Genetics

5.1 Cell Division
 
Chromosome
  • Nucleus contains chromosomes
  • Long and spiral 
  • Consist nucleic acids and protein 
  • Each chromosome contains a long DNA molecule
 
Deoxyribosenucleic acid (DNA)
  • Made up of nucleotide
  • Each nucleotide consists of three components, deoxyribose sugar, a nitrogenous base and a phosphate group
  • Double helix
 
Gene
  • Basic hereditary unit that determines an individual's characteristics
  • Function: to control the inherited characteristics in an organism
 
 
Gender Autosome + sex chromosomes
Male 44 + xy
Female 44 + xx
 
Mitosis

Mitosis is a cell division process that forms 2 identical daughter cells.

A  
  • Chromosome with two chromatids joined at the centromere
B Prophase
  • Replication of chromosome occurs
  • Chromosomes shorten and thicken
  • Spindle fibres begin to form
C Metaphase
  • Chromosome arrange at the equatorial plate of the cell
D Anaphase
  • Pairs of chromatids seperate and move to the opposite poles of the cells
E Telophase
  • Cytoplasm divides
F  
  • Two daughter cells are formed
  • Same number of chromosomes as parent cell
 
Meiosis

Meiosis is a process where the cell divides into 4 distinct cells

A  
  • Parent cells with two pairs of chromosomes
B Prophase I
  • Replication of chromosome occurs
C Metaphase I
  • Crossing over occurs
D Anaphase I
  • Homologous chromosomes seperate and move to opposite poles
E Telophase I and cell division
  • Cytoplasm divides
  • Two daughter cells are formed
F Metaphase II
  • Pairs of chromatids separate and move to opposite poles
  • Cytoplasms divides
G Telophase II & cell division
  • Four daughter cells are formed
  • Each daughter cells have half number of chromosome from parents 
 
 
Similarities of mitosis and meiosis
  • A process of cell division
  • Purpose of both processes are to ensure sustainability of living organisms
  • Both transfer genetic material to daughter cells
  • Both process involve duplication of chromosome
 
Differences between mitosis and meiosis
  Mitosis Meiosis
Definition Cell division in which a cell divides into 2 cells Cell division in which a cell divides into 4 cells
Location of process

Meristem cells in plants

Somatic cells in animals

Anther and ovary in plants

Testis and ovary in animals

Number of daughter cells 2 4
Number of chromosomes in daughter cell Same number of chromosomes of the parents Half the number of chromosomes of the parent cell
Genetic make up in daughter cells Identical  Different
Products Cells for growth and repair Gamates
Importance
  • For growth
  • For tissue repair
  • Asexual reproduction
  • Maintenance and continuity of life
  • Produce gametes
  • Produce variation

 

Genetics

5.1 Cell Division
 
Chromosome
  • Nucleus contains chromosomes
  • Long and spiral 
  • Consist nucleic acids and protein 
  • Each chromosome contains a long DNA molecule
 
Deoxyribosenucleic acid (DNA)
  • Made up of nucleotide
  • Each nucleotide consists of three components, deoxyribose sugar, a nitrogenous base and a phosphate group
  • Double helix
 
Gene
  • Basic hereditary unit that determines an individual's characteristics
  • Function: to control the inherited characteristics in an organism
 
 
Gender Autosome + sex chromosomes
Male 44 + xy
Female 44 + xx
 
Mitosis

Mitosis is a cell division process that forms 2 identical daughter cells.

A  
  • Chromosome with two chromatids joined at the centromere
B Prophase
  • Replication of chromosome occurs
  • Chromosomes shorten and thicken
  • Spindle fibres begin to form
C Metaphase
  • Chromosome arrange at the equatorial plate of the cell
D Anaphase
  • Pairs of chromatids seperate and move to the opposite poles of the cells
E Telophase
  • Cytoplasm divides
F  
  • Two daughter cells are formed
  • Same number of chromosomes as parent cell
 
Meiosis

Meiosis is a process where the cell divides into 4 distinct cells

A  
  • Parent cells with two pairs of chromosomes
B Prophase I
  • Replication of chromosome occurs
C Metaphase I
  • Crossing over occurs
D Anaphase I
  • Homologous chromosomes seperate and move to opposite poles
E Telophase I and cell division
  • Cytoplasm divides
  • Two daughter cells are formed
F Metaphase II
  • Pairs of chromatids separate and move to opposite poles
  • Cytoplasms divides
G Telophase II & cell division
  • Four daughter cells are formed
  • Each daughter cells have half number of chromosome from parents 
 
 
Similarities of mitosis and meiosis
  • A process of cell division
  • Purpose of both processes are to ensure sustainability of living organisms
  • Both transfer genetic material to daughter cells
  • Both process involve duplication of chromosome
 
Differences between mitosis and meiosis
  Mitosis Meiosis
Definition Cell division in which a cell divides into 2 cells Cell division in which a cell divides into 4 cells
Location of process

Meristem cells in plants

Somatic cells in animals

Anther and ovary in plants

Testis and ovary in animals

Number of daughter cells 2 4
Number of chromosomes in daughter cell Same number of chromosomes of the parents Half the number of chromosomes of the parent cell
Genetic make up in daughter cells Identical  Different
Products Cells for growth and repair Gamates
Importance
  • For growth
  • For tissue repair
  • Asexual reproduction
  • Maintenance and continuity of life
  • Produce gametes
  • Produce variation