Life cycles Flashcards
The frequency of cell division depends on what?
Type of cell
What drives the cell cycle?
Specific chemicals in the cytoplasm
What is the cell cycle control system regulated by?
Both internal and external controls
What is the most important checkpoint for most cells?
G1 checkpoint. If I cell passes the g1 checkpoint it will generally complete s, g2 and m phases and divide
What is the g0 phase
When a cell hits the g1 checkpoint and does not get the go ahead it enters the g0 phase and does not continue with division
What do stop and go signs do?
They are internal signals that delay anaphase
What are some external signals that are growth factors?
Proteins release by certain cells that stimulate other cells to divide
How are living organism distinguished?
Reproduce with their own kind
What is genetics?
The scientific study of heredity and variation
What is heredity?
The transmission of traits from one generation to the next
What is variation
Variation is demonstrated by the differences in appearance that offspring show from parents and siblings
People say offspring acquire physical traits from parents, what do they mean?
They acquire genes not physical traits
Genes are pass through what to the next generation?
Reproductive cells called gametes
What are genes?
The unit of heredity and are made up of segments of DNA
What is a locus?
Specific location for gene on a chromosome
What is asexual reproduction?
One parent reproduces genetically identically identical offspring by mitosis
What is a clone?
Group of genetically identical individuals from the same parent
What is sexual reproduction?
2 parent give rise to offspring that have uniques combination of genes from both parents
What is a life cycle
The generation to generation sequence of stages in the reproductive history of an organism
What is a karyotype
An ordered display of the pairs of chromosomes from a cell
What are the 22 pairs of chromosomes that don’t determine sex called?
Autosomes
What’s is a diploid cell? Haploid?
Cell with 2 sets of chromosomes
Call with 1 set of chromosomes
What are the two chromosomes in each pair called?
Homologous chromosomes or homologs
What does a gamete contain?
Single set of chromosomes and is haploid
What is a zygote?
A fertilized egg
What are the only cells in the human body made by meiosis?
Gametes, everything else is mitosis
What do plants and some algae exhibit
An alternation of generations, this lifecycle includes both diploid and haploid multicellular stages
What does the diploid organism called the sporophyte make?
Haploid spores by meiosis
What is a gametophyte?
A haploid organism grown from a spore
What does a gametophyte make?
Gametes by mitosis
What is a diploid sporophyte the result of?
Fertilization of gametes
What is the only diploid stage for fungi and Protists?
Zygote, then the zygote produces haploid cells by meiosis
What is the only kind of cell that can divide by mieosis?
Diploid
What does meiosis do too the number of chromosomes
Reduces number from diploid to haploid
