Answer:
<h2>
Interphase : divided into three phases, i) G1 phase, ii) S phase and iii) G2 phase.</h2><h2>Mitotic phase: i) prophase, ii) metaphase, iii) anaphase and v) telophase.</h2>
Explanation:
interphase : divided into three phases, i) G1 phase, ii) S phase and iii) G2 phase.
G1 phase: cell decide whether to divide or not and prepare itself for replication of DNA and arrange replication machinery. otherwise it goes to G 0 phase.
S phase: DNA replication occurs in this phase.
G2 phase: cell duplicates all their contents and prepares for mitotic phase.
Mitotic phase:
i) prophase- chromosome condensation occurs,
ii) metaphase - chromosome arranges in meta-plate and spindle binds to each chromosomes at centromere.
iii) anaphase- chromosome separates from sister chromatids.
iv) telophase- chromosome moves to each ends and formation of nuclear membrane begins.
cytokinesis: there is division of cytoplasm and forming two daughter cells.
Similar to the other types of muscle, smooth muscle contraction is caused by the sliding of myosin and actin filaments over each other. Calcium initiates contractions in a different way in a smooth muscle than in a skeletal muscle.
Smooth muscles use less energy to generate the given amount of force, can substain contractile force without fatigue & uses calcium from the sarcoplasic reticulum & extracellular space.
Answer:
Explanation:
A boundary that distinguishes inside from outside the cell yet allows materials to enter or leave the cell.
The cell needs a barrier for protection, rigidity and also for easy transportation.
Answer:
Tetraploid
Explanation:
Ploidy:
Ploidy is a biological term used for the presence of number of chromosome sets in a cell. Cells can be haploid (gametes), diploid (two chromosomal sets) and polyploid (more than two chromosomal sets).
Polyploidy:
A condition that entails the possession of more than two sets of chromosomes in the cell. Normal cells are diploid (2n) i.e they contain two sets of chromosomes, one from each parents. Polyploid individuals contain three (triploid, 3n), four (tetraploid, 4n), five (pentaploid, 5n) number of chromosomes and so on.
Under normal disjunction of chromosomes, a tetraploid cell will produce two diploid daughter cells each with two sets of chromosomes.
However, in the case of non-disjunction of all chromosomes in a tetraploid individual, two tetraploid daughter cells will be produced at the end of meiosis 1.
Non-disjunction of all chromosomes means that one daughter cell has received all 4 sets of chromosomes while the other is null i.e. contains zero chromosomal sets.
