Cell Division Flashcards

Question

Cytokinesis in Plant Cell

Answer 1

Vesicles that come from the Golgi move to the center of the cell, and fuse together to form a cell plate. The cell plate continues to develop until it joins with the cell's plasma membrane which completes the division of the cytoplasm, then both daughters secrete cellulose to form their new cell walls.

Answer 2

In animals, the zygote divides rapidly by mitosis and becomes and embryo. This continues until the animal reaches an adult size where growth and cell proliferation stops In plants, meristems, unspecialized cells found at the tip of a shoot and a root, are where cell proliferation occurs.

Answer 3

Kinetochores use spindle fibers to split the centromere of each sister chromatid, thus pulling them to opposite poles Each sister chromatid becomes a chromosome

Answer 4

Haploid: Contains one set of chromosomes and formed by meiosis Diploid: Contains two sets of chromosomes and formed by mitosis

Answer 5

A contractile protein ring forms around the equator of the cell and pulls the plasma membrane inwards. This inward pull is called the cleavage furrow, and when the cleavage furrow reaches the center of the cell it is pinched apart to form two daughter cells

Answer 6

Synapsis and crossing over occurs in Prophase I Synapsis and crossing over doesn't occur in Prophase II Homologous pairs of chromosomes line up in the equator Sister chromatids line up in the equator Homologous pairs of chromosomes separate and move to opposite poles of the cell Sister chromatids separate and move to opposite poles of the cell 2 haploid cells are formed 4 haploid cells are formed

Answer 7

Non-disjunction is when chromosomes fail to separate during gamete formation Can happen in Anaphase I or II In Anaphase I, the chromosomes pair fail to separate properly which results in the formation of 4 abnormal cells In Anaphase II, the sister chromatids fail to separate properly which results in the formation of 2 abnormal cells

Answer 8

Kinetochores and Microtubules Kinetochores are protein complexes that form on the centromere during cell division, and provide an attachment point for spindle fibers with the centromere region Microtubules are hollow cylinders that can rapidly assemble and disassemble at the centrosome Microtubules and Kinetochores work together by lengthening and shortening the microtubules to move chromosomes during cell division

Answer 9

Homologous chromosomes pairs are pulled to opposite poles thus halving the chromosome number Centromeres do not split

Answer 10

In Metaphase I, bivalents line up randomly and independently of each other on the equator Since they line up in any orientation on the equator, they segregate randomly The possible combination of gametes depends on the number of homologous pairs and is calculated using 2^n,where n is the haploid number of chromosomes

Answer 11

Proteins that control the progression of cells through the cycle, and act as checkpoints between two stages to ensure every task is performed Cyclins bind to enzymes named CDK's (cyclin dependent kinases) which phosphorylate specific proteins therefore making them become active and carry out tasks to continue the cell cycle. After the event occurred, the cyclin is degraded and the CDK is inactive

Answer 12

A rapid increases in the number of cells, and happens when cell division happens at a faster rate than cell death Used in multicellular organisms for growth, cell replacement and tissue repair

Answer 13

When cells are lost from the epidermis of the skin, more cells are produced to replace them Cell division happens in the basal later of the epidermis. The cells then get moved towards the skin surface by continued cell division. The continuous cell division allows for the production of a tough protein called keratin, which is hydrophobic and causes cells to dry out, and by the time the cells reach the skin surface they're flattened and dead.

Cell Division Flashcards

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