Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

21.

The main organelle involved in modification and routing of newly synthesized proteins to their destinations is

  • mitochondria

  • endoplasmic reticulum

  • lysosome

  • chloroplast


B.

endoplasmic reticulum

Endoplasmic Reticulum (ER) was coined by Porter. It is a network of tubules, vesicles and cisternae within an eukaryotic cell. Two types of ER are recognised on the basis of presence or absence of ribosomes on the wall of ER:

(i) Smooth ER- It helps in the synthesis of lipid and glycogen. Wall does not contain ribosomes.

(ii) Rough ER- It helps in protein synthesis and transfer. Wall contains ribosomes.

Protein synthesis takes place in ribosomes attached on wall of ER. Newly formed protein enters within the cavity of rough ER and follows following path:

Protein Cavity of rough ER Cavity of smooth ER Golgi membrane Lysosomes or transport vesicles or secretory granules.


22.

Photosynthesis in C4 plants is relatively less limited by atmospheric CO2 levels because

  • four carbon acids are the primary initial CO2 fixation products

  • the primary fixation of CO2 is mediated via PEP carboxylase

  • effective pumping of CO2 into bundle sheath cells

  • RUBISCO in CO4 plants has higher affinity for CO2


B.

the primary fixation of CO2 is mediated via PEP carboxylase

The fixation of CO2 in C4 plants takes place in two places and by two different organic
compounds. Phosphoenol pyruvate (PEP) is found in mesophyll cells which primarily fixes atmospheric CO2 into oxaloaceticacid (4C).
RUBISCO is present in bundlesheath cells where final fixation of CO2 in hexose sugars takes place. CO2 is primarily fixed by PEP carboxylase because this enzyme has greater affinity to CO2 than RUBISCO.


23.

A person is undergoing prolonged fasting. His urine will be found to contain abnormal quantities of

  • fats

  • ketones

  • amino acids

  • glucose


B.

ketones

If a person is undergoing prolonged fasting, his urine will be found to contain abnormal quantities of ketones. During fasting, energy is obtained by the oxidation of reserved fats. As a result of fatty acid oxidation large amount of ketone bodies are produced such as acetoacetate, β-hydroxybutyrate and acetone.


24.

Top-shaped multiciliate male gametes and the mature seed which bears only one embryo with two cotyledons, are characteristic features of

  • polypetalous angiosperms

  • gamopetalous angiosperms

  • conifers

  • cycads


D.

cycads

Cycads is a group of gymnosperms, which have top shaped multiciliated male gametes (largest male gamete) and each mature seed of these plants contain one embryo and two cotyledons (dicotyledonous) eg, Cycas.


25.

At what stage of the cell cycle are histone proteins synthesized in a eukaryotic cell?

  • During entire prophase

  • During telophase

  • During S-phase

  • During G2 stage of prophase


C.

During S-phase

Histone proteins are basic proteins used for the packaging of eukaryotic DNA. Both DNA and histones together comprise of chromatin, forming bulk of eukaryotic chromosomes. There are 5 major kinds of histones- H1, H2A, H2B, H3 and H4

H1 histone is used for linking neighbouring chromosomes while others are used as elements of nucleosomes structure. During S- phase of cell cycle, synthesis of histone proteins takes place as the chromosome number gets doubled to that of somatic number.


26.

Match items in Column- I with those in Column- II

Column- I Column- II
A. Peritrichous flagellation 1. Ginkgo
B. Living fossil 2. Macrocystes
C. Rhizophore 3. Escherichia coli
D. Smallest flowering plant 4. Selaginella
E. Largest perennial alga 5.Wolffia

Select the correct answer from the following

  • A B C D E

    2 1 3 4 5

  • A B C D E

    5 3 2 5 1

  • A B C D E

    1 2 5 3 2

  • A B C D E

    3 1 4 5 2


D.

A B C D E

3 1 4 5 2

 

Column I Column II
Peritrichous flagella (flagella all over the body) Escherichia coli (a bacterium)
Living fossil Ginkgo biloba (maidan hair tree)
Rhizophore (a form of aerial adventitious roots) Selaginella (a pteridophyte)
Smallest flowering plant Wolffia
Largest perennial algae Macrocystes


27.

In which one pair both the plants can be vegetatively propagated by leaf pieces?

  • Bryophyllum and Kalanchoe

  • Chrysanthemum and Agave

  • Agave and Kalanchoe

  • Asparagus and Bryophyllum


A.

Bryophyllum and Kalanchoe

Marginal notches in Kalanchoe and Bryophyllum possess adventitious buds in their leaves for vegetative propagation.


28.

Which one of the following depresses brain activity and produces feelings of calmness, relaxation and drowsiness?

  • Valium

  • Morphine

  • Hashish

  • Amphetamines


A.

Valium

Valium deficiency brain activity and produces feeling of calmness, relaxation and drowsiness.


29.

Chlorophyll in chloroplasts is located in

  • grana

  • pyrenoid

  • stroma

  • both (a) and (c)


A.

grana

Chloroplast, which is a cytoplasmic cell organelle found only in eukaryotic plant cells. It helps in the production of food through, photosynthesis.

Chlorophyll is a specialized light absorbing pigment which is found in the inner wall of granum. Each granum is a flat, sac like structure in which light reaction of photosynthesis takes place.


30.

There exists a close association between the alga and the fungus within a lichen. The fungus

  • fixes the atmospheric nitrogen for the alga

  • provides protection, anchorage and absorption for the alga

  • provides food for the alga

  • releases oxygen for the alga


B.

provides protection, anchorage and absorption for the alga

Lichen is a symbiotic association between a fungus and an algae (green alga or blue green alga). The algal partner of lichen is called as phycobiont while fungal partner is termed as mycobiont. It develops into a unique morphological form which is quite distinct from either partner.

The fungal partner of lichen helps in the absorption of water and mineral to algal partner additionally it also provides protection and anchorage to algal partner of lichen. In exchange of this, the fungal partner absorbs prepared food material from algal partner. This food material is prepared by the algal partner of lichen through the process of photosynthesis.