green Contain chlorophyll

Golgi Complex Packages and distributes proteins Looks like smooth ER Packages lipids and proteins in small bubbles which may be used somewhere else inside or outside of the cell

Vesicle Bubbles that form from the Golgi complex’s membrane Surrounds material to be moved into or out of a cell

Chromosomes Contain DNA (genes)

Vacuoles Vesicle that stores water Very large in plants

Lysosome Vesicles that are responsible for digestion Contain digestive enzymes

Cells Alive!