Tag: cell biology

Questions Related to cell biology

Choose the correct answers from the alternatives given .
Evolution of the DNA $\rightarrow$ RNA $\rightarrow$ protein system was a milestone because the protocell could now

biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

  1. be a heterotrophic fermenter

  2. passon genetic information

  3. use energy to grow

  4. take in preformed molecules

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Correct Option: B

Who first propounded the cell theory stating that all living things are made up of cells or of material formed by cells?

biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

  1. Asa Gray

  2. Matthias Jakob Schleiden

  3. Theodor Schwann

  4. Alfred Russel Wallace

Show answer
Correct Option: B,C
Explanation:

Cell theory is the idea that the cell is the fundamental structural and functional unit of all living organisms and that new cells are formed from other existing cells. This theory is one of the foundations of modern biology. First formulated in the early 1800s in landmark publications by Mathias Jacob Schleiden and Theodor Schwann, the foundations of this theory began in mid-1600s through advances in microscopy. Today, it is held that all organisms are composed of one or more cells, all vital functions of an organism occur within cells, and cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.

So the correct option is 'Mathias Jacob Schleiden and Theodor Schwann'.

Who proposed a modification in the cell theory?

biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

  1. Schleiden and Schwann

  2. Rudolf Virchow

  3. Robert Hooke

  4. Marcello Malpighi

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Correct Option: B
Explanation:

Rudolf Virchow modified the cell theory and gave the concept of 'Omnis cellule e cellulae'- which means new cells develop by the division of the pre-existing cells. This is called the theory of cell lineage or common ancestry.

The Latin phrase omnis cellula e cellula refers to a cellular principle. Which of the following statements is the best translation of this phrase?

biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

  1. The cell is the basic unit of all structures.

  2. All cells arise only from pre-existing cells.

  3. Tissues are composed of similar cells.

  4. All organisms consists of one or more cells.

Show answer
Correct Option: B
Explanation:
Cell theory was postulated by Theodor Schwann and Matthias Schleiden in 1838. It includes the following points-
All living organisms are composed of one or more cells.
The cell is the most basic unit of life. The third was added by Rudolf Virchow in 1855, which stated: "Omnis cellula e cellula" which means all cells arise only from pre-existing cells.

_________ was the first one to observe free living cells. The term cell was given by  ___________ . Cell theory was proposed by  _________ and ________ . All cells arise from pre-existing cells was suggested by ____________ .
Select the correct sequence of names to complete the above paragraph.

biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

  1. Robert Hooke, Virchow, Anton von Leeuwenhoek, Schleiden, Schwann

  2. Anton von Leeuwenhoek, Robert Hooke, Schleiden, Schwann, Virchow

  3. Robert Hooke, Virchow, Schleiden, Schewann, Anton von Leeuwenhoek

  4. Anton von Leeuwenhoek, Virchow, Schleiden, Schewann, Robert Hooke

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Correct Option: B
Explanation:

Antonie Philips van Leeuwenhoek was first to observe the living cell. He is commonly known as "the Father of Microbiology", and considered to be the first microbiologist. He is best known for his work on the improvement of the microscope and for his contributions towards the establishment of microbiology.
The cell was first discovered by Robert Hooke in 1665, which can be found to be described in his book Micrographia. In this book, he gave 60 observations in detail of various objects under a coarse, compound microscope. One observation was from very thin slices of bottle cork. Hooke discovered a multitude of tiny pores that he named "cells". 
Cell theory was eventually formulated in 1838. This is usually credited to Matthias Schleiden and Theodor Schwann.  Cell theory has become the foundation of biology and is the most widely accepted explanation of the function of cells.
Virchow is credited with many important discoveries. His most widely known scientific contribution is his cell theory, which built on the work of Theodor Schwann. He was one of the first to accept the work of Robert Remak, who showed the origins of cells was the division of pre-existing cells.

Which part of the cell is wrongly matched with its function?

bio-chemistry cell biology cytoplasm the components in a cell component of the cell

  1. Nucleus controls the activities of the cell

  2. Cytoplasm makes chlorophyll in green plants

  3. Cell wall protects a plant cell

  4. Cell membrane lets water and gas in and out of the cell

Show answer
Correct Option: B
Explanation:

The nucleus contains the genetic material of the cell and thus regulates all the activities of the cell.

Cytoplasm is the fluid present in the cell. It is present between plasma membrane and nucleus. it helps to maintain the shape of the cell and helps in distribution of cellular materials inside the cell.
Cell wall is a rigid covering mainly present in plant and bacterial cell and provides protection to the plant cell.
Cell membrane is a semipermeable membrane and it regulates the entry and exit of the molecules.
So, the correct answer is option B.

Which of the following is a part of protoplasm present between the nuclear membrane and cell organelle?

bio-chemistry cell biology cytoplasm the components in a cell component of the cell

  1. Leucoplast

  2. Nucleoplasm

  3. Cytoplasm

  4. None of the above

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Correct Option: C
Explanation:

Cytoplasm is a semi-fluid jelly like substance which contains various organelles and inclusions. It also contains a number of inorganic substances forming a clear true solution as well as organic substances like lipids, proteins and carbohydrates. It is homogenous and colourless in nature.

The peripheral zone of cytoplasm is thick and jelly like substance known as 

bio-chemistry cell biology cytoplasm the components in a cell component of the cell

  1. Plasmosol

  2. Nucleoid

  3. Plasmogel

  4. Plastid

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Correct Option: C
Explanation:

The peripheral zone of cytoplasm is a thick and jelly-like substance known as plasmogel. The neighbouring area of the nuclear region is thin and watery and is called as the plasmosol. It helps to regulate the amount of water needed by the cell in the cytoplasm.

So, the correct answer is option C.

A protoplast is

bio-chemistry cell biology cytoplasm the components in a cell component of the cell

  1. A cell organelle

  2. A cell with a wall

  3. A single wall-less cell

  4. Cell without nucleus

Show answer
Correct Option: C
Explanation:

Let's say, that we took a plant cell and used specific digestive enzymes to digest it's cell wall. 

After removing the cell wall, we call that cell as 'Protoplast'.
The protoplast typically consists of cytoplasm and plasma membrane but no cell wall.

Where, Cytoplasm is a fluid like substance present inside the plasma membrane and consisting of nutrients, biomolecules and all the cell organelles.
These cell organelles are such as mitochondria, ribosomes, endoplasmic reticulum, Golgi complex, Nucleus etc.

In the eukaryotic organisms such as plants and animals, nucleus is considered as the largest cell organelle.
Hence, the above explanation justifies the answer as option C  i.e., Protoplast is a single wall-less cell.

The main arena of various types of activities of a cell is

bio-chemistry cell biology cytoplasm the components in a cell component of the cell

  1. Nucleus

  2. Plasma membrane

  3. Mitochondria

  4. Cytoplasm

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Correct Option: D
Explanation:

The main arena of various types of cellular activities is the cytoplasm. Cytoplasm represents a bulk of protoplasm excluding nucleus and vacuoles. The inner part of cytoplasm is called as endoplasm and it is usually in perpetual motion called cyclosis or cytoplasmic streaming. Cytoplasm has various types of cell organelles. Cell organelles are highly organized subcellular protoplasmic structures that have a distinctive shape, chemical composition and function.