BIO 101 | Study Mode

Join Discuss Share to WhatsApp
Question 111
A
mitochondria
B
flagella
C
spindle fibres
D
centrioles.
Explanation
Microtubule is a microscopic tubular structure, with an external diameter of 24 nm and of variable length, found in a wide range of eukaryotic cells Microtubules are composed of numerous subunits of the globular protein tubulin and occur singly or in pairs, triplets, or bundles. Microtubules help cells to maintain their shape. <br /> They also occur in cilia and eukaryotic flagella and the centrioles and form the spindle during nuclear division. A further role is in the intracellular transport of materials and movement of organelles.

Correct option: A
Join Discuss Share to WhatsApp
Question 112
A
Ca
B
Zn
C
K
D
Cu.
Explanation
Middle lamella is the first formed layer, present between the two adjacent cells. It is situated outside the primary cell wall. It is made up of calcium and magnesium pectate.

Correct option: A
Join Discuss Share to WhatsApp
Question 113
A
upper layer is non-polar and hydrophilic
B
upper layer is polar and hydrophobic
C
phospholipids form a bimolecular layer in middle part
D
proteins form a middle layer.
Explanation
In early 1972, S. Jonathan Singer and Garth Nicolson proposed fluid mosaic model for the membrane structure. As per the model, the cell membrane consists of a highly viscous, fluid matrix of 2 layers of phopholipid molecules, having globular proteins associated with them. <br /> The lipids and proteins vary from one type of membrane to another. The cell membrane also has oligosaccharides on the exposed surface. A good amount of cholesterol is also present in the cell membrane of animal cells. <br /> The phospholipids molecules are amphipathic, i.e., have both hydrophilic and hydrophobic regions. They have their polar, hydrophilic heads directed outward and nonpolar, hydrophobic tails pointing inward.

Correct option: C
Join Discuss Share to WhatsApp
Question 114
A
nucleolus
B
cytoplasm
C
mitochondria
D
golgi body.
Explanation
Nucleolus synthesizes and stores RNA. The ribosomal proteins are synthesized in the cytoplasm and shift to the nucleolus for the formation of ribosomal subunits by complexing with rRNA.

Correct option: A
Join Discuss Share to WhatsApp
Question 115
A
only gymnosperm cells
B
all plant cells
C
all eukaryotic cells
D
only bacterial cells
Explanation
Totipotency is the ability of a living somatic plant cell to develop into a complete plant. It was first demonstrated by Steward et. al (,1964) using phloem cells of carrot. This technique is now used for multiplying rare and endangered plants through micro-propagations. This technique is widely used for multiplying plants e.g. Chrysanthemum, Dioscoreafloribunda, Coleus, Crotons, carnation plants etc.

Correct option: B
Join Discuss Share to WhatsApp
Question 116
A
outer membrane
B
inner membrane
C
thylakoids
D
stroma.
Explanation
A chloroplast is a vesicle bounded by an envelope of two unit membranes and filled with a fluid matrix called stroma. The lamellae, after separation from the inner membrane, usually take the form of closed, flattened, ovoid sacs, the thylakoids, which lie closely packed in piles, the grana. <br /> The thylakoid membrane contains photosynthetic pigments namely, chlorophyll a, chlorophyll b, carotenoids (carotene, xanthophylls) and plastoquinone. The thylakoid membranes also contain coupling factors that bring about ATP synthesis.

Correct option: C
Join Discuss Share to WhatsApp
Question 117
A
thymine rich repeats
B
cytosine rich repeats
C
adenine rich repeats
D
guanine rich repeats.
Explanation
Telomeres are highly conserved element throughout the eukaryotes both in structure and function. Telomeric DNA has been shown to consist of simple randomly repeated sequences, characterised by clusters of G residues in one strand and C residues in other strand. A short sequence of (12-16 nucleotides in length) of G rich strand as overhang is another feature of telomere.

Correct option: D
Join Discuss Share to WhatsApp
Question 118
A
chloroplast
B
mitochondria
C
lysosome
D
endoplasmic reticulum.
Explanation
The proteins formed on ribosomes pass into the ER lumen where they are modified. Then the modified proteins move on into the transitional area, where the ER buds off membranous sacs, the transport vesicles, carrying the proteins to the Golgi apparatus. <br /> Here, they are further processed and packaged into secretory vesicles for export by exocytosis at the plasma membrane. Chloroplasts are specialized to perform photosynthesis. Mitochondrion is the power house of the cell. Lysosomes contain hydrolytic enzymes.

Correct option: D
Join Discuss Share to WhatsApp
Question 119
A
membrane potential
B
accumulation of Na ions
C
accumulation of K ions
D
proton gradient.
Explanation
Chemiosmotic coupling hypothesis is the most widely accepted explanation for oxidative phosphorylation in mitochondria and photophos- phorylation in thylakoid membranes. Mitchell proposed the idea of chemiosmotic coupling. <br /> He suggested that a concentration gradient of protons is established across the mitochondrial membrane because there is an accumulation of hydrogen ions on one side of the mitochondrial membrane. The proton accumulation is necessary for energy transfer to the endergonic ADP phosphorylation process.

Correct option: D
Join Discuss Share to WhatsApp
Question 120
A
movement of chromosomes towards poles
B
cytoplasmic cleavage
C
crossing over
D
transcription.
Explanation
Centromere is the point at which the two chromatids of a chromosome are held together. During movement of chromosomes, the spindle fibres (on which the chromatids move) are attached to the centromere. Crossing over involves physical exchange of genetic material between non-sister chromatids of homologous chromosomes. <br /> Cytoplasmic cleavage is the division of cytoplasm. Transcription is the process in which the genetic information of DNA is transferred to mRNA as the first step in protein synthesis.

Correct option: A

Try this quiz in in E-test/CBT Mode
switch to BIO 101 in CBT Mode

Previous Page Next Page