Lab Test 2 Flashcards
Chromatin
Complex of DNA and protein that condenses during cell division
Somatic cells
Non reproductive cells. Have two sets of chromosomes
Cell cycle
The life of a cell from formation to its own division
Checkpoints
Where the cell cycle stops until a go ahead signal is received
Apoptosis
Programmed cell death
What is the significance of the S phase of interphase
During S phase, each chromosome replicates to produce two daughter copies, or sister chromatids. Proteins, such as histones, are synthesized. Duplication of centrioles is completed and they migrate to opposite poles. Microtubules that will become part of the spindle apparatus are synthesized
Why did early scientists call interphase the “resting phase”
Because they did not have the technology to see what actually occurred during this phase. The cell didn’t appear to be dividing so they assumed it was resting.
During cell division, how does interphase set up for prophase
DNA is replicated, important proteins are synthesized, and organelles are produced to supply each daughter cell. Structures to be used during cell division are also assembled. Cell division cannot be successful unless all these processes are carried out
What are several differences between animal and plant mitosis
In animal cell cytokinesis, the cell membrane constricts to pinch the parent cell into daughter cells. In plant cytokinesis, a new cell wall is fashioned between the new daughter cells. There are no centrosomes in plant mitosis
What are the three checkpoints of the cell cycle and the basic functions of each
G1: check for cell size, nutrients, growth factors, and DNA damage
G2: check for cell size and DNA replication
Spindle assembly checkpoint: checks for chromosome attachment to the spindle
What kinds of cells undergo meiosis
Only sex cells (gametes)
Compare and contrast meiosis and mitosis
Mitosis occurs in somatic cells and creates two genetically identical daughter cells that are diploid.
Meiosis occurs in sex cells creates 4 genetically unique haploid cells. It consists of 2 cell divisions
What is spermatogenesis. Where does it take place
The process in which spermatozoa are produced from spermatogonial stem cells by way of mitosis and meiosis
It occurs in the seminiferous tubules of the testes
Chromatin
a complex of DNA and protein that condenses during cell division
Somatic cells
Nonreproductive cells. Have two sets of chromosomes
Cell cycle
The life of a cell from formation to its own division
Checkpoints
Where the cell cycle stops until a go-ahead signal is receieved
Apoptosis
Programmed cell death
Centromere
The narrow “waist” of the duplicated chromosome where the two chromatids are most closely attached
Sister chromatids
Joined copies of the original chromosome that separate during cell division
Homologous chromosome
The cell has two sets of each chromosome; one of the pair is derived from the mother and the other from the father. The maternal and paternal chromosomes in a homologous pair have the same genes at the same loci, but possibly different alleles.
Cytokinesis
the division of the cytoplasm
Centriole
a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.
Spindle fibers
a structure made of microtubules that controls chromosome movement during mitosis
Asters
The asters synthesize and extend polymeric spindle fibers in a dividing cell
Cell plate
(in plant cells) a plate that develops at the midpoint between the two groups of chromosomes in a dividing cell and that is involved in forming the wall between the two new daughter cells
What is the difference between genotype and phenotype
Genotype is the gentic construction of a particular organism. Phenotype is the obervable characteristics of an organism resulting from the genotype
What are the chances of two parents who carry the gene for albinism (recessive) having a child without albinism
25% chance of having an offspring with albinism and 75% chance of having one without
Diploid
A cell that has two sets of chromosomes
Haploid
A cell that contains one set of chromosomes (gametes)
Meiosis I
reductional division): homologs pair up and separate, resulting in two haploid daughter cells with replicated chromosomes
Meiosis II
(equational division) sister chromatids separate
Fertilization
The union of gametes (sperm and egg)
Synapsis
In synapsis, homologous chromosomes loosely pair up, aligned gene by gene
Crossing over
Nonsister chromatids exchange DNA segments
Tetrads
Homologous chromosomes form tetrads when they pair with eachother