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4

The fluidity of membranes in a plant in cold weather may be maintained by

A. increasing the number of phospholipids with unsaturated hydrocarbon tails.

B. increasing the proportion of integral proteins.

C. increasing concentration of cholesterol in membrane.

D. increasing the number of phospholipids with saturated hydrocarbon tail.

Correct Answer :

A. increasing the number of phospholipids with unsaturated hydrocarbon tails.


The concept of membrane fluidity refer to the fact that both lipids and proteins may have considerable freedom of lateral movements within the bilayer. The fluidity of membranes in a plant in cold weather may be maintained by increasing the number of phospholipids with unsaturated hydrocarbon tails.

Related Questions

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4

The fluidity of membranes in a plant in cold weather may be maintained by

A. increasing the number of phospholipids with unsaturated hydrocarbon tails.

B. increasing the proportion of integral proteins.

C. increasing concentration of cholesterol in membrane.

D. increasing the number of phospholipids with saturated hydrocarbon tail.

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4

Which one of the following pairs is not correctly matched?

A. Cristae The tubular structure formed by the folding of the inner membrane of the mitochondrion.

B. Plasmodesmata The membrane surrounding the vacuole in plants.

C. Grana Membrane bound discs in chloroplasts that contain chlorophylls and carotenoids.

D. Middle lamella Layer between adjacent cells walls in plants derived from cell plate.

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4

Which one of the following organelle given below is correctly matched with its function ?

A. Golgi apparatus Protein synthesis

B. Golgi apparatus Formation of glycolipids

C. Rough endoplasmic reticulum Protein synthesis

D. Rough endoplasmic reticulum Formation of glycoproteins

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4

Which of the following is not the function of cell wall?
  1. Provides shape to the cell.
  2. Protects the cell from mechanical damage and infection.
  3. Helps in cell to cell interaction.
  4. Provides barrier to undesirable macromolecules.

A. Only (i)

B. Only (iv)

C. Only (ii), (iii) and (iv)

D. None of the above

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4

Protein synthesis in an animal cell occurs

A. on ribosomes present in cytoplasm as well as in mitochondria.

B. on ribosomes present in the nucleolus as well as in cytoplasm.

C. only on ribosomes attached to the nuclears envelope and endoplasmic reticulum.

D. only on the ribosomes present in cytosol.

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4

Golgi apparatus is absent in

A. higher plants

B. yeast

C. bacteria and blue-green algae

D. None of the above

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4

Difference between the prokaryotic and eukaryotic cells in having

A. cell wall

B. nuclear membrane

C. ribosome

D. none of these

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4

Match column-I with column-II and choose the correct option.
Column-IColumn-II
A. TonoplastI. Contain digestive enzyme
B. Contractile vacuoleII. Store metabolic gases
C. Food vacuoleIII. Excretion
D. Air vacuoleIV. Transport of ions in plants

A. A IV; B III; C I; D II

B. A II; B III; C IV; D I

C. A IV; B II; C III; D I

D. A I; B III; C II; D IV

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4

Nucleolus is

A. rounded structure found in cytoplasm near nucleus.

B. rounded structure inside nucleus and having rRNA.

C. rod-shaped structure in cytoplasm near the nucleus.

D. none of the above.

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4

Who proposed the theory that Cells arise only from the pre-existing cells?

A. Mohl

B. Virchow

C. Haeckel

D. Brown

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4

Chromosomes having equal or almost equal arms are called

A. metacentric

B. acrocentric

C. polycentric

D. acentric.

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4

According to widely accepted fluid mosaic model cell membranes are semi-fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several respects. In this regard, which of the following statements is incorrect?

A. Proteins in cell membranes can travel within the lipid bilayer.

B. Proteins can also undergo flip-flop movements in the lipid bilayer.

C. Proteins can remain confined within certain domains of the membrane.

D. Many proteins remain completely embedded within the lipid bilayer.

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4

In which method of transport, plasma membrane does not require carrier molecule?

A. Active transport

B. Facilitated diffusion

C. Simple diffusion

D. Na+ K+ pump

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4

Satellite means

A. terminal part of the chromosome beyond secondary constriction.

B. terminal part of the chromosome beyond primary constriction.

C. terminal part of chromosome beyond tertiary constriction.

D. none of the above

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4

Grana are

A. protein storing plastids.

B. coloured plastids.

C. stacks of thylakoids.

D. individual thylakoids present in stroma.

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4

Prokaryotic and eukaryotic flagella differ in the

A. type of movement and placement.

B. location and mode of functioning.

C. microtubular structure and function.

D. microtubular organization and type of movement.

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4

Which of the following pair are correctly matched ?
(I) Amyloplasts Store proteins
(II) Mitochondrion Power house of the cell
(III) Stroma Chlorophyll pigment
(IV) Axoneme 9 + 2 array

A. (I) and (III) only

B. (II), (III) and (IV) only

C. (III) and (IV) only

D. (II) and (IV) only

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4

The lipid component of the membrane mainly consists of __________.

A. polysaccharides

B. phosphoglyceride

C. monosaccharaides

D. both (a) and (c)

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4

Membranous extensions in blue green algae are known as

A. phytochrome

B. chromatophore

C. mesosome

D. pneumatophore

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4

Which of the following will determines the shape of the cells and provides a strong structural support to prevent the bacterium from bursting or collapsing?

A. Plasmids

B. Cell wall

C. Mesosome

D. Cell membrane

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4

pH of vacuolar cell sap is

A. neutral and isotonic.

B. alkaline and isotonic.

C. acidic and hypertonic.

D. equal to cytoplasm and isotonic.

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4

Read the statements given below with regard to the functions performed by Golgi apparatus ?
  1. Transport and chemically modify the materials contained within it.
  2. Performs the function of packaging materials.
  3. Important site of formation of glycoproteins and glycolipids.

Which of the following is the correct answer ?

A. (i) is wrong but (ii) and (iii) are correct

B. (ii) is wrong but (i) and (iii) are correct

C. (ii) and (iii) are wrong but (i) is correct

D. All are correct.

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4

8.A student was given cell samples (A and B) to identify parts which are highlighted. He observed the samples under the microscope and list down the function of the part of cell sample. The information collected by the student is listed in the table below, on the basis of which the student infers that the samples contain the organelles.
Sample ASample B
Make energy available for cellular metabolismGenerates ATP and synthes izes s ugar
Absent in cell that carry oxygen throughout the bodyPresent in plant cell
Called the energy currency of cellSource o f all the food energy

Identify the part highlighted in the sample A and B and explain why they were called as semi-autonomous organelles?

A. Sample A - Mitochondria, Sample B - Chloroplast; because both the organelles are double membrane bound structure.

B. Sample A- Mitochondria, Sample B - Chloroplast; because they both are capable of synthesis of their own proteins only.

C. Sample A - Mitochondria, Sample B - Chloroplast; because they are capable of synthesis of their own proteins and contain their own DNA.

D. Sample A- Mitochondria, Sample B - Chloroplast; because they contain their own DNA to transfer the genetic information from one generation to another.

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4

Active transport differs from passive transport in that active transport

A. requires energy.

B. always requires input of ATP.

C. moves molecules against a concentration gradient.

D. both (a) and (c)

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4

Which of the following organelles is directly connected to the outer membrane of the nucleus in a eukaryotic cell?

A. Mitochondrion

B. Lysosome

C. Golgi apparatus

D. Endoplasmic reticulum

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4

Plastids storing fat are called

A. Elaioplasts

B. Sphaerosomes

C. Aleuroplasts

D. Pyrenoids

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4

Which of the following statements are correct?

A. Na+/K+ pump is an example of active transport.

B. In plant cells lipid like steroidal hormones are synthesized in SER.

C. In plant cells, the vacuoles can occupy up to 10% of the volume of the cell.

D. Chlorophyll and leucoplast are responsible for trapping light energy essential for photosynthesis.

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4

Identify the cell organelle given below. Which is an important site of formation of glyeoproteins & glycolipids

A. Rough endoplasmic reticulum

B. Smooth endoplasmic reticulum

C. Golgi body

D. mitochondria

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4

Match column-I (cell organelle) with column-II membrane and select the correct option from the codes given below.
Column-IColumn-II
A. MitochondriaI. Without membrane
B. LysosomesII. Single membrane
C. RibosomesIII. Double membrane

A. A - I, B - II, C - III

B. A - III, B - I, C - II

C. A - III, B - II, C - I

D. A - II, B - III, C - I

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4

In prokaryotes, chromatophores are

A. specialized granules responsible for colouration of cells

B. structures responsible for organizing the shape of the organism.

C. inclusion bodies lying free inside the cells for carrying out various metabolic activities.

D. internal membrane system which becomes extensive and complex in photosynthetic bacteria.