4:1 cell Division Flashcards
(23 cards)
What are the phases of the cell cycle?
G1, S, G2, M phase
S: synthesis of DNA
M: mitosis and cytokinesis
G1+S+G2: interphase
What happens in interphase?
G1 phase: cell growth
S Phase: each chromosome is replicated to form a pair of sister chromatids. (DNA replication)
G2: protein synthesis for chromosome sorting and cell division. Some cell growth
What happens in mitosis/ meiosis (after interphase1/2)
Nuclear division
What happens in cytokinesis? (After interphase and m phase)
Division of cytoplasm
What is the semi conservative DNA model?
replication produces DNA molecules with 1 parent strand and 1 newly made daughter strand.
11>12+12>12+11 + 12+11
What is the conservative mechanism DNA model?
Produces 1 double helix with both parental strands and 2 new daughter strands
11> 11+ 22 > 11+22 + 11+11
Dispersive mechanism DNA model
Produces DNA strands in segments of new DNA mixed with parental DNA
(I can’t model this but it’s like instead of one strand new and one old it’s like old and new mixed for BOTH strands in helix)
What are sister chromatids
Two sides of a chromosome that has the same genes and placement
What are non sister chromatids
Non identical sides of a chromosome
What is a pair of homologous chromosomes
- Same size
- Same centromere location
- Same banding pattern
What replication mechanisms do humans have?
Semi conservative
Process of DNA double helix condensing into chromosome?
- Wrapping of DNA around Justine proteins
- Formation of 3D dimensional zigzag structure via DNA-binding proteins
- Further compaction of radial loops to form heterochromatin
- Metaphase chromosome with 2 copies of DNA formed.
How to identify cell stages in picture?
Interphase: chromosome replication? Prophase: dotty stuff Metaphase: stringy stuff Anaphase: stringy stuff on two sides Telophase; two separate sides
The four stages of mitosis?
Interphase Prophase Metaphase Anaphase Telophase
What happens in cytokinesis
In animals:
Formation of cleavage furrow
In plants
Cell plate is formed as vesicles from golgi move along microtubules to separate cells
Cell wall between daughter cells formed
Significance of mitotic cell cycle?
- enables growth in multicellular organisms (increase in cells= increase in mass)
- replace old/ worn out cells/ damaged tissue repair (genetically identical)
- allows unicellular organisms to asexually reproduce. (Genetically identical)
What happens in interphase?
Chromosomes have already replicated. Cell preparing for division
What happens in prophase?
Sister chromatids condense
Mitotic spindle forms
Nuclear envelope dissociates completely
Sister chromatids attach to spindle via kinetochore proteins
What happens on metaphase
Sister chromatids align along the metaphase plate
What happens in anaphase
Sister chromatids separate, and individual chromosomes move towards poles as kinetochore microtubules shorten.
What happens in telophase (and cytokinesis)
Chromosomes FR condense and nuclear envelope reforms
Cleavage furrow forms (in animal cells)
What is a Karyotype?
It is a photographic representation of a group of chromosomes
What are gametes
Sperm and egg cells
