Lesson 13: Mitosis-Cell Cycle Flashcards
What are chromosomes?
ONE very long DNA molecule that is made of chromatin
What is chromatin?
Complex of DNA and proteins that make up eukaryotic chromosomes
What is the difference between prokaryotes and eukaryotes in cell division?
Prokaryotes:
One chromosome, arranged in a circle, can also have smaller circles of DNA (plasmids) that carry certain genes
Eukaryotes:
Multiple chromosomes, linear in structure, each eukaryotic species has a characteristic number of chromosomes
How many chromosomes do humans have?
46 chromosomes (1 set of 23 from mom and 1 set of 23 from dad)
What are diploid chromosomes?
2 sets of chromosomes
What are haploid chromosomes?
1 set of chromosomes
What is the difference between haploid and diploid chromosomes?
Haploid (n):
1 copy of each chromosome, gametes (sperm and egg), in humans: egg cell= 23 chromosomes and sperm cell= 23 chromosomes
Diploid (2n):
2 copies of each chromosome (1 from mom and 1 from dad), somatic cells (body cells), in humans: body cells have 46 chromosomes (23 pairs)
Where does mitosis occur?
In somatic (body) cells
What does mitosis make?
Identical diploid cells
What does a cell need to do before it divides into two identical cells?
It must copy ALL of its DNA
What happens when a cell duplicates?
Each chromosome becomes a duplicated chromosome (X shaped) and half of each X (chromatid) will go to each new cell
What are chromosomes made of structurally?
Two sister chromatid joined at a centromere
What happens later in mitosis to help pull the chromatids apart?
A protein complex connects at the centromere forming the kinetochore
What happens in the interphase stage of the cell cycle?
Cell has prepared to divide, made (G1) where enough organelles for 2 cells are made and the protein needed for division is made, DNA is copied and centrioles have been duplicated (S), checkpoints have been cleared (G1, S, G2)
What happens in prophase of mitosis?
Nuclear membrane begins to disappear (so that chromosomes can move), chromosomes condense, and centrosomes form and begin moving apart
What kind of centrosomes are in animal and plant cells?
Centrioles: animal cells
Spindle fibers: made of microtubules
What happens in the prometaphase of mitosis?
Nucleus disappears, spindle fibers extend and attach to the kinetochore, and chromosomes begin to move/line up
What happens in the metaphase phase of mitosis?
Chromosomes align in the middle of the cell at the metaphase plate, single
What happens in anaphase?
Sister chromatids separate and move to opposite poles
What happens in telophase/cytokinesis during mitosis?
Daughter cells begin to form nuclear membranes, nucleolus returns, chromosomes unravel and become chromatin again, this happens at the same time/sequentially as cytokinesis (division of the cytoplasm)
What happens in animal cells during cytokinesis in mitosis?
As new nuclei form around each set of chromatin, a cleavage furrow forms between them (looks like a butt cheek), cells pull apart making 2 new cells
What happens to plant cells during cytokinesis in mitosis?
Plant cells can not undergo traditional cytokinesis because of the cell wall, golgi sends vesicles to form a growing cell plate, eventually the cell plate completely divides the two new cells creating a new cell wall
