how are chromosomes put together? how do new cells get their chromosomes? how do new organisms get...
TRANSCRIPT
• How are chromosomes put together?
• How do new cells get their chromosomes?
• How do new organisms get their chromosomes?
• Compare and contrast these two processes.
How are chromosomes put together?
The packaging of CHROMOSOMES! (protein and DNA)
HUMAN DNA AND ITS PACKAGING IN HOMOLOGOUS CHROMOSOMES
MOM
DAD
HUMAN DNA AND ITS PACKAGING IN HOMOLOGOUS CHROMOSOMES
MOM
DAD
How do new cells get their chromosomes?
MITOSIS
INTERPHASE
EARLY PROPHASE: condensation
PROPHASE: Mitosis begins
METAPHASE: Alignment of the chromosomes
ANAPHASE: Separation of the chromatids
TELOPHASE: Re-formation of the nuclei and CYTOKINESIS
RESULT: TWO NEW DAUGHTER CELLS WITH IDENTICAL SET OF CHROMOSOMES OF PARENT CELL
MITOSIS
6
6 6
34
78
94
646
18
Very accurate copies of chromosomes!
How do new organisms get their chromosomes?
INTERPHASE (future egg or sperm)
MIEOSIS
FIRST PROPHASE
Exchange of segments
FIRST METAPHASE
FIRST ANAPHASE
FIRST TELOPHASE AND FIRST DIVISION
SECOND INTERPHASE
SECOND PROPHASE
SECOND METAPHASE: perpendicular axis
SECOND ANAPHASE
SECOND TELOPHASE
RESULT: FOUR NEW UNIQUE DAUGHTER CELLS EACH WITH HALF THE CHROMOSOMES OF THE ORIGINAL CELL
NOTE THAT WHICH COPY OF EACH CHROMOSOME GOES TO WHICH CELL IS COMPLETELY RANDOM
6
66
6
33 3 3
Comparing Mitosis and Meiosis
• Number of divisions
PROPHASE
METAPHASE
mitosis meiosis
6
66
6
33 3 3
Comparing Mitosis and Meiosis • Number of divisions • Number of chromosomes in daughter cells• Genetic identity of daughter cells• Where they occur
• miTosis = each daughter cells get TWO complete sets of chromosomes
• meiOsis = each daughter cells get ONE complete set of chromosomes