Cells
The Basic Unit of Life, Reference, pages 13-23, McGraw-Hill Ryerson
Organelles
Special structures that perform specific functions in cells
Cell Animations science.nhmccd.edu/biol/bio1int.htm
Nucleus
Has a double-layered porous (with pores - very tiny holes) membrane
Contains DNA (deoxyribonucleic acid), DNA forms chromatin (long strands) and has instructions to assemble the necessary substances for building the cell and making it work
Has a nucleolus, a dark structure that manufactures ribosomes
Cytoplasm
The area outside the nucleus and inside the cell membrane. The cell membrane separates the cell contents from its surroundings.
Jelly-like material
Supports nucleus and other organelles
Ribosomes
Structures that make protein
Protein is used to make enzymes, muscle tissue, and other important structures
Endoplasmic Reticulum
Series of canals
Canals are used to transport materials to different parts of the cells
Rough Endoplasmic reticulum has ribosomes attached
Mitochondria
Transform energy for the cell
Golgi Bodies
Package useful materials and secrete them to the outside of the cell for use elsewhere
Vacuoles
Fluid-filled storehouses that contain water, food, wastes and other materials
Lysosomes
Break down food and digest wastes and worn out cell parts
The Cell Cycle
Cell division allows organisms to grow and develop
When cells divide, they must have a complete nucleus, so all the instructions in the DNA are reproduced
The process that makes this happen is MITOSIS
Before Mitosis
Cells copy the chromatin so there are two sets of DNA
The chromatin coils up to form double-stranded chromosomes, joined by a centromere
Copy Figure 1.9 on page 17
Phases of Mitosis
Remember PMAT
Four major phases

Results in two complete sets of DNA
Prophase, Metaphase, Anaphase, Telophase
Prophase
Chromosomes visible with a microscope
Nuclear membrane disappears
Spindle fibres form and stretch across the cell
Spindle fibres attach to centromeres
Metaphase
Spindle fibres pull chromosomes into a line across the middle of the cell
Anaphase
Spindle fibres shorten
Centromeres are pulled apart
Chromosomes move to the opposite (ends) poles of the cell
Telophase
Final phase of mitosis
Spindle fibres disappear
Nuclear membrane forms around each set of chromosomes
Nucleolus appears
Single stranded chromosomes uncoil into strands of chromatin
The cell is ready to dividecytokinesis
Cell Division
After telophase
Animal cells - the membrane pinches together and the cell divides
Plant cells - a cell plate develops across the centre of the cell forming a new cell wall
Two new cells- daughter cells
Number of chromosmes in the nucleus of each cell is identical to the number in the original cell
Interphase
Inter- between
Cell growth, replication of DNA
Prepares for mitosis
Refer to the cell cycle pie graph on page 23
Mitosis is ____ h
Rapid growth is ____ h
Growth and DNA replication is ____h
Growth and preparation for division is ____ h
Sketch the phases of Mitosis to go with your explanations.
Do questions 3 and 4, page 16; 1-7 on page 23.