(I)GCSE Topic 3.24 c) Mitosis 3

- DNA Replication occurs during the Interphase

- For a sign that the cell is entering the stages of Mitosis and cell devision is when we see the breakdown of the nuclear membrane = PROPHASE

- Membrane breaks down and the chromosomes are visible as a pair of CHROMATIDS

- Inside the cell, the nucleus is gone and replaced with a network of protein molecules = SPINDLE / SPINDLE FIBERS

- 'Late Prophase' = pair of chromatids move towards the spindle

- METAPHASE = chromosomes are in the middle -arranged across the equator- of the cell 

- ANAPHASE = the spindle fibre shortens, pair of chromatids move apart to the polls of the cell = separation of chromatids

- TELOPHASE = nucleus begins to reform around the chromosomes at either end of the cell

*Not part of Mitosis*

- CYTOKINESIS = the cell splits into two 

= cell bends inwards, dividing cytoplasm in half 

= membrane will fuse across the equator to form the two cells

*2 new cells each contain a new chromosome-same as the parental cell*

(I)GCSE Topic 3.24 b) Mitosis 2

-For cells to be 'identical', the original cell has to copy its chromosomes

- Copying of Chromosomes = DNA Replication

=> each chromosome undergoes a copying process to form an identical copy of itself with the same genes and alleluias 

=> these two copies are held together by a structure around the center region - CENTRONERE

-While the chromosomes are in a copied pair = A Pair of Chromatids

- Process of DNA Replication takes place in the nucleus while the nucleus is still in tact 

=> INTERPHASE of the cell cycle

(I)GCSE Topic 3.24 a) Mitosis 1

MITOSIS = a form of cell devision which results in growth 

- Growth occurs by an increase in the number of cells

Outline of the Process  

- the number of chromosomes in a nucleus is known as the Diploid number (2n)

- for human 2n = 46 chromosomes

- in the process of Mitosis each cell in the body will divide up onto two cells

- if looked at closely, the two cells can be identified as equal/daughter cells

=> they have the same number of Chromosomes

=> they have the same set of Chromosome

(I)GCSE Topic 3.16 DNA and Genetic Information

(I)GCSE Topic 3.15 Genes

(I)GCSE Topic 3.14 Chromosomes

 - Chromosomes = genetic information of the cell
 - Different organisms have different amount of chromosomes
      - e.g. Cats have 38, Chickens have 78, Chimp has 42, and Humans have 46
 - Chromosomes are known to operate in pairs = "Homologous Pairs"

(I)GCSE Topic 3.6 Germination Conditions

- TESTA = Seed Coat 

- SCAR = from where the seed is detached from the ovary wall

- MICROPYLE = where the pollen tube enters the seed

>Conditions needed to bring about Germination<

- Water 

- Reasonable Temperature - higher temperature - enzymes bring about starch => Maltose (stored in cotyledon)

- Oxygen - Aerobic respiration

(I)GCSE Topic 3.4 Plant Fertilisation

- Pollen Nucleus will fertilise the Ovule
  - formation of the Zygote - grow into the embryonic plant
- Outside the Ovule forms a seed coat = TESTA
- Cotyledon = food store for the seedlings
                    = supports the plant till it develops a fresh sets of leaves

(I)GCSE Topic 3.1 Sexual and Asexual Reproduction

>Describing differences between Sexual and Asexual Reproduction<

- Gametes = Cells
- Type of cell division that produces Gametes is called Meiosis
   - Effects = 1/2 the total adult number of male chromosomes in the Gametes Cell
 - Total Number of cells in an adult human male = 46 cells
 - Total Number of cells in an adult Gametes male = 23 cells

YEAR 11