Biology · Science General

Cell Biology and Structure

3,221 Questions

Cell biology focuses on the structure and function of cellular organelles. Key topics include cellular respiration, DNA inheritance, and energy production. These fundamental biology concepts are crucial for medical entrance and state service examinations.

Cell organelles functionsCellular respiration sitesDNA and ribosomesAnimal cell structurePlant cell components

Cell Biology and Structure Questions

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell

Cell organelles are embedded in

  1. Cytoplasmic membrane

  2. Protoplasm

  3. Cytoplasm

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Cytoplasm is a semifluid matrix present within a cell surrounding the nucleus (i.e without the nucleoplasm) which is enclosed by a cell membrane.
  • They are the nonnuclear content of protoplasm in which all of the cell organelles are embedded.
  • A cytoplasmic membrane or cell membrane is a phospholipid bilayer that separates the cell from the external environment.
  • Protoplasm is the living substance of a cell that is enclosed by a plasma membrane and includes the nucleoplasm.
  • So, the correct answer is 'Cytoplasm'.
Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell


Which of the following is not characteristic of a eukaryotic plant cell?

  1. Ribosomes associated with endoplasmic reticulum

  2. Dictyosomes associated with Golgi bodies

  3. Cristae inside of mitochondria

  4. Thylakoids inside of chloroplasts
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The characteristics of a eukaryotic plant cell are

1. A membrane-bound nucleus.
2. Ribosomes associated with the endoplasmic reticulum.
3.Thylakoids inside of chloroplasts.
4. Dictyosomes are not associated with Golgi bodies. These are discrete tubules of the Golgi Apparatus.
Hence, the correct answer is 'Dictyosomes associated with Golgi bodies'.

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell


Organelles 

  1. Are typical of eukaryotic cells, not prokaryotic cells

  2. Separate chemical reactions in time and space

  3. Are membrane bound compartments

  4. All of the above are features of the organelles
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Organelles are small, specialised structures which perform a specific function within the cell. Organelles are enclosed by their own membrane.  They are found in eukaryotic cells. Their function is from generating energy to the cell to controlling of cell's growth and reproduction.

Hence, the correct answer is 'All of the above are features of the organelles'.

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell

Which cellular organelle would be concentrated at the top of the centrifuged mixture after centrifugation of cells containing solution?

  1. Nuclei

  2. Endoplasmic reticulum

  3. Mitochondria

  4. Ribosomes

  5. Membrane-bound proteins
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Centrifugation of cells is a sedimentation process used to separate certain organelles for analysis of specific parts of cells. a sample of tissue is lysed to break the cell membranes and mix up the contents of the cell. However, while the procedures may break many of the membranes of the cell including the plasma membrane and endoplasmic reticulum, it leaves certain  organelles such as mitochondria, nuclei, Golgi apparatus, peroxisomes and lysosomes intact in a homogeneous extract. During the process, particles of different densities or size sediment at different rates. The largest and most dense particle sediments first followed by less dense and smaller particles. Hence the cellular organelle concentrated on the top of the centrifuged mixture will be the mitochondria due to its less density and small size. Thus, the correct answer is option C.

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell

The structure of the nuclear membrane facilitates

  1. Organization of spindle

  2. Nucleo-cytoplasmic exchange of materials

  3. Anaphasic separation of daughter chromosomes

  4. Synapsis of chromosomes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In eukaryotic cells, the nucleus is bound by a double membrane or nuclear envelope. It possesses openings at certain intervals called as 'nuclear pore'. Nuclear pores are large protein complexes regulates the exchange of material between nucleus and cytoplasm, i.e., nucleo-cytoplasmic exchange of materials. 

Multiple choice biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

Protoplasmic streaming movements are referred as 

  1. Autonomic movements of locomotion

  2. Thigmonasty

  3. Photonasty

  4. Movements of curvature
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Protoplasmic streaming: Rapid movement of cytoplasm inside the cell. It is an autonomic movement of locomotion. Autonomic movements are the movements which occur due to factors are inherent in plant body.

Multiple choice bio-chemistry coordination in life processes digestive system - organs process of digestion coordination in the process of digestion

Single-layer of flattened cells with boundaries is observed in all of the following except

  1. Blood vessels

  2. Lining of oesophagus

  3. Air sacs of lungs

  4. Both (A) and (B)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Single layered of flattened cells with irregular boundaries constitute the squamous epithelium which is found in walls of blood vessels and air sacs of lungs. The epithelium that lines the oesophagus is stratified epithelium.

So, the correct option is 'lining of the oesophagus'.

Multiple choice zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

A membranous coiled semicircular structure attached to plasma membrane and found in blue-green algae is called

  1. Lamellasome

  2. Lomasome

  3. Mesosome

  4. Microsome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A membranous coiled semicircular structure attached to plasma membrane and found in blue-green algae is called as Lamellasome. It is approximately 200 mμ in diameter. Mesosome is folded invagination found in the plasma membrane of bacteria that increases the surface area. They are the site of respiration. Microsome is a fragment of endoplasmic reticulum. It is an artificial structure and is not present in living cell.

Thus, the correct answer is 'Lamellasome.'

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

The cells of sclerenchyma can be classified as

  1. Fibres and fibriosis

  2. Ligaments

  3. Fibre and sclereids

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The chief mechanical tissue of the plant body composed of highly thick walled cell with little or no protoplasm is called as sclerenchyma.

The cells of sclerenchymatous cells can be classified as:
1. Fibres- Fibres are long, elongated sclerenchymatous cells with pointed ends.
2. Sclereids- Sclerenchymatous cells which are short and possess extremely thick lignified walls. 
Therefore, the correct answer is option C.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

The sclerenchyma cells are thick walled due to the presence of

  1. Acetone

  2. Lignin

  3. Lipids

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The chief mechanical tissue of the plant body composed of highly thick walled cell with little or no protoplasm is called as sclerenchyma. The thickening of cell wall is due to deposition of cellulose or lignin or both. Lignin deposited cells are said lignified.

Therefore, the correct answer is option B.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

The tissue which has dead cells in the functional state is

  1. Collenchyma

  2. Sclerenchyma

  3. Parenchyma

  4. Phloem
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Sclerenchyma cells are dead cells at maturity and have a very thick cell wall due to the deposition of lignin. 
  • They are either present in the form of fibres or sclereids (stone cells).
  • They are located in the leaf veins, hard coverings of the seeds and vascular bundle. 
  • Its main function include- 1) provide rigidity and mechanical support to the plant body, 2) It also makes the plant stiff and hard.
  • So, the correct answer is 'Sclerenchyma'.
Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Which of the following tissues has dead cells?

  1. Parenchyma

  2. Sclerenchyma

  3. Collenchyma

  4. Epithelium
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Parenchyma cells have thin cellulosic cell walls. Collenchyma cells have thicker cellulosic walls and also may have pectin deposition on corners. Sclerenchyma cells have thick lignified cell walls and are dead at maturity and provide protection to the different parts of the body. Epithelial cells are thin-walled and living.

So, the correct answer is option B.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Intercellular spaces are absent in sclerenchymatous tissues because___________.

  1. They are stratified.

  2. They are lignified.

  3. They are classified.

  4. They are columnar.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Walls of sclerenchyma cells are lignified, which make them thick. Due to this, are no intercellular spaces between them. Hence, option B is correct.  

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Choose the correct answer from the alternatives given.
Sclerenchymatous cells in their cell walls have large percentage of:

  1. silica

  2. lignin

  3. pectin

  4. cellulose
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer B: Lignin

Sclerenchyma is composed of dead cells with extremely thick cell walls that make up to 90% of the whole cell volume. Their walls consist of cellulose and/or lignin.

               

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

We get a crunchy and granular feeling, when we chew pear fruit because of the

  1. Presence of stone cells (sclerenchyma)

  2. Presence of stone cells (parenchyma)

  3. Presence of stone cells (collenchyma)

  4. Presence of stone cells (aerenchyma)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Parenchyma cells are alive, thin-walled cells. They are present in soft parts of the plant. But pear fruit has hard parts inside, which give it a gritty texture. Therefore, option B is incorrect. 
  • Collenchyma cells are thin-walled with some areas of secondary thickening. They provide extra structural support and flexibility to plant. Therefore, option C is incorrect.
  • Aerenchyma cells are present in an aquatic plant. Such cells have large air cavities, which enable the plant to float in water. 
  • Sclereid is a reduced form of sclerenchyma, which has thickened lignified walls. In pear fruit, sclereid cells are present in bundles, which give a gritty texture to the fruit. Such cells are also called "stone cells" because of their hardness.

So, the correct answer is option A.