Biology Test - 9

The sperms of Cycas are the largest in the plant kingdom reaching a size of 300 µm . Egg of Cycas and its nucleus are also the largest in the plant kingdom.

Hence option C is the correct answer.

In Biology, "Karyon" refers to the nucleus of the cell. So karyokinesis is the division of the nucleus during cell division.

Hence option C is the correct answer.

Seeds having fleshy testa are the edible parts in pomegranate. In case of induced parthenocarpy, the seeds will not be produced thereby making fruit seedless. Therefore they become useless and lose their economic importance.

So, the correct answer is 'pomegranate'

Linnaeus evolved a system of nomenclature called the binomial system of nomenclature. In this system, the organism is named with two words, the first word provides the name of the genus and the second word provides the name of the species the organism belongs to.

Hence option C is the correct answer.

A = Kinetochore - It is a complex of proteins associated with the centromere of a chromosome during cell division, to which the microtubules of the spindle attach.

B = Spindle - Spindle fibres are protein structures that form early in mitosis or cell division. They consist of microtubules that originate from the centrioles, two wheel-shaped bodies located in the centromere area of the cell.

C = Chromosomes - Thread-like structure of nucleic acids and protein found in the nucleus of most living cells. These carry genetic information in the form of genes.

The bonding of sugar residue to another organic compound is known as glycosylation. Glycoprotein are formed in the lumen of granular or rough endoplasmic reticulum(RER), but may subsequently be modified in the lumen of the Golgi apparatus while other amino acids of the protein may become glycosylated.

Hence option C is the correct answer.

The underside of echinoderms' body bears a mouth at the center and a groove running along each arm. The grooves contain rows of tiny, flexible appendages called tube feet. Starfish move by means of the tube feet, which are operated by a hydraulic or water-vascular system unique to echinoderms. Sea water, circulates through the radiating canals of this system, enters and extends the tube feet. Each tube foot can be withdrawn by its attached muscles. The tube feet are equipped with suction cups, and the animal moves in any direction by gripping with some of its tube feet and pulling itself forward. A starfish that is turned upside down can right itself by turning an arm under and walking with the tube feet.

Hence option D is the correct answer.

Based on key changes and the given image, this stage of Mitosis is Metaphase.

[Metaphase is a stage of mitosis in the eukaryotic cell cycle in which chromosomes are at their second-most condensed and coiled stage. These chromosomes, carrying genetic information, align in the equator of the cell before being separated into each of the two daughter cells.]

Stomata are minute specialised pores on the epidermal layers of leaves. Closing and opening mechanism of stomata depends on some factors like photosynthetic production, turgidity of guard cell , sugar-starch interconversion, active K+ transport. According to the photosynthetic production theory,stomata close when CO₂ concentration is maximum and O₂ concentration is less.

Hence option D is the correct answer.

Cell division is the process by which a parent cell divides into two or more daughter cells.

Generation time is 1 minute means after every min. The cell is going to be double of its initial value.

In 20 mins culture tube ->1/8 filled

Means after 1 min it will be doubled so in 21-minute culture tube will be 1/8 *2 = 1/4 quarterly filled

Again after 1 min. It will be 1/4 *2=1/2 half filled

Again after 1 min, it will be1/2*2 = 1 (fully filled)

means in 23 minutes vessel will be completely filled.

So, the correct answer is '23 minutes'.

Spindle fibres are made up of microtubules. These fibres form a protein structure that divides the genetic material in a cell. The spindle is necessary to equally divide the chromosomes in a parental cell into two daughter cells during both types of nuclear divisions - mitosis and meiosis.

Hence option D is the correct answer.

Phellem is outermost layer of cork cambium, which is suberised. Hence, this is the first layer to be found. Endodermis is one the layer of cortex, which is to be found under the phellem. Pericycle is the layer present between endodermis and vascular bundles.

Dicotyledonous stem possess conjoint, collateral vascular bundle, where xylem is internal and phloem is external. Therefore, phloem is to be encountered after the pericycle.

Hence option C is the correct answer.

During cytokinesis in animal cells, a ring of actin filaments forms at the metaphase plate. The ring contracts, forming a cleavage furrow, which divides the cell in two. In plant cells, Golgi vesicles coalesce at the former metaphase plate, forming a phragmoplast.

Hence option C is the correct answer.

Essential micro elements are Fe, Mn, Zn, B, Cu, Mo and essential macronutrionts are C, H, N, P, S, Ca, K, Mg.

Hence option C is the correct answer.

Tendons are modified cords of white fibrous connective tissues which connect the skeletal muscles with the bone.

Hence option C is the correct answer.