Cytology

Cell Structure & Function

– the study of

Objective: C1 - Summarize the principles of the cell theory, compare & contrast prokaryotic & eukaryotic cells, and analyze the levels of organization in biological systems

Discovering the Cell

Robert Hooke– used a

microscope to study cork coined the term “cell”

Anton van Leeuwenhoek– first person to record looking at

water under a microscope– a direct result of his work was…

Chp. 7-1 Life is Cellular

I. Introduction to the Cell

A. Cell Theory

– All organisms are made upof one or more cells.

– Cells are the basic unit of structure & function in organisms.

– All cells come from preexisting cells.

B. Cells differ in size, shape, & organization

– Cell Size Small cells function more efficiently

than large cells. Large cells cannot function efficiently in

the transport of materials & waste into and out of the cell.

B. Cells differ in size, shape, & organization.

– Cell Shape The shape of the cell depends on its function.Cell Specialization – separate roles for each type of cell in multicellular organisms

– Most cells contain a variety of membrane bound ORGANELLES - cell parts that PERFORM SPECIFIC FUNCTIONS FOR THE CELL

C. Internal Organization

Nucleus

Chloroplast

Golgi Body

Mitochondria

– NUCLEUS – contains the cell’s genetic information

– controls the activities of the cell

– Whether a cell has or does not have a NUCLEUS is important for classifying cells.

II. Prokaryotes Vs. Eukaryotes

EUKARYOTES – ORGANISMS WHOSE CELL CONTAIN

a NUCLEUS AND membrane-bound ORGANELLES

– Most are multicellular; some are unicellular

– Examples: Animals, Plants, Fungi, Protists

II. Prokaryotes Vs. Eukaryotes

PROKARYOTES

– ORGANISMS WHOSE CELLS LACK A NUCLEUS AND membrane-bound ORGANELLES

– Have ribosomes (they are not membrane-bound)

– Smaller than Eukaryotes– All are UNICELLULAR ORGANISMS – Example: Bacteria (it is the only example) If it’s a

prokaryote, it is always a bacteria cell. If it is a bacteria cell, then it’s prokaryote.

Note: The difference between Prokaryotes and Eukaryotes is such an important distinction that they are placed in separate Kingdoms.

Prokaryotes Vs. Eukaryotes Size

Etymology

Cytology: cyto-, -cyte, -cytic (Gk. KUTOS, cell) + -logy (LOGOS, word; hence the study of)

Cell: (L. CELLAE, chambers)

Eukaryotic: eu- (Gk. EU-, good or true) + -karyotic (KARUOTIS, with a central part/ nucleus)

Levels of Organization in Multicellular Organisms

Individual cells → Tissues → Organs → Organ systems