17: Cell Division Flashcards
What is diploid (Number)?
Diploid is a number of chromosomes found in body cells. Diploid cells contain both chromosomes of each homologous pair.
What is haploid (number)?
Haploid is a number of chromosomes found in gametes. Haploid cells contain one chromosome from each homologous pair
What is mitosis?
Mitosis is a type of cell division that produces two genetically identical diploid cells for growth and repair of tissues
What is meiosis?
meiosis is a Type of cell division that produces haploid cells (gametes)
What does clone mean?
Clone is a group of cells, or organisms, that are genetically identical
What is another name used for Meiosis?
Meiosis is sometimes called a reduction division. This is because it produces cells with only half the number of chromosomes of the original cell.
What are the two things the dividing cell must do to ensure that the daughter cells are genetically identical to the parent cell?
-Before a cell divides, it must copy each chromosome. This means the DNA replicates, and more proteins are added. This ensures each daughter cell receives a complete set of chromosomes and DNA during division.
-The cell must divide so that each daughter cell gets one copy of every chromosome. If this doesn’t happen, the daughter cells won’t have all the genes.
During meiosis the parent cell must do two things:
-It must copy each chromosome so that there is enough genetic material to be shared between the four daughter cells
-It must divide twice, in such a way that each daughter cell receives just one chromosome from each homologous pair.
There are two main events during meiosis:
-during the first division, one chromosome from each homologous pair goes into each daughter cell
-during the second division, the chromosome separates into two parts. One part goes into each daughter cell.
What is the low estimate of the different types of human gametes?
The low estimate of the different types of human gametes is 8.5 million different types of sperm and 8.5 million different types of ova. The number of possible combinations of chromosomes (and genes) in the zygote is 8.5 million x 8.5 million = 7.2 x 10¹³, or 72 trillion!
What is another name used for identical twins?
Another name used for identical twins is monozygotic twins
What’s the difference between identical twins and non-identical twins?
When the zygote of identical twins divides by mitosis, the two identical cells separate and act like individual zygotes. Each develops into an embryo. Since they come from the same zygote and identical cells, the embryos (and later, the children) will be genetically identical.
Non-identical twins develop from different zygotes and so are not genetically identical.
What are some environmental factors that can influence the height of the plants?
-They may not all receive the same amount of light and so some will not photosynthesise as well as others
-They may not all receive the same amount of water and mineral ions from the soil - this could affect the manufacture of a range of substances in the plant.
-They may not all receive the same amount of carbon dioxide. Again, some plants will not photosynthesise as well as others.
