Grade 8 Curiosity: Cell - The Building Block of Life

Practice flashcards covering the concepts of cell structure, organelles, microscopy, and cell theory based on the provided lecture notes.

Where are the hot springs in India located that maintain temperatures near the boiling point of water even in a cold climate?

Puga Valley in Ladakh.

What are the heat-loving, unicellular bacteria found in hot springs called?

Thermophiles.

Who was the first person to observe and name 'cells' in 1665 using a self-designed microscope?

Robert Hooke.

What is the limit of resolution of the human eye when viewed from about $25\,cm$?

$0.1\,mm$.

the total magnification of a light microscope calculated

By multiplying the magnifying power of the eyepiece by the magnifying power of the objective lens (e.g., $10X \times 10X = 100X$).

What is the name of the movement of water through a selectively permeable membrane from an area with more water to an area with less water?

Osmosis.

What type of solution is defined by a solute concentration of the extracellular medium being greater than the solute concentration of the intracellular medium?

Hypertonic solution.

What is the structural thickness of the cell membrane?

About $7$ to $10\,nm$ (nanometres).

What model explains the structure of the cell membrane as a lipid bilayer with proteins embedded in it?

The fluid-mosaic model.

What rigid, permeable structure is found outside the cell membrane in plants, fungi, and bacteria?

Cell wall.

What carbohydrate is the primary component of the plant cell wall?

Cellulose.

In which type of cell is the genetic material present in a region called the nucleoid without a surrounding membrane?

Prokaryotic cells.

What is the typical diameter range of a eukaryotic cell?

$10$ to $100\,\mu m$.

What are the functional segments of DNA molecules that contain genetic information called?

Genes.

Which cell organelle is known as the 'protein factory' of the cell?

Ribosome.

Which type of Endoplasmic Reticulum (ER) lacks ribosomes and is involved in the synthesis and storage of fats and hormones?

Smooth Endoplasmic Reticulum (SER).

What molecule, produced in the mitochondria, acts as the energy currency for most cellular activities?

Adenosine Triphosphate (ATP).

What type of plastids contain yellow, orange, or red pigments and give bright colours to flowers and fruits?

Chromoplasts.

Which German scientist expanded the Cell Theory in 1855 by stating that all cells arise from pre-existing cells?

Rudolf Virchow.

What term describes the ability of a fully mature plant cell to develop into a complete plant under suitable conditions?

Totipotency.