Biology Chapter 8 Flashcards
Cell Division
A process in which a cell reproduces by splitting in two. The original cell and both new cells are all genetically identical.
Chromosomes
The structures that contain most of a cell’s DNA
Purposes of Cell division
- Repairs damaged cells
- Allows for growth
- Allows for reproduction
Asexual reproduction
reproduction by cell division (there is no egg fertilized by a sperm)
Mitosis
The type of cell division responsible for asexual reproduction AND growth and maintenance of multicellular organisms.
Sexual Reproduction
Fertilization of a egg by a sperm using a special type of cell division called meiosis
Chromosome
A threadlike DNA molecule bearing thousands of genes
What are chromosomes made out of?
Chromatin (DNA and protein molecules)
Cell cycle
The ordered sequence of events that extend from the time a cell is first formed from a dividing parent cell to its own division into two cells
Interphase
1 stage of cell cycle, cell performs its normal functions, doubles everything in its cytoplasm, and grows in size
Mitotic phase
2nd stage of cell cycle, includes mitosis and cytokinesis
Mitosis
1st part of mitotic phase, nucleus and its contents divide evenly into two daughter nuclei
cytokinesis
2nd stage of mitotic phase, cytoplasm is divided in two
meiosis
a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.
haploid
gametes that have only one member of each homologous pair of chromosomes.
diploid
cells containing two sets of chromosomes
zygote
a diploid cell resulting from the fusion of two haploid gametes
fertilization
Fusing male and female gametes to form a zygote
Gamete
a mature haploid male or female cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
Explain what is unusual about Komodo dragon reproduction.
There are two known instances of a female Komodo dragon reproducing asexually by parthenogenesis (they produced eggs that hatched young without a male being present).
Describe the consequences of nondisjunction in autosomes and sex chromosomes.
- the members of a chromosome pair fail to separate at anaphase,
- producing gametes with an incorrect number of chromosomes.
