Cellular Organization and Cell Reproduction

4th Quarter

Background Information Living things are made up of

cells. (Cell Theory) Cells vary in structure in

relation to the function they perform.

Background Information Cells differ greatly in shape and

size. However they have the same main parts:

- cytoplasm, the part of the cell where most life activities take place;

- cell membrane, which envelopes the cytoplasm; and

- nucleus, the part of the cell where the genetic material is formed.

Background Information

Background Information The cell membrane, a living

double layer of fats and proteins, regulates the entry and exit of materials in the cell.

Background Information Found in the cytoplasm

are the following: mitochondria, lysosomes, Golgi bodies, endoplasmic reticulum, ribosomes and vacuoles.

Background Information

Background Information The nuclear membrane, a

double layer of fats and proteins, covers the nucleus. Inside it are the nuclear sap (nucleoplasm), nucleolus and chromosomes.

Background Information

Importance of Cell Division to Living Things

Growth Development Repair of damaged body

parts and tissues (gametes).

Reproduction

At Interphase cell grows, accumulates

nutrients and replicates its genetic material – all important events that prepare the cell division.

three stages: G1 phase, S phase, G2 phase

90% of the entire cycle is devoted to the interphase.

Stage 1 – G1 (Growth or Gap 1) Phase

cell is still young and undergoes rapid growth, cell attains its normal size

organelles are formed DNA and proteins the longest phase in most

cells

Stage 2 – S (Synthesis) Phase

DNA inside the chromosome doubles by a process called replication

sister chromatid – strand of the double-stranded chromosome produced joined by the centromere

Stage 3 – G2 (Growth) Phase

preparations for cell division cell synthesizes proteins and

continues to increase in size assembly of proteins RNA and proteins are made

Stage 4 – M (Mitosis/Meiosis) Phase

cell undergoes division division of nucleus –

karyokinesis (nuclear division)

2 types of karyokinesis: mitosis and meiosis

division of cytoplasm – cytokinesis