A&P - Chapter 7 (Part 2) Flashcards
What phase is a cell in when it is not actively dividing?
Interphase
What are the stages of cell growth? (3)
- G1
- S
- G2
What process is it when a cell is actively dividing?
Mitosis
How many chromosomes do humans have?
46
- 23 pairs
What process does every cell go through?
Mitosis
What process is not necessary for every cell?
Meiosis
What does a cell need to do before it divides?
Make a copy of its DNA so that is can be equally shared among the daughter cells
DNA replication
Is a process by which each half of a DNA molecule becomes a whole molecule identical to the original DNA molecule
How does DNA replication work? (2)
- DNA unwinds and separates its base pairs
2. Those base pairs attract its complementary bases until the strand is whole again
What are 2 forms of cell reproduction?
- Mitosis
2. Meiosis
What are the 4 stages of mitosis?
- Prophase
- Metaphase
- Anaphase
- Telophase
What happens in prophase? (5)
- Chromatin granules become organized to form chromosomes
- Chromosomes form a pair link strand
- chromatid - Centrioles move away from each other to opposite ends of the parent cell
- Spindle fibres form between the centrioles
- The nuclear envelope disappears, freeing genetic material
Chromatids
One copy of a newly copied chromosome which is still joined to the original copy by a single centromere. Its main function is to keep the proper DNA count where it needs to be
Centrioles
Are tube like organelles that help organize microtubules in dividing/replication
What happens in metaphase? (4)
- The nuclear envelope and nucleolus have disappeared
- Chromatids align across the centre of each cell
- Centrioles have moved to opposite ends
- Spindle fibres attach themselves to the centromeres
What happens in anaphase? (5)
- Centromeres break apart
- Chromatids are separated
- chromosomes - Chromosomes are pulled to opposite ends of the cell
- Cleavage furrow develops at the end of anaphase
- Begins to divide cells into 2 daughter cells
- cytokinesis
What are separated chromatids called?
Chromosomes
Cytokinesis
Cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells
What happens in telophase? (5)
- Cell division is completed
- Nuclei appear in each daughter cells
- Nuclear envelope and nucleoli appear
- Cytoplasm and organelles divide equally
- Daughter cells grow and become fully functional
Meiosis
Is the process by which the diploid number of chromosomes in the immature cells is reduced to the haploid number of chromosomes found in mature sex cells
What are mature sex cells called?
Gametes
What are 2 examples of gametes?
- Sperm
2. Ovum
What will lead to a zygote?
Fertilization of an ovum and sperm
Zygote
A diploid cell resulting from the fusion of two haploid gametes
- fertilized ovum
How many chromosomes will a zygote have?
23 from each parent
What happens in both mitosis and meiosis?
DNA replication
How many times does mitosis divide?
Once
How many times does meiosis divide?
Twice
Does mitosis have synapsis?
No
Does meiosis have synapsis?
Yes
What is the number of daughter cells in mitosis?
2
What is the number of daughter cells in meiosis?
4
What is the chromosome number in mitosis?
2n
What is the chromosome number in meiosis?
4n
What does mitosis produce?
Somatic cells
What does meiosis produce?
Sex cells
- gametes
