Biology · Science General

Cell Biology and Structure

3,062 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

Which of the following statements is correct?

  1. Prokaryotic cells are surrounded by a cell membrane.

  2. Prokaryotic cells have a nucleus.

  3. Eukaryotic cells have genetic information.

  4. Eukaryotic cells have membrane bound organelles.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Organelles are the specialised and organised structures in a living cell. These may be bound by a single or double membrane (Exception is ribosomes which are non-membranous cell organelles present in both prokaryotes and eukaryotes). Membrane-bound cell organelles include nucleus, vacuole, endoplasmic reticulum, chloroplasts, mitochondria, lysosomes, Golgi apparatus and are present only in eukaryotes.
Hence D is the correct option.

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 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 biology digestive system of human digestive glands liver pancreas

Kupffer's cells of liver are an example of ________________.

  1. Anatomical barrier

  2. Inflammatory barrier

  3. Physiological barrier

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

Kupffer cells are also known as stellate macrophages (star-shaped) located in the liver, lining the walls of the sinusoids. They form part of the mononuclear phagocyte system. This means that they are a part of the first line of defense (inflammatory barrier) of the body and are involved in engulfing any invading pathogen (virus, bacteria, etc.) and destroy them.

So, the correct answer is 'Inflammatory barrier'. 

Multiple choice biology digestive system of human digestive glands liver pancreas

The cells which occupy only 5% of the islets are known as 

  1. Alpha cells

  2. Beta cells

  3. Gamma cells

  4. Both of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The islets of Langerhans are the cells in the pancreas. These cells are responsible for the endocrine functions of the pancreas. There are three type of cells, alpha cells, beta cells and gamma cells. The gamma cells are known delta cells. These cells comprise only 5% of the islets cells. These cells are responsible for the production of somatostatin hormone.

Thus, the correct answer is option C. 

Multiple choice biology digestive system of human digestive glands liver pancreas

$\beta$ cells in the islet of Langerhans of man comprise.

  1. $60\%$ to $90\%$
  2. $40\%$ to $50\%$
  3. Less than $40\%$

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

In the human pancreas, beta cells are the most abundant cell type within the islets of Langerhans, typically comprising about 60 to 80 percent of the islet cells.

Multiple choice biology digestive system of human digestive glands liver pancreas

Match the columns and find the correct choice.

a Kupffer's cells p Islet of Langerhans
b $\beta$-cells q Liver sinusoids
c Brush border cells r Thyroid gland
d Paneth cells s Proximal convoluted tubule
t Small intestine

  1. a-s, b-t, c-p, d-q

  2. a-r, b-, c-s, d-q

  3. a-r, b-t, c-s, d-p

  4. a-q, b-p, c-s, d-t
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Kupffer cells are found in liver sinusoids (a-q). Beta-cells are in the Islets of Langerhans (b-p). Brush border cells are in the small intestine (c-t). Paneth cells are also in the small intestine (d-t). Note: The provided option D matches a-q and b-p, which are correct.

Multiple choice biology digestive system of human digestive glands liver pancreas

Alloxan treatment destroys 

  1. STH cells

  2. Sertoli cells

  3. Leydig's cells
  4. $\beta$- cells of islets of Langerhans
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A. STH or somatotropin hormone is known as growth hormone and stimulates body growth and carbohydrate, protein, fat metabolism.
B. Sertoli cells are part of seminiferous tubules and help in spermatogenesis (production of sperms from germ cells) as they provide nourishment to the developing sperms.
C. Leydig cells, also known as interstitial cells are present in the testis near seminiferous tubules. They secrete testosterone hormone which helps in the development of secondary sexual characteristics in males.
D. ββ-cells of islets of Langerhans are part of pancreas and secrete insulin hormone which regulate blood glucose levels.
Alloxan is a toxic analogue of glucose which destroys insulin producing cells of pancreas i.e. ββ-cells of islets of Langerhans.
So, the correct answer is 'ββ-cells of islets of Langerhans'.

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

Common between sclerenchyma and collenchyma is

  1. Material transport

  2. Conduction of water and minerals

  3. Providing buoyancy

  4. Providing support
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Plants are composed of a variety of different cells, two of which are sclerenchyma and collenchyma. The similarity of both cells is that both of them function for support. These cells are two of the three classes of ground tissue together with Parenchyma cells. Collenchyma cells are responsible for giving support to extra structural regions and Sclerenchyma cells are the main structural support for plants. 
So, the correct answer is 'Providing support.'
Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Compare the statements a and b
Statement a. Sclerenchyma cells do not have plasmodesmata
Statement b. Cell walls of some permanent tissues are heavily lignified.

  1. Statement a is correct and b is wrong

  2. Both the statements a and b are wrong

  3. Both the statements a and b are correct

  4. Statement a is wrong and b is correct
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Plasmodesmata are narrow channels that act as intercellular cytoplasmic bridges to facilitate communication and transport of materials between plant cells and are not found in Sclerenchyma cells. Sclerenchyma fibres are long and narrow and have thick lignified cell walls. They provide mechanical strength to the plant and allow for the conduction of water. Sclereids are specialised sclerenchyma cells with thickened, highly lignified walls with pits running through the walls.

So, the correct answer is 'Both the statements a and b are correct.'

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

In which of the following sclerenchyma cells, the secondary cell walls are present

  1. The cells containing cytoplasm only

  2. The cells with protoplast

  3. Cells which are living at maturity

  4. Cells which are non-living at maturity
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sclerenchyma, in plants, support tissue composed of any of various kinds of hard woody cells. Mature sclerenchyma cells are usually dead cells that have heavily thickened secondary walls containing lignin. 

So, the correct answer is 'Cells which are non-living at maturity.'