PRACTICE QUESTIONS AND COMPREHENSIVE
SOLUTION SET
◉ Cloning (plants) advantages. Answer: All plants have the same
advantageous features as the original plant, value is consistent,
ripen at the same time, quality is consistent, genetic modification is
easily replicated.
◉ Cloning (plants) disadvantages. Answer: All are equally
susceptible to the same diseases, all susceptible to the same pests,
can strip the soil of nutrients, genetic diversity of the species is
reduced.
◉ Cloning (animals) advantages. Answer: Animals with the best
traits can be replicated, the general quality of heards can be more
rapidly improved, genetically modified animals can be replicated so
no specialised genes are lost.
◉ Cloning (animals) disadvantages. Answer: Genetic diversity
decrease, cloned animals will all be equally susceptible to the same
disease/parasites, hybrids vigour may be lost.
,◉ Reproductive technologies. Answer: Range from those that
manipulate fertilisation like artificial insemination, IVF, artificial
pollination to those that split up embryonic stem cells and involve
embryo implantation like embryo splitting and cloning.
◉ Cell cycle. Answer: G1 phase, S phase (synthesis), G2 phase
(collectively known as interphase) and M phase (mitosis and
cytokinesis).
◉ Mitosis. Answer: It is the cell division that produces two daughter
cells that are genetically identical to parent cells (same number of
chromosomes). It has five stages: prophase, metaphase, anaphase,
telophase and interphase.
Ensures that every single cell contains the same genetic information
which is necessary for the growth, repair and protein production.
◉ Interphase (mitosis). Answer: The cells are not dividing.
Chromosomes are duplicating but not visibly.
◉ Prophase (mitosis). Answer: Each chromosome is visible as two
identical, joined strands called chromatids. The nucleus membrane
breaks down and disappears by the late stage.
, ◉ Metaphase (mitosis). Answer: Tapered system of microtubules
stretches across the cell, forming a spindle. It then lines up at the
centre of the cell and attached to spindle fibres known as the
centromere. The chromatids separate.
◉ Anaphase (mitosis). Answer: The single-stranded chromosomes
(chromatids) move towards opposite poles carried on the spindle
fibers.
◉ Telophase (mitosis). Answer: The spindle disappears. New
nuclear membranes form around two sets of chromosomes.
◉ Meiosis. Answer: Cell division that produces four daughter cells
that are genetically different to parent cells and can only occurs in
sex organs with sex cells (gametes).
Stages of meiosis include: prophase I, metaphase I, anaphase I,
telophase I, prophase II, metaphase II, anaphase II and cytokinesis.
It ensures genetic variation within a species is maintained; this is
central to a species surviving changes to the environment.
◉ Interphase (meiosis). Answer: Cell growth where chromosomes
are replicating to form identical sister chromatids joined at the
centrosome.