Cells The Basic Unit of Life

A cell is the smallest unit that is capable of performing life functions.

What does this mean? Think of all that you do to be able to live and grow. Cells do these things too. Unicellular organisms perform all life functions. While your individual cells perform all life functions, they must interact with each other to make sure that you survive.

Important “Cellular” Figures Anton van Leeuwenhoek Robert Hooke

Robert Hooke In 1665, Robert Hooke looked at a piece of cork under an early compound microscope. He noticed that the cork looked like thousands of tiny chambers, which he called cells. Cell means ____________.

Anton van Leeuwenhoek Anton van Leeuwenhoek is known as the Father of the microscope. He was the first to notice small organisms in pond water. He called these organisms “animalcules.” He also observed the scrapings from his teeth.

The Cell Theory Developed by Three Men: 1. Matthias Schleiden 2. Theodor Schwann 3. Rudolf Virchow

The Cell Theory States: All organisms are made up of one or more cells. The cell is the basic unit of organization. All cells come from other cells.

Compare and Contrast these Cells

Cells that do not have membrane-bound organelles and are simple are called prokaryotic. Bacteria are prokaryotic cells.

Cells that do have membrane- bound organelles and are complex are called eukaryotic.

Plant and animal cells are eukaryotic.

Two Cell Types

CELL ORGANELLES

Organelles are structures in the cell that do a specific job Organelles are structures in the cell that do a specific job. Some organelles are membrane-bound.

Cell Membrane or sometimes called Plasma Membrane This is the outer covering of the cell. It is very selective. It will let some things pass in and out of the cell. It protects the cell. If a cell has a cell wall, the cell membrane will be inside the cell wall.

Cytoplasm This is a thick, clear, gel-like fluid between the cell membrane and the nuclear membrane. Cytoplasm constantly flows inside the cell. (Mainly Water) Chemical reactions occur here.

Nucleus This is the control center of the cell or “the boss.” This is usually the largest organelle in the cell and often found in the center of the cell. The nucleus is separated from the rest of the cell by the nuclear membrane.

The nucleus contains the DNA or CHROMATIN material.. DNA is the chemical code of life that determines everything a cell will do and become. This makes the nucleus the boss. Chromosomes are made of DNA.

Nucleolus The nucleolus is found in the nucleus. It is a sub-organelle. The nucleolus is involved in producing ribosomes.

Nuclear Membrane This surrounds the nucleus. It has pores for nuclear transport (in and out of nucleus.

Golgi Bodies/Apparatus/Complex They sort proteins and other materials from the ER, package them into vesicles (small vacuoles) for delivery around and out of the cell.

Golgi Apparatus, Golgi Complex Golgi bodies look like a stack of flattened membranes.

Endoplasmic Reticulum The ER is a network of tub that begins at the nuclear membrane and runs throughout the cytoplasm. These produce materials and help transport these materials. The endoplasmic reticulum takes up so much space it must be folded

The endoplasmic reticulum can be rough or smooth If the ER has attached ribosomes (small protein structures), it is rough ER. If it does not have ribosomes attached to it, it is smooth ER.

Ribosomes Ribosomes are considered sub- organelles, and are NOT membrane-bound. These organelles make or synthesize the cell’s proteins. Proteins take part in nearly every cell activity.

Mitochondria Mitochondria break down food into carbon dioxide and water to release energy. “Powerhouse of the Cell”

NOTE THIS under Mitochondria ATP Molecule Made Here Provides Energy Mitochonrion (singular for Mitochondria) Mitochondria have their own DNA, Mitochondrial DNA

Vacuoles Vacuoles are membrane-bound sacs for storage, digestion, and waste removal. Add: Small vacuoles are called vesicles.

Lysosomes These are the digestive structures for food molecules, cell waste, and worn-out cell parts. Garbage Collectors or Recyclers

Lysosomes, the Controversy, Discovered in 1970s Plant cells do have vacuoles that perform similar function to lysosomes. These vacuoles contain digestive enzymes. The make-up of the enzymes is not the same as those found in animal cell lysosomes. These vacuoles do not have phagocytic function or exocytosis.

http://highered. mcgraw-hill http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__lysosomes.html

How are plant and animal cells different? Plants have two structures that animal cells do not. One structure is different in plant and animal cells.

Chloroplast These are large green, oval shaped organelles. Photosynthesis takes place here. (uses solar energy to produce glucose/food) These contain chlorophyll which gives plants their green color.

Cell Wall The cell wall is found outside of the cell membrane. It is a rigid, outer covering that protects the plant cell and gives it shape. Made of mostly cellulose Materials move through cell wall.

Large Plant Vacuole Vacuoles are found in animal cells, but they are smaller. This storage site is for water and food materials in plant cells.

Organization From cell to organism Multicellular organisms have five levels of organization. Cell-Tissues-Organs-Systems Organism neurons (nerve cells) --> nervous tissue --> brain --> central nervous system --> human