Cells

Discovery of Cells 1665: Robert Hooke: looking at cork under crude microscope

In 1673, van Leeuwenhoek saw unicellular organisms in pond scum First to see bacteria and yeast

Two centuries later, Schleiden (1838) proposes all plants are made of cells Schwann makes same claim for animals Wrote first Cell Theory: 1.All organisms are made of one or more cells. 2.Cell is basic unit of life. All plants are made of cells! Wow! So are all animals! Let’s make up a “cell theory”!

Who wrote the first two parts of the cell theory? A. Hooke B. van Leeuwenhoek C. Schleiden D. Schwann E. Both C and D

20 years later, Virchow saw that all cells come from other cells Added 3 rd part of cell theory: 3.All cells come from existing cells. All cells come from other cells!!

All cells have… Lots of different kinds of cells, but all have: Cell Membrane DNA Cytoplasm Organelles Small Size

Which of the following is NOT something that ALL cells have in common? A. A. Cell Membrane B. B. DNA C. C. Chloroplasts D. D. Cytoplasm E. E. Organelles F. F. Small Size

Cell Membrane Also called plasma membrane Surrounds all cells Has holes to allow materials in and out

Which of the following is NOT true of the cell membrane? A. a. Also called plasma membrane B. b. Surrounds all cells C. c. Only found in animal cells D. d. Has holes to allow things in and out

DNA Hereditary material Controls all of the cell’s activities Has info needed to make new cells

Which of the following is NOT true of DNA? A. a. It is the hereditary material B. b. It makes fats for the cell C. c. It controls all of the cell’s activities D. d. It has the info needed to make new cells

Cytoplasm Fluid that fills the cell

What is cytoplasm? A. a. Protein that fills the cell B. b. Fat that fills the cell C. c. Fluid that fills the cell D. d. All of the above.

Organelles Structures inside that perform special jobs for the cell (example: ribosomes=make protein, etc.)

Small Size Almost all require use of microscope Large organisms have more cells, not bigger ones!!

True/False: Elephants have larger cells than mice. A. True B. False

Two types of Cells Prokaryotic Bacteria! No nucleus Organelles are not covered with a membrane DNA is circular and floating in the cytoplasm Eukaryotic All other cells Has a nucleus Organelles are covered with a membrane (skin) DNA is linear; shaped like a twisted ladder

True/False: There are three main types of cells: prokaryotic, eukaryotic, and plant cells. A. A. True B. B. False

Identify which cell is prokaryotic. ABAB

Eukaryotic Cells Very complex! Inside parts (organelles) are difficult to see

Cell Membrane Double layer Has pores (holes) which allow things in and out Selectively permeable =

True/False To be selectively permeable means that you are not “choosy” about what materials you allow to enter and leave the cell. A. True B. False

Cell Wall Plants, algae and fungi only Made of cellulose Strength and support

Which of the following is NOT true of cell walls? A. A. Plant cells and fungi cells have them. B. B. Animal cells have them. C. C. They are made of cellulose. D. D. They provide strength and support for the cell.

Nucleus “kernel” or “nut” Membrane covered, with holes so materials can pass through Control center: stores DNA (instructions for making protein and reproduction)

Which of the following is not true of the nucleus? A. A. Its name means “kernel” or “nut”. B. B. It has holes in it. C. C. It is only found in plant cells. D. D. It is the control center of the cell, containing the DNA.

Ribosomes Cells are made of proteins. Amino acids link together to make proteins at ribosomes Abundant = Protein

True/False: Proteins are assembled at ribosomes A. True B. False

True/False: Amino acids are chemicals which link together to make carbohydrates. A. True B. False

Endoplasmic reticulum Also called ER Makes lipids (fats) and proteins Breaks down drugs and other dangerous chemicals Also delivery system of cell Rough (protein) Smooth

Which of the following is not true of endoplasmic reticulum? A. A. Also called ER B. B. Makes lipids (fats) C. C. Breaks down drugs and other dangerous chemicals D. D. Delivery system of cell E. E. Comes in only one type: rough ER

Mitochondria Cells need energy. Where do they get it? Food is broken down for energy at the mitochondria Needs oxygen to function ATP ADENOSINE TRI- PHOSPHATE

True/False: Oxygen is not needed when energy is made at the mitochondria. A. A. True B. B. False

Chloroplasts In plants and algae Organelle which converts light energy, water, and carbon dioxide into sugar (FOOD!) Contain chlorophyll, the pigment that does this

Which of the following is NOT true of chloroplasts? A. A. Found in plants and algae. B. B. Changes sunlight and water into food. C. C. Found in some animal cells D. D. Contain the pigment chlorophyll.

Golgi Complex Packages and ships materials out of the cell Looks like ER, but closer to cell membrane Little pieces can pinch off and leave the cell (vesicles)

True/False: The Golgi Complex is similar to a post office or FED EX; it packages materials for shipment out of the cell. A. A. True B. B. False

Lysosomes Filled with enzymes (chemicals which break things down) Destroy waste and old cell parts, as well as invaders

True/False: Lysosomes digest waste and invaders through the use of enzymes (special chemicals). A. A. True B. B. False

Storage Centers Vesicles: membrane covered “bubbles” that form when part of the cell membrane surrounds something and pinches off Vacuoles: huge storage areas for water and other liquids, especially in plants