Surface Area : Volume

Ratio

The best combination of surface area and volume factors is one in which:

The surface area is GREAT

The volume is SMALL

The surface area to volume ratio is LARGE

What do cells do when they reach their maximum size?

Why do they do this?

The cell divides from one cell into two cells.

It does this for growth, repair and reproduction of organisms

Asexual Reproduction

Qualities

a) no mixing of genes

b)  offspring are genetically identical to the parent

c)  best form of reproduction in a stable or non-changing environment.

d)  Typical in most unicellular orgnaisms and some multicellular organisms like hydra and jellyfish

Sexual Reproduction

Qualities

a)  mixing of genes from 2 parents

b)  offspring are genetically similar, but not identical to either parent

c)  Advantageous in a changing environment

d)  Typical in most multicellular organisms

What form is the DNA in non-dividing cells?

What form is the DNA in dividing cells?

chromatin

chromosomes

Sister Chromatids

Otherwise known as double-arm chromosomes.

Are made up of paired, genetically identical chromatids.

Centromere

The location on the double-arm chromosomes where sister chromatids are joined

What is happening during interphase?

What form is the DNA in?

 Interphase is the period of cell growth, DNA replication and when all the metabolic activities take place.

The DNA is in the form of chromatin.

What is mitosis?

What form is the DNA in during mitosis?

Mitosis is the division of replicated chromosomes (and the nucleus)

The DNA is in the form of (2 sets of) chromosomes

What is cytokinesis?

What form is the DNA in during cytokinesis?

Cytokinesis is the division of the cytoplasm and the formation of 2 new cells.

The DNA is in the form of chromatin

What 3 phases makes up the cell cycle?

1) Interphase

2)  Mitosis

3)  Cytokinesis

At this exact moment, what phase of the cell cycle would most of your (body) cells be in?

What form is your DNA in during this phase?

Interphase

Chromatin

S Phase of Interphase

DNA Replication

Prophase

1) DNA condenses into double-arm chromosomes

2) Nuclear membrane breaks down and nucleoli disappear.

3)  Spindle fibers form at the ends of the cell

4)  Centrioles in animal cells move to the poles

Metaphase

1)  Double-arm chromosomes line up on the middle or equator of the cell

2)  Spindle fibers attach to chromatids at the centromeres

Anaphase

1)  Spindle fibers contract, causing centromeres to split and identical chromatids to separate.

2)  Single-arm chromosomes (chromatids) move to opposite ends of poles of the cell

Telophase

1)  Chromosomes unravel into chromatin

2)  Nuclear membrane and nucleolus reform.

3)  Spindle fibers break down.

4)  Furrow in animal cell forms (or a cell plate in plant cells.

Cytokinesis

1)  cytoplasm divides

2)  Furrow or cell plate is complete

3)  Two, identical "daughter" cells are formed

The differences between animal cells and plant cells during mitosis and cytokinesis?

1)  Centrioles only present in animal cells.

2)  During cytokinesis:  Furrow in animal cells

Cell plate in plant cells

What is cancer?

Uncontrolled mitotic division in cells.

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