CBSE 11TH BIOLOGY - Online Test
Q1. Which among the following is called Portuguese man-of-war?
Answer : Option B
Explaination / Solution:
The Portuguese man-of-war is a siphonophore, an animal that is made up of a colony of organisms working together.Physalia is called Portuguese man-of-war. It is also called as blue bottle or floating terrror it is found floating on water surface. " The name comes from the uppermost polyp, a gas filled bladder, or pneumatophore, which sits above the water and somewhat looks like an old warship at full sail. They are also, known as bluebottles for the purple-blue color of their pneumatophores" (A Portuguese man of war). The tentacles can extend to 165 feet, although, the average length is 30 feet (Portuguese Man-of War Physalia physalis).
Q2. 98% of living body is formed of six elements- C, H,N,O and
Answer : Option C
Explaination / Solution:
Everything in universe is made up of elements. The body of living organisms contain mainly six elements. These are carbon, hydrogen, oxygen phosphorous and Sulphur. In facts, 98% of living body is formed on these six elements.
Q3. Each cardiac cycle takes 0.8 seconds to occur. Calculate how many cardiac cycles occur in 4 minutes ?
Answer : Option C
Explaination / Solution:
4 min = 240 sec. Therefore, 240/0.8 = 300 cardiac cycles.
Q4. In electron transport system, the two copper centres are found in
Answer : Option C
Explaination / Solution:
The enzyme cytochrome c oxidase or Complex IV,is a large transmembrane protein complex found in bacteria and the mitochondrion of eukaryotes.
The complex contains two hemes, a cytochrome a and cytochrome a3, and two copper centers, the CuA and CuB centers. The cytochrome a3 and CuB form a binuclear center that is the site of oxygen reduction.
Q5. Cup-like structure formed by adnation of sepals, petals and stamens is
Answer : Option D
Explaination / Solution:
In angiosperms a hypanthium is a structure where basal portions of the calayx, the corolla and the stamens form a cup-shaped tube.
Q6. During zygotene stage chromosomes start pairing together and the process is called as
Answer : Option B
Explaination / Solution:
During zygotene stage, the homologous chromosomes start pairing together and this process of association is called synapsis. The paired homologous chromosomes are called bivalents.
Q7. Vasopressin is a hormone involved in regulation of urine formation. It is secreted from :
Answer : Option B
Explaination / Solution:
An excessive loss of fluid from the body can activate receptors which stimulate the hypothalamus to release antidiuretic hormone (ADH) or vasopressin from the neurohypophysis.
Q8. In leaves, the ground tissue consists of thin-walled chloroplast containing cells are called
Answer : Option C
Explaination / Solution:
The tissues of a leaf that are located in between the layers of epidermis and carry on photosynthesis, consisting of the palisade layer and the spongy parenchyma. Most mesophyll cells contain chloroplasts.
Q9. The number of categories in hierarchical classification is
Answer : Option B
Explaination / Solution:
Taxonomical studies of all known organisms have led to the development of common categories such as kingdom, phylum (for animals) or division (for plants), class, order, family, genus and species. Hence, the correct option is 7.
Q10. Which one prevents premature fall of fruit?
Answer : Option A
Explaination / Solution:
They help to prevent fruit and leaf drop at early stages but promote the abscission of older mature leaves and fruits.
