Question
Why is reproduction considered non-essential for the survival of an individual organism?
Answer
Unlike essential life processes like nutrition or respiration, it is not required to keep an individual alive.
Question
What is the primary reason that human beings are able to notice and identify specific species?
Answer
The large number of individuals created through reproduction makes the species prominent.
Question
What is the fundamental requirement for two different individuals to be classified as belonging to the same species?
Answer
They must possess similar body designs, making them look like each other.
Question
What is the most basic event involved in the process of biological reproduction?
Answer
The creation of a $DNA$ copy.
Question
Which molecules in a cell nucleus act as the information source for inheriting features from parents?
Answer
$DNA$ ($Deoxyribo\ Nucleic\ Acid$) molecules within chromosomes.
Question
What is the primary cellular function of $DNA$ concerning protein synthesis?
Answer
It acts as the information source for making proteins.
Question
How does a change in the $DNA$ information source affect an organism's physical structure?
Answer
It causes different proteins to be made, which eventually leads to altered body designs.
Question
Why is $DNA$ copying accompanied by the creation of an additional cellular apparatus during reproduction?
Answer
A $DNA$ copy alone lacks the organised structure required to maintain life processes.
Question
What is the result of the inherent unreliability in biochemical $DNA$ copying reactions?
Answer
The generation of $DNA$ copies that are similar to but not identical to the original.
Question
What is the typical fate of a newborn cell if its inherited $DNA$ variation is too drastic for its cellular apparatus?
Answer
The cell will simply die.
Question
What fundamental biological process is supported by the inbuilt tendency for variation during reproduction?
Answer
Evolution.
Question
Define 'niches' in the context of an ecosystem.
Answer
Well-defined places or roles filled by populations of organisms through their ability to reproduce.
Question
Why is consistency in $DNA$ copying vital for a species' stability?
Answer
It maintains the body design features that allow the organism to inhabit its specific niche.
Question
How does variation help a population of bacteria survive if water temperatures rise due to global warming?
Answer
A few heat-resistant variants may survive and grow, preventing the population from being wiped out.
Question
What is the general term for reproductive modes where new generations are produced by a single individual?
Answer
Asexual reproduction.
Question
How do many bacteria and protozoa create new individuals during cell division?
Answer
They split into two equal halves through a process called fission.
Question
In which unicellular organism can the splitting of cells during fission occur in any plane?
Answer
$\textit{Amoeba}$.
Question
Which unicellular organism causing kala-azar undergoes binary fission in a definite orientation?
Answer
$\textit{Leishmania}$.
Question
Identify the mode of reproduction used by the malarial parasite, $\textit{Plasmodium}$.
Answer
Multiple fission.
Question
How does $\textit{Yeast}$ typically reproduce asexually?
Answer
By putting out small buds that separate and grow into new individuals.
Question
Identify the asexual reproductive method used by simple multicellular organisms like $\textit{Spirogyra}$.
Answer
Fragmentation.
Question
Why is simple cell-by-cell division impractical for most complex multicellular organisms?
Answer
Their specialised cells are organised into tissues and organs placed at definite positions.
Question
What is 'regeneration' in organisms like $\textit{Hydra}$ and $\textit{Planaria}$?
Answer
The ability of a body piece to grow into a complete, new individual.
Question
Which specific cell types enable the process of regeneration?
Answer
Specialised cells that proliferate and undergo changes to become various cell types and tissues.
Question
Why is regeneration not considered the same as reproduction?
Answer
Most organisms do not naturally depend on being cut up to be able to reproduce.
Question
What triggers the development of a bud in $\textit{Hydra}$ during the budding process?
Answer
Repeated cell division at one specific site.
Question
Which three plant parts are commonly used in vegetative propagation?
Answer
Roots, stems, and leaves.
Question
List two agricultural techniques that utilise vegetative propagation.
Answer
Layering and grafting.
Question
State one advantage of vegetative propagation regarding the production of flowers and fruits.
Answer
Plants raised this way can bear flowers and fruits earlier than those produced from seeds.
Question
How does vegetative propagation help plants like bananas or jasmine that have lost the ability to produce seeds?
Answer
It allows them to continue reproducing without the need for seed formation.
Question
Which plant produces buds along its leaf margins that can fall to the soil and grow into new plants?
Answer
$\textit{Bryophyllum}$.
Question
Define 'callus' in the context of plant tissue culture.
Answer
A small group of cells formed by the rapid division of separated tissue in an artificial medium.
Question
What is one major advantage of using tissue culture for growing ornamental plants?
Answer
Many plants can be grown from a single parent in disease-free conditions.
Question
Which structures in bread mould ($\textit{Rhizopus}$) are specifically involved in reproduction?
Answer
Sporangia (the 'blob-on-a-stick' structures).
Question
What is the function of the thick walls covering the spores in $\textit{Rhizopus}$?
Answer
They protect the spores until they land on a moist surface and can begin to grow.
Question
Why is the sexual mode of reproduction significant for a species' survival?
Answer
It allows for the generation of greater variation within a population.
Question
How does sexual reproduction speed up the creation of genetic variants?
Answer
It combines accumulated variations from two different individuals to create novel combinations.
Question
How do complex organisms solve the problem of $DNA$ doubling in sexual reproduction?
Answer
They use specialised germ-cells with only half the number of chromosomes and half the amount of $DNA$.
Question
Name the cell division process that results in the formation of germ-cells.
Answer
Meiosis.
Question
Contrast the size and motility of male and female gametes in complex organisms.
Answer
The male gamete is small and motile, whereas the female gamete is large and contains food stores.
Question
Where are the reproductive parts of angiosperms located?
Answer
In the flower.
Question
List the four main components of a typical flower.
Answer
Sepals, petals, stamens, and pistil.
Question
What defines a 'unisexual' flower, and provide one example.
Answer
It contains either stamens or pistil; examples include $papaya$ and $watermelon$.
Question
What defines a 'bisexual' flower, and provide one example.
Answer
It contains both stamens and pistil; examples include $\textit{Hibiscus}$ and $mustard$.
Question
Identify the male reproductive part of a flower and its product.
Answer
The stamen, which produces yellowish pollen grains.
Question
Identify the three structural parts of the pistil in a flower.
Answer
Stigma, style, and ovary.
Question
Where are the egg cells located within the pistil of a flower?
Answer
Inside the ovules within the ovary.
Question
Distinguish between 'self-pollination' and 'cross-pollination'.
Answer
Self-pollination occurs within the same flower, whereas cross-pollination occurs between different flowers.
Question
How does a male germ-cell reach the female germ-cell in the ovary after pollination?
Answer
It travels through a tube that grows out of the pollen grain and down the style.
Question
What does a zygote develop into within the ovule after fertilisation in plants?
Answer
An embryo.
Question
What do the ovule and ovary respectively become after successful fertilisation?
Answer
The ovule becomes a seed, and the ovary ripens to form a fruit.
Question
Define the process of 'germination' in seeds.
Answer
The development of a seed's embryo into a seedling under appropriate conditions.
Question
Define 'puberty' in human beings.
Answer
The period during adolescence when reproductive tissues begin to mature and secondary sexual features appear.
Question
Name one common skin change that affects both boys and girls during puberty.
Answer
The skin frequently becomes oily, often leading to the development of pimples.
Question
What are two distinct physical changes seen in girls at the onset of puberty?
Answer
Increase in breast size and the beginning of menstruation.
Question
What are two distinct physical changes seen in boys at the onset of puberty?
Answer
Growth of facial hair and the cracking of the voice.
Question
Why are human testes located in the scrotum outside the abdominal cavity?
Answer
Sperm formation requires a temperature lower than the normal body temperature.
Question
Identify the hormone secreted by the testes that regulates sperm formation.
Answer
$testosterone$.
Question
Which human structure serves as a common passage for both sperms and urine?
Answer
The urethra.
Question
What is the function of the fluid secreted by the prostate and seminal vesicles?
Answer
It makes sperm transport easier and provides nutrition to the sperms.