Biology Test - 47

Phloem in gymnosperms lacks both sieve tubes and companion cells.

Phloem in Gymnosperms lacks both sieve tube and companion cells. They only contain seive cells for conduction of food material and also have albuminous cells that have functions similar to that of companion cells.

According to Chargaff's rule, the amount of adenine is always equal to that of thymine and the amount of guanine is always equal to that of cytosine i.e. \(\mathrm{A}=\) \(\mathrm{T}\) and \(\mathrm{G}=\mathrm{C}\).

If dsDNA has \(20 \%\) of cytosine, then according to the law, it would have \(20 \%\) of guanine. The remaining \(60 \%\) represents both \(\mathrm{A}+\mathrm{T}\) molecule. Since adenine and guanine are always present in equal numbers, the percentage of adenine molecule is \(30 \%\).

The correct answer is a - 3, b - 2, c - 1.

Mons pubis: The mons pubis is the coarse hair-bearing prominent area of skin and fatty tissue overlaying the symphysis pubis and other pubic bones that is bounded superiorly by the pubic hairline and inferiorly by the clitoris.

Clitoris: It is a solid structure containing erectile tissues and is made up of two erectile bodies. 

Labia Majora: It is a set of two large thick folds of skin which forms the boundary of the vulva. The labia majora are a prominent pair of cutaneous skin folds that will form the lateral longitudinal borders of the vulval clefts.

In eubacteria, a cellular component which resembles a eukaryotic cell is calledPlasma membrane.

The cell wall of eubacteria is made up of peptidoglycan while in some eukaryotes like fungi, the cell wall is made of chitin and in plants it is cellulosic.

In eubacteria, the nucleus is not bounded by any membrane and is called nucleoid while in eukaryotes it is bounded by a double membrane envelope.

Eubacteria ribosomes are 70S type while eukaryotic ribosomes are 80S type.

'Cornea consists of dense matrix of collagen and is the most sensitive portion the eye' statement is correct.

Cornea consists of dense matrix of collagen, it is the transparent continuation of the sclera, that covers the iris and lens. It protects the eye ball from damage and prevents entry of micro-organisms into the eye.

The phenotype of the heterozygous pea plant with violet flowers is Vv (V for dominant violet allele and v for recessive white allele). The phenotype of the homozygous pea plant with white flowers is vv. This is a monohybrid cross.
When we create a Punnett square for this cross, we have :

The Punnett square shows us that in this cross, half of the progeny will be heterozygous (Vv) with violet flowers (dominant trait), and the other half will be homozygous recessive (vv) with white flowers. Therefore, out of 40 progeny, we expect 20to have violet flowers and 20 to have white flowers.

The prophase of mitosis cannot progress iconclude about this drug.

Lamins are intermediate filaments found inside the nucleus. Lamins attach to nuclear proteins and form a layer underneath the nuclear envelope (nuclear membrane) called the nuclear lamina. The nuclear lamina functions to position nuclear pores to let molecules pass between the cytoplasm and the nucleoplasm. It also functions to break and resynthesize the nuclear envelope during mitosis. Recall that the nuclear envelope is broken down during the prophase of mitosis; therefore, lack of lamins will directly affect this phase of mitosis.

Wastewater treatment generates a large quantity of sludge, which can be treated by anaerobic digesters.

Wastewater treatment generates a large quantity of activated sludge during secondary treatment which is used as an inoculum and a small part of it is pumped back to the large aeration tanks whereas the remaining part of that sludge is treated by anaerobic sludge digesters anaerobically.During this digestion, bacteria produces a mixture of gases called biogas.

In plants showing Kranz anatomy, the bundle sheaths surrounding the vascular bundles have characteristics such as thick walls, a large number of chloroplasts and no intercellular spaces. They are layered around the vascular bundles.

In gel electrophoresis, separated DNA fragments can be visualized with the help ofEthidium bromide in UV radiation.

Agarose gel electrophoresis is used to segregate DNA fragments according to the mass and size. Ethidium bromide is the fluorescent stain used in this technique. Ethidium bromide, when exposed to ultraviolet light, produces a fluorescent effect. Thus, the DNA tagged by it can be traced quickly on the transparent gel.