Cells – Scientists and their Theory

Cells are the basic unit of life. All living things are made of cells. Living organisms are very organized. The level of organization of an organism is as follows…… Atoms  Molecules  Cells  Tissue  Organs  Organ Systems  Organism (individual)

In 1665, Robert Hooke used a microscope to examine a thin slice of cork (dead plant cell walls). What he saw looked like small boxes. Hooke is responsible for naming cells. Hooke called them “CELLS” because they looked like the small rooms that monks lived in called Cells.

Cell Theory  Nearly a century after Hooke’s findings, several other scientist’s discoveries led to the formation of the cell theory. Schleiden - botanist Schwann - zoologist Virchow – medical doctor

CELL THEORY IS FORMED  All living things are made of cells  Cells are the basic unit of structure and function in all living organisms (basic unit of life)  Cells come from the reproduction of existing cells (cell division)

DAY 2 NOTES

All cells have the following parts: * cell membrane * ribosomes * cytoplasm * genetic material (DNA)

CELL MEMBRANE: Function: a barrier around the cell that allows only certain materials into and out of the cell. It is said to be semi-permeable.

The cell membrane structure is mainly made of phospholipids and is embedded with protein channels and carbohydrate chains (used for identification).

LIPIDS are one of the 4 major macromolecules that are important to all living organisms. Their function is to store long term energy, waterproofing and some make up biological membranes. Lipids are made of the elements Carbon, Hydrogen and Oxygen (CHO) Lipids are commonly called FATS. Lipids are non-polar making them hydrophobic. The monomer (building block) for a lipid is called a triglyceride made up of a glycerol and 3 fatty acid tails.

RIBOSOMES Ribosomes are small organelles that are scattered throughout the cytoplasm of all cells and their function is to produce proteins. In Eukaryotic cells, many ribosomes are located on the Endoplasmic Reticulum (ER).

PROTEINS are another important macromolecule needed by all living things. Proteins are made of the elements Carbon, Hydrogen, Oxygen and Nitrogen (some also have Sulfur) – (CHONS) Their primary functions are to form bones and muscles, repair, control the rate of chemical reactions (enzymes) and transport substances into and out of the cell to help immune system fight off diseases.

The monomer (building block) used to make proteins is called an amino acid. There are many different amino acids. Basic Amino Acid Structure

CYTOPLASM It is a thick solution that fills each cell and is enclosed by the cell membrane. It is mainly composed of water, salts, and proteins. In eukaryotic cells, the cytoplasm includes all of the material inside the cell and outside of the nucleus.

GENETIC MATERIAL (DNA) All cells, both PROKARYOTIC and EUKARYOTIC, contain genetic material (DNA). In Prokaryotes, the DNA is scattered throughout the cytoplasm. In Eukaryotes, the DNA is contained inside an organelle called the NUCLEUS.

NUCLEIC ACIDS are another macromolecule important to all living things. It can be either DNA or RNA. Nucleic Acids are made of the elements Carbon, Hydrogen, Oxygen, Nitrogen and Phosphorous. (CHON-P) The primary function of DNA is to provide each individual living organism their genetic information which makes them unique and store it in the nucleus. The primary function of RNA is to transport the genetic code to the ribosomes so proteins can be made.

The monomer (building block) of any nucleic acid is called a nucleotide. A nucleotide is made up of 3 parts: A 5-carbon sugar, a phosphate group and a nitrogen base.

DAY 3 NOTES

There are 2 types of Eukaryotic Cells: PLANT CELLANIMAL CELL

Plant Cells contain Cell Wall, Chloroplasts and a Central Vacuole which are not found in animal cells. Animal Cells contain Centrioles and Lysosomes which are not found in plant cells. Although Eukaryotic Cells contain most of the same organelles, there are some differences.

Cell Wall: lies outside the cell membrane of plant cells and provides additional support and protection.

CHLOROPLASTS: The job of the chloroplast is where photosynthesis takes place in a plant. It is where plants produce their own food. Plants have this, animals do not.

CENTRAL VACUOLE – a rather large organelle surrounded by a membrane and its function is to hold materials and wastes. It also functions to maintain the proper pressure within the plant cells to provide structure and support for the growing plant.

Lysosomes are organelles found in animal cells that contain digestive enzymes. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria.

CENTRIOLES: The main function of the centriole is to help with cell division in animal cells only. The centrioles help in the formation of the spindle fibers that separate the chromosomes during cell division (mitosis).

Organelles that both Plant and Animal have in common are: Endoplasmic Reticulum (ER) Mitochondria Golgi Apparatus (golgi bodies)

ENDOPLASMIC RETICULUM - mainly responsible for the transportation of proteins and other carbohydrates to other organelles, which includes lysosomes, Golgi apparatus, plasma membrane, etc.

MITOCHONDRIA - are known as the powerhouses of the cell. They are organelles that act like a digestive system which takes in nutrients (CARBOHYDRATES), breaks them down, and creates energy rich molecules (ATP) for the cell.

CARBOHYDRATES: the 4 th and final important macromolecule to all living things. Carbohydrates are made of the elements Carbon, Hydrogen and Oxygen (CHO) in a 1:2:1 ratio. (C 6 H 12 O 6 ) Carbohydrates can be simple or complex. Carbohydrates are the main energy source for all cells. It provides quick energy for the cell to carry out life processes such as physical activity, brain activity etc.

The monomer (building block) for a carbohydrate is called a monosaccharide (mono = one and saccharide = sugar)

GOLGI APPARATUS (Golgi bodies) The function of the Golgi body is modifying, sorting and packaging proteins for secretion from the cell. It is also involved in the transport of lipids around the cell, and the creation of lysosomes.

Inside each nucleus is a NUCLEOLUS. It is a very important job inside of the cell. Its function is to produce ribosomes.