Asexual and sexual reproduction

The Cell Cycle

  • Time to complete is not the same for all cells,

  • Interphase= time for growth and development for eukaryotic cells 

  1. Cells grow, function, and organelles duplicate 

  2. DNA is copied

  3. The cell grows and prepares for mitosis 

Not a phase of mitosis. Most cells are in interphase. a normal functioning cell 

interphase spends most of its time growing, replicating its DNA & carrying out its cell functions

Mitosis 

  • Nucleus divides to form two identical nuclei

              Steps of mitosis 

  1. Prophase

  2. Metaphase 

  3. Anaphase 

  4. Telophase 

What is in the nucleus

 Heredity material: genetic information

  • DNA: genetic material code? Instructions for all living things, double helix, twisted ladder, deoxyribonucleic acid 

  • Chromatin: unraveled DNA “invisible” DNA during interphase (ex. extension cord)

  • Chromosome: Raveled DNA “visible” DNA during mitosis/cell division (ex. Coiled extension cord)  

  • Pair of chromomatids: identical copies of chromosomes, held together by a centromere 

DNA has to be identical in order for the cell replication to work properly

   Prophase  

  • Chromatid pairs of chromosomes are visible

  • The nuclear membrane breaks down

  • The spindle is beginning to form between centrioles

   Metaphase 

  • Pairs of chromatids line up at the center of the cell

  • Centromeres are attached to spindle fibers

   Anaphase 

  • Centromere divides, chromatid pairs separate, and move to opposite ends of the cell

  • Chromatids are now called chromosomes

   Telophase 

  • Spindle fibers disappear

  • Chromosomes uncoil

  • A new nucleus forms with the nucleolus

   Cykocinesis 

  • Division of cytoplasm and organelles

  • Cell membrane pinches in the middle

   Asexual reproduction 

  • A new organism is produced from one organism with identical hereditary material

  • Eukaryotic cells (nucleus) = cell division

                                                     budding

                                                     regeneration

  • Prokaryotic cells (no nucleus) = binary fission

sexual reproduction

  • Gametes are produced in the reproductive organs by meiosis 

  • Contain half of the number of chromosomes found in normal body cells 

  • Mitosis = asexual reproduction of cells 

  1. Make exact copies

  2. Many at one time

  • meiosis= sexual prodcution

  1. Make different cells ½ of chromosomes

  2. Few at one time

  • diploid= cells with both members of each homologous pair (in humans, 2n=46)

  • haploid= cells with only one member of each homologous pair (in humans, 23) 

  •  In meiosis, the number of chromosomes in a diploid cell is reduced by half, producing a haploid