Biology Test - 54

The part of the stem between two nodes is called the internode.

A node is a point on the stem from which leaves or buds arise. Node and internode are two structural parts found in the stem. Nodes bear axillary buds, which can either develop into branches, flowers, or cones while an internode is responsible for the elongation of the stem.

In bryophytes, the sporophyte is parasitic (partially or wholly) on the gametophyte as it is organically attached and is nutritionally dependent upon the gametophyte.

In bryophytes, the main plant body is gametophytic which is independent and may be thallose (no differentiation in root, stem and leaves) e.g. Riccia, Marchantia, Anthoceros, etc. or foliose (having leafy axis) e.g. Sphagnum, Funaria, etc. The gametophyte bears the sex organs antheridium and archegonium. Sexual reproduction is of oogamous type. It forms a zygote that gives rise to the sporophytic phase. It is differentiated into foot, seta and capsule. The capsule produces spores after meiosis that again gives rise to the gametophytic phase. The sporophyte is partially or full dependent upon the gametophyte and is of shorter duration.

Biomolecules including peptides, hormones and antibodies can be analysed by ELISA test. Enzyme-linked immunosorbent assay (ELISA), also known as an enzyme immunoassay (EIA), is a biochemical technique used mainly in immunology for detecting and quantifying substances such as peptides, proteins, antibodies and hormones. They are termed as an analyte.

According to IUCN Red list, the status of Red panda (Ailurus fulgens) is endangered species. Endangered species are those species that are facing a very high risk of extinction in the wild in the near future. This category is used when the species suffered a population reduction of 80% or more.

Vulnerable species have sufficient population at present but are depleting fast. e.g., Golden langur, leopard cat. Extinct species no longer exist, e.g., Dodo. Critically endangered species are threatened to a greater extent.

During Aerobic Respiration, ATP synthesis occurs in mitochondria.

The breaking of the C-C bonds of complex compounds through oxidation within the cells, leading to the release of a considerable amount of energy is calledrespiration.The compounds that are oxidized during this process are known asrespiratory substrates.Along with theenergycarbon dioxideandmetabolic water is also released as a by-product in respiration.

$C_6{H}_{12}{O}_6+6O_2\to 6C{O}_2+6H_{2}O+Energy$

Respiration is of two types:

1. Aerobic Respiration:It occurs in the presence of oxygen. Here the food is completely oxidized into CO2. More ATPs are produced here(38 ATP). It occurs in themitochondria
2. Anaerobic respiration:It occurs in the absence of oxygen. Here the food is partially oxidized into alcohol & organic acids. It is generally observed in bacterias and human muscle cells. Only2 ATPsare produced in this process

Steps of Aerobic respiration:

1. Glycolysis- Occurs inCytosplasm/ Cytosol
2. Formation of Acetyl COA/ Link reaction- Occurs in themitochondrial matrix
3. TCA cycleorKrebs cycle- occurs in the matrixofmitochondria
4. Electron Transport System (ETS)- Occurs in cristae or inner mitochondrial membrane ofmitochondria

During the ETS ATP is synthesizedin the inner mitochondrial membrane by the action of the enzyme ''ATP synthase''

So, it is clear that ATP synthesis occurs in mitochondria.For this reason, only mitochondria are also called thepowerhouse of the cell.

Sea cucumberdoes not belong to the phylum Coelenterata.

Sea pens, sea feathers and sea fans all are Coelenterates. Sea cucumbers are echinoderms from the class Holothuroidea. They are marine animals with leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the seafloor worldwide.

Cyclosporin A, used as an immunosuppressive agent is obtained fromTrichoderma polysporum.

Cyclosporin A is one of the mostly used drugs that are easily produced from a biological organism such as fungi. Cyclosporin A is produced by fermentation of aerobic fungi called as Trichoderma polysporum.

A - offset of water hyacinth (Eichhornia)
B− Antheridiophore of Marchantia
C− Antipodals of the mature embryo sac
D− Oogonium of Chara

In humans, implantation occurs during the mid-secretory phase, between cycle days (CD) 20 and 24, or 6–10 days after ovulation (Blesa et al. 2014; Donaghay and Lessey 2007; Psychoyos 1973), which is a temporally framed period called the window of implantation (WOI). At this stage of prenatal development, the concept is called a blastocyst.

Factor 2clotting factor in a patient on Warfarin therapy, would have decreased gamma carboxyglutamate residue.

• Factor 2 deficiency is a very rare blood clotting disorder. It results in excessive or prolonged bleeding after an injury or surgery.
• Factor 2, also known as prothrombin, is a protein made in your liver. It plays an essential role in blood clot formation. It’s one of about 13 clotting factors involved in the proper formation of blood clots.
• Vitamin K is a cofactor for the enzymatic conversion of glutamic acid (Glu) residues to gamma-carboxyglutamic acid (GLA) in vitamin Kdependent proteins, via the endoplasmic reticulum resident vitamin K-dependent gamma-glutamyl carboxylase.
• This carboxylase activity is found in essentially all mammalian tissues, and its reaction product, Gla, has been observed in both vertebrates and invertebrates; both play an important biological role in protein function.
• Vitamin K–dependent clotting factor deficiency (VKCFD) is a rare autosomal recessive bleeding disorder that often presents with severe hemorrhage during infancy.
• A rare inherited form of defective γ-carboxylation resulting in the early onset of bleeding was first described by McMillan and Roberts in 1966 and subsequently has been termed vitamin K–dependent clotting factor deficiency (VKCFD).
• Combined deficiency of vitamin K–dependent clotting factors II, VII, IX, and X (and proteins C, S, and Z) is usually an acquired clinical problem, often resulting from liver disease, malabsorption, or warfarin overdose.
• Patients plasma showed less than 3% activity of factors II, VII, IX, and X.