Chapter 3 Cells and Tissues
In the late 1600s, Robert Hooke was looking through a microscope at some plant tissue - cork. He saw some cube-like structures that reminded him of the long rows of monk's rooms (or cells) at the monastery, so he named these structures cells. The living cells that had formed the cork were long since dead. However, the name stuck and is still used to describe the unit, or building block, of all living things, plants and animals alike. The human body has trillions of these microscopic building blocks.
Cells
* Name the four elements that make up the bulk of living matter and list several trace elements.
* Carbon, oxygen, hydrogen, nitrogen = bulk
* Iron, sodium, potassium – smaller amounts
* Calcium, iron, iodine = trace
* Define cell, organelle, and inclusion.
* Cell – The basic structural and functional units of all organisms – enclosed by a limiting membrane – could be prokaryotic or eukaryotic
* Organelle – metabolic machinery of the cell – each carries out a specific function for the cell such as nucleus, mitochondria, Golgi apparatus, ER, cytoplasm…
* Inclusion – not functioning units, but are chemical substances that may or may not be present depending on the type of cell such as fat droplets, glycogen granules, pigments (melanin), crystals
* Identify on a cell model or diagram the three major cell regions (nucleus, cytoplasm, and plasma membrane).
* See page 57
* List the structures of the nucleus and explain the function of chromatin and nucleoli.
* Nuclear envelope – double membrane, selectively permeable with nuclear pores
* Nucleoplasm – jelly-like substance inside the nucleus that holds the nucleoli and chromatin
* Nucleoli – sites of ribosome construction and partial assembly – may be more than one
* Chromatin – uncoiled DNA being used for transcription
* Chromosomes – shortened, coiled DNA ready for cell division...
