Cell Division Flashcards
What are 4 reasons cells divide?
growth, reproduction, renewal/replacement, to keep the surface area to volume ratio big
What happens if a cell gets too big?
The demands of the cell (materials and energy needed) cannot be met. The cell membrane cannot diffuse the amount of material that is needed by the bigger cell.
What are some characteristics of asexual reproduction?
only one parent, genetic info is the same from parent to offspring, no fertilization of egg and sperm
What are some characteristics of sexual reproduction?
two parents, fertilization of egg by sperm, genetic information of new cell is different than parent
What is meiosis?
the formation of sex cells (sperm and eggs- 23 chromosomes)
What is mitosis?
the formation of body cells (46 chromosomes)
What is chromatin?
DNA wrapped around proteins called histones, (DNA in an unwound state)
What is a chromosome?
Chromatin tightly wound up
When is DNA in the chromatin state?
During Interphase (preparation for division)
When is DNA in the chromosome state?
During Mitosis ( prophase, metaphase, anaphase, telophase)
How many chromosomes do humans have?
23 pairs or 46 total
Which sex chromosomes do you have if you are female?
XX
Which sex chromosomes do you have if you are male?
XY
What is a karyotype?
an organized picture of someones chromosomes
Why is DNA replication so important?
it ensures that the parent cell and new daughter cells have the same genetic information (same number of chromosomes)
What are sister chromatids?
identical copies of chromosomes attached by the centromere
When does the nuclear envelope break down?
prophase
When do the sister chromatids line up at the equator?
metaphase
When does the nucleolus disappear and spindles form?
prophase
When do 2 nuclei appear?
telophase
When do the sister chromatids get pulled apart and move to opposite sides of the cell?
anaphase
When does chromatin coil and condense to form chromosomes
prophase
When do chromosomes uncoil and turn back into chromatin?
telophase
When do spindles shorten?
anaphase
When do centrioles move to opposite poles?
prophase
In which stages do you have chromosomes instead of sister chromatids?
anaphase and telophase because the sister chromatids have separated and are thus not called sister chromatids anymore…but chromosomes
What is mitosis?
nuclear division
What is interphase?
preparation for division
What is cytokinesis?
cytoplasmic division
When does DNA replicate?
during the S phase of interphase
When does a cell grow and double its contents including Cytoplasm, proteins and organelles
G1 and G2
In which type of cell would you have a cleavage furrow?
animal cell
In which type of cell would you have a cell plate?
plant cell
Why would a cell plate form over a cleavage furrow?
Because the cell wall is rigid and hard. It is too difficult to pinch inward
What causes cancer?
mutations at the DNA level usually for the cyclins (proteins that control the cell cycle)
What is a tumor
mass of growing cells
Benign tumors are
not cancerous
Malignant tumors are
cancerous
Metastatic cancer is one in which
the cancer has spread from its original site
Slashing refers to
removing the cancer via surgery
