Mitosis and Meiosis Lab Flashcards
Why is the reproductive strategy of producing offsprings same as the parent
To ensure the survival of the species
Why is the reproductive strategy of producing offsprings that were different from the parent
To allow for adaptation and ensure survival of the species
A Sexual Reproduction
The strategy of producing offsprings that are genetically the same as the parents (clones)
How do a sexual organisms reproduce
Mitosis ( Binary Fission)
The oldest form and the simplest form of reproduction
Asexual reproduction ( relies on a single parent)
Sexual Reproduction
The stately of producing offsprings that are genetically diverse.
it is a more complex process and relies on two parents
Genetic variation is generated through two processes
- Meiosis ( a form of cell division)
2. Fertilization ( the fusion of gametes)
Modern biologist view of reproduction
That organisms exist to serve and reproduce the genome: it is the reproduction of the the genes not the individual.
GENOME
Is one complete set of instructions for specifying an individual of a species.
1 genome = 1 set of chromosomes= 23 chromosomes in a cell.
How are genetic instructions written
They written in the language of nucleotide in the DNA of the cell
CHROMATIN
Describes DNA as loose strands in the nucleus
When stretched out how long is one DNA molecule from a human cell
4 cm
CHROMOSOME
a single molecule of DNA when it is condensed
Each chromosome carries a piece of the total genome
Every chromosome is different
1 set of chromosomes (n) =
1 genome (N) = 23 chromosomes= 1 set
The number of chromosomes in a set depends on what
it depend on the particular species.
The greek for set
“ploidy”
HAPLOID CELLS
a cell with a single set of chromosomes ( 23)
.Contain 1 genome
They have a chromosome number of n
They have one genome for that species ( 1 set of chromosomes= 23 chromosomes)
examples of organisms whose somatic cells are haploid
simple organisms ( like prokaryotic)
haploid cells examples
- prokaryotic organisms
2. gametes
Complex organisms that reproduce sexually require
2 sets of chromosomes per cell: 2 genomes: 2n : 2 sets of 23 pairs of chromosomes
How is a haploid cell represented
n=1 set of chromosomes=1genome= 23 chromosomes
How is a diploid cell represented
2n= 2 ( set of chromosomes)= 2 genomes = 2 sets of 23 chromosomes =46 chromosomes.
DIPLOID
2 sets of chromosomes in each cell
2 reasons a cell divides
- cellular ( growth, healing, replace) Mitosis
2. sexual ( to produce a sex cell) Meiosis)
Before a cell can divide for any reason a eukaryotic cell must
go through one round of cell cycle
The cell cycle
- Interphase ( G1, S, G2): all essential cellular molecules and organelles are duplicated in preparation for cell division.
Once everything is duplicated, each round of cell cycle then ends of some form of nuclear division, followed by cell division( cytokinesis)
what happens at the end of a cell cycle
some form of nuclear division ( Mitosis or Meiosis
Interphase( cell cycle)–Mitosis/ meiosis ( nuclear division)—–Cytokinesis ( cellular division)
2 types of cells of cells as it relates to
- Somatic Cells ( body cells ) undergo Mitosis ( Diploid Cells)
- Germ Cells ( gametes) undergo Meiosis (Haploid cells)
purpose of mitosis
To sort out the chromosomes that were replicated ( duplicated) during S phase, package them and ensure that each daughter cell will get both versions
What happens to germ cells after going through many rounds of cell cycle
It goes through mitosis. This is how more germ cell gets made. Then finally go through meiosis instead
The purpose of meiosis
To sort out the chromosomes of germ cells prior to cell division
End result of cell division after meiosis is
4 daughter cells
Representation of meiosis summary
A diploid nucleus gives rise to 4 haploid nuclei
2n –//meiosis — n + n( haploid)—- meiosis —1/2 n + 1/2 n( haploid)
