Tag: biology

Questions Related to biology

Thread like protoplasmic projections found on free surface of absorptive cells are

biology cell structure animal cell plant and animal cell cell structure and micro-organisms

  1. Cilia

  2. Microfilaments

  3. Microvilli

  4. Plasmodesmata

Show answer
Correct Option: C
Explanation:

Microvilli are microscopic cellular membrane protrusions that increase the surface area of cells and are involved in a wide variety of functions including absorption, secretion, cellular adhesion and mechanotransduction.

Functional units of food absorption are

biology cell structure animal cell plant and animal cell cell structure and micro-organisms

  1. Villi

  2. Brunners glands

  3. Crypts of Lieberkuhn

  4. Peyers patches

Show answer
Correct Option: A
Explanation:
The villi and microvilli, with their many folds with finger-like projection, present on the lining of the small intestine, increase the surface area of the intestine for more absorption of the nutrients. The microvilli have protein channels and pumps in their membranes to allow the rapid absorption of food by facilitated diffusion and active transport. Also, the villi contain an epithelial layer, which is only one cell layer thick so that food can pass through easily and be absorbed quickly. This thin layer of cells contains mitochondria to provide the ATP needed for the active transport of certain food molecules. Finally, there is a lacteal branch at the centre of the villus, which carries away fats after absorption.
So, the correct answer is option A.

Lysosomes are absent in animal cells

biology cell structure and micro-organisms animal cell plant and animal cell cell structure

  1. Erythrocytes

  2. Plasma cells

  3. Nerve cells

  4. Muscle cells

Show answer
Correct Option: A
Explanation:
  • The Red blood cells do not contain lysosomes, mitochondria, nucleus etc.
  • The absence of cellular organelles help them to accommodate maximum space for haemoglobin and helps in carrying more oxygen.
  • It also gives a distinctive bi-concave shape to these cells and also helps in diffusion.
  • So, the correct answer is 'Erythrocytes'.

Which of the following terms relate to an animal cell?

biology cell structure and micro-organisms animal cell plant and animal cell cell structure

  1. No cell wall

  2. Cell membrane

  3. Nucleus

  4. All of the above

Show answer
Correct Option: D
Explanation:

Animal cell lacks a cell wall, that is why it has no particular shape. It has other organelles like cell membrane and nucleus inside its cell.

State whether the following statement is true (T) or False (F) :
All animal cell contain a cell wall.

biology cell structure and micro-organisms animal cell plant and animal cell cell structure

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Animal cells are typical of the eukaryotic cell, enclosed by a plasma membrane and containing a membrane-bound nucleus and organelles. Unlike the eukaryotic cells of plants and fungi, animal cells do not have a cell wall.

Therefore the statement is false. 

Given below are types of cells present in some animals. Which of the following cells can differentiate to perform different functions?

biology cell structure and micro-organisms animal cell plant and animal cell cell structure

  1. Choanocytes

  2. Interstitial cells

  3. Gastrodermal cells

  4. Nematocytes

Show answer
Correct Option: B
Explanation:

Interstitial cells are reserve cells which can differentiate into any type of cells. Nematocytes are stinging cells used for offence and defence. Gastrodermal cells line the gastrodermis and intracellular digestion takes place inside these cells. All these cells are found in cnidarians. Choanocytes are found in sponges; they are specialised flagellated cells that line spongocoel and canals.

So, the correct answer is 'Interstitial cells'

A scientist was studying the production of a protein that was released by an animal cell into a culture medium. She found that the protein only appeared in the culture medium after she added a few drops of a hormone to the cell. Before adding the hormone, she labelled the protein inside the cell with a fluorescent dye and looked at the cell under the light microscope. The dye was seen in flattered sheets and tube-like structures throughout the cell, and in stacks of flattened sac-like structures. After adding the hormone, the dye was also seen as small dots clustered against the cell membrane. Which statement most likely explains these observations?

biology cell structure and micro-organisms animal cell plant and animal cell cell structure

  1. The hormone stimulates protein synthesis in the cell vacuole, the protein is then passed to the Golgi apparatus, and eventually passes through the cell membrane by passive diffusion

  2. The hormone triggers the synthesis of the protein in the endoplasmic reticulum and it is then secreted outside of the cell via channel proteins in the cell membrane

  3. The protein is made in the endoplasmic reticulum, is passed to the Golgi apparatus and is secreted through hormone-stimulated exocytosis

  4. The protein is made in the Golgi apparatus is passed to the endoplasmic reticulum and is secreted through hormone-stimulated pinocytosis

Show answer
Correct Option: C
Explanation:

Hormones bring about their characteristic effects on target cells by modifying cellular activities. The given experiment shows that the hormone is a releasing hormone which has increased the secretion of protein product in the target cell.

Which of the following is not common in chloroplasts & mitochondria?

biology cell structure and micro-organisms animal cell plant and animal cell cell structure

  1. Both are present in animal cells

  2. Both contains their own genetic material

  3. Both are present in eukaryotic cells

  4. Both are present in plant cells

Show answer
Correct Option: A
Explanation:

The similarities in chloroplasts and mitochondria are 

1. Both are present and animal cells
2. Both are present in eukaryotic cells and have own genetic material
They are not present in animal cells.
So, the correct option is 'Both are present in animal cells'.

Which of the following is a type of intercellular junction between animal cells?

biology cell structure and micro-organisms animal cell plant and animal cell cell structure

  1. Middle lamella

  2. Plasmodesma

  3. Desmosome

  4. Glycocalyx

Show answer
Correct Option: C
Explanation:

Desmosomes are circular regions where adjacent membranes possess disc-shaped thickening on the inner side, a number of tonofibrils and transmembrane linkers embedded in the dense intercellular material. Desmosomes act as 'spot welds' and keep the cells firmly together. They occur in epithelia subjected to disruption. 

Plasmodesma is protoplasmic bridge amongst plant cell wall which occur in the areas of cell wall pits or pores.
Middle lamella is a layer of cell wall and cell wall is absent in an animal cell.
Therefore, the correct answer is option C.

You will not find a cell wall in which of these kinds of organisms?

biology cell structure and micro-organisms animal cell plant and animal cell cell structure

  1. Fungi

  2. Animal

  3. Plants

  4. All of the above

Show answer
Correct Option: B
Explanation:

Plants, fungi, some protozoa and some bacteria unlike animal cells have a distinct structure called a cell wall.