2.2 Replicating cells
Making more DNA
-Somatic cells contain the exact copies of the chromosomes that were in the original
zygote that became you.
-Replication is the process of copying DNA.
-Steps of replication are as follows:
Strands of double helix separate from each other (like unzip at one end).
Bases are exposed.
Nucleotides in nucleus which are not parts of DNA come and pair up with exposed
bases following the rule of complementary base pairing.
Sugar and phosphate molecules bond with neighbouring nucleotides and new
strands of DNA are formed.
2 identical DNA strands are produced(Identical to parent DNA).
-Each chromosome has the 2 identical DNA molecules which are now called
chromatids.
-2 Copies are joined at the centromere.
, Cell division
-2 types.
Mitosis Meiosis
- Produces 2 daughter cells that are -Produces gametes(eggs and sperms)
identical to the parent cell. -They have the half the number of
chromosomes of parent cell.
-This type involves in
*Growth
*Repair of the body
*Regeneration of tissues in some
animals
*Asexual reproduction
-Unicellular organisms reproduce by this -Many multicellular organisms produce
way. by this way.
-Doesn’t produce variation in offspring. -Produce variation in offspring.
Chromosome number
- The number of chromosomes in your body cells--> diploid number (2n)
- Diploid number includes 2 sets of autosomes + 2 sex chromosomes.
-At the end of mitosis , each daughter cell should have a full diploid set of
chromosomes --> 44 autosomes + 2 sex chromosomes
*Daughter cells are genetically identical to parent cell, that is they are clones.
-When gametes are made, they have only one copy of chromosomes--> haploid
number (n).
Making more DNA
-Somatic cells contain the exact copies of the chromosomes that were in the original
zygote that became you.
-Replication is the process of copying DNA.
-Steps of replication are as follows:
Strands of double helix separate from each other (like unzip at one end).
Bases are exposed.
Nucleotides in nucleus which are not parts of DNA come and pair up with exposed
bases following the rule of complementary base pairing.
Sugar and phosphate molecules bond with neighbouring nucleotides and new
strands of DNA are formed.
2 identical DNA strands are produced(Identical to parent DNA).
-Each chromosome has the 2 identical DNA molecules which are now called
chromatids.
-2 Copies are joined at the centromere.
, Cell division
-2 types.
Mitosis Meiosis
- Produces 2 daughter cells that are -Produces gametes(eggs and sperms)
identical to the parent cell. -They have the half the number of
chromosomes of parent cell.
-This type involves in
*Growth
*Repair of the body
*Regeneration of tissues in some
animals
*Asexual reproduction
-Unicellular organisms reproduce by this -Many multicellular organisms produce
way. by this way.
-Doesn’t produce variation in offspring. -Produce variation in offspring.
Chromosome number
- The number of chromosomes in your body cells--> diploid number (2n)
- Diploid number includes 2 sets of autosomes + 2 sex chromosomes.
-At the end of mitosis , each daughter cell should have a full diploid set of
chromosomes --> 44 autosomes + 2 sex chromosomes
*Daughter cells are genetically identical to parent cell, that is they are clones.
-When gametes are made, they have only one copy of chromosomes--> haploid
number (n).
