Ch. 8 The Cellular Basis of Reproduction and Inheritance Flashcards
Life Cycle
The entire sequence of stages in the life of an organism, from the adults of one generation to the adults of the next
What are the 2 parts of the life cycle?
1) Development - fertilized egg to adult
2) Reproduction - formation of new individual from pre-existing
Sexual reproduction
2 parents each give a gamete (w/ DNA) so that a zygote is formed from fertilization.
- complex organisms
- great variation
Genome
A complete (haploid) set of an organism’s genes; genetic material
Asexual reproduction
The creation of offspring by a single parent, w/o the participation of sperm and egg, who gives up all/part of self.
- found in simple organisms
- identical offspring
Chromosomes
“Colored bodies”
A threadlike, gene-carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis/meiosis
- main gene carrier of prokaryotic cells
- consist of chromatin
- # varies from species to species (46 for humans, 23 in gamete)
Where do cells come from?
Other cells
Cell division
The reproduction of a cell and perpetuates life.
Binary fission
“dividing in half”
A means of asexual reproduction in which a parent organism (single cell) divides into 2 individual of equal size
- describes cell division in prokaryotic cells
Reproduction
One of the 9 life processes required to be considered living.
- organisms are able to make more of own kind
What is the advantage and disadvantage of asexual reproduction?
Advantage: Repopulate fast
Disadvantage: Lack of variation (Evolutionary)
What does cell division accomplish?
1) Growth
- increase in size, more cells
- allows fertilized egg to become embryo to become adult
2) Maintenance
- replacing of worn out/dead cell
3) Continuity
- genetic material is passed b/w generations
What does “like begets like” mean?
Similar type of organisms produce similar type of organisms by genetic info
Chromatin
Combination of DNA and proteins that constitute eukaryotic chromosomes
- refers to the diffused, extended form taken by chromosomes
- protein structure only seen in cell division
- chromatid is half of chromosomes and contains one long DNA
Duplication
Occurs right before cell division and is the copying of genetic material.
What is the centromere?
A button that holds chromatid together and connects the spindle fibers during mitosis and meiosis
- divides at onset of anaphase during mitosis and anaphase II of meiosis
Sister chromatid
One of the two identical parts of a duplicated in a eukaryotic cell
What happens before the cell divides?
1) Duplicate all of chromosomes
2) Cell divides and sister chromatids separate
Cell Cycle
An orderly sequence of events (including interphase and mitotic phase) from the time a cell is produces to the time it divides
Interphase
The period in the eukaryotic cell cycle between cell division
- most of the cell cycle is this phase (90%)
- metabolic activity is very high
- chromosomes duplicate, cell parts made, cell grows
- DNA synthesis
What are the 3 sub phases of interphase?
1) G1
2) S
3) G2
What occurs during G1?
Gap of time from after cell division to S phase
- half the size of normal size
- cell increases protein supply, # of organelles, grows in size
What occurs during S phase?
Synthesis (duplicating)
- DNA replication
- chromatid to chromosome
What occurs during G2 phase?
Gap of time after synthesis and to cell division
- proteins synthesized
What are the two processes of cell division?
1) Mitosis
2) Cytokinesis
Mitosis
Division of nucleus and its material
- unique to eukaryotes
- 4 phases
Cytokinesis
Division of cytoplasm and organelles
Mitotic phase (M)
Part of cell cycle with division
- Mitosis and cytokinesis
What are the 4 phases of mitosis?
1) Prophase
2) Metaphase
3) Anaphase
4) Telophase
What is the Cell Cycle Control System?
A set of proteins in the cells that trigger and coordinate cell cycle.
- 3 check points in G1, G2, M phase with proteins
When does cleavage furrow form?
Late anaphase
During telophase…
Identical daughter cells formed from parent cel but only half the size
What is the difference between animals and plants during mitosis?
Plants have no cleavage furrow or centrioles. Due to the presence of a cell wall, cell plate is formed.
What are the three factors that affect cell division?
1) Anchorage Dependence
2) Density Dependent Inhibition
3) Growth factor
Anchorage dependence
Most cells don’t divide if not connected to solid surface
Density dependent inhibition
Too dense population, slows down cell division
Grown factor
Protein secreted cause cells to divide and lack of protein can inhibit cell division
Somatic cells
Body cells
- for humans, contain 46 homologous chromosomes (23 pairs)
- full set of chromosomes that are diploid (2N)