Biology 112 – Chapter 7 CELLS Section 7-1 and 7-2 of textbook objectives: List scientists who contributed to the cell theory List the components of the cell theory Compare prokaryote and eukaryote cells Label a plant and an animal cell Know the functions of cell organelles

Early Contributions Robert Hooke - First person to see cells, he was looking at cork and noted that he saw "a great many boxes. (1665) Anton van Leeuwenhoek - Observed living cells in pond water (1673)

Leeuwenhoek saw these things in pond water. What did he call them?

Theodore Schwann - zoologist who observed tissues of animals had cells (1839) Mattias Schleiden - botanist, observed tissues of plants contained cells ( 1845) Rudolf Virchow - also reported that every living thing is made of up vital units, known as cells. He predicted that cells come from other cells. (1850 )

The Cell Theory Every living organism is made of one or more cells. (Schwann/Scheilden) 2. The cell is the basic unit of structure and function. (Hooke) 3. All cells arise from pre- existing cells. (Virchow) *Why is the Cell Theory called a Theory and not a Fact?

Cell Features ALL cell have these parts Ribosomes – make protein for use by the organism Cytoplasm – fluid material within  cell DNA – genetic material Cytoskeleton – internal framework of cell Cell Membrane – outer boundary, some things can cross the cell membrane

Comprehension Checkpoint Answer true or false Robert Hooke was the first person to see cells. Bacteria cells have a cell membrane. The Cell Theory was developed by a single scientist. Plant cells have cytoplasm. Cells taken from fungi do not have DNA. Cells can only come from pre-existing cells. It only took five years to develop the Cell Theory.

Prokaryote Cells The first cells to inhabit the earth Simple cells Bacteria Conjugation These cells do NOT have a nucleus, their DNA is circular and floats in the cytoplasm Some bacteria have a tail-like structure called a flagella, that helps it to move. A capsule surrounds some bacteria and helps them avoid the body’s immune system

Bacteria Images Bacteria that causes Anthrax

Benefits of Plasmids https://www.addgene.org/mol-bio-reference/plasmid-background/

Bacteria belong to a group of cells that do not have a ____________ CHECKPOINT LABEL THE BACTERIA H Bacteria belong to a group of cells that do not have a ____________

Eukaryotic Cells Cells found in plants, animals, protists, and fungi   The cell is composed of 4 main parts: Cell membrane Cytoplasm Nucleus – “control center” of cell, DNA Organelles – small structures that carry out specific functions (“little organs”)

Compare Prokaryote to Eukaryote http://www.youtube.com/watch?v=WRO-DPyB9Bk

Nucleus Usually found at center of cell Has a nuclear membrane & nuclear pores  Contains cell’s DNA in one of 2 forms chromatin - DNA and proteins, becomes... chromosomes - during cell division Nucleolus (little nucleus) which makes the cell’s ribosomes is not an organelle Not enclosed

http://www.answers.com/topic/cell-nucleus-1

True of False 1. All cells have a nucleus. 2. All cells have a cell membrane. 3. Eukaryote cells are the only cells to have a flagellum. 4. The nucleus contains the cell’s DNA. 5. Chromatin will become chromosomes. 6. The nucleolus makes the cell’s DNA.

Cell Organelles Mitochondria – cell’s energy center; turns food into a chemical energy called ATP The mitochondria is sometimes called the “powerhouse” of the cell Some muscle cells have 20,000 mitochondria. Cells near the skin have many less (few hundred). The number varies by tissue and organism

Mitochondria

Cell Organelles Golgi Apparatus – processes, packages and secretes proteins. It is comparable to a factory or a post office. Transforms proteins into more complex molecules *A vesicle forms with Golgi to transport substances outside cell.  

GOLGI BODIES (GAWL jee)

MITOCHONDRIA Quick fact: In humans, Mitochondrial DNA is inherited from the mother only Mitochondrial DNA from the male is destroyed at fertilization In animals, mtDNA inheritance varies

Cell Organelles Lysosome – Contains digestive enzymes, breaks things down, "suicide sac”, built in the golgi bodies Endoplasmic Reticulum – Transport, "intracellular highway".   -Rough ER contains many ribosomes & is involved in protein synthesis  -Smooth ER no ribosomes

Rough Endoplasmic Reticulum Involved with the production and processing of proteins In cells that produce an abundance of proteins, there are many rough ER It is connected to the nuclear envelope Result: the nucleus has direct access to proteins and other materials There are two basic kinds of endoplasmic reticulum morphologies: rough and smooth. The surface of rough endoplasmic reticulum is covered with ribosomes, giving it a bumpy appearance when viewed through the microscope. This type of endoplasmic reticulum is involved mainly with the production and processing of proteins that will be exported, or secreted, from the cell. The ribosomes assemble amino acids into protein units, which are transported into the rough endoplasmic reticulum for further processing. These proteins may be either transmembrane proteins, which become embedded in the membrane of the endoplasmic reticulum, or water-soluble proteins, which are able to pass completely through the membrane into the lumen. Those that reach the inside of the endoplasmic reticulum are folded into the correct three-dimensional conformation, as a flattened cardboard box might be opened up and folded into its proper shape in order to become a useful container. Chemicals, such as carbohydrates or sugars, are added, then the endoplasmic reticulum either transports the completed proteins to areas of the cell where they are needed, or they are sent to the Golgi apparatus for further processing and modification. http://micro.magnet.fsu.edu/cells/endoplasmicreticulum/endoplasmicreticulum.html

RIBOSOMES Synthesize (make) proteins Float freely or attached to the endoplasmic reticulum (ER) Ribosomes are made in the nucleolus

Cytoskeleton – Helps cell maintain support & shape; movement a. microtubules- hollow tubes made of tubulin b.  microfilaments-threadlike made of actin Centrioles- only in animal cells; used during cell division (paired) 

Vacuole – storage area for water and other substaces, plant cells usually have a large central vacuole

Protein Production The cell is like a factory. Its product is protein which goes to body to serve different functions. DNA has instructions to build protein Instructions are sent to ribosomes The ribosomes build protein and sends it through ER The proteins go to golgi bodies where they are packaged for export

THE ANIMAL CELL

Cheek Cells Seen Through Microscope

NAME THE PARTS

Plant Cells CELL WALL – provides additional support / protects the cell/ gives it shape / made of cellulose CHLOROPLASTS – contain green pigment, photosynthesis Chrolophyll - A green pigment that gives leaves & stems their color CENTRAL VACUOLE – large water container

PLANT CELL Can you identify the parts?

Anacharis Cells Viewed With a Microscope

Animal Cell vs Plant Cell

Organelles With DNA Mitochondria and chloroplasts have their own DNA (separate from the nucleus) This supports the ENDOSYMBIOSIS THEORY which states that eukaryotic cells evolved when prokaryote cells engulfed or absorbed other cells.

CELL MEMBRANE Selectively permeable ; it regulates what comes into the cell and what leaves the cell It is composed of a double layer of phospholipids with proteins embedded throughout

Group of cells working together FROM CELL TO ORGANISM Cell The basic unit of life Tissue Group of cells working together Organ Group of tissues working together Organ System Group of organs working together Organism Any living thing made of 1 or more cells

Inner Life of a Cell http://www.youtube.com/watch?v=wJyUtbn0O5Y