Chapter 9 & 10 (Cell Cycle, Mitosis, & Meiosis) 11. Please name and describe (e.
ID: 151784 • Letter: C
Question
Chapter 9 & 10 (Cell Cycle, Mitosis, & Meiosis) 11. Please name and describe (e.g. what is going on during these events?) the all stages of the cell cycle. 12. A) Compare and contract with detail: mitosis vs. meiosis. Please describe the details associated with each stage and what happens during each one. Be sure to include in your answer what type of cell these processes occurs 1. A) State 1) when C3 plants open their stomata, 2) what will happen when C3 plants are in high light and temperature conditions, 3) what the advantage of using C3 photosynthesis is and in what conditions it works best in and 4) the types of plants that use C3 photosynthesis. B) State 1) when C4 plants open their stomata, 2) what the advantage of C4 photosynthesis is when dealing with water loss and photorespiration in high light and temperature conditions, and 3) one specific type of plant that uses C4 photosynthesis C) State 1) when CAM plants open their stomata, 2) what the advantage of CAM photosynthesis is when dealing with water loss and photorespiration in high light and temperature and 2) one type of plant that uses CAM photosynthesis.Explanation / Answer
11. Stages of the cell cycle:
The cell cycle is actually the life cycle of a cell. In eukaryotic cells, the stages of the cell cycle are divided into two major phases: interphase and the mitotic phase.
1. During interphase, the cell grows and replicates its DNA.
2. During mitotic phase, the cell segregates its DNA into two sets and divides its cytoplasm to form two new cells.
Interphase:
G1 phase: During G1 phase (first gap phase), the cell grows physically larger, copies its organelles, and makes proteins, it will need later.
S phase. During S phase, the cell replicates its DNA in its nucleus. It also duplicates the centrosome. The centrosomes help segregate DNA during M phase.
G2 phase. During G2 phase (second gap phase), the cell grows more, makes proteins and organelles, and starts reorganizing its contents for mitosis.
M phase: During M phase (mitotic), the cell divides its DNA and cytoplasm to make two new cells. M phase involves two processes: mitosis and cytokinesis.
In mitosis, the nuclear DNA of the cell condenses into visible chromosomes which is pulled apart by the mitotic spindle. Mitosis has four stages: prophase, metaphase, anaphase, and telophase.
In cytokinesis, the cytoplasm of the cell splits in two new cells. Cytokinesis begins as mitosis is ending. Cytokinesis occurs differently in animal and plant cells.
In animals, cell division occurs when a band of cytoskeletal fibers, which is called as contractile ring contracts inward and pinches the cell in two. This process is called as contractile cytokinesis. The indentation which is produced as the ring contracts inward is called as the cleavage furrow. Animal cells can be pinched in two as they are relatively soft and squishy.
Plant cells are rigid and stiffer than animal cells. They are surrounded by a rigid cell wall and they have high internal pressure. Thus, plant cells divide in two by building a new structure down the middle of the cell. This is called as the cell plate, which is made up of plasma membrane and the cell wall components delivered in vesicles, thus it partitions the cell in two.
Cell cycle exit and G0
Some cells divide rapidly, and in these cases, the daughter cells immediately undergo another round of cell division. Ex: Many cell types in an early embryo and tumor divide rapidly.Other cells divide slowly. These cells exit the G1 phase and enter a resting state which is G0 phase. In G0, a cell does not prepare to divide.
12)A. Mitosis vs Meiosis
Mitosis
Meiosis
Number of divisions
One
Two
Number of cells generated
two
Four
Chromosome sets
2n to 2n
2n to 1n
Role
Vegetative growth
Sexual reproduction that produces spores to initiate gametophyte generation, or produce sex cells, called gametes in animals.
Place
Apical, root meristems and vascular cambium in plants
Microsporangia and megasporangia in plants
Cell division phase
Prophase I
Chromosomes duplicate to become chromatids and they do not pair
Chromosomes duplicate to become chromatids and chromosomes pair
Metaphase I
Paired chromatids (during pro metaphase) line up at equatorial plate
Paired chromatids (4) line up at equatorial plate
Anaphase I
Chromatids separate
Chromosomes pairs separate, where chromatids stay together
Telophase I
2 identical cells form
2 cells formed, each gets one set of chromosomes as paired chromatids
Prophase II
Does not occur
Paired chromatids start to be condensed
Metaphase II
Does not occur
Paired chromatids place themselves equatorial plate
Anaphase II
Does not occur
chromatids separate
Telophase II
Does not occur
Formation of 4 cells, each of them are haploid (1n)
1. A) 1.During day time, C3 plants open their stomata.
2. When C3 plants are in high light and temperature condition, the stomata close to prevent excessive water loss and continuous fixation of carbon in the Calvin cycle reduces the concentration of CO dramatically.
3. In regions where temperatures are cooler and sunlight is limited, the rates of photosynthesis are lower too. There, C3 plants have the advantage.
The C3 mechanisms works best in cool, wet environments.
4. Cereal grains, most trees, lawn grasses use C3 photosynthesis.
B. 1. During day time, C4 plants open their stomata.
2. The advantages of C4 plants are that, in hot conditions, the reduced photorespiration exceeds the ATP cost of moving CO2 from the mesophyll cell to the bundle-sheath cell.
3. Corn is an example of C4 plants.
C. 1. During night, CAM plants open their stomata.
2. The advantages of CAM photosynthesis is that they not only avoid photorespiration, but thet are very water-efficient too. Their stomata only open at night, when humidity is higher and temperature is cooler, both factors reduce water loss from leaves.
3. Cacti are the example of CAM plants.
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Mitosis
Meiosis
Number of divisions
One
Two
Number of cells generated
two
Four
Chromosome sets
2n to 2n
2n to 1n
Role
Vegetative growth
Sexual reproduction that produces spores to initiate gametophyte generation, or produce sex cells, called gametes in animals.
Place
Apical, root meristems and vascular cambium in plants
Microsporangia and megasporangia in plants
Cell division phase
Prophase I
Chromosomes duplicate to become chromatids and they do not pair
Chromosomes duplicate to become chromatids and chromosomes pair
Metaphase I
Paired chromatids (during pro metaphase) line up at equatorial plate
Paired chromatids (4) line up at equatorial plate
Anaphase I
Chromatids separate
Chromosomes pairs separate, where chromatids stay together
Telophase I
2 identical cells form
2 cells formed, each gets one set of chromosomes as paired chromatids
Prophase II
Does not occur
Paired chromatids start to be condensed
Metaphase II
Does not occur
Paired chromatids place themselves equatorial plate
Anaphase II
Does not occur
chromatids separate
Telophase II
Does not occur
Formation of 4 cells, each of them are haploid (1n)