Answer:
Option (a) and (d).
Explanation:
The breaks in DNA molecule may occur due to replication error and oxidizing agent. The double-stranded breaks in DNA can be corrected by Homologous end joining and non homologous end joining.
Homologous end joining is used to repair the DNA present in G2 nad S phases of the cell cycle. The homologous sequences of DNA is used to repair the DNA. Non homologous end joining occurs in the cell present at G0 and G1 phase of the cell cycle. The DNA broken ends are juxtaposed and later rejoin together by DNA ligase.
Thus, the correct answer is option (a) and (d).
Answer:
A mutation is the changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes. Mutations in sex cells are more serious because they are heritable and affect the next generation.
Explanation:
The male
human has a sperm cell and the female has an egg cell. The cells from the male
and female that combine to form a zygote are called gametes. The human sperm
and egg cells each contain 23 chromosomes. . A combination of gametes forms a
zygote with 46 chromosomes. The type of cell division that produces gametes
with half the normal chromosome number is the meiosis. Meiosis is the type of
cell division used in sexual reproduction. It will occur in the testes and
ovaries.<span>Chromosomes get
shuffled when eggs and sperm are made. Though most adult cells contain two sets
of chromosomes, sperm and egg cells are different. These special cells have
just one chromosome from each pair. Which chromosome they get from each pair is
random, making each sperm or egg cell unique. There is also a bit of mixing
before the chromosomes are sorted into individual sperm or egg cells.
Chromosomes from each pair in a mother or father, respectively, make contact
and exchange pieces of DNA, creating hybrid chromosomes. </span>
Answer:
propose is the correct answer
