NEET : Biology (Zoology)- 2019 – Exam Mode

Solution.

Genes for flower colour in snapdragon shows incomplete dominance which is an exception of Mendel’s first principle i.e. Law of dominance.
Whereas Law of segregation is universally applicable.

Solution.

In birds female heterogamety is found thus sex of progeny depends on the types of egg rather than the type of sperm.

Solution.

The correct sequence of phases of cell cycle is G1 -> S > G2 > M

Solution.

Thiobacillus denitrificans cause denitrification
i.e., conversion of oxides of nitrogen to free

Solution.

Polyblend is a fine powder of recycled modified plastic waste. The mixture is mixed with bitumen that is used to lay roads

Solution.

In Pteridophyte, megaspore is retained for some times in female gametophyte, however the permanent retention is required for seed formation in Gymnosperms.
That’s why Pteridophytes exhibit precursor to seed habit only.

Solution.

• Vertebrosternal ribs are true ribs, dorsally they are attached to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage. First seven pairs of ribs are called true ribs.
• 8th, 9th and 10th pairs of ribs do not articulate directly with the sternum but join the seventh ribs with the help of hyaline cartilage. These are vertebrochondral or false ribs.
• Last 2 pairs (11 & 12) of ribs are not connected ventrally and are therefore, called floating ribs.
• Only first seven pairs of ribs are ventrally connected to the sternum.

Solution .

Concanavalin A is a secondary metabolite e.g is lectin, it has the property to agglutinates RBCs.

Solution

Extrusion of second polar body from egg nucleus occurs after entry of sperm but before fertilization.
The entry of sperm into the ovum induces completion of the meiotic division of the secondary oocyte.
Entry of sperm causes breakdown of metaphase promoting factor (MPF) and turns on anaphase promoting complex (APC).

Solution.

Fungus associated with roots of Pinus increases minerals & water absorption for the plant by increasing surface area and in turn fungus gets food from plant. Therefore, mycorrhizal association is obligatory for Pinus seed germination

Solution.

Earth Summit (Rio Summit)-1992, called upon all nations to take appropriate measures for conservation of biodiversity and sustainable utilisation of its benefits

Solution.

During the isolation of desired gene, chilled ethanol is used for the precipitation of DNA.

Solution.

Bulliform cells become flaccid due to water loss. This will make the leaves to curl inward to minimise water loss

Solution.

Crypts of Lieberkuhn are present in small intestine. Glisson’s capsule is present in liver. Islets of langerhans constitutes the endocrine portion of pancreas. Brunner’s glands are found in submucosa of duodenum.

Solution.

-> Insulin deficiency leads to diabetes mellitus
-> Hypersecretion or hyposecretion of thyroxine can be associated with enlargement of thyroid gland called goitre
-> Deficiency of corticoids (Glucocorticoid + mineralocorticoid) leads to Addison’s disease
-> Growth hormone hypersecretion in adults leads to Acromegaly

Solution.

-> In lactational amenorrhoea, due to high prolactin level, gonadotropin level decreases.
-> Oral pills are either progestogens or progestogen-estrogen combinations used by the females.
-> Emergency contraceptives includes the administration of progestogens or progestogen-estrogen combination or IUDs within 72 hour of coitus.
So, lactational amenorrhoea, oral pills and emergency contraceptives involve a role of hormone.

Solution.

Heroin, commonly called smack and is chemically diacetylmorphine which is synthesized by acetylation of morphine.

Solution.

The given data shows stabilising selection as most of the newborn having average weight between 3 to 3.3 kg survive and babies with less and more weight have low survival rate.

Solution.

Hexokinase catalyse the conversion of Glucose to Glucose-6 phosphate. It is the first step of activation phase of glycolysis.

Solution.

Cornea consists of dense matrix of collagen and corneal epithelium. It is the most sensitive part of eye.

Solution.

In an aquatic ecosystem, the pyramid of biomass is generally inverted.
TC = Large fishes SC = Small fishes PC = Zooplanktons PP = Phytoplanktons

Solution.

Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group. A complete catalytic active enzyme with its bound prosthetic group is called holoenzyme.

Solution.

Asthma is a difficulty in breathing causing wheezing due to inflammation of bronchi and bronchioles. It can be due to increasing air born allergens and pollutants. Asthma is an allergic condition. Many people in urban areas are suffering from this respiratory disorder.

Solution.

Following are the post-fertilisation changes.
• Ovule -> Seed
• Ovary -> Fruit
• Zygote -> Embryo
• Central cell -> Endosperm

Phloem in Gymnosperms lacks both sieve tube and companion cells.

Plant hormone auxin induces flowering in pineapple. Ethylene also helps in synchronization of flowering and fruit set up in pineapple.

Persistent Nucellus is called Perisperm
e.g.: Black pepper, Beet

Cells in G0 phase are said to exit cell cycle. These are at quiescent stage and do not proliferate unless called upon to do so.

Saprophytes – Decomposition of dead organic materials
Parasites – Grow on/in living plants and animals
Lichens – Symbiotic association of algae and fungi
Mycorrhiza – Symbiotic association of fungi with plant roots

Solution

Cardiac output = stroke volume × Heart rate
=> Cardiac output = 5L or 5000 ml
=> Blood volume in ventricles at the end of diastole = 100 ml
=> Blood volume in ventricles at the end of systole = 50 ml
Stroke volume = 100 – 50
= 50 ml.
So,
5000 ml = 50 ml × Heart rate
So, Heart rate = 100 beats per minute.

Bacillus thuringiensis forms protein crystals during a particular phase of their growth. These crystals contain a toxic insecticidal protein. These protein exist as inactive protoxins but once an insect ingest the inactive toxin, it is converted into an active form of toxin due to alkaline pH of the gut which solubilize the crystals. The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and eventually cause death of insect.

Bronchioles and Fallopian tubes are lined with ciliated epithelium to move particles or mucus in a specific direction.

Growth rings are formed by the seasonal activity of cambium. In plants of temperate regions, cambium is more active in spring and less active in autumn seasons. In temperate regions climatic conditions are not uniform throughout the year. However in tropics climatic conditions are uniform throughout the year.

In flowering plants, out of the two male gametes discharged in synergids, one fuses with the egg and other fuses with the secondary or definitive nucleus present in central cell.
Egg (n) + 1st male gamete (n)-> Zygote (2n)
Secondary nucleus +  2nd male gamete (n) -> PEN (3n)

[ Secondary nucleus  – (2n) – (central cell nuclei)]

The correct sequence of organs in the alimentary canal of cockroach starting from mouth is :
Pharynx -> Oesophagus -> Crop -> Gizzard -> Ileum -> Colon -> Rectum

The correct match of hominids and their brain sizes are :

Homo habilis — 650-800 cc
Homo neanderthalensis — 1400 cc
Homo erectus — 900 cc
Homo sapiens — 1350 cc

Salmonella typhi is the causative agent. Confirmatory test = Widal test, it’s based on antigen antibody reaction.

Steroid hormones directly enter into the cell and bind with intracellular receptors in nucleus to form hormone receptor complex. Hormone receptor complex interacts with the genome

Tidal Volume = 500 ml
Expiratory Reserve Volume = 1000 ml Expiratory Capacity = TV + ERV
= 500 + 1000
= 1500 ml

• Statin is obtained from a yeast (Fungi) called Monascus purpureus
• It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.

In mitochondria, enzymes for electron transport are present in the inner membrane.

In ECG P-wave represents depolarisation of atria. QRS complex represents depolarisation of ventricles. T-wave represents repolarisation of ventricle i.e. return from excited to normal state. Reduction in the size of T-wave i.e. if the T-wave represents insufficient supply of oxygen i.e. coronary ischaemia.

Fungs Trichoderma, Baculoviruses (NPV) and Bacillus thuringiensis are used as
iocontrol agents. Rhizobium, Nostoc, Azospirillum and Oscillatoria are used as biofertilisers, whereas TMV is a pathogen and aphids are pests that harm crop plants.

According to rules of binomial nomenclature, correctly written scientific name of mango is Mangifera indica Linn.