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

Cells are small in size because of their outer ____________.

  1. length

  2. volume

  3. surface area

  4. width
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cells are limited in size by their surface area to volume ratio. As a cell grows, its volume increases faster than its surface area, making it difficult to transport enough nutrients and waste across the membrane.

Multiple choice

All organisms are made up of _______.

  1. compounds.

  2. atoms

  3. organs

  4. cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Cells are the fundamental structural and functional units of all living organisms. While organisms contain atoms and compounds, cells are the specific biological building blocks.

Multiple choice

_____ explains the organization of cells.

  1. Cellular hierarchy

  2. Molecules

  3. Organisms

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

Cellular hierarchy describes how cells are organized into tissues, organs, and organ systems to perform complex functions in an organism.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Apoplast is located

  1. Outside the plasma membrane

  2. In the entire cytosol

  3. inside the plasma membrane

  4. In the plastidial content
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the Apoplast pathway water cannot enter the protoplasm.

It travels through  the space between the cell wall and cell membrane and intercellular spaces.
So the correct answer is 'Outside the plasma membrane'.

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

Which of the following statements is not correct?

  1. In plant cells, vacuoles are absent.

  2. Vacuole is bounded by a single membrane.

  3. In Amoeba, contractile vacuole is important for excretion.

  4. Flagellum is important for transport of bacteria.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plant cells typically have large central vacuoles, which are essential for maintaining turgor pressure and storage. Therefore, the statement that vacuoles are absent in plant cells is incorrect.

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

A higher plant cell covered with cutin and suberin is placed in water. After 15 minutes the cell

  1. Will be killed

  2. Size will increase

  3. Size will remain unchanged

  4. Size will decrease
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Suberin and cutin are complex macromolecules which mainly function as a barrier to movement of water and solutes. Thus if a higher plant cell is covered with cutin and suberin and placed in water then there will not be any change in the size of the cell as cutin and suberin are hard and water repulsive substances. There will not be any exosmosis or endosmosis in such type of cell.

So the correct answer is 'Size will remain unchanged'.

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

Osmotic pressure of a cell kept in water is chiefly regulated by

  1. Vacuoles

  2. Plastids

  3. Ribosomes

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

Vacuoles are the organelles that store all the extra water and salts that are the basis of creating osmotic pressure in the cell. The vacuole takes up a huge central place in the cell. The solution outside the cell is hypertonic, hypotonic or isotonic with respect to the contents inside the vacuole. Plastids are the centres for photosynthesis, Ribosomes are small granule-like structures that help in protein synthesis whereas mitochondria generate energy for the cell by utilising sugars. 

So the correct answer is 'Vacuoles'.

Multiple choice botany photosynthesis cam cycle cam plants photosynthetic cycle

In Kranz anatomy, the bundle sheath cell have

  1. Thick walls, many intercellular spaces and no chloroplasts

  2. Thin walls, no intercellular spaces and large number of chloroplasts

  3. Thick walls, no intercellular spaces and large number of chloroplasts

  4. Thin walls, many intercellular spaces and several chloroplasts
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Kranz anatomy is found in leaves of $C _{4}$ plants. The $C _{4}$ pathway requires the presence of two types of cells i.e. mesophyll cells and bundle sheath cells. The particularly large cells around the vascular bundles of $C _{4}$ plants are called bundle sheath cells, these cells may form several layers around the vascular bundles, they are characterized by having a large number of chloroplasts, grana are absent, thick walls impervious to gaseous exchange and no extracellular spaces. This special anatomy of leaves of the $C _{4}$ plants is called Kranz anatomy. 'Kranz' means wreath and is a reflection of the arrangement of cells.
Multiple choice botany photosynthesis cam cycle cam plants photosynthetic cycle

In kranz anatomy, the bundle sheath cells have

  1. thin walls, many intercellular spaces and no chloroplasts

  2. thick walls, no intercellular spaces and large number of chloroplasts

  3. thin walls, no intercellular spaces and several chloroplasts

  4. thick walls, many intercellular spaces and few chloroplasts.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
In Kranz anatomy, the bundle sheath cells are characterized by having a large number of agranal chloroplasts, thick walls impervious to gaseous exchange and no intercellular spaces.
Thus, the correct answer is 'thick walls, no intercellular spaces and large number of chloroplasts.'
Multiple choice bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

Enzymes required for phosphorylation are located in .......... of chloroplast.

  1. Peristromium

  2. Plastidome

  3. Stroma

  4. Quantosome
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In chloroplast, the space enclosed by the inner membrane is called the stroma. It is colorless and homogeneous fluid. Phosphorylation is the process of addition of a phosphate group to ADP. The process of non-cyclic photophosphorylation takes place in the stroma lamellae with the help of enzymes present in it. Thus, the correct answer is option C. 

Multiple choice bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

Centre of phosphorylation is

  1. Ribosome

  2. Oxisome

  3. Peroxisome

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

  • Oxidative phosphorylation refers to the process by which ATP molecules (energy currency) are produced in the mitochondria.
  • ATP is produced by the transfer of electrons from NADH or FADH2 to oxygen molecule with the help of electron carriers.
  • Oxysomes or F0-F1 particles refers to small round structures present within the folds of the cristae of the inner mitochondrial membrane.
  • F0 and F1 particles are found in the inner mitochondrial region and are attached to the cristae and help in ATP production and oxidation.
So, the correct answer is 'Oxisome'.

Multiple choice bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

Kreb's cycle takes place in

  1. Vesicles of E.R

  2. Mitochondria

  3. Dictyosomes

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

Kreb cycle is also known as the citric acid cycle or tricarboxylic acid cycle takes place in the inner membrane of mitochondria. It occurs there because the necessary enzyme for the Krebs cycle, succinic dehydrogenase is only found in the inner membrane of the mitochondria.

This is the only enzyme that has FAD as coenzymes and thus there is a formation of FADH₂ molecule.
Mitochondria are only associated with aerobic respiration.
So, the correct option is 'Mitochondria'