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Explain how cell division functions in reproduction, growth, and repair.
Mitosis causes growth and repair by providing more identical cells to replace old, damaged or missing cells for repair or to produce more tissue for growth. It also helps with reproduction by creating haploid cells to form zygotes for reproduction.
Describe the structural organization of a prokaryotic and a eukaryotic genome.
Prokaryotic genomes are found in a single strand of DNA in a circular shape. Eukaryotic are packed into chromosomes in a double helix shape.
Describe the major events of cell division that enable the genome of one cell to be passed on to two daughter cells.
In cell division, the S phase ensures that all 46 chromosomes are duplicated for the cell to give to each daughter cell. G2 phase checks them for error, and then mitosis happens in which the cell divides to give each daughter cell the same genome.
Describe how chromosome number changes throughout the human life cycle.
The egg cell starting out has n genomic content. When the zygote enters and attaches, it has 2n genomic content.
List the phases of the cell cycle and describe the sequence of events that occurs during each phase.
In the G1 Phase, all cellular contents of the cell, excluding the chromosomes are duplicated. The cell grows, ensures it has enough nutrients, and space. Then in the S phase, the chromosomes are all duplicated. After S phase, is the G2 phase, where the cell double checks for error and ensure the chromosomes were duplicated properly. After it gets it's Ok signal, Mitosis occurs, and then cytokenisis.
List the phases of mitosis and describe the events characteristic of each phase.
In Mitosis, the DNA is replicated during the S phase of Mitosis. This ensures that the DNA of the original genome is copied. In prophase, the chromatin condense to form chromosomes, and the nuclear envelope dissapears. Then in Metaphase, the chromosomes line up into the middle of the cell, and spindle fibers attach to them. In anaphase, the chromosomes are pulled apart giving each new daughter cell a copy of the original genome.
Compare cytokinesis in animals and in plants.
In cytokinesis in animals, the cell splits into two with a cleavage furrow in the middle, in plants, a cell plate forms in between the splitting cells.
Describe the roles of checkpoints, cyclin, Cdk, and MPF in the cell cycle control system.
The chekpoints in the cell cycle, ensure that there are no errors or mistakes in each part of the cycle. Cyclin is a regulatory protein that a kinase much be attached to. The maturation promoting factors give the go ahead signals at the checkpoints after the cell has been checked.
Describe the internal and external factors that influence the cell cycle control system.
An internal factor that influences the cell cycle control system is for instance in the M phase; the cell cannot split the chromosomes until they are all aligned at the metaphase plate. An external factor could be the fibroblasts which give a signal for the cell to go past the G1 checkpoint.
Explain how the abnormal cell division of cancerous cells escapes normal cell cycle controls.
They ignore checkpoints and signals and keep dividing without any regulation. Because of this an overabundance of cells is created and tumors may appear.
Distinguish between asexual and sexual reproduction.
Asexual reproduction is when an offspring can be produced by one parent, and they inherit the genetic information from that one parent. Sexual reproduction occurs when two parents produce an offspring and the offspring receive genetic information from both parents.
Distinguish between the following pairs of terms:
a. somatic cell and gamete
b. autosome and sex chromosome
The difference between somatic cells and gametes are somatic cells have a diploid number of chromosomes, gametes have a haploid (half) number
An autosome is is any chromosome but the X and Y chromosomes. The Sex chromosomes are the X and Y chromosomes that distinguish he sex of the living things.
Explain how haploid and diploid cells differ from each other. State which cells in the human body are diploid and which are haploid
Haploid cells differ from Diploid cells because haploid have half the 46 chromosomes. Diploid has the full set. Only the sperm cells and cells in the ova are haploid cells. The body cells are mostly all Diploid.
List the phases of meiosis I and meiosis II and describe the events characteristic of each phase.
In meiosis I, the cell goes through prophase I, Metaphase I, Anaphase I, and Telophase I. In prophase I Synapsis occurs and the chromosomes form tetrads. Chaismata occurs here. Genetic information is swapped. In Metaphase they align in the middle of the cell, and in Anaphase I they are pulled apart as full chromosomes still. In telophase I the cell splits into two daughter cell with chromosomes with different genetic info. Then In Meiosis part two, the basic mitosis happens. Half the number of chromosomes.
Describe the process of synapsis during prophase I and explain how genetic recombination occurs.
During synapsis, the chromosomes in the cell come together to form tetrads. When they are in tetrads, chiasmata occurs and during the crossing over, genetic information is swapped between the ends of the chromosomes. When the cells eventually divide into 4 cells, each cell has a new variety of genetic information.
Describe three events that occur during meiosis I but not during mitosis.
Three events are Synapsis, Crossing over, and Splitting twice.
Explain how independent assortment, crossing over, and random fertilization contribute to genetic variation in sexually reproducing organisms.
Independent assortment basically means that the chromosomes can align in any free willed way. There is no set place in the metaphase plate that a specific chromosome must be. Because of this, during crossing over, two chromosomes with two completely different genes on them can swap genes, and now change the genetic info that the new cells will get. The random fertilization is that any one of the new gametes can fertilize the egg so the chances of it getting different genetic info is high.
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