The Cell Cycle and Reproductive Theories Flashcards
What is the cell cycle?
The cell cycle is a process in which a cell creates a new cell and splits after making that cell in one cell membrane.
What are the phases of the cell cycle?
G1 and G2 - Gap phases where a cell that is replicating DNA goes through quality control to see if it is healthy to go through the cell cycle and that the copy of the DNA is also proper to create a new cell. The S phase (Synthesis) is when the DNA is copied. If the DNA turns out to be good, then the cell proceeds to mitosis. If the copy is damaged or unsuccessful, the copy is broken down in G zero phase and mitosis does not continue.
What is the group of stages before mitosis begins called?
Interphase is the name of the process. (G1, S, and G2 phases make up Interphase as a whole).
Why are the G phases important?
Without the G phases, the cells could become cancerous or serve an incorrect purpose if the DNA or its copy is damaged.
What is the differences between mitosis and meiosis?
Mitosis is used for creating somatic cells.
Meiosis is used to create sex cells, otherwise known as gametes.
Why is asexual reproduction advantageous?
It uses less resources, is relatively low in difficulty, and can repopulate an area very quickly.
When is asexual reproduction non-advantageous?
Due to genetics being the same as they are all clones from a single parent, disease will decimate an entire population as there is no genetic variation.
Why is sexual reproduction advantageous?
It creates diversity, and allows a large amount of variation in a population.
When is sexual reproduction non-advantageous?
When there is a shortage of resources. It take a ton of energy to reproduce this way. Organisms also take a much longer time to develop, so death of offspring can cause extinction. STDs and the spread of other disease is also common in sexual reproduction. Meiosis can also not complete correctly and cause offspring to have serious, sometimes fatal genetic flaws and diseases.
What is the Purifying Selection hypothesis and why is it important?
It states that asexual reproduction is selected against when genes are damaged, as all daughter clones will inherit that gene, sometimes making a population quickly die off. With sexual reproduction, this would only happen half of the time, so it is selected to be more advantageous, as some offspring will survive. This is why many organisms opt to be able to do both forms of reproduction.
What is the Changing Environment Hypothesis and how does it affect asexual reproduction and sexual reproduction?
If the environment is stable, asexual reproduction and sexual reproduction stay relatively at the same rate. If an environment suddenly changes, sexual selection is favored because there will be some individuals who will be able to adapt to the changes. This includes temperature, moisture, predation, parasites, competition, and food sources.
What is karyotyping and how does it relate to the problems associated with sexual reproduction?
It is comparing typically healthy chromosome sets to that chromosome sets that have genetic abnormalities or deficiencies. Such diseases include disjunction, trisomy, and monosomy.
