Biology Test - 13

Recombinant DNA technology has enabled the production of insulin through genetically engineered bacteria or yeast. Insulin produced in this way is identical to human insulin and is used as a therapeutic agent to manage diabetes by regulating blood sugar levels.

Chara is a monoecious plant, as both male and female reproductive structures are in the same organisms.

In flowering plants, both male and female flowers occur in the same individuals. These plants are called monoecious plants.

Unisexual flowers are incomplete flowers, containing either male or female reproductive organs in the flower. That means, androecium, which is the male reproductive structure and gynoecium, which is the female reproductive structure, are found in separate flowers.

Heterothallic and dioecious is the term used to describe the unisexual condition.

In dioecious plants, either male or female flowers may occur.

Sexual flowers are complete flowers, containing both androecium and gynoecium in one flower. Therefore, bisexual flowers contain both stamens and pistils in the same flower. So, bisexual flowers are called hermaphrodite or androgynous flowers as well.

A single chromosome containsonly one DNA (deoxyribonucleic acid) moleculeandso many genes. Humans have23 pairs of chromosomes.

• 22 pairs of autosomes chromosomesandone pair of sex chromosomes, X and Y.

Theinformation in DNA (double helix structure) is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T).

• DNA has two base pairs,A-TandG-C, attached to asugar-phosphate backbone.

In thecell nucleus, theDNA molecule is packaged into thread-like structures called chromosomes.

• A chromosome (microscopic structure) is made up ofDNAtightly coiled many times aroundproteins called histones that support its structure.
• A chromosome hastwo arms - p arm (short arm) and q arm (long arm), joined in the location of thecentromere.

This is an example of Mutualism. Mutualism is a type of symbiotic relationship in which both organisms involved benefit. In this case, the plant benefits by having its pollen dispersed by the animal, thus facilitating pollination, and the animal benefits by obtaining food in the form of pollen and nectar.

Klinefelter or XXY syndrome is a medical syndrome that can lead to gynecomastia or enlarged male breasts.

(gynecomastia is an enlargement of the male breast gland because of a hormonal imbalance)

Klinefelter syndrome is a genetic disorder wherein a human male is born with an extra X chromosome in the cells (due to nondisjunction of X chromosomes, and the egg carrying XX getting fertilised by a Y carrying sperm), resulting in a total of 47 chromosomes - XXY. The additional X chromosome leads to severe hormonal imbalance. The patient would have lesser amount of testosterone in the body and higher production of estrogen, resulting in sterility and poor development of male secondary sexual characters.

The genotype of plant 7 is RrTt of plant 12 is rrTt, as they are crossed they produce 2 plants out of 8 with the genotype rrtt, rrTT i.e. 25%.

Coagulation of blood in blood vessels is prevented by heparin. It is secreted by the basophil cells. Heparin is the most powerful anticoagulant. It activates the Antithrombin III present in the blood plasma. The antithrombin binds and deactivates the serum clotting factors, this prevents the clotting of blood.

According to Tamil Literature

• Maruta Makkal-Ploughmenliving in villages and inhabiting fertile tracts.
• Kuravan Makkal-Hill peoplewho told people their fortunes.
• Mullai Makkal-Pastoralist, Shepherds.
• Neytal Makkal- Fishing people living in coastal villages calledpattinam.
• Palai Makkal- People of thedry plains.

Bacillus thuringiensis a gram-positive bacteria which are generally used as a pesticide. It works on many plants eating insects. It gives out toxins during sporulation that stops the gut of insects and kills them. Naturally, occurring Bacillus thuringiensis is contained within the bacterium. Bt has a very short half-life when they are exposed to sunlight and the elements.

Cells of nucellus are always Diploid.

The nucellus encloses the embryo sac and this acts as the nutritive tissue to the nucleus and the embryo sac. This nucellus is also helpful in providing the nutrients for the growth of the embryo. Hence the nucellus of the ovule is diploid in nature.