cell division
increase the number of cells and causes many-celled organisms to grow
life cycle
cells have periods of formation, growth, development and death which is called the _____________
interphase
a cell cycle begins with ______________
MITOSIS
INTERPHASE PROCEEDS THE STEPS OF ____________
growth and development
In mitosis most of the life of any eukaryotic cell is spent in a period of ______________________
chromosomes
structure in the nucleus that contains hereditary material-DNA
cell division
during interphase, a cell duplicates its chromosomes or hereditary material and prepares for _______________
mitosis
process in which the nucleus divides to form TWO IDENTICAL NUCLEI with identical chromosomes
divide
Body cells _______ through Mitosis.
prophase
metaphase
anaphase
telophase
what are the 4 phases of mitosis in order:
Prophase
- nucleolus and nuclear membrane disintegrate
-centrioles move to opposite ends of the cell
Metaphase
-pairs of chromatids line up across the center (middle) of the cell
-spindle fibers stretch across the cell (spindle fibers are also found in plant cells)
Anaphase (away)
- each centromere divides
-each pair of chromatids separates and moves to opposite ends of the cell
- the separated chromatids are now called identical chromosomes
Telophase
-spindle fibers disappear and a new nucleus forms
- then the cytoplasm separates and 2 new cells are formed
Results of mitosis:
46
23
each cell in your body, except for sex cells, has the same number of ____ chromosomes, which is ____ pairs of chromosomes
worn out or damaged cells
Mitosis allows growth and replaces ___ ____ or ____ ___
Asexual reproduction
a new organism is produced from one parent organism
fission
divides into two identical organisms, happens with an organism with no nucleus
Example: bacteria
budding
a small, exact copy of the adult grows from the body of the parent
Example: Hydra
regeneration
in __________________, a whole new organism grows from each piece of the parent
Example: sponge
Sexual reproduction
Two sex cells, usually an egg and a sperm, come together a new organism is produced
Fertilization
The joining of an egg and a sperm, generally from two different organisms of the same species
male
Sperms are formed in the ______ reproductive organs.
female
Eggs are formed in the ______ reproductive organs.
Zygote
A cell that forms from fertilization is a _________
Mitosis
Following fertilization, ___________ begins and a new organism develops
Meiosis
A nuclear division that forms sex cells
nucleus
Meiosis consist of 2 divisions of the _____
In meiosis 1 (one)
the nucleus divides and produces two new cells with Same number of chromosomes in each.
In meiosis 2 (two)
the nuclei divides and produces four new cells with half the number of chromosomes of the original nucleus
Diploid
Body cells are ___________, because they have 23 pairs of similar chromosomes. (46)
Haploid
Sex cells are ___________ because they have 23 single chromosomes
23
46
A sex cell has ____ single chromosomes so that when it joins another sex cell, the two sets of single chromosomes can pair up and produce an organism with ____ chromosomes and unique traits