Biology: Topic-wise Test- 2 - NEET MCQ

The symbols % and ⊕ are used to represent zygomorphic (bilaterally symmetrical) and actinomorphic (radially symmetrical) flowers, respectively.

Actinomorphic flower - star shaped or radial- that can be divided in to two identical parts by a plane passing through the center. and is represented by a plus sign contained within a circle.

Example, Hibiscus,Rosa etc

Zygomorphic flower: can be divided into identical halves only through a single plane, bilateral symmetry.

represent in floral formula as %

Gynoecium with fused carpels is known as syncarpous. The term is used for the flower with reference to the fused carpels or pistils in the gynoecium of that flower.

Vital capacity is the maximum volume of air a person can breathe in after a forced expiration or the maximum volume of air a person can breathe out after a forced inspiration.This equals the inspiratory reserve volume (IRV) + expiratory reserve volume (ERV) + tidal volume (TV). Its value is 3400 mL - 4800 mL.

Correct option is A.
A-V node functions as a secondary pacemaker because when the wave of contraction originating from the sinoatrial node reaches the atrioventricular node (AV node – pace setter), the latter is stimulated and excitatory impulses are rapidly transmitted from it to all parts of the ventricles to contract simultaneously. The ventricles force blood through long system of arteries and hence must exert great pressure on the blood.

During ventricular systole, the contraction of ventricular muscles causes the closure of bicuspid and tricuspid valves (AV valves), producing a low pitched 'lubb' sound. At the end of ventricular systole, semilunar valves close, producing the second heart sound, the 'dup'. Pulsation of the radial artery is due to rhythmic contraction and relaxation in the aorta. Initiation of the heart beat occurs in the SA node.

During micturition, parasympathetic stimulation causes the detrusor muscle to contract and the internal urethral sphincter to relax. The external urethral sphincter (sphincter urethrae) is under somatic control and is consciously relaxed during micturition. 

Detailed Solution:

Option A is right because, during micturition, parasympathetic stimulation causes the detrusor muscle to contract and the internal urethral sphincter to relax.

Option B is wrong because the muscles of the urinary bladder contract and do not relax. 

Option C is wrong because during micturition, the muscles don't show fatigue. 

Hence, the correctb option is A. 

In our body, the neural and the endocrine system jointly coordinate and integrate all the activities of the organs so that they function in a synchronised fashion.

The pituitary gland is a tiny organ, the size of a pea, found at the base of the brain. As the “master gland” of the body, it produces many hormones that travel throughout the body, directing certain processes or stimulating other glands to produce other hormones.

In anaphase, the centromeres of chromosomes start to divide into two, forming daughter chromosomes with centromere in each. Daughter chromosomes are repulsive, so they migrate towards opposite poles. Spindle fibres attached to the centromeres shorten and pull the chromosomes to the poles.

The SA node possesses a unique property of self-excitation, which enables it to act as the pacemaker of heart. It spontaneously generates a wave of contraction which spreads over both the auricles more or less simultaneously along the muscle fibres that fan out from the pacemaker. The pacemaker establishes the basic rhythm at which the heart beats. Thus, if the pacemaker becomes nonfunction, then the cardiac muscles do not undergo co-ordinated rhythmic movements.

Inspiration is an active process while expiration is a passive process.

• The narrow tubes found inside the lungs are called bronchioles. 
• When we breathe, air travels from the nose or mouth, and goes down the trachea and reaches the part called the carina.
• From here the tube branches into two, creating two bronchi that lead to the left and right lung each.
• From there onwards, the bronchi split into smaller and smaller bronchioles until it terminates in the alveoli where gas exchange occurs.

Hence, the correct option is C.

NCERT Reference: Topic- Human Respiratory System” of chapter "Breathing and Exchange of Gases" of NCERT.

Superior vena cava and inferior vena cava are the large veins. Superior vena cava brings deoxygenated blood from upper part of the body while inferior vena cava brings blood from lower part of the body into the right atrium of the heart.

When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentaion is said to be axile, as in china rose, tomato and lemon. In these plants, the ovules are attached to a central column in the ovary, allowing for the development of multiple chambers within the ovary, each containing ovules.

Renal corpuscle, also called malpighian body, filtration unit of vertebrate nephrons, functional units of the kidney.
It consists of a knot of capillaries (glomerulus) surrounded by a double-walled capsule (Bowman’s capsule) that opens into a tubule.

Due to contraction of the ventricles (ventricular systole), the pressure inside the ventricles rises, that force open the semilunar valves of aorta and pulmonary artery so that the blood enters into these vessels. Oxygenated blood is pumped into the aorta from the left ventricle while deoxygenated blood is pumped into the pulmonary artery from the right ventricle.

(a) When circulating in the bloodstream and inactivated, neutrophils are spherical.
Once activated, they change shape and become more amorphous or amoeba-like and can extend pseudopods as they hunt for antigens.

(b) Eosinophil cells are 12 - 17 µm in diameter - larger than neutrophils, and about 3 times the size of a red blood cell. You can see that eosinophils only have two lobes to their nucleus.

(c) In blood, basophils are round, but the shape changes as they migrate into tissues. They generally have a multilobed nucleus and no evidence of nucleoli.
Basophils also have an abundance of condensed chromatin around the periphery of the nucleus.

(d) Monocytes are the largest type of white blood cells and can be up to 20µm in diameter.
They have a large eccentrically placed nucleus, which is kidney bean-shaped. They have abundant cytoplasm and some fine pink/purple granules in the cytoplasm.

(e) Lymphocytes can look like monocytes, except that lymphocytes do not have a kidney-bean shaped nucleus, and lymphocytes are usually smaller.
They have a small spherical nucleus and have abundant dark staining condensed chromatin. Not much cytoplasm can be seen, and it is basophilic (pale blue/purple staining).

Root hairs in plants have a large surface area and are surrounded by water, soil and nutrients and due to large surface area root hairs absorb water for the growth of plants.

Hence, the correct option is A.
NCERT Reference: Topic “Regions of the Root” of chapter Morphology of Flowering Plants.

• Platelets, also called thrombocytes, are cell fragments produced from megakaryocytes.
• Platelets can release a variety of substances most of which are involved in the coagulation or clotting of blood.

The process of release of urine is called micturition and the neural mechanism causing it is called the micturition reflex.

I. Infants and toddlers can not control this reflex action, thus micturition is an involuntary action for them.

II. Adults and grown-up children can control the reflex process of micturition voluntarily to some extent.

Hence, both statements are correct.

Grass is the correct option because veins on the lamina run parallel to one another is called parallel venation. It is characteristically found in monocot plants and grass is a characteristic of monocot plant.

Hence, the correct option is B.
NCERT Reference:  Topic “Venation” of chapter Morphology of Flowering Plants. 

Thomas Addison was the first person who showed the relation between the secretion of the adrenal gland and Addison’s disease named after him.

• The arteries carry blood from the heart to all over body parts. Hence, statement (i) is correct.
• The vessels which carry blood from the heart to the lungs is the pulmonary artery but it carries deoxygenated blood. Hence, statement (ii) is correct.

The pelvic girdle is made up of three fused bones that are ischium, ilium, and pubis. The pubis forms the anterior part of the pelvic girdle. It is a flattened, irregular- shaped bone that articulates with the pubic symphysis, a cartilaginous joint.
The acetabulum is a concave surface of the pelvis, the head of the femur meets the pelvis at the acetabulum to form the hip joint. 

• The Blade, or lamina, is the broad, flat part of the leaf. Photosynthesis occurs in the blade, which has many green food-making cells.
• The leaf is attached to the stem by the leaf base and may bear two lateral small leaf-like structures called stipules.
• The petiole help hold the blade to light. Long thin flexible petioles allow leaf blades to flutter in wind, thereby cooling the leaf and bringing fresh air to leaf surface. 

Hence, the correct option is C.
NCERT Reference: Topic “THE LEAF” of chapter Morphology of Flowering Plants.

• In hypogynous flower, gynoecium occupies the highest position.
• Superior ovary is present in hypogynous flower.
• In epigynous flower, gynoecium is the bottom most whorl. China rose is an example of hypogynous flower.

• The pleural membranes are two layers of the serous membrane which enclose and protect the lung.
• The superficial layer is called the parietal pleura and lines the wall of the thoracic cavity.
• The deep layer is called the visceral pleura and covers the lungs themselves.

Hence, the correct option is B.

NCERT Reference: Topic- Human Respiratory System of "Breathing and Exchange of Gases" of NCERT 

• Globulins are not present in the Glomerular filtrate.
• Glomerular filtrate is the fluid that is filtered from the blood in the glomeruli of the kidneys. 
• It contains water, electrolytes (inorganic salts), glucose, amino acids, urea, and creatinine. 
• However, globulins, which are a type of protein, are not typically found in the glomerular filtrate because they are too large to pass through the filtration barrier.

Inspiratory reserve volume (IRV) + tidal volume (TV) + expiratory reserve volume (ERV) represents vital capacity (VC). Now, inspiratory capacity is the total volume of ai that can be inhaled after a normal expiration. It includes tidal volume and inspiratory reserve volume i.e., IC = TV + IRV. Thus, option (a) is correct which says that vital capacity i.e., IRV + TV + ERV = IC + ERV.

During an injury, the blood platelets release thromboplastin which converts plasma protein prothrombin into thrombin in the presence of calcium ions. Thrombin then converts soluble plasma protein fibrinogen into fibrin which forms a meshwork by trapping red blood cells, thus forming a clot.