Biology Test - 16

Osteoblasts are found in bones. Osteocytes and osteoclasts are the other two types of cells that are present in the blood. Blood, cartilage and muscles do not have osteoblasts.

Merocrine are the glands referred to as when secretary granules leave cells by exocytosis with no loss of other cellular material.

Merocrine (or eccrine) is a term used to classify exocrine glands and their secretions in the study of histology. A cell is classified as merocrine if the secretions of that cell are excreted via exocytosis from secretory cells into an epithelial-walled duct or ducts and then onto a bodily surface or into the lumen.

Here, phenotypic ratio- 3 purple : 5 white

Turgor pressure is the pressure, that develops inside the cell due to the entry of water. It opposes further entry of water. The cellular contents exert turgor pressure on the cell wall and this pressure is responsible for the turgidity of a plant cell.

Azolla pinnate is a small free-floating freshwater fern which is widely used as a biofertilizer in Indian rice fields.

Four long and two short stamens are found in brassicaceae.

Brassicaceae species are characterized by four-petalled cross-shaped flowers that feature two long and two short stamens and produce podlike fruits known as siliques. Brassicaceae is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family.

Archaebacteria is the oldest living organisms on earth. They are prokaryotes and unicellular. The cell membrane contained branched-chain lipids, decrease membrane fluidity. They are mostly obligate anaerobes.

Their cell wall is made up of complex polysaccharides and the complex polypeptide that differ from other bacteria having a different cell wall.

This composition of the cell wall is responsible for survival in extreme conditions .This is thought to be because the early Earth’s atmosphere was filled with poisonous gases and was very hot – nothing could survive, except the archaebacteria.

There are three phyla, or groups, of archaebacteria: Methanogens, Halophiles and Thermoacidophiles.

Alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place.

It is a hollow cup-shaped cavity where the gaseous exchange takes place.In other words, Alveoli facilitates gaseous exchange of oxygen and carbon dioxide between inhaled air and the bloodstream.A typical pair of human lungs contain approximately 480 million alveoli.

A human protein which is obtained from transgenic animals and is used to treat emphysema is \(\alpha-1\)-antitrypsin. Transgenic animals, particularly goats and sheep, have been genetically engineered to produce human \(\alpha-1\)-antitrypsin in their milk. This recombinant protein can then be extracted from the milk and used as a therapeutic treatment for individuals with A1AT deficiency, helping to alleviate symptoms and slow the progression of emphysema.

An egg apparatus contains: An egg + Two synergids

An egg apparatus is a group of three cells in the seven celled embryo sac of an angiosperm(seed plants). It comprises an egg cell and two associated cells called synergids. The Egg apparatus is located at the end of the embryo sac closer to the micropyle.